U.S. patent application number 11/614525 was filed with the patent office on 2007-05-10 for watercraft having a four stroke engine with a supercharger.
This patent application is currently assigned to BRP-ROTAX GMBH & CO. KG. Invention is credited to Andreas Bilek, Rudolf Tscherne, Alois Wolfsgruber.
Application Number | 20070105465 11/614525 |
Document ID | / |
Family ID | 26881381 |
Filed Date | 2007-05-10 |
United States Patent
Application |
20070105465 |
Kind Code |
A1 |
Wolfsgruber; Alois ; et
al. |
May 10, 2007 |
Watercraft Having a Four Stroke Engine with a Supercharger
Abstract
A personal watercraft is disclosed with a hull, a seating
assembly, and a four stroke internal combustion engine below the
seating assembly. The engine has at least one intake valve for each
of the combustion cylinder chambers, at least one exhaust valve for
each of the combustion cylinder chambers, and a valve actuation
assembly located in a cylinder head for operating the intake and
exhaust valves. At least one air intake passageway is operatively
coupled to the combustion cylinder chambers through the intake
valves. An air intake manifold is connected to the cylinder bead
and operatively connected to the at least one air intake
passageway. The engine also has a supercharger for boosting air to
the air intake manifold. The watercraft also includes a propulsion
unit, operatively coupled to the crankshaft, which is located on
one end of the two ends of the crankcase.
Inventors: |
Wolfsgruber; Alois;
(Gmunden, AT) ; Tscherne; Rudolf; (Buchkirchen,
AT) ; Bilek; Andreas; (Buchkirchen, AT) |
Correspondence
Address: |
OSLER, HOSKIN & HARCOURT LLP (BRP)
2100 - 1000 DE LA GAUCHETIERE ST. WEST
MONTREAL
H3B4W5
CA
|
Assignee: |
BRP-ROTAX GMBH & CO. KG
Welser Strasse 32
Gunskirchen
AT
|
Family ID: |
26881381 |
Appl. No.: |
11/614525 |
Filed: |
December 21, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11456395 |
Jul 10, 2006 |
|
|
|
11614525 |
Dec 21, 2006 |
|
|
|
10673353 |
Sep 30, 2003 |
7101238 |
|
|
11456395 |
Jul 10, 2006 |
|
|
|
09794238 |
Feb 28, 2001 |
6626140 |
|
|
10673353 |
Sep 30, 2003 |
|
|
|
60185703 |
Feb 29, 2000 |
|
|
|
60257174 |
Dec 22, 2000 |
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Current U.S.
Class: |
440/88R ; 440/38;
440/88A |
Current CPC
Class: |
F02M 35/10039 20130101;
F16H 2007/0806 20130101; F01L 2001/0535 20130101; F01M 2011/0033
20130101; F02M 35/116 20130101; F02M 35/10222 20130101; F01L 1/2411
20130101; F01P 3/02 20130101; F02B 75/20 20130101; F01L 1/024
20130101; F02B 67/10 20130101; F02F 7/0031 20130101; F01P 3/20
20130101; F02M 35/10072 20130101; Y02T 10/12 20130101; F02B 67/04
20130101; F01M 1/08 20130101; F01N 13/02 20130101; F01P 2050/06
20130101; F02B 77/085 20130101; F02B 61/045 20130101; F02F 1/242
20130101; F02F 1/243 20130101; F02M 35/167 20130101; F01L 1/053
20130101; F01L 1/245 20130101; F02B 33/44 20130101; F05C 2201/021
20130101; F16H 9/12 20130101; F02M 35/10032 20130101; F01N 13/004
20130101; F02M 35/10163 20130101; F16H 61/662 20130101; F02M
35/10111 20130101; F16H 55/563 20130101; F01P 2060/16 20130101;
F02M 69/465 20130101; F01M 13/04 20130101; F01N 2590/022 20130101;
F02B 2275/20 20130101; F01L 1/022 20130101; F01P 9/00 20130101;
F02B 2075/027 20130101; F02B 2275/08 20130101; F01L 1/181 20130101;
F01P 2050/04 20130101; F02M 35/10275 20130101; F01L 1/18 20130101;
F01M 2011/002 20130101; F02M 35/112 20130101; F01N 3/046 20130101;
F02B 63/04 20130101; F02B 75/16 20130101; F16H 2007/0812 20130101;
F02M 35/10144 20130101; F16H 55/56 20130101; F01L 1/26 20130101;
F02B 75/22 20130101; F02M 35/10268 20130101; F02B 33/40 20130101;
F02B 39/04 20130101; F02B 67/00 20130101; F01B 1/12 20130101; F01M
2001/126 20130101; F02B 1/04 20130101; F02B 33/26 20130101; F02M
69/462 20130101; F02F 1/4214 20130101; F02B 33/34 20130101; F02M
35/10216 20130101; F01L 2301/00 20200501; F01N 3/04 20130101; F02B
39/14 20130101; F02F 2001/245 20130101; F02B 2075/1808 20130101;
F16H 7/0848 20130101; F01L 1/02 20130101; F01M 2011/0066 20130101;
F01N 3/043 20130101; F02B 61/02 20130101; F01L 2305/00 20200501;
F01M 2013/0427 20130101; F01P 2050/02 20130101; F16H 2007/0859
20130101; F01M 11/02 20130101; F02B 2075/1812 20130101; F02B
2275/18 20130101; F02B 75/224 20130101; F01P 2060/04 20130101; F02B
67/06 20130101; F02B 61/04 20130101 |
Class at
Publication: |
440/088.00R ;
440/038; 440/088.00A |
International
Class: |
B63H 11/00 20060101
B63H011/00; F02B 61/04 20060101 F02B061/04; B63H 21/10 20060101
B63H021/10 |
Claims
1. A personal watercraft comprising: a hull; a deck disposed on the
hull; an engine compartment defined between the hull and the deck;
a four stroke internal combustion engine disposed in the engine
compartment, the engine comprising: a crankcase having a top, a
bottom, two sides, and two ends, the crankcase being separable
along a plane defining an upper crankcase and a lower crankcase,
the plane being disposed at an angle from horizontal when viewed
from one of the ends of the crankcase; a crankshaft rotatably
mounted in the crankcase between the two ends; a balance shaft
rotatably mounted in the crankcase between the two ends parallel to
the crankshaft, the crankshaft and the balance shaft being disposed
in the plane such that the balance shaft is vertically higher on
the crankcase than the crankshaft; a cylinder head housing
operatively connected to the top of the crankcase, the crankcase
and the cylinder head housing forming at least one combustion
chamber therebetween; at least one intake valve for the at least
one combustion chamber; at least one exhaust valve for the at least
one combustion chamber; a valve actuation assembly located in the
cylinder head housing for actuating the at least one intake valve
and the at least one exhaust valve; and at least one air intake
passageway fluidly connected to the at least one combustion
chamber; a propulsion unit operatively coupled to the crankshaft;
and at least one air intake manifold fluidly connected to the at
least one air intake passageway.
2. The personal watercraft of claim 1, wherein the at least one
combustion chamber is disposed at an angle from vertical when
viewed from one of the ends of the crankcase.
3. The personal watercraft of claim 2, wherein the at least one air
intake manifold has a central passage; wherein a line extending
from a centre of the crankshaft to a centre of the central passage
is disposed at an angle from vertical when viewed from one of the
ends of the crankcase; and wherein the line and the at least one
combustion chamber form a "V" when viewed from one of the ends of
the crankcase.
4. The personal watercraft of claim 1, wherein the at least one air
intake manifold has a central passage.
5. The personal watercraft of claim 4, further comprising a flame
arrester disposed in the central passageway.
6. The personal watercraft of claim 1, further comprising a
supercharger for boosting air to the at least one air intake
manifold fluid connected with the at least one air intake
manifold.
7. The personal watercraft of claim 6, wherein the supercharger has
a blower drive shaft disposed outside the plane.
8. The personal watercraft of claim 7, wherein the blower drive
shaft is disposed above the plane.
9. The personal watercraft of claim 6, wherein the supercharger is
a mechanically driven supercharger.
10. The personal watercraft of claim 9, wherein the supercharger is
operatively driven by the crankshaft.
11. The personal watercraft of claim 1, further comprising at least
one exhaust passageway fluidly connected to the at least one
combustion chamber; and an exhaust manifold fluidly connected to
the at least one exhaust passageway.
12. The personal watercraft of claim 11, wherein the valve
actuation assembly has a camshaft; wherein a line extending from a
centre of the crankshaft to a centre of the camshaft is disposed at
an angle from vertical when viewed from one of the ends of the
crankcase; and wherein the at least one air intake manifold is
disposed above the line and the exhaust manifold is disposed below
the line.
13. The personal watercraft of claim 1, wherein the upper crankcase
is fastened to the lower crankcase.
14. The personal watercraft of claim 1, wherein the crankshaft is
disposed horizontally.
15. The personal watercraft of claim 1, wherein the at least one
combustion chamber is three combustion chambers.
16. The personal watercraft of claim 15, wherein the three
combustion chambers are disposed in line between the two ends of
the crankcase.
17. The personal watercraft of claim 16, wherein the three
combustion chambers are disposed at an angle from vertical when
viewed from one of the ends of the crankcase.
18. The personal watercraft of claim 1, wherein the at least one
intake valve for the at least one combustion chamber is two intake
valves for the at least one combustion chamber; and wherein the at
least one exhaust valve for the at least one combustion chamber is
two exhaust valves for the at least one combustion chamber.
19. The personal watercraft of claim 1, further comprising an oil
pump and a coolant pump assembly, at least one of the oil pump and
the coolant pump assembly being operatively driven by the balance
shaft.
20. The personal watercraft of claim 19, further comprising a
connecting shaft driving at least one of the oil pump and the
coolant pump assembly, the connecting shaft being coaxial with the
balance shaft.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. Non-provisional
Application No. 09/794,238, which was filed on Feb. 28, 2001, and
which issued as U.S. Pat. No. 6,626,140 on Sep. 30, 2003. That
application relates to and relies for priority on U.S. Provisional
Application No. 60/185,703, filed on Feb. 29, 2000, and U.S.
Provisional Application No. 60/257,174, filed on Dec. 22, 2000. All
three applications are incorporated herein by reference. In
addition, this application is related, but does not claim priority,
to U.S. Pat. No. 6,544,086 (Ser. No. 09/794,219 to Tscherne et
al.), No. 6,390,869 (Ser. No. 09/794,240 to Korenjak et al.), No.
6,601,528 (Ser. No. 09/794,237 to Bilek et al.), No. 6,591,819
(Ser. No. 09/794,215 to Tscherne et al.), and No. 6,415,759 (Ser.
No. 09/794,245 to Ohrenberger et al.), the contents of all of which
are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to a new engine for
use in, for example, personal watercraft. In particular, the
present invention relates to a new four-stroke in-line engine that
was developed with a view to the future stricter environmental and
emission regulations. The engine has a supercharger for enhancing
engine performance.
BACKGROUND OF THE INVENTION
[0003] There is a very popular type of watercraft known as a
"personal watercraft" which is designed to be operated primarily by
a single rider. Although this type of watercraft is commonly
employed for single riders, frequently provisions are made for
accommodating additional passengers although the maximum number of
passengers is more limited than conventional types of
watercraft.
[0004] This type of watercraft is also generally quite sporting in
nature and normally accommodates at least the rider on a type of
seat in which the rider sits in a straddle fashion. The passenger's
area is frequently open through the rear of the watercraft so as to
facilitate entry and exit of the rider and passengers to the body
of water in which the watercraft is operating, as this type of
watercraft is normally ridden with passengers that are wearing
swimming suits.
[0005] These personal watercraft are generally quite small so that
they can be conveniently transported from the owner's home to a
body of water for its use. Because of the small size, the layout of
the components is extremely critical, and this gives rise to
several design considerations that are peculiar to this type of
watercraft. However, due to its sporting nature it is also
desirable if the watercraft is powered by an engine and propulsion
device that are not only efficient but also generate sufficient
power.
[0006] Traditionally, two-cycle engines have been used to power
watercraft, including personal watercraft. These engines have the
advantage that they are fairly powerful, relatively lightweight,
and compact.
[0007] One particular disadvantage to the two-cycle engine is its
emission content. Two-cycle engines generally exhaust larger
quantities of hydrocarbons and other pollutants than four-cycle
engines due to cylinder charging inefficiencies and the combustion
of lubricating oil among other things. When measures are taken to
reduce emissions of the two-cycle engine, other generally
undesirable consequences can result, such as an increase in the
weight of the engine, a reduction of its power output or the like.
With concern for the environment and increasingly strict emissions
requirements being instituted by various governing bodies. There is
motivation to provide a power plant that reduces exhaust emissions
while retaining other advantageous characteristics such as
compactness, low weight and high power output.
[0008] Four-cycle engines are commonly used as power plants in
other applications, such as automobiles. These engines have the
advantage that their emissions output are generally desirably lower
as compared to a two-cycle engine for a given power output. These
engines are typically larger than two-cycle engines and present
numerous spatial issues when located in a personal watercraft.
[0009] Superchargers are used to enhance engine performance. To
date, the present inventors are not aware of the use of a
supercharger in an engine for a personal watercraft. U.S. Pat. No.
5,634,422 to Kobayashi et al., entitled "Personal Watercraft With
V-Type Engine," U.S. Pat. No. 5,647,779 to Nanami, entitled
"Manifold and Water Trap System For A Marine Engine," U.S. Pat. No.
5,839,930 to Nanami et al., entitled "Engine Lubricating System For
Watercraft," and U.S. Pat. No. 5,846,102 to Nitta et al., entitled
"Four-Cycle Engine For A Small Jet Boat" disclose various engines
for personal watercraft. None of these references disclose the use
of a supercharger.
OBJECT OF THE INVENTION
[0010] It is an object of the present invention to provide a four
stroke, in-line engine having a compact construction.
[0011] It is another object of the present invention to provide a
four stroke, in-line engine having a modular construction to permit
the interchange of parts between various engine models.
[0012] It is another object of the present invention to provide a
four stroke, in-line engine having improved exhaust emission
characteristics.
[0013] It is another object of the present invention to provide a
four stroke engine having a narrow and low profile.
[0014] It is another object of the present invention to provide a
four stroke engine having a low profile valve actuation assembly
for controlling the operation of the intake and exhaust valves.
[0015] It is another object of the present invention to provide a
cylinder head having a low profile to reduce engine height.
[0016] It is another object of the present invention to offset the
placement of the intake valves and exhaust valves with respect to a
vertical axis within the cylinder head to reduce engine height.
[0017] It is another object of the present invention to provide an
improved spark plug mounting assembly for easy access within the
cylinder head.
[0018] It is another object of the present invention to provide a
Y-shaped intake rocker arm assembly providing compact
construction.
[0019] It is yet another object of the present invention to provide
a four stroke engine having an improved oil collection system and
oil holding tank.
[0020] It is another object to provide a four stroke engine which
combines a closed loop cooling system and an open loop cooling
system for enhanced cooling of the engine in accordance with the
present invention.
[0021] It is another object to provide an open loop cooling system
for cooling an exhaust manifold in accordance with the present
invention, wherein the open loop cooling system enhances cooling of
the crankcase and cylinder head.
[0022] It is another object to provide an open loop cooling system
for cooling an exhaust manifold in accordance with the present
invention, wherein the open cooling system lowers the temperature
of the exhaust manifold such that the exhaust manifold functions as
a heat sink for the crankcase and cylinder head.
[0023] It is another object of the present invention to provide a
closed loop cooling system for selectively cooling the crankcase
and cylinder head of the four stroke engine.
[0024] It is another object of the present invention to provide a
closed loop cooling system having a selectively operable heat
exchanger.
[0025] It is another object of the present invention to provide a
supercharger for enhanced engine performance.
SUMMARY OF THE INVENTION
[0026] The present invention is directed to a supercharged four
stroke internal combustion engine. The supercharged engine includes
a crankcase having a crankshaft rotatably mounted therein and a
cylinder head connected to the crankcase. The crankcase and the
cylinder head form at least three combustion cylinder. Each
cylinder includes at least one intake valve and at least one
exhaust valve. A valve actuation assembly operates the intake and
exhaust valves. An air intake passageway is operatively coupled to
the cylinders through the intake valves. An air intake manifold is
connected to the cylinder head and operatively connected to the air
intake passageways. A power take off housing is located on one end
of the crankcase. The crankshaft terminates within the power take
off housing. The engine includes a supercharger for boosting air
intake to the air intake manifold. The supercharger is mounted to
the power take off and operatively connected to the crank shaft
within the power take off housing.
[0027] In accordance with the present invention, the air intake
manifold is preferably formed from a plastic material and includes
a central air passageway. The central air passageway is operatively
connected to the supercharger. The air intake manifold further
includes a flame arrester located within the central air
passageway. The flow of air from the supercharger travels through
the central air passageway and the flame arrester.
[0028] In accordance with the present invention, the supercharger
includes a mounting portion. The mounting portion is positioned
within a mounting opening in the power take off housing. The
supercharger Further includes an inlet portion having an inlet
opening. The inlet portion is connected to the mounting portion. An
air passageway extends from the inlet opening to the air intake
manifold.
[0029] The supercharger further includes a blower located within
the inlet portion for directing a stream of air to the air intake
manifold. The blower includes a blower drive shaft, which is
rotatably mounted within the mounting portion. The blower drive
shaft is operatively connected to the crank shaft through a
connection assembly.
[0030] The connection assembly dampens the transmission of
vibrational from the crankshaft to the blower drive shaft. The
connection assembly includes a blower drive pinion located on one
end of the blower drive shaft and a biased intermediate member
located on the one end of the blower drive shaft. The biased
intermediate member applies a force on the blower drive pinion such
that the blower drive pinion is engaged with a rotating member
secured to the crankshaft.
[0031] The rotating member includes a plurality of rotating gears.
One of the rotating gears engages the blower drive pinion. Another
rotating gear engages an engine starting mechanism. One of the
rotating gears drives a balance shaft located within the
crankcase.
[0032] The present invention is also directed to a personal
watercraft. The personal watercraft includes a hull, a seating
assembly, and a four stroke internal combustion engine secured to
the hull below the seating assembly. The engine includes a
supercharger for boosting air intake to the air intake
manifold.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The invention will be described in conjunction with the
following drawings in which like reference numerals designate like
elements and wherein:
[0034] FIG. 1 is a downward rear schematic perspective view of a
left side of an overhead camshaft aspirated engine in accordance
with the present invention;
[0035] FIG. 2 is a downward rear schematic perspective view of a
right side of the engine of FIG. 1;
[0036] FIG. 3 is a downward front schematic perspective view of the
left side of the engine of FIG. 1;
[0037] FIG. 4 is a downward front schematic perspective view of the
right side of the engine of FIG. 1;
[0038] FIG. 5 is a rear end view of the engine of FIG. 1
illustrating one possible positioning of the engine within a
personal watercraft;
[0039] FIG. 6 is a downward rear schematic perspective view of a
variation of the engine of FIG. 1 having a supercharger;
[0040] FIG. 7 is a rear end view of the engine of FIG. 6;
[0041] FIG. 8 is a partial cross-sectional end view of the
crankcase and cylinder head housing in accordance with the present
invention;
[0042] FIG. 9 is a bottom view illustrating the upper crankcase of
the engine in accordance with the present invention;
[0043] FIG. 10 is a top view of the lower crankshaft illustrating
the positioning of the crankshaft and the balance shaft;
[0044] FIG. 11 is a right side partial schematic sectional view of
the engine of FIG. 6;
[0045] FIG. 12 is a partial schematic sectional view of the piston,
valves and valve actuator assembly in accordance with the present
invention;
[0046] FIG. 13 is a partial overhead schematic view of the rocker
arm assemblies of the valve operating assembly for operating the
intake and exhaust valves;
[0047] FIG. 14 is an end cross sectional view of one of the exhaust
rocker arm assemblies and a portion of the intake rocker arm
assembly taken along section line 14-14 of FIG. 13;
[0048] FIG. 15 is a cross sectional view of the operative end of
the rocker arm assemblies showing a collapsed position of the
hydraulic adjuster on the left side and an extended position of the
hydraulic adjuster on the right side;
[0049] FIG. 16 is a right side cross sectional view of the valve
operating assembly located within the cylinder head having the
camshaft in cross section;
[0050] FIG. 17 is another right side cross sectional view of the
valve operating assembly located within the cylinder head;
[0051] FIG. 18 is an end cross sectional view illustrating the
spark plug assembly within the cylinder head;
[0052] FIG. 19 is a cross sectional view illustrating the placement
of the cylinder head cover on the cylinder head;
[0053] FIG. 20 is a cross sectional view of the engine of FIG. 1
through one cylinder of the engine;
[0054] FIG. 21 is a schematic perspective view of the exhaust
manifold in accordance with the present invention;
[0055] FIG. 22 is a longitudinal cross sectional view of a portion
of the exhaust manifold of FIG. 21;
[0056] FIG. 23 is a side cross sectional view of a portion of the
exhaust manifold of FIG. 21;
[0057] FIG. 24 is a schematic view of the exhaust manifold and open
loop cooling system in accordance with the present invention;
[0058] FIG. 25 is a schematic diagram of the cooling system for the
engine in accordance with the present invention;
[0059] FIG. 26 is a rear perspective view of a right side of the
air intake and fuel injection system for the engine in accordance
with the present invention;
[0060] FIG. 27 is a cross sectional view of the air intake and fuel
injection system of FIG. 26 taken along a longitudinal axis of the
system;
[0061] FIG. 28 is a side cross sectional view of the air intake and
fuel injection system of FIG. 26 through a swing pipe;
[0062] FIG. 29 is a variation of the air intake and fuel injection
system of FIG. 28 illustrating a cooling jacket within the swing
pipe;
[0063] FIG. 30 is a front perspective view of a right side of the
air intake and fuel injection system for the engine having a
supercharger in accordance with the present invention;
[0064] FIG. 31 is a cross sectional view of the air intake and fuel
injection system of FIG. 30 taken along a longitudinal axis of the
system;
[0065] FIG. 32 is a rear view of the engine illustrating the power
take off lid and cooling system in accordance with the present
invention and the oil filter housing in partial cross section;
[0066] FIG. 33 is a side cross sectional view of a thermostat and
pump assembly of a portion of the cooling system and a lubrication
pump of the lubrication assembly in accordance with the present
invention;
[0067] FIG. 34 is a partial schematic/partial side cross sectional
view of an oil filter unit in accordance with the present
invention;
[0068] FIG. 35 is a schematic diagram illustrating the oil channel
system for the lubrication system for the cylinder head
housing;
[0069] FIG. 36 is a cross sectional side view of the power take off
assembly for the engine illustrating the generator assembly in
accordance with the present invention;
[0070] FIG. 37 is another cross sectional side view of the power
take off assembly for the engine illustrating the starter assembly
in accordance with the present invention;
[0071] FIG. 38 is a cross sectional side view of the power take off
assembly having a supercharger for the engine in accordance with
the present invention;
[0072] FIG. 39 is a partial schematic/partial sectional view of the
cam chain tensioner in accordance with the present invention;
[0073] FIG. 40 is a schematic view of the blow-by ventilation
system and suction pump in accordance with the present
invention;
[0074] FIG. 41 is a schematic view of the blow-by ventilation
system and suction pump of FIG. 38 having the suction pump cover
removed;
[0075] FIG. 42 is a schematic view of the engine management system
for the engine in accordance with the present invention;
[0076] FIG. 43 is a schematic perspective view of the exhaust
manifold according to an alternative embodiment;
[0077] FIG. 44 is a cross sectional view of a portion of the
exhaust manifold of FIG. 43;
[0078] FIG. 45 is a schematic diagram of the cooling system for the
engine in accordance with the present invention for use in
connection with the exhaust manifold of FIG. 43;
[0079] FIG. 46 is a cross sectional view of the cyclone of the
blow-by ventilation system;
[0080] FIG. 47 is a partial overhead cross sectional view of the
engine of FIG. 6 having a cut away of the balance shaft and the
power take off assembly;
[0081] FIG. 48 is an overhead view of the valve train;
[0082] FIG. 49 is a partial side cross sectional view of the
balance shaft and power take off assembly; and
[0083] FIG. 50 is a side view of the engine of FIG. 1 illustrating
one possible positioning of the engine within a personal
watercraft.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0084] A four-stroke three cylinder in-line engine 1 in accordance
with the present invention is illustrated generally in FIGS. 1-4.
The engine 1 in accordance with the present invention will be
described in connection with a personal watercraft 5, shown in
cross-section in FIG. 5. A variation of the engine 1 is illustrated
in FIGS. 6 and 7. The engine 2 shown in FIGS. 6 and 7 includes a
supercharger. The engines 1 and 2 are adapted to be installed below
a raised pedestal having a seating bench of the personal watercraft
5 inside the hull 4, as shown in FIGS. 5 and 50. With this
arrangement, the oil filter cannot be placed on the lower side of
the engine or of its crankcase, respectively, if it is to be
accessible for maintenance purposes because the hull 4 would
prevent access to the oil filter. To address this, the oil filter
is installed at the power take off side of the engine, to be easily
accessible from above. The access through the seating area at
present is the only access to the engine.
[0085] While designed for use in personal watercraft, it is
contemplated that the engine 1 (or engine 2) can be used in all
terrain vehicles, snowmobiles, boats and other vehicles with minor
modifications. For example, the cooling system for the exhaust
manifold must be modified for non-marine applications. Further,
while the embodiments shown disclose an engine positioning with the
power take off to the rear of the engine, the orientation can be
altered to have the power take off to the front or to the side
depending on the specific vehicle or specific application.
Engine Configuration
[0086] The engine 1 includes a crankcase 10. A cylinder head
housing 20 is connected to the crankcase 10 to form a plurality of
combustion chambers. The crankcase 10 and cylinder head housing 20
are inclined with respect to a vertical axis, as shown in FIGS. 5
and 8. This arrangement provides sufficient space for the air
intake and fuel injection system 40 while maintaining an overall
reduced engine profile. The engines illustrated and described
herein include three cylinders. The present invention, however, is
not limited to three cylinders; rather, it is contemplated that a
greater or fewer number of cylinders are considered to be well
within the scope of the present invention. For example, a single
cylinder version of the engine may be employed in a fishing boat.
Two or three cylinder versions of the engine may be employed in a
personal watercraft. A four cylinder version of the engine may be
employed in a jet boat. Four or more cylinders are considered to be
well within the scope of the present invention.
[0087] The engine 1 or 2 provides for the location of various
engine components including, but not limited to the starter
assembly, the generator, the oil pump, coolant pump and other
devices at one end of the engine in the power take off assembly 50,
described below and shown in FIGS. 33, 36, 37 and 38. This unique
construction and layout of components permits the use of similar
parts and engine components for one, two, three and four cylinder
versions of the engine. Furthermore, this arrangement permits the
addition of additional cylinders on the end of the engine opposite
the power take off assembly. The layout of the parts is the same.
Minimal redesign of these components is necessary when increasing
or reducing the number of cylinders.
[0088] The engine 1 contemplated herein includes an exhaust
manifold 30 that is secured to one side of the cylinder head
housing 20 and an air intake and fuel injection system 40. The air
intake and fuel injection system 40 is secured to an opposite side
of the cylinder head housing 20 in the area above the cylinder head
housing 20.
[0089] The present invention, however, is not limited to having a
fuel injection system; rather, it is contemplated that the engine
can instead be equipped with a carburetor.
[0090] A power take off assembly 50 is located on an end of the
cylinder block 10 within the hull 4. The power take off assembly 50
defines the rear side of the engine when located within the
personal watercraft 5. The engine 1 or 2 further includes a
lubrication system 60 as shown in FIG. 11. The engine 1 further
includes a blow-by ventilation system 70, as shown in FIG. 11, and
an engine cooling system 80, as shown in FIG. 25.
[0091] An engine 2 is shown in FIGS. 6 and 7, which is a variation
of the engine 1. The engine 2 has substantially the same
configuration as the engine 1. The engine 2 further includes a
supercharger 90. The use of a supercharger for an engine for use in
a personal watercraft is a new development, which is described in
greater detail below. The engine 1 can be converted with minor
modification to the engine 2 having a supercharger 90. In
particular, as described below, the supercharger 90 is attached to
an opposite end of the intake manifold 41 as compared to the
normally aspirated engine 1. The ignition and induction parameters
of the engine may be modified to enhance engine performance when
the supercharger 90 is used. It is also contemplated that the
compression ratio of the engine may have to be altered to
accommodate the supercharger 90. In accordance with the present
invention, it is contemplated that the engines 1 and 2 will be
produced on the same assembly line.
[0092] Because it is contemplated that the engine in accordance
with the present invention will be used in marine applications, the
exterior surfaces of the engines 1 or 2 will be provided with a
suitable coating to reduce corrosion and the direct exposure of the
engine to the elements. The individual components of the engines 1
and 2 will now be described in greater detail.
Crankcase
[0093] As illustrated in FIG. 8, the crankcase 10 contains a
plurality of passageways and compartments formed therein.
Furthermore, the crankcase 10 is formed with vertical partitions,
as shown in FIGS. 9 and 10, which separate the individual crank
chambers, described below and external fins located on the
crankcase 10. These vertical partitions and external fins increase
the strength of the crankcase 10. The spaced apart vertical fins
provide additional strength for an upper crankcase 13 of the
crankcase 10 while minimizing the weight. The vertical partitions
increase engine strength and separate the crank chambers 121 in the
upper and lower crankcases 13 and 12. The vertical partitions also
secure the upper and lower crankcases together using suitable
fasteners. The fasteners extend through bores in the vertical
partitions from a lower end of the lower crankcase to the upper
crankcase. The fasteners also serve to secure the bearings,
described below, within the vertical partitions. The crankcase 10
is preferably formed from a cast aluminum alloy (e.g. AlSi) for
both strength and weight considerations. The crankcase 10 is
preferably die cast. The present invention, however, is not limited
to the use of aluminum alloys; rather, other materials including
but not limited to steels, alloys and composites are considered to
be well within the scope of the present invention provided the
materials have sufficient strength for use in engine
applications.
[0094] The crankcase 10 includes an upper crankcase 13 containing
the cylinder block and a lower crankcase 12. A balance shaft 115
and a crankshaft 123 are located at the union between the lower
crankcase 12 and the upper crankcase 13. An oil tank 11 formed in a
bottom portion of the lower crankcase 12, as shown in FIG. 8. The
oil tank 11 has a generally u-shaped configuration that partially
surrounds a lower portion of a crankcase 12. The oil tank 11 is
located on both the bottom and side of the engine to house the
necessary volume of oil while maintaining the engine's reduced
profile such that oil is located on the bottom of the crankcase and
the side of the crankcase 10. An interior of the upper crankcase 13
and the lower crankcase 12 are connected to the oil tank 11 through
outlet openings 111, as shown in FIGS. 8 and 11. A channel 112
extends from each opening 111 to an upper portion 113 formed in the
lower crankcase 13. The oil collected from the crank chamber 121
flows through outlet openings 111 and channels 112, then enters the
upper channel portion 113 and returns to the oil tank 11. This oil
then flows under the influence of gravity downward into a lower
portion 114 of the oil tank 11.
[0095] A balance shaft 115 extends through the crankcase 10. The
balance shaft 115 and the crankshaft 123 are located at the union
of the lower crankcase 12 and the upper crankcase 13. To prevent
oil from flowing from upper channel portion 113 and contacting the
balance shaft 115, an optional baffle assembly is located within
the upper portion 113. The balance shaft 115 is provided to
counteract the moment generated by rotation of the crankshaft 123,
shown in FIG. 10. This arrangement produces mass balancing of the
first order. The balance shaft 115 and the crankshaft 123 extend in
a parallel relationship, as shown in FIG. 10. The balance shaft 115
is rotatably mounted within a bore 1132 that extends through the
crankcase 10, as shown in FIGS. 9 and 10. Suitable bearing
assemblies are provided for smooth rotation of the balance shaft
115. The bearing assemblies are fixed using the fasteners described
above. Preferably, the balance shaft 115 should be mounted in an
anti-friction shell bearing but, alternatively, roller bearings can
also be used. The balance shaft 115 is operatively connected by
gear 1151 to the crankshaft 123 through gear 1231. This connection
is preferably located within the power take off assembly 50 on one
end of the crankcase 10.
[0096] The oil tank 11 forms a portion of a dry sump lubrication
system. The lubrication system and the operation of the same will
be described in greater detail below.
[0097] As FIGS. 9 and 10 illustrate, the crankcase 10 includes at
least one crank chamber 121 and in the preferred embodiment
includes one isolated crank chamber for each engine cylinder. In
accordance with the presently disclosed embodiments of engines 1
and 2, three crank chambers 121 are provided. Each crank clamber
121 includes an outlet opening 111 connected to the channel 112,
described above. A bore 122 extends through the crankcase 10 and
each of the crank chambers 121, as shown in FIGS. 9 and 10. A
crankshaft 123 is received therein, as shown in FIG. 10. The
crankshaft 123 can be a one-piece forging, cast or assembled
depending upon the engine application. For example, a cast
crankshaft may be used in low performance applications. The
crankshaft 123 is rotatably mounted within a bore 122. Suitable
bearing assemblies are provided for smooth rotation of the
crankshaft 123.
[0098] As shown in FIG. 25, a cylinder 124 extends through the
crankcase 10 above each of the crank chambers 121. In accordance
with the present invention, the engines 1 and 2 each include three
cylinders 124, as shown in FIG. 11. A piston 1241 is slidably
received within the cylinder 124. The piston 1241, shown in FIG.
11, reciprocates axially within the cylinder 124 as is known. The
piston 1241 is connected to the crankshaft 123 through a connecting
rod 1242 and piston pin 1243 to convert axial movement of the
pistons 1241 to rotational movement of the crankshaft 123 and
vice-versa. A cooling passageway 125 extends around the cylinders
124, as shown in FIG. 25. The cooling passageway 125 is connected
to the engine cooling system 80 further described below. As shown
in FIG. 25, the cooling passageway 125 extends substantially around
the perimeter of the cylinders. This passageway has a generally
U-shaped configuration.
[0099] At present, the cylinder liners are formed with grey cast
iron. The upper crankcase 13 is then cast around the liners. The
upper crankcase 13 may be formed from under-eutectic AlSi (e.g.
cast-AlSi 9)(with 9% silicon). The interior of the cylinder liners
may then be honed. The use of grey cast iron increases the weight
of the crankcase 13. It is desirable to eliminate the use of the
cylinder liners. With this in mind, it is contemplated that the
cylinder liners may be eliminated. Instead, an interior surface of
the upper crankcase 13 can include a thermal coating to reduce
friction. This coating may be applied plasma spraying or other
suitable process. Alternatively, AlSi-alloys (alloys of aluminum
and silicon) are used to form the liners for the cylinders 124. The
cylinder liners may be formed from over-eutectic AlSi with primary
silicon grains therein (e.g. AlSi 19) (with 19% silicon) to
minimize friction and wear. The crankcase 10 may be formed from
under-eutectic AlSi (e.g. cast-AISi 9) (with 9% silicon). The
cylinder liners are assembled to the cylinder block during the
casting of the upper crankcase 13. Beforehand, a binding layer
consisting of eutectic AlSi 12 (with 12% silicon) is thermally
sprayed (e.g. plasma sprayed) onto the outer wall of the liner to
provide a better bond and a better heat-removal property (high heat
transfer coefficient) between the liner and the cylinder block 10.
Alternatively, the cylinder liners can also be inserted into the
cylinder block of the upper crankcase 13 mechanically with a force
fit. It is also contemplated that the cylinder block 10 can be
formed from over-eutectic AlSi (e.g. AlSi 19) without the need for
separate cylinder liners. With this arrangement, however, the
cylinder is more difficult to machine, more expensive and thus, is
not presently preferred. In such a liner-less embodiment, the
cylinders can be optionally provided with a surface coating for
enhanced wear and friction properties. It is contemplated that the
pistons 1241 may be formed of aluminum coated with iron.
Cylinder Head Housing
[0100] The cylinder head housing 20 is secured to the upper end of
the crankcase, as shown in FIG. 8. The cylinder head housing 20 is
bolted to the crankcase and provides a combustion chamber 2001
above each cylinder 124. A pair of exhaust valves 21 and a pair of
intake valves 22 are mounted in each combustion chamber 2001. As
shown in FIG. 11, the pair of exhaust valves 21 are located on one
side of the cylinder head housing 20 and the pair of intake valves
22 are located on an opposite side of the cylinder head housing 20.
The present invention, however, is not limited to a pair of exhaust
valves and a pair of intake valves; rather, a single exhaust valve
and a single intake valve may be employed. Furthermore, more than
two intake and exhaust valves may be provided. Furthermore, any
combination of intake and exhaust valves is contemplated provided
each cylinder includes more intake valves than exhaust valves.
[0101] As shown in FIG. 8, the intake valves 22 and the exhaust
valves 21 are disposed at an angle with respect to the vertical
axis of the engine 1 or 2. This reduces the height of the cylinder
head housing 20, which reduces the overall height of the engine 1
or 2.
[0102] The cylinder head housing 20 further includes at least one
exhaust passageway 23 for each combustion chamber 2001 extending
through the cylinder head housing 20, as shown in FIGS. 8, 12 and
13. The passageway 23 includes a pair of siamesed exhaust ports 231
that connect the exhaust passageway 23 to the chamber 2001, as
shown in FIGS. 12 and 13. Each of the pair of exhaust valves 21 is
positioned in one of the respective exhaust ports 231 to
selectively open and close the ports 231 at predetermined intervals
to permit the removal of exhaust gases from the chamber 2001. An
opposite end of the exhaust passageway 23 has an opening 232, as
shown in FIG. 14, that is operatively connected to the exhaust
manifold 30. The exhaust manifold 30 is secured to the cylinder
head housing 20 using suitable fasteners on a downwardly facing
side of the cylinder head housing 20, as shown FIG. 5.
[0103] The cylinder head housing 20 further includes at least one
intake passageway 24 for each cylinder 124 extending through the
cylinder head housing 20, as shown in FIGS. 8, 12 and 13. The
passageway 24 includes a pair of siamesed intake ports 241 that
connect the intake passageway 24 to the chamber 2001. Each of the
pair of intake valves 22 is positioned in one of the intake ports
241 to selectively open and close the ports 241 at predetermined
intervals to permit the influx of fuel and air into the chamber
2001. An opposite end of the intake passageway 24 has an opening
242, as shown in FIG. 14, that is operatively connected to the air
intake and fuel injection system 40. The air intake and fuel
injection system 40 is secured to the cylinder bead housing 20
opposite the exhaust manifold 30 using suitable fasteners on an
upwardly facing side of the cylinder head housing 20, as shown in
FIG. 5. While the intake and exhaust ports are shown as being
siamesed, they can alternatively remain separated until connected
to the respective intake and exhaust manifolds. The cylinder head
housing 20 includes a spark plug 27 that is located in a central
inclined position, as described in greater detail below.
Valve Operating Assembly
[0104] A valve operating assembly illustrated in FIGS. 8 and 12-17
operates the intake valves 22 and exhaust valves 21 in accordance
with predetermined engine operating parameters. The valve operating
assembly is located within the cylinder head housing 20 and is
driven by the crankshaft 123. As discussed in greater detail below
in connection with the power take off assembly 50, the crankshaft
123 extends from the crankcase 10 into a power take off housing 59.
A gear assembly 54 is secured to the crankshaft 123 within the
power take off housing 59 and includes a chain gear 542.
[0105] A cam shaft 29 is rotatably mounted within the cylinder head
housing 20. One end of the cam shaft 29 extends into a control
chain chamber 202 within the cylinder head housing 20. The control
chain chamber 202 extends into the cylinder block of the upper
crankcase, as shown in FIG. 48, and enters the power take off
assembly 50. A cam gear 551 is operatively coupled to a chain gear
542 by a control chain 55, which extends around both the gear 551
and gear 542. The control chain 55 extends through the control
chain chamber 202 into the power take off assembly 50. The cam gear
551 and chain gear 542 are sized to have a 2 to 1 relationship.
[0106] The camshaft 29 is rotatably mounted to the cylinder head
housing 20 in a position between the intake and exhaust valves 21
and 22. Suitable bearing assemblies are provided for the smooth
operation and rotation of the camshaft 29 within the cylinder head
housing 20. As shown in FIG. 12, a plurality of cam lobes 291 and
292 are provided along the camshaft 29 to operate the valves 21 and
22 in each cylinder. A cam lobe 291 provides the necessary motion
to operate the intake valves 22 through the rocker arm assembly 25.
A pair of cams 292 provide the necessary motion to operate the
exhaust valves 21 through the rocker arm assemblies 26. A cam 291
and a pair of cams 292 are positioned over each cylinder, as shown
in FIGS. 16 and 17. The cams 291 and 292 are oriented on the
camshaft 29 to produce a predetermined timing for opening and
closing the valves 21 and 22. The orientation of the cams 291 and
292 vary for each cylinder such that all cylinders do not operate
at the same time, rather the cylinders operate in a predetermined
sequence. While the camshaft 29 is illustrated with a solid
construction, it is contemplated that the camshaft 29 may have a
hollow construction. Furthermore, the camshaft may be forged, cast
or assembled.
[0107] The valve operating assembly includes a Y-shaped intake
rocker arm assembly 25 that operates both of the pair of intake
valves 22, as shown in FIG. 13, in response to the cam lobe 291.
The valve operating assembly further includes a pair of exhaust
rocker arm assemblies 26 that operate the pair of exhaust valves
21, as shown in FIG. 13, in response to cam lobes 292. The intake
rocker arm assembly 25 is a forked assembly rocker arm having a
pair of valve operating arms 251 and 252. One operating arm 251
operates one of the intake valves 22 and the other operating arm
252 operates the other intake valve 22. The fork like shape of the
rocker arm assembly 25 provides access to the spark plug assembly
27 positioned within the cylinder head housing 20. The spark plug
assembly 27 will be described in greater detail below. The fork
like shape of the rocker arm assembly 25 reduces the overall width
of the necessary assemblies to operate the valves for each
cylinder.
[0108] In an effort to reduce the weight of the rocker arm
assemblies 25 and 26, the rocker arm assemblies 25 and 26 may be
produced from an aluminum alloy (AlSi) by forging or casting. The
present invention, however, is not limited to rocker arm assemblies
formed from aluminum; rather, it is contemplated that other
materials including but not limited to steel and alloys of the same
may be cast or forged to form the rocker arm assemblies 25 and
26.
[0109] The rocker arm assemblies 25 and 26 are rotatably mounted on
a rocker arm support axle 28 in a position between the intake and
exhaust valves 21 and 22. The stationary support axle 28 is mounted
to the cylinder head by a plurality of fastener assemblies 281, as
shown in FIGS. 16 and 17. The fastener assemblies 281 may include
screw type fasteners, pin fasteners or other similar fastener
assemblies for securing the support axle 28 within the cylinder
head housing 20 and preventing its rotation. The rocker arm support
shaft 28 is mounted to the cylinder head housing 20. The axle 28 is
laterally offset and vertically spaced from the camshaft 29, as
shown in FIGS. 12, 14 and 18. This arrangement results in a compact
construction that reduces the overall height of the cylinder head
housing 20. It is contemplated that the axle 28 may be located on
the vertical axis of the cylinder or adjacent to the same.
[0110] The camshaft 29 is operatively connected to the crankshaft
123, as described below. The cam gear associated with the
crankshaft gear are sized to have a 2 to 1 relationship. The angled
intake and exhaust valves 21 and 22 provide an enlarged area within
the cylinder head housing 20 between the valves in which to locate
the cam shaft, axle and the rocker arm assemblies 25 and 26. This
also provides sufficient space to maintain the 2 to 1 relationship
between the cam gear and the crankshaft gear without increasing the
height of the cylinder head housing 20.
[0111] The rocker arm assembly 25 wil now be described in greater
detail, reference being made to FIGS. 12 and 14. As described
above, the rocker arm assembly 25 has a pair of operating arms 251
and 252. A free end of each of the pair of operating arms 251 and
252 is positioned over a respective intake valve 22 and includes an
hydraulic adjuster 253 for contacting the intake valve 22. The
hydraulic adjuster 253 abuts the upper surface of the valve stem of
the intake valve 22. The hydraulic adjuster 253 is located within a
cavity in the respective arm 251 and 252. Passageways 2512 and 262
extend from the cavities, respectively, to the rocker arm support
axle 28, as shown in FIGS. 8, 12, and 14. The passageways are
hydraulically linked to the rocker arm support axle 28. The rocker
arm support axle 28 includes a central passageway through which a
supply of hydraulic fluid (preferably lubricant from the lubricant
system) or other suitable lubricant flows. The fluid passes from
the central passageway through radial openings 282 to the
passageways. The fluid flows through the passageways to the
cavities where it biases the hydraulic adjuster 253 into contact
with the intake valve 22. The fluid insures that the hydraulic
adjuster 253 is always in contact with the intake valve 22 such
that zero lash exists between the valve and hydraulic adjuster 253.
This insures that the entire motion of the cam 291 is transferred
to the intake valves 22 to facilitate their opening and closing.
Although fluid is used to bias the hydraulic adjuster 253 into
engagement with the valves 22 in the embodiment illustrated, it is
contemplated that a screw adjuster assembly or other mechanical
assembly can be provided to perform the same operation.
[0112] An opposite end of the rocker arm assembly 25 includes a cam
follower 254. The follower 254 may include a roller assembly having
bearings that is rotatably mounted to the rocker arm assembly 25.
The follower 254 travels along the cam 291, which causes the rocker
arm assembly 25 to pivot about the rocker support axle 28. The
motion of the cam 291 is transferred to open ad close the intake
valves 22. Fluid from the central passageway 281 may be directed
through another passageway, not shown, in the rocker arm assembly
25 to provide a supply of fluid to lubricate the follower assembly
254 to provide for smooth operation. The present invention,
however, is not limited to the roller followers described herein;
rather, it is contemplated that other followers including but not
limited to sliding blocks may be utilized to follow the cam
291.
[0113] The rocker arm assembly 25 has a compact angled
construction, as shown in FIG. 14 so as to allow for a narrow and
low construction. Similarly, the low arrangement of the camshaft 29
and associated drive chain wheel, which also does not project
beyond the cylinder head housing 20, as seen in FIGS. 16 and 17
assists in constructing an engine with a narrow and low
profile.
[0114] As seen in FIGS. 8, 12 and 14, the camshaft 29 and the
support axle 28 are offset relative to the longitudinal axis of the
cylinder. The camshaft 29 is offset to provide room for the spark
plug assembly 27, described below. Both the camshaft 29 and the
support axle 28 are located closer to the exhaust valves 21 than
the intake valves 22. The offset nature of the support axle 28
increases the overall length of the intake rocker arm assembly 25.
This increases the lever arm of the intake rocker arm assembly 25
and maximizes the force (within the size constraints of the
cylinder head housing 20) applied to operate both intake valves 22
with one rocker arm assembly. The intake and exhaust valves are
disposed at an angle with respect to the cylinder axis. In
principle, however, also other geometries (e.g. with a central
arrangement of the camshaft 29) are conceivable. Alternatively, the
rocker arm support axle 28 may be located closer towards the intake
valves so as to make the forked operating arms 251 and 252--which
are heavy due to this construction--shorter and thus less heavy.
With this arrangement, the location of the camshaft 29 should also
be relocated to maintain the lever arm of the intake rocker arm
assembly 25.
[0115] The rocker arm assemblies 26 will now be described in
greater detail. Each exhaust rocker arm assembly 26 has the same
construction. A free end of the rocker assembly 26 is positioned
over a respective exhaust valve 21 and includes a hydraulic
adjuster 263 for contacting the exhaust valve 21. The hydraulic
adjuster abuts the upper surface of the valve stem of the exhaust
valve 21. Like the hydraulic adjuster 253, the hydraulic adjuster
263 is located within a cavity 261. A passageway 262 extends from
the cavity 261 to the rocker arm support axle 28. The passageway
262 is hydraulically linked to the rocker arm support axle 28
through radial openings 282. The fluid flows through the passageway
262 to the cavity 261 where it biases the operating assembly 263
into contact with the exhaust valve 21. The fluid ensures that the
hydraulic adjuster 263 is always in contact with the exhaust valve
21 such that zero lash exists between the valve and hydraulic
adjuster 263. This insures that all motion of the cam 292 is
transferred to the exhaust valve 21 to facilitate opening and
closing. Although fluid is used to bias the hydraulic adjuster 263
into engagement with the valve 21, it is contemplated that a
mechanical assembly (e.g. a screw adjuster) may be provided to
perform the same operation.
[0116] An opposite end of the exhaust rocker arm assembly 26
includes a cam follower 264. The follower 264 has a similar
construction to the follower assembly 254, described above. The
rocker arm assembly 26 also has a compact angled construction, as
shown in FIG. 14 so as to allow for a narrow and low
construction.
[0117] The construction of the hydraulic adjusters 253 and 263 will
now be described in greater detail in connection with FIG. 15. The
hydraulic adjusters 253 and 263 have the same construction. The
hydraulic valve adjusters 253 and 263 are maintenance free and
require no adjustment. The hydraulic adjuster 263 is positioned
within the cavity 261. The hydraulic adjuster 263 includes an inner
stationary piston 2631 and an outer movable piston 2632, which is
located between the cavity 261 and the inner stationary piston
2631. The inner stationary piston 2631 includes a central cavity
2633 that is in communication with the cavity 261, as shown in FIG.
15.
[0118] An opposite end of the piston 2631 includes an aperture 2634
such that the cavity 2633 is in fluidic communication with a cavity
2635 in the piston 2632. A ball and seat check valve 2636
selectively closes the aperture 2634. A valve contacting cap 2637
is pivotably mounted on an end of the piston 2632. The cap 2637
contacts the valve stem of the exhaust valve 22 when the piston
2632 is in an extended position, as shown in the right side of FIG.
15.
[0119] In operation, hydraulic fluid flows through channel 262 into
the cavity 261. After the cavities 261 and 2633 have filled with
fluid, the valve 2636 opens to permit the flow of fluid into cavity
2635 through aperture 2634. As the cavity 2635 fills with hydraulic
fluid, the piston 2632 extends to the position shown in the right
side of FIG. 15. The spring assembly 2638 is located in the cavity
2635. The downward travel of the piston 2632 is limited by contact
with the valve stem and a seal 2639 that is secured to one end of
the piston 2632 and is slidably received around the piston 2631.
When in the normal downward steady state position, the contacting
cap 2637 contacts the valve stem such that motion of the rocker arm
assembly is transferred to the valve to open the valve at
predetermined locations of the camshaft 29. After engine shut off,
a sufficient amount of fluid is maintained in the cavity 2635 to
maintain the outer movable piston 2632 in engagement with the
corresponding valve stem.
[0120] FIGS. 16 and 17 illustrate an axial section through the
camshaft 29 and the rocker arm support axle 28. The camshaft 29 is
mounted in a bearing bracket 293 with two collars 294 and 295.
Lubricant is supplied to the clearance region between these two
collars 294 and 295. By means of this double plain bearing in the
respective bearing bracket 293, the bearing becomes very rigid and
the dynamic changing loads occurring during operation can be
accommodated efficiently. Mounting of the camshaft 29 is effected
by inserting it in from one end of the cylinder head housing 20
near the power take off end of the engine. The camshaft 29 is
secured by a plate positioned within the cylinder head housing 20
against axial shifting. The plate extends through a vertical slot
located within the cylinder head housing 20. The plate may be
further used to orient the axle 28 within the cylinder head housing
20. It is also contemplated that a pin may be used to secure the
camshaft against axial shifting. The pin may be located in a slot
or groove extending around the perimeter of the camshaft.
[0121] Although the operation of the intake valves 22 and exhaust
valves 21 has been described in connection with rocker arm
assemblies 25 and 26, other assemblies are contemplated for
operating the valves. For example, the valves may be
electromagnetically operated. Alternatively, the valves may be
hydraulically operated using a slave piston/master piston
arrangement. Furthermore, the Y-shaped rocker may be used to
actuate the exhaust valves. Individual rocker arms may be used to
operate intake valves. With this arrangement, the location of the
spark plug assembly 27 must be relocated. It is also contemplated
that gas springs may be used to bias the valves into a closed
position when high rotation speeds are desired for high rpm output.
It is also contemplated that a variable valve train may be
substituted to vary the timing of the valve operation.
Spark Plug Assembly
[0122] The spark plug assembly 27 will now be described in greater
detail in connection with FIG. 18. A spark plug 271 is connected by
threaded engagement to the cylinder head housing 20, as shown in
FIG. 18 such that an electrode portion of the spark plug 271
extends into the cylinder. The spark plug assembly 27 is located
between the intake valves 22 and the exhaust valves 21 closer to
the intake valves 21 because the intake side of the engine is
cooler than the exhaust side of the engine. It is desirable to
isolate the spark plug 271 from the remainder of the cylinder head
housing 20, which contains oil therein. A tube assembly 272
surrounds the spark plug 271. The tube assembly 272 is preferably
formed from a die cast plastic. It, however, is contemplated that
other light weight materials may be used to form the tube assembly
272 so long as the tube assembly 272 isolates the spark plug 271
from the oil-carrying portions of the cylinder head housing 20. It
is preferable that the spark plug assembly 27 be inclined at an
angle with respect to the central axis of the cylinder. The angle
between the spark plug assembly and the intake valves is small
(e.g. 3.degree. is preferable). The angle, however, may be
zero.
[0123] Each tube assembly 272 is sealingly inserted into a pedestal
273 on the cylinder head housing 20, which forms a socket for the
spark plug 271. A slight compression fit between the tube 272 and a
bore in the pedestal 273 can provide a sealing engagement between
the two components although this sealing engagement can also be
augmented by providing an o-ring between the two compartments. On
an outer end, a seal 274 is vulcanized onto the tube assembly 272
which effects the sealing between the tube assembly 272 and a
cylinder head cover 275. Alternatively, the seal 274 can be
provided as a separate component between the tube 272 and cover
275. Use of the tube 272 provides for a lighter weight head
assembly and also simplifies the casting of the cylinder head since
the isolating tube is not cast as part of the cylinder head. The
tube assembly 272 accommodates a plastic body spark plug connector
276 in which the ignition coil or the spark transformer are cast.
In this way, the path of the high voltage to the spark plug 271 can
be kept extremely short. From the outside, only a low voltage is
supplied to the plastic body spark plug connector 276 and the
ignition coil contained therein. The plastic body spark plug
connector 276 and the spark plug 271 can easily be removed through
the tube assembly 272. The plastic body spark plug connector 276
abuts the inner side of the tube assembly 272. A venting assembly
is provided to enable venting from the spark plug region towards
the environment. A splash water screen 2763 is attached to the
plastic body 276.
[0124] A cylinder head cover 275 is attached to the cylinder head
housing 20 using a plurality of fastener elements 2751, as shown in
FIG. 19. The cylinder head cover 275 is preferably formed from
aluminum or some synthetic material. The connection between the
cylinder head housing 20 and the cylinder head cover 275 is
acoustically decoupled. An elastomeric gasket 2753 is positioned
between the cylinder head housing 20 and the cylinder head cover
275 to provide a seal between the two components. The gasket 2753
has a protruding portion 2754 that is configured to sealingly
engage a slot 2755 in the cylinder head cover 275. This engagement
maintains the gasket in a desired position between the cylinder
head housing 20 and the cylinder head cover 275 and helps prevent
the gasket 2753 from dislocating and causing leaks. In addition,
the elastomeric gasket also reduces and prevents a direct sound
propagation from the cylinder head housing 20 to the cylinder head
cover 275 thereby reducing overall noise emanating from the engine.
A further elastomeric gasket 2752 is provided between the fastener
element 2751 and cylinder head cover 275 to seal the connection
therebetween and also block direct sound propagation from the
cylinder head housing 20 to the cylinder head cover 275 through the
fastener 2751. With this arrangement, the cylinder head cover 225
is isolated from the cylinder head housing 20.
Exhaust Manifold
[0125] A preferred embodiment of the exhaust manifold 30 will now
be described in connection with FIGS. 21-24. The exhaust manifold
30 includes a first manifold 31 and a second manifold 32, as shown
in FIG. 24. The first manifold 31 is connected to one side of the
cylinder head housing 20. It is preferably located on the smaller
downward facing side of the cylinder head housing 20 because it
does not require as much space as the induction system 40,
described below. The first manifold 31 includes at least one
exhaust passageway 311 that is operatively coupled to each exhaust
passageway 23 in the cylinder head housing 20. Each exhaust
passageway 311 connects to a main exhaust passageway 312, which
extends in a direction towards the power take off assembly 50. With
this arrangement, exhaust gases exit the cylinder head housing 20
through each exhaust passageway 23 when the respective exhaust
valves 21 are opened. The exhaust gases then travel through the
exhaust passageway 311 to the main exhaust passageway 312.
[0126] The first manifold 31 is connected at the end nearest the
power take off assembly 50 to the second manifold 32. The second
manifold 32 includes a main exhaust passageway 321. The exhaust
gases travel through the main exhaust passageway 321 into the
muffler system 33.
[0127] Due to U.S. Government regulation, it is necessary to cool
the exhaust components to limit the temperature of these components
below a threshold value. It is desirable to cool the exhaust gases
as the gases pass through the exhaust manifold 30 and an associated
muffler system 33. The muffler system 33 preferably includes a
first muffler 331 directly connected to the exhaust manifold 30 and
a second muffler 332 connected to the first muffler 331.
[0128] The first and second manifolds 31 and 32 are equipped with
an open loop cooling system for cooling the manifolds 31 and 32 and
the exhaust gases contained therein. Each manifold 31 and 32 has a
double jacket construction that permits cooling water to flow
around the interior of the manifolds 31 and 32 without mixing with
the exhaust gases. The first manifold 31 is preferably cast. The
second manifold 32 is preferably formed from stainless steel.
[0129] The first manifold 31 has an inner manifold 313 and an outer
manifold 314, as shown in FIGS. 22 and 23. The spacing between the
inner and outer manifolds 312 and 314 forms a cooling passageway
315. The inner and outer manifolds 313 and 314 are interconnected
at various points along the manifold. The cooling passageway 315
has a generally unshaped configuration when viewed from a vertical
cross section such that it surrounds the main passageway 311 on the
top, bottom and at least one side. The cooling water enters the
passageway 315 through at least one inlet 316. The cooling water
then travels through the cooling passageway 315 and exits through
at least one outlet 317.
[0130] The second manifold 32, as shown in FIG. 24, also has an
inner manifold 322 and an outer manifold 323. The spacing between
the inner and outer manifolds 322 and 323 forms a cooling
passageway 324, therebetween. The cooling passageway 324
substantially surrounds the main exhaust passageway 321. The
cooling water enters the cooling passageway 324 through at least
one inlet 325 located near the connection between the first
manifold 31 and the second manifold 32. The cooling water exits the
cooling passageway through at least one outlet 326 located near the
point where the second manifold 32 enters the first muffler
331.
[0131] The cooling system for the exhaust manifold 30 and muffler
system 33 is an open loop cooling system. Cooling water is supplied
to the first and second manifolds 31 and 32 by a jet pump of the
propulsion unit of the personal watercraft 5, which draws cooling
water from the body of water in which the personal watercraft 5 is
operating. An open loop cooling system can be used for the exhaust
manifold 30 because the geometry of the cooling jacket for the
exhaust manifold 30 is relatively simple with larger passageways.
There is less concern for the clogging of these passageways. On the
contrary, the geometry of the cooling system for the cylinder head
housing 20 and crankcase 10 is more complex with smaller
passageways. There is a greater concern about clogging that may
occur when using a coolant drawn from outside the watercraft 5. As
such, a closed loop cooling system is preferred for the cylinder
head housing 20 and crankcase 10.
[0132] The cooling passageways 315 and 324 sufficiently cool the
manifolds 31 and 32. The temperature of the exhaust gases, however,
remains too high. It must be further cooled before venting to the
atmosphere or released into the water. It is desirable to cool the
exhaust gases as the exhaust gases enter the first muffler 331. At
least one injection nozzle 34 is located adjacent the end of the
main exhaust passageway 321, such that a stream of cooling water is
injected into the exhaust stream as the exhaust stream enters the
first muffler 331. Although it is preferable that the at least one
injection nozzle 34 be located within the muffler 331, it is
contemplated that the injection nozzles 34 may be located within
the main exhaust passageway 323.
[0133] It is possible for the personal watercraft 5 to overturn or
rollover during operation. It is desirable to prevent the cooling
water used to cool the exhaust gases from traveling within the main
exhaust passageways 314 and 323 to the cylinder head housing 20.
The design of the second manifold 32 and the connection between the
second manifold 32 and the first muffler 331 prevent the return of
the cooling water to the cylinder head housing 20.
[0134] The second manifold 32 terminates within the first muffler
331 at a central location. The outlet opening for the main exhaust
passageway 323 is spaced from the top, bottom and side walls of the
first muffler 331. With this arrangement, cooling water that has
accumulated within the first muffler 331 should not enter the main
exhaust passageway 323 because the cooling water should travel
along the sides of the first muffler 331 (spaced from the outlet)
when rollover occurs.
[0135] In the event that some cooling water enters the main exhaust
passageway 323, the configuration of the second manifold 32
prevents passage of cooling water to the cylinder head housing 20.
The second manifold 32 contains a unshaped bend or gooseneck
portion that traps the cooling water. With this arrangement in a
rollover condition, the cooling water must first travel downward
from the first muffler 331 through the bend or gooseneck portion
and then upward before entering the first manifold 31. The change
in direction of the main exhaust passageway 323 in the gooseneck
portion essentially prevents any cooling water from entering the
first manifold 31 or the cylinder head 32.
[0136] The present invention is not limited to the above-described
gooseneck portion for preventing water from entering the first
manifold 31 at the cylinder head 20; rather, other geometries that
produce a similar effect are considered to be well within the scope
of the present invention.
[0137] An alternative embodiment of the exhaust manifold will now
be described in connection with FIGS. 43 and 44. The exhaust
manifold 300 is connected to one side of the cylinder head housing
20. Like the manifold 30 described above, the manifold 300 is
preferably located on the smaller downward facing side of the
cylinder head housing 20. The exhaust manifold 300 includes at
least one exhaust passageway 310 that is operatively coupled to
each exhaust passageway 23 in the cylinder head housing 20. Each
exhaust passageway 310 connects to a main exhaust passageway 320.
The exhaust gases exit the cylinder head housing 20 through each
exhaust passageway 23 when the respective exhaust valves 21 are
opened. The exhaust gases then travel through the exhaust
passageway 310 to the main exhaust passageway 320. The main exhaust
passageway 320 first directs the exhaust gases toward the front of
the personal watercraft, then in an opposite direction through knee
bend 330 toward the rear of the personal watercraft. The exhaust
gases may then exit the exhaust manifold 300 to a muffler system
and/or water trap. The muffler system may include a pair of
mufflers.
[0138] In this alternative arrangement, the exhaust manifold 300
also has a double jacket construction that permits cooling water to
flow around the exhaust gases without mixing the cooling water and
the exhaust gases. The double jacket construction includes an inner
manifold 340 and an outer manifold 350, which create a cooling
chamber 370 therebetween. Webs 360 separate the cooling chamber 370
into a first portion 3701 and a second portion 3702, as shown in
FIG. 22. The cooling water passes through the cooling chambers 3701
and 3702, as shown in FIG. 44.
[0139] Like the manifold 30 the exhaust manifold cooling system is
an open loop cooling system. As such, a jet pump of the propulsion
unit draws cooling water from the body of water in which the
personal watercraft 5 is operating, shown in FIG. 44. The cooling
water is supplied to the exhaust manifold 300 through a primary
inlet port 510 located in the bend 330 of the exhaust manifold 300,
as shown in FIGS. 43 and 45. The cooling water then flows through
the first chamber portion 3701 until it connects with the second
chamber 3702 at the rear portion of the exhaust manifold 300. The
cooling water then flows back through the second chamber 3702 until
it is discharged through the outlet port 3520 back into the body of
water, as shown in FIG. 45. Thus, the separation of the chamber 370
into two portions 3701 and 3702 that are interconnected only at an
end of the exhaust manifold distant from the cooling intake and
outlet ports provides for a U-shaped cooling circuit in the
manifold, enhancing the cooling efficiency of the manifold.
[0140] These cooling arrangement maintain the exhaust manifolds 30
and 300 at a lower temperature than the cylinder head housing 20
and the cylinder block 10. As a result, the exhaust manifolds 30
and 300 function as a heat sink, withdrawing heat from the cylinder
head housing 20 and the cylinder block 10. This reduces the cooling
requirements placed on the closed loop cooling system 80, described
below. The coolant in the exhaust manifold (e.g. the water drawn
from the body of water) has a lower temperature than the coolant
for the closed loop cooling system, described below.
[0141] At least one temperature sensor 39 is located in the muffler
to measure the temperature of the exhaust gases, as shown in FIG.
42. The exhaust manifold 300 is equipped with an injection cooling
system, which supplies additional cooling water to the exhaust
manifold. A first injection nozzle 381 sprays cooling water
directly into the exhaust passageway 320 in a direction away from
the cylinder head housing 20. A second injection nozzle 383 sprays
cooling water directly into the exhaust passageway 320 also in a
direction away from the cylinder head housing 20. The location of
the nozzles in the knee of the exhaust manifold prevents the
backward travel of the cooling water into the cylinder head. The
combined open loop cooling system with the injection cooling system
functions to cool both the exhaust manifold and the exhaust gases
within the manifold.
Air Intake and Fuel Injection System
[0142] The air intake and fuel injection system or induction system
40 will now be described in connection with FIGS. 26-31. The system
40 is connected to the cylinder head housing 20 opposite the
exhaust manifold 30. The air intake into the engine 1 or 2 is
effected from within the hull of the personal watercraft 5 via an
air box, not shown, but disclosed in U.S. Provisional Patent
Application No. 60/224,355, filed on Aug. 11, 2000, entitled
"WATERCRAFT HAVING AIR/WATER SEPARATING DEVICE" and U.S.
Provisional Patent Application No. 60/229,340, filed on Sep. 1,
2000, entitled "PERSONAL WATERCRAFT HAVING IMPROVED FUEL,
LUBRICATION AND AIR INTAKE SYSTEMS" the specifications of which are
incorporated specifically herein by reference. The air box
comprises an air inlet in the form of a snorkel, a water separator
unit and a muffler unit. The air box is located apart from the
engine and connected to the engine via a tube or hose to prevent
water from entering the air intake system.
[0143] The air flows through the tube connecting the air box with
the engine, and then passes to an air intake manifold or plenum 41,
illustrated in FIGS. 26-31. The air manifold 41 is preferably
formed from a plastic material. The present invention, however, is
not limited to the use of a plastic material; rather, metals, high
strength alloys and other suitable synthetic materials may be
used.
[0144] The air manifold 41 has a symmetrical geometry. With this
arrangement, air flow into the air manifold 41 can be provided at
either end of the air manifold 41, thereby enabling use of the same
air manifold 41 in either a normally aspirated engine 1 or a
supercharged engine 2, which engines have different flow paths for
air into the air intake manifold. In the normally aspirated engine,
the air from a throttle (if the engine has fuel injection) or a
carburetor (if the engine does not have fuel injection) flows into
one end of the air manifold 41, as shown for example in FIG. 4.
Preferably, this end faces the airbox to shorten the distance and
the pressure loss between the intake manifold and the airbox.
[0145] Irrespective of which end of the air manifold is used to
intake air, in a fuel injection version of the engine, the air
manifold 41 includes a throttle body 411 containing a throttle at
the plenum inlet to regulate the flow of air into the manifold 41.
The degree of opening of the throttle of the throttle body 411 is
controlled by the engine management system 200, as shown in FIG.
42. The throttle body 411 further includes a by-pass idle valve
4111. The by-pass idle valve 4111 is preferably controlled by a
stepper motor that controls the cross sectional opening of the
by-pass idle valve 4111 and the amount of air flowing through it.
Alternatively, it is contemplated that the idle valve 4111 may
include an electromagnetically operated valve. The operation of the
by-pass idle valve 4111 is controlled by the engine management
system 200. The engine management system operates the stepper motor
based on the engine speed to adjust it to a given threshold value.
In normal operation, the idle valve 4111 is open when the throttle
of the throttle body 411 is closed. This permits the flow of a
predetermined amount of air into the manifold 41 during an engine
idling less than the normal air intake into the air manifold 41.
The idle valve 4111 is not fully closed when the throttle of the
throttle body 411 is open. In a normal full load steady state
operating condition, the idle valve 4111 is partly but not entirely
open. This provides a reserve of intake air used for transient
engine operating conditions (e.g., a rapid deceleration phase). The
stepper motor is operated such that the maximum amount of air can
be drawn into the air manifold 41 so that the air/fuel mixture is
not too high. The location of the throttle body 411 is different
for the normally aspirated engine 1 and the supercharged engine 2.
It is contemplated that the throttle body 411 may be replaced by a
carburetor in a non-fuel injected version of the engine.
[0146] The air manifold 41 further includes at least one swing pipe
412 for each cylinder. Each swing pipe 412 is operatively connected
to the respective intake passageway 24 to supply air to the
combustion chambers through intake openings 241. The flow pattern
of the air within the air manifold 41 is indicated by the arrows in
FIGS. 27-29 and 31. As shown, the air enters the air manifold 41
via the throttle body 411. The air passes radially through a
cylindrical flame arrester 42 and then flows through each swing
pipe 412 to the respective intake passageway 24.
[0147] The flame arrester 42 in the air manifold 41 prevents
backfire of flames from entering the engine compartment interior
within the hull of the personal watercraft. The flame arrester 42
includes a perforated inner pipe 421 and a pleated porous outer
shell 422. In accordance with the present invention, the location
of the flame arrester 42 is advantageous. The flame arrester 42 is
located within the central passageway in the air manifold 41. As
such, the flame arrester 42 is located between the swing pipe 412
and the air inlet. In the event of a backfire, this location is
advantageous because all flames are caught by the flame arrester 42
before passage to the air inlet (i.e., the throttle or the
supercharger). Thus, backfire flame cannot reach outside of the
engine, especially important when the engine is installed on a
watercraft or aircraft where an engine compartment fire can be more
disastrous than in an automobile. Although a cylindrical flame
arrester 42 is illustrated, it is also contemplated that the flame
arrester may be in the form of a flat plate or an arcuate
member.
[0148] The air manifold 41 is constructed to withstand the build up
of back pressure in the event of a backfire. The manifold 41 is
configured such that the back pressure is dissipated within the
swing pipe 412. To prevent failure or cracking of the manifold in
the event of a significant build up of back pressure, a pressure
relief valve may be provided. The pressure relief valve may be made
integral with an end cap 413, which is secured to an end of the air
manifold 41, as shown in FIG. 27. The end cap 413 may be integrally
formed with the air manifold 41.
[0149] In the supercharger version of the engine 2, the
supercharger 90 and the throttle body 411 are interconnected
between the air box and the air manifold 41. The throttle body 411
is located between the air manifold 41 and the supercharger 90. The
supercharger assembly 90, however, is connected to an opposite end
of the air manifold 41, as shown in FIGS. 30 and 31. The location
of the throttle body 411 is also relocated to this end. As such,
the air manifold 41 is designed such that the throttle body 411 and
the pressure relief valve, if provided, can be located on either
end of the manifold 41 to provide increased flexibility such that
the same manifold geometry can be used for either the supercharger
version or the normally aspirated version of the engine.
[0150] The intake manifold 41 also includes at least one drainage
port. The drainage plug is removably located within the drainage
port. In the event that water enters the interior of the intake
manifold 41, the plugs can be removed to drain the water.
Alternatively, a hose can be connected to the drainage port having
a valve at an opposite end for more controlled drainage.
Furthermore, it is contemplated that an automatically operated
drainage valve may be provided to drain the air manifold upon
engine shutdown.
[0151] It is contemplated that the air manifold 41 may include a
cooling jacket 49 along an exterior wall of the air manifold 41, as
shown in FIG. 29. The cooling jacket 49 cools the air within the
air manifold 41 and, more particularly, the swing pipe 412 before
entering the combustion chambers. The cooling of the intake air is
especially useful for a supercharge version of the engine because
the operation of the supercharger (by compressing) the air
increases the temperature of the air. The cooling jacket may be
linked to the open loop cooling system.
[0152] The air intake and fuel injection system 40 further includes
a fuel injection assembly 43. The fuel injection assembly 43
includes a common fuel rail 431. The fuel rail 431 extends along an
upper portion of the intake manifold 41, as shown in FIGS. 26, 27,
30 and 31. It is preferred that the pressure of the fuel into the
fuel rail 431 be regulated by the fuel supply assembly 203 located
in the fuel tank 204. In an arrangement where the fuel supply is
not controlled in the fuel tank, an optional pressure control valve
432 is located at one end of the fuel rail 431. The pressure
control valve 432 is provided to control fuel pressure within the
fuel injection assembly 43. In this arrangement, a separate fuel
return line is required.
[0153] At least one fuel injection nozzle 434 extends from the fuel
rail 431 to the each swing pipe 412 adjacent the connection to each
intake passageway 24. A fuel injection nozzle 434 is provided for
each engine cylinder. The swing pipe 412 extends along the sides of
the fuel injection nozzle 434. This increases air flow ar und the
injection nozzle 434 such that no pockets of reduced air flow are
produced adjacent the nozzle 434 because reduced air flow may
produce residue on the wall of the swing pipe adjacent the nozzle,
which could reduce performance and flow of fuel into the cylinder
chamber. Additionally, to prevent the formation of pockets, the
nozzles 434 may extend into the swing pipe 412. Fuel from the
injection nozzle 434 is mixed with the air within the swing pipe
412 as the air enters the intake passageway 24. The fuel injection
nozzles 434 are electromagnetically controlled by the engine
management system 200 so that the nozzles 434 are independently and
sequentially operated.
Power Take Off Assembly
[0154] The power take off assembly 50 of the engine 1 or 2 will now
be described in connection with FIGS. 32-34 and 36. The crankshaft
123, described above, extends from one end of the crankcase 10, as
shown in FIG. 33. The rotation motion of the crankshaft 123 is
transferred to a drive shaft 51. A threaded connecting assembly 52
is secured to the end of the crankshaft 123. The threaded
connecting assembly 52 includes a plurality of teeth 521 that
extend around an inner periphery of one end of the connecting
assembly 52. The teeth 521 are adapted to mate with complementary
teeth 511 on the drive shaft 51. As shown in FIGS. 36 and 37, the
teeth 511 have a generally arcuate shape. Although a generally
linear tooth arrangement is considered to be well within the scope
of the present invention, the arcuate tooth is preferred. The
arcuate arrangement allows for slight angular deviations between
the crankshaft 123 and the drive shaft 51. This is especially
important when the crankshaft 123 and the drive shaft 1 are not in
exact alignment or when the personal watercraft is operated in
extreme conditions, such as, for example, when jumping waves. The
use of the threaded connecting assembly 52 is also advantageous. In
the event of wear resulting from non-exact alignment, only the
connecting assembly 52 need be replaced.
[0155] The arcuate teeth 511 of the connecting assembly 52 are
lubricated with engine oil. The oil is supplied from a first
crankshaft main bearing 1232 via hollow bores 1233 in the
crankshaft 123. The oil then flows to the arcuate teeth 511. This
arrangement reduces engine maintenance because the operator no
longer needs to grease the connection between the crankshaft and
the drive shaft. The lubrication is performed by the lubrication
system of the engine. The power take off housing 59 seals the
components contained therein with the power take off assembly 50.
Thus, protecting these components from exposure to marine
conditions.
[0156] The connecting assembly 52 includes a sealing extension 522,
wherein the extension 522 extends along a portion of the drive
shaft 51. An o-ring seal 523 or other suitable sealing member is
positioned between the sealing extension 522 of the connecting
assembly 52 and the drive shaft 51. There is no relative rotational
movement between the drive shaft 51 and the connecting assembly 52.
As such, there are no rotational stresses on the o-ring seal 523.
The sealing extension 522 and the o-ring 523 prevents lubricant
from escaping from the engine. A labyrinth sealing arrangement may
be provided between the sealing extension 522 and the power take
off housing 59 to prevent the passage of lubricant from the power
take off assembly 50 around the drive shaft 51. Alternatively, a
screw or worm conveyor may be provided, which conveys lubricant
back to the power take off assembly. At least one bore may be
provided to form a shortcut such that the oil is drawn into the
screw conveyor.
[0157] Additionally, the sealing of the drive shaft 51 with respect
to the outside is effected by a sealing assembly 53. The sealing
assembly 53 includes several sealing elements that can be used
alone or in combination. The sealing assembly 53 includes flexible
bellows 531, a shaft seal ring 532, and sealing rings 533. The
flexible bellows 531 connects the power take off housing 59 with an
external bearing carrier race 5311, which in turn is rotatably
mounted on the drive shaft 51 via two self lubricating antifriction
bearings (rolling bearings) 5312 and a bearing carrier inner race
5313. Sealing between the two bearing carrier races 5311 and 5313
is effected by the shaft sealing ring 532. The sealing rings 533
(in the form of polymeric o-rings) act as a seal between the
bearing carrier inner race 5313 and the drive shaft 51. The sealing
rings 533 also ensure a reliable fit between the two parts. A
safety ring or clip 534 secures the bearing carrier inner race 5313
on the drive shaft 51 against any axial displacement. This may also
be accomplished using a step formed in the drive shaft 51. The
flexible bellow 531 is clamped to the power take off housing 59 and
the external bearing carrier race 5311 by clamps 5314 and 5315,
respectively.
[0158] Alternatively, the antifriction bearings 5312 are lubricated
with engine oil. The oil is supplied from a first crankshaft main
bearing 1232 via hollow bores 1233 in the crankshaft 123. The oil
flows through the arcuate teeth 511 to the antifriction bearings
5312 and finally returns between the power take off housing 59 and
the connecting assembly 52 into the interior of the engine. With
this arrangement, a second flexible seal is provided in the event
the flexible bellow 531 fails.
[0159] The power take off assembly 50 further includes a gear
assembly 54, as shown in FIGS. 36 and 37. The gear assembly 54
includes a main gear 541 secured to the crankshaft 123 for driving
the balance shaft 115, a chain gear 542 integrally connected to the
main gear 541 for driving a cam control chain 55, and a large gear
543. It is contemplated that the chain gear 542 may be a separate
component that is either force fit, fastened to or integrated into
the crankshaft 123. The large gear 543 includes at least a first
gear 5432 for engagement with a starter 56 through intermediate
gear 561, as shown in FIG. 37 A second gear 5431 may be secured to
the large gear 543 if the engine 2 is so equipped for driving a
supercharger 90, as described below and shown in FIG. 38 For
reducing the number of required parts for the engine family, a
single gear 543 having both gears 5431 and 5432 may be used in
either the blown or normally aspirated engines. It is also
contemplated that the large gear 543 is formed as a single gear
such that a portion of each tooth of the gear is used to drive the
supercharger and another portion is used to drive the starter.
[0160] Linking the intermediate gear 561 for the starter assembly
56 to the crankshaft 123 through the gear 543 results in a
reduction of the engine profile. A thrust screw drive within the
intermediate gear 561 for the starter assembly 56 allows for an
automatic engagement of a drive pinion 562 with the first gear 5432
during the starting procedure. The intermediate gear 561 moves the
drive pinion 562 into engagement with the first gear 5432 against
the bias of a return spring 563. At least one dampening spring 564
is provided to absorb vibration. After the starters operation is
complete, the thrust screw drive disengages such that the return
spring 563 biases the drive pinion 562 out of engagement with the
first gear 5432. The drive pinion 562 is mounted to a pinion shaft
565 that is connected to the starter assembly 56 such that
rotational movement generated by the starter assembly 56 is
transferred to the drive pinion 562. The pinion shaft 565 is
slidably and rotatably received within a recess in the power take
off housing 59.
[0161] As illustrated in FIG. 36, a generator assembly 57 is also
part of the power take off assembly 50. The generator assembly 57
includes a magnet wheel 571 connected to the gear assembly 54, as
shown in FIG. 36 using suitable fasteners. The generator assembly
57 is a permanently excited 3-phase generator, in which permanent
magnets 572, which are fastened to magnet wheel 571, rotate around
a stator 573. The stator 573 is fixed to the inner side of the
power take off housing 59. The location and arrangement of the
generator assembly 57 provides for easy encapsulation because of
reduced wiring requirements. The magnet wheel 571 rotates around
the stationary coils. This arrangement is advantageous because it
eliminates the need for rotating coil members and also in view of
possible repair work. Furthermore, it reduces the weight of the
rotating masses. Additionally, the magnet wheel 571 is constructed
as an extrusion-molded part.
[0162] The rotational speed of the crankshaft 123 is measured by an
engine or crankshaft speed sensor 58 located within the power take
off housing 59. A cup shaped actuator 544 is secured to the gear
assembly 54 between the large gear 543 and the magnet wheel 571 of
the generator assembly 57. The actuator 544 extends between the
gear 543 and wheel 571 and between the sensor 58 and the wheel 571,
as shown in FIG. 36. The actuator 544 includes a plurality of teeth
extending around the perimeter thereof. A predetermined number of
teeth are missing at predetermined locations along the perimeter.
The sensor 58 detects the absence of the teeth as the actuator 544
rotates. The speed of the crankshaft and engine speed can be
determined from this.
[0163] Alternatively, it is contemplated that the magnet wheel 571
may include at least one conductor piece mounted therein. The
conductor piece triggers the crankshaft or engine speed sensor 58.
Instantaneous values of the crankshaft position can be received
therefrom and the angular speed (rotational speed) is then
calculated by the engine management system 200, described below.
The angular resolution is 10.degree., i.e. during rotation of the
crankshaft 123, after every 10.degree. of rotation, a pulse is sent
by the crankshaft position sensor to the control device. It is
contemplated that the present invention is not limited to an
angular resolution of 10.degree.; rather, angular resolutions
greater than and less than 10.degree. are considered to be well
within the scope of the present invention.
[0164] The arrangement of the components within the power take off
housing 59 results in a more compact engine design. As described
above, the engine components are located on the power take off end.
The power take off housing 59 protects these elements from the
marine conditions in which the personal watercraft operates.
Furthermore, a common drive assembly connected to the crankshaft
123 is provided to drive these components without the need for
numerous belts and other connections. Additional features and
benefits of the power take off assembly 50 will be described below
in connection with the description of the lubricating system 60,
the blow-by ventilation system 70, engine cooling system 80 and
supercharger 90.
Lubricating System
[0165] The lubricating system 60 will now be described in greater
detail in connection with FIGS. 8, 11, 12, 14-16 and 32-35.
[0166] The engines 1 and 2 have a dry-sump lubricating system 60.
The lubrication system 60 includes the oil tank 11, described above
and shown in FIG. 8. The oil collected in the crank chambers 121
emerges therefrom via outlet openings 111 into a channel 112. The
oil then flows to the upper portion 113 of the oil tank 11 adjacent
the balance shaft 115. From there, the oil flows back by gravity to
the bottom of the oil tank 11, where the oil is collected and
stored.
[0167] From the oil tank 11, the oil is conveyed to an oil cooling
assembly 86, shown in FIGS. 23 and 25, by an oil pump 61, as shown
in FIGS. 25 and 33 through integrated channels in the lower
crankcase 12. The oil pump 61 is integrated into the power take off
housing 59 and is coaxially disposed and driven by the balance
shaft 115 via a connecting shaft 612. The connecting shaft 612 is
received within a suitable recess within the end of the balance
shaft 115 such that rotation movement of the balance shaft 115 is
transferred to the drive shaft 612. The oil pump 61 is preferably a
troichoid pump. It is preferred that the oil be sucked from the
bottom of the oil tank 11. Furthermore, it is also preferred that
the oil be removed from a more centrally located pickup position
within the tank 11, rather than the front or rear of the tank 11.
This is a preventative measure to avoid air entrapment in extreme
operating conditions (extreme acceleration and deceleration modes).
The oil cooling assembly 86 is designed as a plate-type cooler and
is fixed onto the cylinder block 10. To cool the engine, water is
used in a closed cooling system 80, described in greater detail
below.
[0168] From the oil cooling assembly 86, the oil is conveyed to the
oil filter unit 62, as shown in FIGS. 32 and 34 through integrated
channels in the lower crankcase 12. The oil filter unit 62 has an
oil filter casing 621 that is integrated to the power take off
housing 59. The oil filter unit 62 is closed at one end by a
removable oil filter cover 622. Located within the oil filter
casing 621 is an annular oil filter 623 and a valve rod 624. One
end of the valve rod 624 is connected with the oil filter cover
622. The valve rod 624 is secured to the cover by a suitable
fastener. The valve rod 624 acts as a fastener to secure the cover
622 to the filter casing 621. The other end of the valve rod 624
extends into a drainage opening 625. When the valve rod 624 is
pulled out of the drainage opening 625, the oil which has remained
in the filter casing 621 can automatically drain through the
drainage opening 625. Alternatively, the oil filter cover 622 may
be configured as a screw lid.
[0169] Unlike conventional oil filter units where the overflow
valve is integrated in the upper region of the filter cover 622,
the oil filter unit 62 includes an external overflow valve 626 and
a bypass duct 627. In the event that the oil filter unit 62 is
clogged, a direct connection is formed between an inlet channel 628
and an outlet channel 629 of the oil filter unit 62. This
arrangement has the advantage that the oil does not flow around a
dirty oil filter. Thus, no dirt particles can contaminate the oil
circuit.
[0170] The filtered oil is then supplied to the engine 1 or 2 for
lubricating the various components through the main oil gallery in
the upper crankcase 13 of the crankcase 10, as illustrated in the
oil circuit in FIGS. 8 and 11.
[0171] One aspect of the lubricating system 60 relates to the
return of the oil from the crank chambers 121 in the upper
crankcase 12 into the integrated oil tank 11. The oil is pushed out
of the crankcase. This is effected by a differential pressure
acting between the crank chambers 121 and the oil tank 11 and the
induction system, respectively. This differential pressure is a
result of the pressure pulses caused by the pistons 1241 in the
crank chambers 121. It is also partially due to a consequence of a
"Blow-By" effect, which refers to cylinder pressure losses. The
piston 1241 does not provide a 100% sealing on the cylinder wall,
so part of the combustion gas caused during combustion leaks past
the cylinder downwardly into the lower crankcase 12. This so-called
blow-by gas creates additional pressure in the crank chambers 121
below the pistons 1241 and is dependent on the load and the
rotational speed of the engine. However, on account of the
above-mentioned blow-by effect, the overall effect results in a
pressure that is always above the pressure between the air box and
the throttle body. The return of the blow-by gas is described in
greater detail below in connection with the blow-by ventilation
system 70.
[0172] The rotational movement of the crankshaft 123 is also
utilized to carry oil to the outlet openings 111, and here two
effects are to be found. First, by the direct contact of the crank
webs 1231 with the oil, in case of direct wetting, there occurs an
entrainment effect as a consequence of the shearing forces. Second,
with smaller amounts of oil in the crank chambers 121, if there is
no direct contact between crank web 1231 and oil, gas forces will
occur which likewise drive the oil to the respective outlet
openings 111. At the base of the crank chambers 121, in the
vicinity of the outlet openings 111, stripper edges may be arranged
which strip the oil from the crank webs 1231.
[0173] To enable an optimum utilization of the above-described
effect for the oil return, the three crank chambers 121 (discussed
above) in the crankcase 12 are hermetically separated from each
other, and each crank chamber 121 is equipped with a separate
outlet opening 111 for the oil. Thus, the pressure in one chamber
is not affected by the pressure in the other chambers. The
cross-sections of the channel system for the oil return following
the outlet openings 111 are dimensioned suitably (i.e. not too
large) so as to ensure the conveyance of the oil back to the oil
tank 11 on account of the differential pressure, without the risk
of a pressure equalization between oil tank 11 and crankcase 12.
Alternatively, the channels can also unify, so that one single
channel 112 leads to the oil tank 11. The arrangement should be
designed such that no oil "short-circuit" and no pressure balance
will occur between the individual crank chambers 121, i.e. oil must
not be permitted to flow directly from one crank chamber 121 into
another chamber.
[0174] The return channels 112 for the oil return from the three
hermetically closed crank chambers 121 to the oil tank 11 may be
realized by channels cast into the lower crankcase 12 which enter
the oil tank 11 adjacent the union between the upper crankcase 13
and the lower crankcase 12. Alternately, they may be realized by
separate ducts, in particular hoses or tubes. As such, normally
hoses are only used in connection with external oil tanks. In the
present "in-case oil tank," hoses can be avoided. To prevent an
undesired flow-back of oil from the oil tank 11 to the crank
chambers 12 and--in consequence--a flooding of the crank chambers
in extreme inclined positions or in flip-over position of the
personal watercraft 5, non-return valves (not illustrated) may be
installed in the channels 112.
[0175] To remove the lubricating oil which has collected in the
region close to the bottom of the crank case 12 adjacent the bottom
of the power take off housing 59, a separate suction pump 71 is
provided. Like the oil pump 61, the suction pump 71 is coaxially
arranged along and driven by the balance shaft 115. The pump 71 is
preferably a troichoid pump. The pump 71 is located on an opposite
end of the balance shaft 115 when compared to the pump 61. The oil
is conveyed from the bottom of the power take off housing 59
through a duct 126 cast into the lower crankcase 12 to the suction
pump 71. Alternatively, it is contemplated that the blow-by gas
created in the crank chamber 121 adjacent the power take off
housing 59 is fed into the power take off housing 59 to provide
pressure to remove the oil from the bottom of the power take off
housing 59 near the bottom of the crank case.
[0176] The oil collected in the bottom of each crank chamber 121
exits through the opening 111. The oil is then driven through the
channel 112 back to the oil tank 11 by the blow-by gas pressure.
The oil collected inside the power take off housing 59 is removed
by a suction pump 71 or other suitable pumping assembly. The oil
flows through a channel 126, shown in FIGS. 11, 41 and 49, again
integrated into the lower crankcase 12 from the power take off side
to the opposite side, where the suction pump 71 is mounted, as
shown in FIGS. 40 and 41. The oil passes through an oil sieve 72
before it enters the suction pump 71 and is finally conveyed back
through a U-shaped channel 711 to the oil tank 11, as shown in
FIGS. 11, and 40. It is contemplated that the channel 711 is
integrated in the housing of the suction pump 71.
[0177] Regarding the oil circuit, it is added that cooling and
lubrication of the pistons 1241 and liners are effected by aid of
spraying nozzles 64 at the lower side of the piston 1241, as shown
in FIG. 8. Oil is supplied to the nozzles 64 from the main oil
gallery 65. The spray nozzle 64 is positioned such that the jet
reaches the piston lower side not only in the lower dead center
position illustrated, but also in the upper dead center
position.
[0178] FIGS. 8 and 35 illustrate one possible oil channel system 63
in the region of the cylinder head housing 20 by way of a schematic
3D representation. Other systems are contemplated to be well within
the scope of the present invention. The oil is conveyed to the
cylinder head housing 20 through at least one ascending duct 631 in
the upper crankcase 13. The ascending duct 631 is connected to the
main oil gallery 65. The oil enters cylinder head housing 20 from
the ascending duct 631 through a transverse bore 632. In the
ascending duct 631, a throttle 6311 is installed which restricts
the amount of oil flowing therethrough. In addition, a check valve
6312 is disposed in the ascending duct 631, which blocks the oil
conduit as soon as the engine 1 or 2 is stopped. As such, a certain
amount of oil can be stored in the channels in the cylinder head
housing 20. This stored oil is particularly useful during a cold
start since lubrication can be initiated rapidly therewith and
provided to the valve train sooner to prevent damage to the valve
train.
[0179] Connecting bores 633 branch off of the tansverse bore 632
and connect the latter with the bores 634. The bores 634 also
receive the cylinder head fastening screws. The oil rises upwardly
in the annular gap between the cylinder head screw and the
corresponding bores 634. The oil then enters into a V-shaped
channel section 635 formed by two obliquely downwardly directed
bores 6351 and 6352. From the ascending branch 6352 of the V-shaped
channel section 635, the oil directly enters into the interior of
the hollow rocker arm support axle 28. From there, the oil is
directed to the bearing places of the rocker arm assemblies 25 and
26 via the radial openings 282, as shown in FIG. 14. Also, the oil
is admitted to the operating assemblies 253 and 263. It is
contemplated that other channel systems and arrangements are well
within the scope of the present invention provided the channel
systems conduct lubricant from the main oil gallery 65 to the
support axle 28.
[0180] Lubricant is supplied to the camshaft 29 via bearing bracket
293, described above, through bore 636.
[0181] Below the camshaft 29, the oil may accumulate in a small
basin in which the lobes 291 and 292 of the camshaft 29 may be
immersed for lubricating purposes. The lubricant within the
cylinder head housing 20 collects in a depression under the
camshaft 29 adjacent the cylinder closest to the power take off
assembly 50. The oil from the other cylinders within the cylinder
head flows to the depression through passageways 295, which
interconnect the areas in the cylinder head adjacent the other
cylinders. The oil exits the cylinder head housing 20 through an
inclined passageway into the control chain chamber 202 where it
flows into the power take off assembly 50. This lubricant
contributes to the lubrication of the gears and supercharger 90 (if
present) within the power take off assembly 50.
Blow-By Ventilation System
[0182] The engines 1 and 2 are preferably equipped with a blow-by
ventilation system 70 for separating oil from the vented blow-by
gas. A preferred form of the blow-by ventilation system 70 is
illustrated in FIGS. 3, 4, 11, 40, 41 and 46.
[0183] The blow-by gas originating from the combustion chambers 124
due to leakage between the pistons 1241 and cylinder liners first
accumulates in the (sealed) crank chambers 121 and from there it
flows together with the oil through the channels 112 to the oil
tank 11, where it accumulates and mixes in the upper portion 113 of
the oil tank 11 with any gas in the oil tank 11 from the power take
off assembly 5d. From the oil tank 11, the gas mixture is then
conveyed through a channel 712 (in the housing of the suction pump
71 and the lid of the sieve 72), shown in FIG. 40 to a shutoff and
pressure relieve valve 73, which is open in normal engine
operation. The pressure relief valve 73 includes a valve rod 731
that moves the valve 73 between open and closed positions by a
solenoid assembly 77. In the event that the solenoid assembly 77 is
not operational, the pressure relief valve 73 includes a spring
assembly 732 that permits the opening of the valve 73 in the event
of a build up of pressure within the tank 11.
[0184] The gas mixture from the oil tank 11 is split into two
partial flows: a first portion flows back to the cylinder head
chamber within the cylinder head housing 20 through a passageway
74, shown in FIGS. 40 and 41. A second portion is vented
tangentially into an oil separator 75 designed as a cyclone. In the
cyclone, the gas mixture is separated from oil by centrifugal
forces due to the swirling of the gas/oil mixture in the cyclone.
The cleaned gas mixture leaves the cyclone through a central pipe
751. The cleaned gas mixture then passes a second shutoff and
pressure relief valve 76 and is finally conveyed to the air intake
between the airbox and the throttle body 411, where it merges with
the fresh air drawn in by the engine.
[0185] The shutoff and pressure relief valve 76 is also mounted on
the valve rod 731 and is also actuated by the solenoid 77. With
this arrangement, the valves 73 and 76 operate simultaneously. The
valves 73 and 76 are closed by drawback springs 732 and 761 when
the solenoid 77 is not activated and they are open when the
solenoid 77 is activated. With this arrangement, the engine is
sealed, preventing oil leaks when the engine is shut down. In
normal (upright vehicle) engine operation, the solenoid 77 is
activated and the valves 73 and 76 are opened respectively.
However, in the event of a roll-over of the vehicle, the valves are
closed instantly to prevent oil from entering the induction system
40 and/or the airbox and leaking into the environment. The closure
of valve 73 prevents oil from accumulating in the cylinder head
housing 20 in a roll-over event. This would cause a temporary lack
of oil in the oil tank 11, when the personal watercraft 5 has
returned to a normal upright position and could result in an
undersupply of lubricant to the engine, which may result in severe
damage to the engine 1 or 2. The valves 73 and 76 are also closed
when the engine is shut down.
[0186] A pressure sensor or sensor switch may be provided in the
oil tank 11 or in the channel 712 to sense the pressure within the
tank 1l. If the oil pressure exceeds a certain threshold value, the
engine management system 200 operates in an emergency mode (e.g.
limp home function). The engine management system operates the
engine at a reduced speed. The engine management system also
interacts with other onboard computer systems to notify the
operator of the engine malfunction. Additionally, the pressure
sensor can be used to detect oil leakage in the lubrication
circuit.
[0187] The gas mixture enters the upper portion of the cyclone 75
through the opening 755. As such, the gas mixture tangentially
enters the cyclone 75. Oil droplets within the gas mixture are
thrust against the inner wall of the cyclone 75 as a result of
centrifugal forces within the cyclone 75.
[0188] The separated oil then flows down the inner wall of the
cyclone 75 towards opening 752; collects in the bottom of the
cyclone 75; and exits the cyclone 75 through an opening 752 into a
channel 753 integrated in the sieve lid 721, and merges with the
oil flow from the power take off assembly 50 in front of the oil
sieve 72, to be conveyed back to the oil tank 11. Within the
channel 753 there is provided a throttle 754 which ensures that a
sufficient height negative pressure (vacuum) can build up in the
suction port of the suction pump 71, so that the power take off
housing 50 is drained reliably in all operating conditions. In a
cold start condition (when the oil is very viscous) the throttle
754 may even be closed by an additional valve (not shown)
especially at idling speed to guarantee the aforesaid
requirement.
[0189] An oil filler tube 78 is integrated to the cyclone 75. A cap
781 is provided for closing the filler tube 78. Fresh oil flows
down the filler tube 78 into a channel 722 integrated in the sieve
lid 721. The oil enters a U-shaped duct through a port 715, shown
in FIG. 40, in the housing of the suction pump, merges with the oil
from the power take off assembly 50 and is finally conveyed to the
oil tank 11.
[0190] In the preferred embodiment, the valves 73 and 76, the
cyclone 75 and the oil filler tube 78 are assembled to form a
single unit.
[0191] In accordance with the blow-by gas ventilation system 70
described herein, a slight vacuum (underpressure, negative
pressure, subpressure) is generated in the interior in the power
take off assembly 5q and within the cylinder head housing 20. As a
result, no oil or contaminated blow-by gas can escape to the
environmnent.
Engine Cooling System
[0192] An engine cooling system 80 will now be described in
connection with FIGS. 25, 32 and 33. The engine cooling system 80
is a closed system utilizing a coolant such as glycol, water or a
mixture of them. The present invention, however, is not limited to
these coolants; rather, it is contemplated that other cooling
liquids are considered to be well within the scope of the present
invention. The cooling circuit of the engine cooling system 80 is
illustrated in FIG. 25. The closed loop cooling system 80
cooperates with the open loop cooling arrangement described above
in connection with the exhaust manifold 30 to effectively cool the
engines 1 and 2.
[0193] The engine cooling system 80 includes a pump assembly 81
located on one end of the engine 1 or 2, as shown in FIG. 32.
[0194] As illustrated in FIG. 33, the pump assembly 81 is arranged
externally of the power take off housing 59. The power take off
housing 59 and pump lid 611 together form the pump casing. It is
designed as a rotary pump and consists of an impeller 811 which is
located, screwed or attached onto the end of the connecting shaft
612, which projects from the power take off housing 59. The
connecting rod 612 also drives the oil pump 61. Impeller 811 is
driven by connecting rod 612. The connecting rod 612 also drives
the oil pump 61. The pump assembly 81 also includes a pump lid 812,
which is fastened to the power take off housing 59 and forms the
pump casing in cooperation therewith. The pump assembly 81 has a
one piece housing having an integrated thermostat.
[0195] As shown in FIG. 25, the coolant flows from the pump
assembly 81 through a passageway 82 to the cylinder block of the
upper crankcase 13. The passageway 82 includes a main passageway
821 and a by-pass passageway 822. The passageways 821 and 822
direct coolant to the cooling passageway 125 in the cylinder block.
The coolant flows along the exterior of the cylinders 124, as shown
in FIG. 25. With this arrangement, the coolant travels in a
generally U-shaped manner along a side of the cylinders 124
adjacent the intake manifold; around the end of the cylinder
furthest from the power take off assembly 50 and then along the
side of the cylinders adjacent the exhaust manifold in a direction
back towards the power take off assembly 50. At the same tire, the
coolant is directed in an upward direction towards the cylinder
head housing 20. The by-pass passageway 822 reduces the load on the
main passageway 821 and improves the flow pattern in the cooling
passageway 125 at an end portion of the cooling passageway 125
opposite the inlet. The coolant from the by-pass passageway 822
mixtures with the coolant in the coolant passageway 125 to reduce
the temperature of the coolant in the end portion of the cooling
passageway 125. Furthermore, the entry of coolant into the cooling
passageway 125 from the by-pass passageway 822 improves the upward
flow of coolant into the cylinder head housing 20. It is preferred
that the passageways 821 and 822 are integrally formed in the power
take off housing 59 and crankcase 10. It, however, is contemplated
that the passageways may be hoses connecting the components to one
another.
[0196] From the upper crankcase 13, the coolant then passes
upwardly to the cylinder head housing 20 through bores 131 in a
head gasket 130 positioned between the upper crankcase 13 and
cylinder head housing 20, as schematically illustrated in FIG. 25.
The bores 131 are located on the exhaust manifold side of the
gasket 130. These bores 130 act as throttles to adjust the flow of
coolant into the cylinder head housing 20. Additional small bores
are located on the intake manifold side of the gasket 130. These
bores vent air trapped within the passageway 125 into the cylinder
head housing 20. The coolant first passes over the exhaust side of
the cylinder head toward the intake side of the cylinder head
before exiting the cylinder head housing 20 through a common
passageway.
[0197] From the cylinder head housing 20, the coolant is then
conveyed through a hose to a thermostat 83 through an inlet
passageway 817 located on the pump assembly 81, as shown in FIGS.
25 and 32. As illustrated in FIG. 33, the thermostat 83 is directly
mounted on the pump lid 812. The thermostat 83 comprises a two-part
thermostat casing 831 and 832 including hose connections and a
temperature-sensitive valve 833, which automatically opens if a
predetermined temperature threshold value is exceeded. The coolant
then flows through outlet passage 816 to a heat exchanger 84 (shown
schematically in FIG. 25), where the coolant is cooled by
exchanging heat to the atmosphere. This can be in the form of a
cooling plate exposed to the body of water. The cooling plate may
be located in a lower portion of the hull of the personal
watercraft 5. The cooling plate is described in U.S. Provisional
Patent Application Ser. No. 60/160,819, filed Oct. 21, 1999
entitled "WATERCRAFT WITH CLOSED-LOOP HEAT EXCHANGER," and U.S.
patent application Ser. No. 09/691,129, filed Oct. 19, 2000
entitled "WATERCRAFT HAVING A CLOSED COOLANT CIRCULATING SYSTEM
WITH A HEAT EXCHANGER THAT CONSTITUTES AN EXTERIOR SURFACE OF THE
HULL" the specifications of which are incorporated herein
specifically by reference. The coolant is then returned to the pump
assembly 81 through an inlet 815.
[0198] The primary purpose of the cooling system 80 is to cool the
engine 1 or 2 during operation. The operation of the cooling system
80 is temporarily modified during engine start-up so that the
engine quickly reaches an optimal operating temperature. During
initial engine start-up, the thermostat 83 deactivates the heat
exchanger 84. As such, the coolant is not cooled prior to reentry
into the pump assembly 81; rather, the coolant returns directly
from the inlet 817 into the coolant pump 81.
[0199] The cooling system 80 furthermore includes an oil cooling
assembly 86. The oil cooling assembly 86 is connected to pump
assembly 81 and thermostat 83. With this arrangement, a portion of
the coolant from the pump assembly 81 is directed to the oil
cooling assembly 86 through passageway 861 to cool the engine oil.
After passing through the oil cooling assembly 86, the coolant
returns to the thermostat 83 via return passageway 862. The coolant
from the passageway 862 enters the thermostat housing in the
vicinity of the inlet 817. The oil cooling assembly 86 preferably
is a plate-type cooler and disposed on the side of the lower
crankcase 12. The coolant, which heats sooner than the oil, is used
to heat the engine oil during engine start-up.
[0200] The cooling system 80 further includes a temperature sensor
87, which is linked to the engine management system, shown in FIGS.
25 and 42. As shown in FIG. 25, an expansion reservoir 88 is
provided in the return from the cylinder head housing 20 to the
thermostat 83, as shown in FIG. 23. The expansion reservoir 88
adjusts for expansion of the cooling fluid within the system 80.
The expansion reservoir 88 further a refill port 881 for refilling
the system 80. The reservoir 88 further provides a venting function
for removing air from the cooling system 80. In this manner, the
interconnecting duct between the reservoir 88 and the cylinder head
housing 20 has to be linked to the highest point in the cylinder
head housing 20 to prevent the formation of an air barrier which
could cause overheating.
Supercharger Assembly
[0201] As discussed above, the engines in accordance with the
present invention may include a supercharger 90. The engine 2
having a supercharger 90 is illustrated in FIGS. 6, 7, 30, 31 and
38. The supercharger 90 is provided to increase the air intake and
enhance engine performance. The preassembled supercharger 90 is
plugged in a corresponding port 591, as shown in FIG. 33, in the
power take off housing 59 and sealed with sealing rings 592, as
shown in FIG. 38. It is contemplated that a turbocharger may be
used in connection with the present invention. The supercharger,
however, provides improved operating characteristics when compared
to the turbocharger. Furthermore, the turbocharger produces
additional heat as compared to the supercharger, which places
increased demands on the cooling systems.
[0202] The supercharger 90 includes a cast housing 91, which is
preferably formed from a metal, however, it may be formed from a
high strength plastic or other suitable material. The housing 91
includes an inlet portion 911. The inlet portion 911 is operatively
connected to the airbox (not shown). Air enters the supercharger 90
through the inlet portion 911. Located within the housing 91
adjacent the inlet portion 911 is an impeller 92, which operates to
draw air into the supercharger from the airbox. An air passageway
912 extends around the impeller 92 to collect the air compressed by
the impeller. The air passageway 912 is connected to the intake
manifold 41 through the throttle body 411. The housing 91 further
includes a mounting portion 913 that extends backward from the
inlet portion 911. The mounting portion 913 is received within the
port 591 in the power take off housing 59 and sealed with at least
one sealing assembly 592.
[0203] As shown in FIG. 38, a blower drive shaft 922 extends
through the mounting portion 913 and inlet portion 911. The blower
drive shaft 922 is rotatably mounted within the housing 91 with at
least one bearing assembly 921. A drive pinion 93 is coupled to the
blower drive shaft 922. It is preferred that this be a non-positive
coupling. As such, the drive pinion 93 is non-positively connected
with the blower shaft 922 via an intermediate element 94 by a
biasing spring force, which is preferably supplied by a spring
assembly 95. The spring assembly 95 includes a plurality of cup
springs. Other spring assemblies and means for providing a
connection that can slip under high torque to prevent damage to the
impeller or other components, however, are considered to be well
within the scope of the present invention. The drive shaft 922
includes splines to prevent rotational movement of the intermediate
element 94 with respect to the drive shaft 922. The shaft 922
includes a lubrication passageway that delivers lubricant to the
drive pinion 93 to reduce wear. The lubrication passageway is
connected to the lubrication system. The connection between the
drive pinion 93 and the intermediate element 94 is formed as a
plane frictional surface. This unique connection assembly can
dampen the rotational and torsional vibrations transmitted by the
crankshaft 123.
[0204] The supercharger 90 is operatively coupled by the drive
pinion 93 to the gear assembly 54 through gear 5431. The
supercharger 90 preferably includes a cooling jacket connected to
the open or closed loop cooling system to cool and prevent failure
of the supercharger 90. The cooling of the supercharger 90 improves
engine performance.
[0205] In accordance with the present invention, the supercharger
90 preferably utilizes a low-cost rotary (radial or radial-axial)
blower. The present invention, however, is not limited to these
blowers; rather, it is contemplated that a positive displacement
blower (e.g. a Rootes or Wankel blower) may be employed.
Furthermore, the supercharger 90 may be used for separating a
certain water content from the intake air.
Control Tensioner
[0206] In accordance with the present invention, the engines 1 and
2 are preferably equipped with a control tensioner for controlling
the tension within chain 55. The present invention, however, is not
limited for use with a chain; rather, it is contemplated that the
control tensioner can be used with other flexible linkages,
including but not limited to belts. A mechanical chain tensioner
100 is illustrated in FIG. 39. The tensioner 100 includes a driving
element 101. The driving element 101 preferably includes a spring
assembly. The spring assembly is preferably a rotationally active
helical pressure spring. The spring assembly 101 is rotationally
biased by aid of a thread cap 102. The spring includes a spring
ender 1011 that engages a slot 1021 in thread cap 102. The thread
cap 102 is externally screwed into a retainer 103. The spring
assembly 101 is received at one end in a blind hole bore of a
hollow adjustment element 104 which is screwed into a thread bore
of the retainer 103. The spring also includes a spring end 1012
that engages a slot 1042 in adjustment element 104. The overlapping
thread engagement of adjustment element 104 with retainer 103 is
designed to be relatively long. As oil gets into this threaded
connection, it provides a small damping effect to the adjustment
element 104 due to vibrations of the cam chain. This small damping
effect is enhanced if the thread overlap is kept relatively long.
The external thread of the adjustment element 104 preferably
includes multiple threads and it is designed such that it is
borderline self-locking in the retainer 103. This design must take
into account the presence of oil between the threads, which reduces
friction, when determining the necessary inclination of the
threads. If the inclination is too small (very self locking), a
strong spring force is required to overcome the locking action of
the threads. It is desirable to avoid unnecessary tension on the
chain to avoid wear and decreases in the lifetime of the chain. The
self tensioning action is effected by the interaction of the chain
vibration and the borderline self locking of the threads. That is,
it will maintain its extended position under normal loads but can
retract a distance under high loads to prevent damage to the cam
chain. For instance, if automatic adjustment occurs when the engine
is cold, upon reaching operation temperature, the aluminum cylinder
and head have expanded more than the steel cam chain and can create
too high of a tension in the chain. The borderline self locking
feature allows the plunger to retract slightly before chain tension
becomes so high as to damage the chain. The adjustment element 104
is rotationally driven by the spring assembly 101 if the tension of
the chain 55 slackens and is axially outwardly displaced. The
adjustment element 104 acts via a balancing arcuate intermediate
piece 105 on a tensioning rail 106. The chain tensioner 100 enables
a later adjustment by aid of the combined biasing and fixing
element 102 if the chain 55 undergoes elongation.
[0207] The thread piece 102, the retainer 103 and adjustment
element 104 preferably are made of synthetic material because of
the smaller thermal elongation encountered as compared to aluminum.
The adjustment element 104 includes a steel insert 1041 on one end
to reduce wear.
[0208] In accordance with the present invention, the engines 1 and
2 described herein are not limited to the mechanical chain
tensioner 100; rather, other tensioner assemblies are contemplated
to be well within the scope of the present invention. For example,
a hydraulic tensioner may be used. The mechanical tensioner 100,
however, has numerous advantages over this hydraulic counterpart.
First, the mechanical tensioner 100 can be manufactured at a lower
cost and does not require a complicated oil supply.
Engine Control Unit
[0209] The operation of the engine 1 or 2 is controlled by an
engine management system 200, as shown in FIG. 42. The engine
management system 200 includes an electronic control unit 201
monitors and controls the operation of various engine components
including but not limited to ignition, the fuel pump, the fuel
injection assembly, the air intake, engine cooling, engine speed,
engine lubrication, exhaust gas in the muffler in response to input
from various sensors and monitors located with the engines 1 and 2.
It is contemplated that the electronic control unit 201 may further
control functions, such as, e.g., realization of a departing lock,
realization of a start/stop control, and the identification of
authorized personal watercraft users. The electronic control unit
201 further communicates with the other computer systems on the
personal watercraft for the control of instruments, non engine
watercraft functions and service needs.
[0210] The engine management system 200 also controls the gas pump
203 in the gas tank 204, which includes a coarse filter 2041 and a
float assembly 2042.
[0211] The gas pump 203 has an associated pressure regulator 2043,
such that a constant gas pressure is mechanically provided. From
there, a retumless fuel system 205 leads to the injection nozzles
or valves 434 seated on the fuel rail 431. These injection nozzles
434 inject the fuel in the form ofjets in the air in the intake
passageway. The engine management system 200 controls the operation
of the nozzles 434 such that there is sequential injection, wherein
each cylinder has an individual injection (i.e., no group
injection). The injection amount is determined by the engine
control device 201 on the basis of the applied characteristic
fields by the pulse width, i.e. by the duration of the injection
time.
[0212] A returnless fuel system 205 prevents the fuel from heating
due to the engine heat, as could otherwise be the case with a fuel
return from the engine to the fuel tank.
[0213] The engine management system 200 also includes various
sensors, such as the temperature sensor 39 in the exhaust muffler,
an air temperature sensor 43 attached to the intake manifold 41 and
a water temperature sensor 87.
[0214] A knock sensor 206 senses at an early time the knocking
critical for the engine--which has a high specific performance
level. The knock sensor 206 includes a piezo quartz element, which
measures the solid-borne acoustic signals at the cylinder block and
transmits the corresponding signals to the electronic control unit
201. The latter has a detection software to detect a possible
knocking combustion and to cause a correction in a manner known per
se, by ignition angle displacement.
[0215] The sensors further include the crankshaft position sensor
207. A corresponding rotary position sensor 208 is associated with
the camshaft. By aid of this camshaft sensor 208, it is recognized
whether the crankshaft is present in the angle range of 0 to
360.degree. or in the range of 360 to 720.degree., which is
possible via the camshaft because the latter rotates at half the
rotational speed of the crankshaft. For the sake of simplicity, the
camshaft sensor 208 is directly associated with the chain wheel 551
at the camshaft.
[0216] For load measurement, the actual load of the engine is
calculated by the intake manifold pressure measured by sensor 210
and engine speed measured from the crankshaft 123 in the power take
off assembly 50. A throttle potentiometer 209 is used for
corrections and a limp home function. In the event the engine is
operating in a limp home function (e.g., broken intake air pressure
sensor), the engine control unit 201 communicates with another
onboard computer system to notify the operator via an instrument
panel that the engine is operating in a limp home function. A
pressure sensor 210 is arranged in the suction pipe to sense the
absolute pressure, which is especially useful for the engine 2
containing the supercharger assembly 90 and for all operation modes
with slightly opened or closed throttle valve. Thus, there is no
direct air amount or air mass measurement, but auxiliary parameters
are used therefor.
[0217] Finally, for the sake of completeness, various voltage
checks should be mentioned which are carried out by the electronic
control unit 201, e.g. for the supply voltage of the injection
valves, which is useful insofar as the board voltage on the
personal watercraft 5 may very well fluctuate.
[0218] It will be apparent to those skilled in the art that various
modifications and variations may be made without departing from the
scope of the present invention. Thus, it is intended that the
present invention covers the modifications and variations of the
invention, provided they come within the scope of the appended
claims and their equivalents.
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