U.S. patent application number 09/404238 was filed with the patent office on 2001-08-23 for air-intake system for watercraft.
Invention is credited to HATTORI, TOSHIYUKI.
Application Number | 20010015164 09/404238 |
Document ID | / |
Family ID | 16879901 |
Filed Date | 2001-08-23 |
United States Patent
Application |
20010015164 |
Kind Code |
A1 |
HATTORI, TOSHIYUKI |
August 23, 2001 |
AIR-INTAKE SYSTEM FOR WATERCRAFT
Abstract
An improved air-intake system and engine layout for use on a
small watercraft provides for a lower temperature, vapor fuel/air
charge with less water vapor content. The watercraft includes an
engine-air intake system incorporating an air-intake box which
inhibits the engine from intaking water present in the engine
compartment, especially during high speed maneuvering. An extended
flywheel case is also provided that prevents water located in the
engine compartment from being sprayed by moving parts directly into
the air-intake box. Furthermore, the improved air-intake system of
the present invention incorporates external air-intake valves that
prevent water from entering the engine and propulsion compartments
through the air intakes while the watercraft is in an inverted.
Inventors: |
HATTORI, TOSHIYUKI;
(SHIZUOKA, JP) |
Correspondence
Address: |
KNOBBE MARTENS OLSON AND BEAR LLP
620 NEWPORT CENTER DRIVE
SIXTEENTH FLOOR
NEWPORT BEACH
CA
926608016
|
Family ID: |
16879901 |
Appl. No.: |
09/404238 |
Filed: |
September 23, 1999 |
Current U.S.
Class: |
114/88 ; 440/88A;
440/88F; 440/88L; 440/88M; 440/89F; 440/89J; 440/89R |
Current CPC
Class: |
F02M 35/10301 20130101;
F02B 2275/18 20130101; F02B 61/045 20130101; F02M 35/168 20130101;
B63H 21/14 20130101; F02M 35/1233 20130101; F02B 2075/1812
20130101; F02B 75/20 20130101; F02M 35/10255 20130101; B63B 34/10
20200201; F02B 2075/027 20130101; F02M 35/10013 20130101; F02M
35/112 20130101 |
Class at
Publication: |
114/88 ;
440/89 |
International
Class: |
B63H 021/10; B63H
021/32 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 29, 1996 |
JP |
8-228665 |
Claims
What is claimed is:
1. A small watercraft is comprised of a hull having a longitudinal
axis and an engine compartment containing an engine, the engine
including a plurality of cylinders and an output shaft arranged to
lie generally parallel to said longitudinal axis, a flywheel
carried by the output shaft on a rear side of the engine and
generally covered by a flywheel casing, an impeller shaft coupled
to said output shaft, an air intake system connected to one side of
said engine and communicating with each cylinder of the engine
through intake passages in said engine, an exhaust system connected
to another side of said engine and communicating with each cylinder
of the engine through exhaust passages in said engine, said exhaust
system extending from said engine exhaust passages to a discharge
end that opens outside of said engine compartment, said exhaust
system including a water lock located at least in part behind the
engine with a least a portion of the flywheel casing being arranged
between the water trap and at least a portion of the air intake
system.
2. The small watercraft as in claim 1, wherein said air intake
system includes an downwardly-facing opening that communicates with
an intake air silencer.
3. The small watercraft as in claim 2, wherein said air intake
system includes a plurality of intake pipes that lie between the
intake air silencer and the intake passages of the engine, and said
intake pipes are bent downward toward said intake air silencer.
4. The small watercraft as in claim 2, wherein said air intake
system additionally includes an intake air box into which said air
flows from the downwardly-facing opening, and from which air flows
into the intake air silencer.
5. The small watercraft as in claim 1, wherein said engine is
oriented within the engine compartment such that axes of the engine
cylinders are skewed from a vertical plane that contains the
longitudinal axis.
6. The small watercraft as in claim 5, wherein each intake passages
of said engine slope downward toward a respective cylinder of said
engine.
7. The small watercraft as in claim 1 wherein said hull includes a
rider's area comprising a longitudinally extending, straddle-type
seat located above the engine, and a pair of foot areas that extend
along both sides of the seat.
8. The small watercraft of claim 1 additionally comprising an air
duct, said air duct allowing external air to travel into an engine
compartment of said watercraft, said air duct having an opening
located below an intake opening of said intake air system.
9. The small watercraft of claim 1, wherein said air intake system
includes an intake opening located forward of said flywheel casing,
and a coupling, which interconnects said engine output shaft and
impeller shaft, being located behind said flywheel casing.
10. The small watercraft of claim 1 additionally comprising a
bulkhead which separates said engine compartment from a propulsion
chamber which is located behind the engine compartment near a stern
of the watercraft, said bulkhead being located proximate a coupling
between said engine output shaft and said impeller shaft, and an
air inlet port disposed above said engine compartment and
communicating with an air duct, said air duct extending through
said bulkhead and opening into said propulsion chamber.
11. The small watercraft of claim 1 additionally comprising a
second engine with plural cylinders, said engines being mounted
parallel to each other, each of said engines being oriented within
the engine compartment such that axes of the engine cylinders are
skewed from a vertical plane that contains the longitudinal
axis.
12. The small watercraft of claim 11, wherein the cylinder axes of
the first engine and the cylinder axes of the second engine are not
parallel.
13. The small watercraft of claim 12, wherein the cylinder axes of
the first engine slope downward generally toward the longitudinal
axis and the cylinder axes of the second engine also slope downward
generally toward the longitudinal axis so as to arrange the engines
in generally a V-configuration.
14. The small watercraft as in claim 1 additionally comprising an
air duct which extends into the engine compartment to introduce
ambient air into the engine compartment, the air duct including a
lower opening which is positioned next to an air inlet opening of
said intake air system.
15. The small watercraft as in claim 14, wherein said air duct
includes a normally-open valve.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to the field of small watercraft and,
more particularly, to an improved air-intake system for use on a
small watercraft.
[0003] 2. Description of Related Art
[0004] Personal watercraft have become increasingly popular in
recent years. This type of watercraft is sporting in nature; it
turns swiftly, is easily maneuverable, and accelerates quickly. A
personal watercraft today commonly carries one rider and possibly
one or two passengers.
[0005] A relatively small hull of the personal watercraft,
comprising an upper deck and a lower hull, commonly defines a
riders' area above an engine compartment. An internal combustion
engine frequently powers a jet propulsion unit which is positioned
in a tunnel formed on the underside of the watercraft hull. The
propulsion unit propels the watercraft. The engine lies within the
engine compartment, below the riders' area. An exhaust system
extends between the engine and a discharge opening to expel exhaust
gases either to the atmosphere or to the water. The exhaust system
usually includes a water trap device that inhibits a reverse flow
of water through the exhaust system from the discharge opening
toward the engine.
[0006] It has become commonplace for small watercraft, such as for
example, personal watercraft, to be operated in virtually any water
condition, including ocean surf. Due to the design of the
engine-air path, it is often possible for such small watercraft to
operate for short periods of time submerged or in a substantially
non-vertically oriented position. By drawing its air supply from
the internal engine compartment of the small watercraft, these
small watercraft engines are generally able to avoid periodic
interruptions in the engine-air supply occasioned by waves or other
rough weather conditions submerging the external air intakes.
SUMMARY OF THE INVENTION
[0007] The present invention includes the recognition that prior
layout of the engine and exhaust components in the watercraft's
engine compartment can lead to reduced engine performance under
some operating conditions. One such instance is when a significant
amount of water fills the engine compartment. Where the small
watercraft experiences extremely rough water conditions such as
ocean surf, or is being maneuvered sharply at high speeds, a
significant amount of water can quickly flow through the air ducts
into the engine compartment of the watercraft. This influx of
water, combined with the water already present inside the engine
compartment of the watercraft, can possibly submerge or splash into
the air-intake(s) of the watercraft engine. Furthermore, this
trapped water will often contact various moving parts of the
engine, such as a coupling between the engine's crankshaft and the
impeller shaft, which will cause further splashing of water in the
engine compartment. Where water enters the air-intake(s), this
water will become entrained in the fuel/air change delivered to the
engine's cylinders, which can cause the engine to lose power,
sputter, stall, or, in extreme conditions, possibly damage the
engine components.
[0008] While it is possible to reduce the amount of water present
in the engine compartment through the use of additional bilge pumps
or special hull designs, such solutions increase the number and
weight of components in the small watercraft and/or may minimize
the cooling-air flow through the engine compartment. In addition,
it is extremely difficult to remove all water from the engine
compartment. A need therefor exists for a device that reduces the
possibility of a small watercraft engine intaking water in the
engine compartment during rough water conditions and/or high speed
maneuvers.
[0009] In addition, the exhaust system of the engine can become
quite hot after extended periods of watercraft operation. The heat
from the exhaust system, and in particular, from the water trap,
which usually functions also as an expansion chamber or muffler,
heats the surrounding air in the engine compartment. When the
engine intakes the heated air, a fuel/air ratio of the produced
fuel/air charge does not correspond to a desired fuel/air ratio
because the heated intake air has less oxygen per given volume than
normal. Engine performance consequently suffers. Accordingly, a
need exists for inhibiting a flow of air within the engine
compartment from the space surrounding the water trap to the
engine's induction system.
[0010] In accordance with one aspect of the present invention there
is provided an improved intake system for use with a small
watercraft engine located within the engine compartment of a small
watercraft. The intake system comprises an air-intake box connected
to the air-intake pipes of an engine located within the engine
compartment of a small watercraft. The air intake box incorporates
valves which serve to isolate the air intake box from splashing
water in the engine compartment, thereby preventing the small
watercraft from intaking a substantial amount of water. This
air-intake box also permits the engine to briefly operate while the
entire air-intake box is submerged.
[0011] Another aspect of the present invention involves extending a
portion of the flywheel case over the flywheel and crankshaft
coupling. This extension will redirect any water spray caused by
the moving crankshaft coupling, thereby preventing such spray from
entering the air-intake and being ingested by the engine. The
extension also acts as a heat insulator, reducing the ambient heat
level in the engine compartment near the air-intake system and
inhibiting air flow from about this heated exhaust system with trap
to the air-intake system.
[0012] Another aspect of the present invention involves the
positioning of the engine in the engine compartment of the small
watercraft. In one embodiment, the engine is tilted approximately
10 degrees towards the engine exhaust side of the engine, thereby
raising the air-intakes of the engine above the air-exhausts. This
orientation allows an air-intake box of the present invention to be
attached to a standard small watercraft engine without
substantially changing the air-intake/exhaust components and/or
hull design.
[0013] In another aspect of the present invention is provided an
improved valve design for use on the external hull of the
watercraft, which prevents water from entering the engine and/or
propulsion chamber through the intake-air ducts when the watercraft
is inverted or in a substantially non-vertical orientation. This is
accomplished by providing buoyant closures in air duct valves which
are normally open but, when submerged, operate to close the air
ducts and prevent water from traveling through the duct. Once the
watercraft is returned to its substantially upright position, the
buoyant closures reopen the air duct, returning air flow to the
engine.
[0014] Further aspects, features and advantages of the present
invention will become apparent from the detailed description of the
preferred embodiment which follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The above-mentioned and other features of the invention will
now be described with reference to the drawings of a preferred
embodiment of the present watercraft. The illustrated embodiments
are intended to illustrate, but not to limit the invention. The
drawings contain the following figures:
[0016] FIG. 1 is a longitudinal cross-sectional side view of a
small watercraft in accordance with preferred embodiment of the
present invention;
[0017] FIG. 2 is a sectional, top plan view of the small watercraft
of FIG. 1 with portions of the components as an upper deck shown in
phantom;
[0018] FIG. 3 is a lateral cross-sectional view of the small
watercraft of FIG. 1;
[0019] FIG. 4 is a side view of a rubber valve member construed in
accordance with a preferred embodiment of the present
invention;
[0020] FIG. 5 is a cross-sectional side view of the rubber valve
member of FIG. 3 with the valve illustrated in an open position and
phantom lines illustrating a closed position;
[0021] FIG. 6 is a cross-sectional side view of another embodiment
of a rubber valve member constructed in accordance with the present
invention;
[0022] FIG. 7 is a cross-sectional rear view of a small watercraft
incorporating another embodiment of the present invention;
[0023] FIG. 8 is a side, perspective view of an intake merging box
constructed in accordance with the present invention;
[0024] FIG. 9 is a sectional side elevational view of a small
watercraft incorporating an additional embodiment of the present
invention;
[0025] FIG. 10 is a sectional top plan view of the small watercraft
of FIG. 8 and illustrates several components on the upper deck in
phantom;
[0026] FIG. 11 is a cross-sectional rear view of the small
watercraft of FIG. 8;
[0027] FIG. 12 is a partial sectional side view of a small
watercraft incorporating another embodiment of the present
invention;
[0028] FIG. 13 is a partial sectional top plan view of the small
watercraft of FIG. 11;
[0029] FIG. 14 is a cross-sectional rear view of the small
watercraft of FIG. 11;
[0030] FIG. 15 is a cross-sectional rear view of a small watercraft
incorporating an additional embodiment of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0031] FIGS. 1 through 3 illustrate different views of a small
watercraft incorporating an air intake box and engine arrangement
configured in accordance with a preferred embodiment of the present
invention. While the present invention has particular utility with
a small watercraft having an engine located within the engine
compartment of the small watercraft, some aspects of the present
equal utility with watercraft utilizing external-hull air intakes
or externally mounted engines. As such, the invention will be
described with the small watercraft design in this context;
however, it is understood that the present invention may also be
employed on other types of watercraft.
[0032] The following description describes several embodiments of
the present invention which include unique induction system
construction and orientation within the engine compartment. Where
appropriate, the same reference numerals have been used between the
various embodiments to indicate like components. In addition,
various aspects of the different embodiments can be incorporated
into the other embodiments, as will be readily apparent to those
skilled in the art.
[0033] With initial reference to FIGS. 1 through 3, a small
watercraft, indicated generally by reference numeral 1, includes a
hull 3 formed by a lower hull section 2a and upper deck section 4.
These hull sections 2a, 4 are formed from a suitable material such
as, for example, a molded fiberglass reinforced resin. For
instance, the deck 4 and the hull 2a can be formed using a sheet
molding compound (SMC), i.e. a mixed mass of reinforced fiber and
thermal setting resin, that is processed in a pressurized, closed
mold. The molding process desirably is temperature controlled such
that the mold is heated and cooled during the molding process. For
this purpose, male and female portions of the mold can include
fluid jackets through which steam and cooling water can be run to
heat and cool the mold during the manufacturing process. The lower
hull section 2a and the upper deck section 4 are fixed to each
other around the peripheral edges in any suitable manner commonly
known to those skilled in the art.
[0034] As viewed in a direction from the bow to the stern of the
watercraft, the upper deck section 4 includes a bow portion 2, a
control mast 7, a front seat 5 and a rear seat 6. The bow portion 2
slopes upwardly toward the control mast 7 and includes at least one
air duct through which air can enter the hull 3.
[0035] The control mast 7 extends upward from the bow portion 2 and
supports a handlebar assembly 150. The handlebar assembly 150
controls the steering of the watercraft in a conventional manner
well known to those skilled in the art. The handlebar assembly also
carries a variety of the controls of the watercraft such as, for
example, a throttle control, a start switch and a lanyard switch.
The handlebar assembly 150 is enclosed by a handle cover 155 and is
pivotally provided in front of the front seat 5.
[0036] A hatch cover 9 is provided in front of the steering handle
7. The hatch cover 9 is secured to the upper deck 4 by a hinge 9a,
and is able to open and close freely, thereby exposing the forward
section of the interior of the hull 3. A latch (not shown) is
provided to secure the hatch cover 9 in its closed position during
operation of the watercraft 1. A storage box 8 is removably
provided in the deck below the hatch cover 85. This storage box 8
is covered by the hatch cover in a water sealing manner.
[0037] A forward air opening 160, located adjacent to the front
seat 5, desirably allows ambient air traveling over the upper deck
4 to travel below the front bottom plate 5a of the front seat 5.
This airflow then travels into an air inlet port 25a, located below
the front seat 5, and into the air duct 25. A rearward air opening
175, located behind the rear seat 6, desirably allows ambient air
to travel through cover 27, through air inlet port 26a, and into
the rear-air duct 26.
[0038] The front and rear seats 5, 6, are desirably straddle-type
seats having an elongated shape that extends along the longitudinal
axis of the watercraft. These seats are centrally located between
the sides of the hull and are mounted on front bottom plate 5a and
rear bottom plate 6a, respectively. In the illustrated embodiment,
the rear seat 6 is positioned at an elevated level relative to the
front seat 5. This advantageously positions the riders at different
levels.
[0039] A fuel tank 12 is located within the hull 1. A fuel supply
pipe 12a extends from the surface of deck 4 to the fuel tank 12.
Conventional means such as straps (not shown) secure the fuel tank
to the lower hull 2a. In the illustrated embodiment, a filler cap
assembly 165 is secured to the bow portion 2 of the hull upper deck
4. In this manner, the fuel tank 12 may be filled from outside the
hull 1 with the fuel passing through the fuel supply pipe 12a into
the tank 12.
[0040] A bulkhead 15 desirably is vertically provided behind the
engine 10 and divides the hull 3 into an engine chamber or
compartment 13 and a propulsion chamber 14. Air ducts 25, 26, for
guiding air into the engine chamber 13, are provided in the
forward/rear parts of the engine chamber. Air inlet ports 25a, 26a
of each air duct 25, 26 are located in openings formed in the upper
deck 4. Air-outlet ports 25b, 26b of each air duct are respectively
opened to the forward and rear sides of the engine 10. These air
outlet ports 25b, 26b are positioned lower than the engine
intake-air system (to be described later) so as to prevent water
flowing through the air ducts 25, 26 from traveling directly into
the engine intake-air system. Although air is supplied to the
engine compartment 13 though both ducts, a flow of air from the
front duct to the rear duct also occurs to air cool the engine and
the other components of the watercraft located in the engine
compartment 13.
[0041] A jet propulsion unit, indicated generally by reference
numeral 16, is provided in the pump chamber 21. This jet propulsion
unit 16 includes an impeller shaft 19 to which an impeller 18 is
fixed. The impeller shaft 19 is positioned in the longitudinal
directions and extends through a propulsion duct 17 that has a
water inlet port 17a positioned on the keel of the lower hull
section 2a. The lower hull section 2a includes an opening at the
stem 2b of the watercraft 1 in which a jet outlet port 17b of the
propulsion unit 16 is positioned. A front end of the impeller shaft
18 and an output shaft 40 (e.g.-a crankshaft) of the engine are
coupled through a conventional shock-absorbing coupling 41 to
transfer power from the crankshaft to the impeller shaft. The
propulsion unit 16 generates the propulsive force by applying
pressure to water drawn up from the water inlet port 17a by means
of the rotation of the impeller shaft 18, and forcing the
pressurized water through the jet outlet port 17b in a manner well
known to those skilled in the art.
[0042] A nozzle deflector or steering nozzle 20 is connected to the
jet outlet port 17b of the propulsion unit 16. The nozzle deflector
20 desirably moves in the left/right and vertical directions via a
known gimbal mechanism. The nozzle deflector 20 is connected to the
handlebar assembly 150 through a steering mechanism and trim
mechanism (not shown), whereby the steering and trim angles may be
changed by the operation of the handlebar assembly 150 and
associated trim controls.
[0043] The upper deck 4 of the watercraft includes a longitudinally
extending pedestal 170, preferably formed as part of the upper
deck. The pedestal 170 supports the front and rear seats 5, 6. Foot
areas 4b are formed along side this pedestal 170, between the
pedestal 170 and a pair of raised side gunnels or bulwarks 4a that
extend along the outer sides of the watercraft. These foot areas 4b
are sized to accommodate the lower legs and feet of the riders who
straddle the front and rear seats 5, 6 when seated. In the
illustrated embodiment, a deck 4b', formed at the rear of the
watercraft behind the pedestal, extend above the propulsion unit 16
and allow eased entry into the watercraft 1, as is well known in
the art.
[0044] A maintenance opening 4c is formed on the top surface of the
seat pedestal 170 and is desirably positioned below the rear seat
6. This maintenance opening 4c is covered by the rear bottom plate
6a in a water-sealing manner. The engine chamber 13 can be accessed
through this maintenance opening 4c by removing the rear seat
6.
[0045] An in-line, three-cylinder, four-cycle engine 10 is mounted
in the center of the main body of the watercraft; however, other
types of engines also can be used to power the watercraft. For
instance, engines with other numbers of cylinders, with other
cylinder arrangements and which operate on other operating
principles (e.g., two-stroke) can be used for this purpose.
[0046] The general construction of the four-stroke 10 is well known
to those of ordinary skill in the art. As depicted in FIGS. 1 and
2, the engine 10 comprises cylinder block 10b, a cylinder head 10c,
head covers 10d, and a crank case 10a. Intake valves 43 are
disposed in the cylinder head 10c for controlling the delivery of a
fuel/air mixture to the cylinders of the engine 10. Exhaust valves
44 are similarly disposed in the cylinder head 10c for controlling
the expulsion of exhaust gases. Opening and closing of the intake
and exhaust valves is regulated by the operation of the camshafts
45, the sprockets 46, 47, and the timing chain 48. The timing chain
48 is connected to the drive sprocket 47, and is enclosed by a
cover 49 which protects the timing chain 48 and prevents accidental
contact between a rider and the chain during maintenance of the
engine 10.
[0047] Power from the crankshaft 40 is transferred to the impeller
shaft 19 through the coupling 41. The crankshaft 40 also carries a
flywheel 77 on the rear side of the engine 10. A starter motor 78
rotates the crankshaft 40 through a ring gear 77a formed on the
periphery of the flywheel 77, and operates to start the engine in a
manner well known to those of ordinary skill in the art. An
alternator 50 is connected to the crankshaft 40, and coverts
rotation of the crankshaft 40 into electrical power for the engine
10 and associated systems in a manner well known to those of
ordinary skill in the art. For this purpose a drive pulley 51
located on the front side of the engine 10 is attached to the
crankshaft 40. A belt interconnects the drive pulley 51 to a pulley
on the alternator 50 to drive the alternator in a known manner.
[0048] The flywheel 77, located within the flywheel case 79, is
coupled to the crankshaft 40 to ensure smooth and even rotation of
the crankshaft during operation of the engine 10. The flywheel case
79 extends rearwardly, substantially surrounding the flywheel. In
addition, this extension of the flywheel case will prevent water in
contact with rotating coupling 41 from spraying into the engine
intake-air system (to be described later). Furthermore, the
flywheel case 79 acts as an insulator between the air in the engine
compartment forward of the flywheel case 79 and the air in the
engine compartment behind the flywheel case 79. The case 78 also
inhibits the airflow in the engine compartment in the forward
direction, thereby limiting heating of the engine intake-air system
and the intake air.
[0049] On top of the engine 10 is a lubricating oil supply port 56,
through which oil may be added to the engine 10. An oil cap 57
closes and seals this supply port 56, thereby preventing a loss of
oil from the engine and ensuring that water does not contaminate
the oil supply. An oil pan 10e is provided in the bottom of the
engine 10. An oil filter 55, located adjacent to the oil pan 10e,
is provided to continuously clean the engine oil. A drain plug 42
is provided in the oil pan 10e to facilitate removal of engine oil
for maintenance.
[0050] On one side of the engine 10 an exhaust system is provided.
In this exhaust system, exhaust runners 60 extend from the side of
the engine and downward into an exhaust-air merging box 61. An
exhaust-air merge pipe 61a, extending rearwardly from the
exhaust-air merging box 61, connects to a front end of a water lock
or trap 63. The water lock 63 inhibits a reverse flow of water
toward the engine. In the rear end of the water lock 63, a
through-hull exhaust pipe 64 is connected. This exhaust pipe 64
extends upwardly and across the hull and over the pump chamber, and
is connected to a pump chamber of the watercraft to exhaust at this
location. The outlet of the exhaust pipe 64 can also be located on
the lower surface of the hull, on the transom of the hull or on the
side of the hull.
[0051] The engine 10 desirably is oriented within the hull 3 to
locate a crankshaft 40 of the engine 10 along a longitudinal axis
of the main body. The engine 10 is mounted above the lower hull
section 2a of the watercraft through a damper member or mount 11.
As best depicted in FIG. 3, in one embodiment of the present
invention the engine 10 is mounted such that the cylinder block 10b
is skewed from vertical such that the axes of its cylinders are
about by approximately 10 degrees off vertical. This engine
orientation places the engine-air intake approximately 2 to 3
inches above the engine-air exhaust. This rotation permits an
intake-air merging box 73 (to be described later) to be positioned
in the intake air system without requiring substantial redesign of
the intake system components, engine design and/or an increase in
the cross-sectional width of the seat pedestal. Furthermore, the
increased height of the engine-air intake allows the intake-air
merging box to be generally equally distanced from the upper deck
and the lower deck of the small watercraft, a location that is
least subject to water invasion during operation of the small
watercraft.
[0052] The intake air system comprises fuel/air-intake pipes 70
connected to intake passage of the engine 10 which communicate with
the engine's cylinders through the valve 43. The fuel/air intake
pipes 70 also communicate with at least one charge former. In the
illustrated embodiment, the opposite end of each intake pipe 70 is
connected to carburetors 71. The carburetors 71 vaporize and mix
fuel with the intake-air, and regulate this fuel/air mixture using
butterfly-type throttle valves 72, in a manner well known to those
skilled in the art.
[0053] As can best be seen in FIGS. 1 and 3, the carburetors 71 are
also connected to air intake pipes 175, which are in turn connected
to an intake-air silencer 73. The intake-air silencer is connected
to an air filter 74, which is in turn connected to the intake box
75. A trumpet-shaped air-inlet port 75a is disposed on the bottom
surface of the intake box 75, which allows air to be drawn into the
intake box 75 at a low velocity while inhibiting entrance of water.
The intake box 75 is located on the front side of the engine with
its opening facing down. Water entrained in the air flow desirably
is separated in the intake box 75 and is drained through the
downward opening 75a.
[0054] As best seen in FIG. 2, the case 79 of the flywheel 77 lies
between the intake silencer 73, as well as the balance of the
components of the induction system, and the watertrap 63 and the
exhaust pipe 64. At this location, the casing 79 generally
insulates, at least to some degree, the induction system from the
heat radiated by the exhaust system, principally by the water trap
63 and the exhaust pipe 64. The casing also inhibits air from the
rear of the engine compartment toward the intake opening 75a . The
casing 79, as mentioned above, also generally shields the intake
port 75a from water which may be splattered by the rotating
coupling 41 and the associated shafts. As a result, the air
entering into the intake box 75 generally contains less water vapor
and is cooler than the air circulating about the rear end of the
engine compartment.
[0055] FIG. 4 shows a rubber valve member 30 constructed in
accordance with one embodiment of the present invention. This type
of valve 30 is desirably disposed at the upper end of each axis
inlet port 25a, 26a of the front and rear air ducts 25, 26.
[0056] Rubber valve member 30 is comprised of peripheral walls 30a
and disc 30c. Air windows 30b are formed in the walls 30a. The
lower section of the peripheral walls 30a encircles and is secured
to an external projection of each air inlet port 25a, 26a. A flange
180, formed integral with and perpendicular to the air inlet port
25a, 26a, secures the air inlet port to the upper deck 4 of the
watercraft 1. In the preferred embodiment, the peripheral walls 30a
and disc 30c are formed of a buoyant, flexible material such as a
low density foam rubber.
[0057] As shown in FIG. 5, during normal operation, the disc 30c of
the rubber valve member 30 is supported by the peripheral walls
30a, thereby allowing air to travel through the air windows and
into the air ducts 25,26. However, when the watercraft is inverted
and the rubber valve member is submerged, the natural buoyant
forces acting on the disc overcome the strength of the column-like
wall 70a exerted by the peripheral walls 30a, thereby buckling the
peripheral walls 30a and allowing the disc 30c to assume new
position 30c', effectively sealing the air ducts 25, 26 and
preventing further water from entering the watercraft. When the
watercraft resumes its normal orientation, this buoyant force on
the disc is removed, thereby allowing the spring force exerted by
the peripheral walls 30a to lift the disc 30c into its normal
operating position and resuming the flow of air into the air ducts
25, 26.
[0058] FIG. 6 shows an alternate embodiment of a valve member
constructed in accordance with the present invention. Spring valve
185 is comprised of buoyant block 31, spring valve shaft 190,
spring 32, shaft support 33, and stopper pin 34. A flange 180,
formed integral with and perpendicular to the air inlet port 25a,
26a, secures the air inlet port to the upper deck 4 of the
watercraft 1. The shaft support is disposed within the respective
air inlet port 25a, 26a.
[0059] During normal operation of the spring valve 185, the lower
surface of the buoyant block 31 is held above the upper surface of
the air inlet ports 25a, 26a by a force exerted by the spring 32,
thus allowing air to travel into the corresponding air duct 25, 26.
Vertical motion of the buoyant block is limited by the interaction
of stopper pin 34 with the lower surface of the shaft support 33.
When the watercraft is inverted and the spring valve 185 is
submerged, however, buoyant forces acting on the buoyant block are
greater than the force exerted by the spring, thereby allowing the
buoyant block to travel towards and abut the air inlet ports 25a,
26a. This substantially seals the air inlet ports and prevents
water from entering the engine compartment of the watercraft. When
the watercraft resumes its normal orientation, the buoyant force on
the buoyant block is removed, thereby allowing the force exerted by
the spring to lift the buoyant block off of the air inlet port 25a,
26a, and resuming the flow of air into the corresponding air duct
25, 26.
[0060] With reference now to FIGS. 7 and 8, depicted is a small
watercraft incorporating another embodiment of an intake-air
merging box constructed in accordance with the present invention.
The intake-air merging box 73 is comprised of a ceiling wall 73b,
an inner wall 73c, a bottom wall 73d, an outer wall 73e and two cap
walls 73f and 73g, bonded together to form a watertight box.
Disposed in the inner wall are trumpet-shaped intake ports 80,
which allow air to be drawn into the merging box 73 at a low
velocity while inhibiting entrance of water. Disposed in the
ceiling and bottom walls 73b, 73d are drain holes 81a, 81b, which
permit water trapped within the merging box 73 to drain into the
engine compartment 13. While this embodiment of an intake-air
merging box 73 is a square or rectangular box, it should be noted
that various other shaped boxes may be used with equally
utility.
[0061] As can best be seen from FIG. 7, air-intake pipes 175
connect the carburetors to the intake-air merging box 73. These
air-intake pipes are comprised of upstream parts 70a, located
adjacent to the carburetors, and expanding parts 70b, located
within the intake air merging box 73. The trumpet-shaped design of
the expanding parts 70b allows air to be drawn into the air-intake
pipes at low velocity while inhibiting water from being drawn into
the air-intake pipes.
[0062] FIGS. 9 through 11 depict a small watercraft 100
incorporating an additional embodiment of an air intake system
constructed in accordance with the present invention. In this
embodiment, the engine 10 utilizes a charge forming device such as
a fuel injector 101 (see FIG. 11) for forming the fuel/air mixture
utilized in the engine 10. Air is supplied to the engine through a
number of intake pipes 102 connected to the engine 10. The opposite
ends of the intake pipes 102 are connected to an intake-air merging
pipe 103, which is in turn connected to a throttle body 104. The
throttle body is connected to the intake box 106, and an air filter
105 is disposed within the intake box 106 to clean and filter air
passing into the engine 10. An intake opening 106a is located on
the bottom surface of the intake box 106.
[0063] In operation, the air intake system of the small watercraft
of FIGS. 9 through 11 will draw air into the intake opening 106a,
through the filter 105, through the throttle body 104, and into the
air merging pipe 103. Air in the air merging pipe will subsequently
be drawn into and through the intake pipes 102 and into the engine
10 where it will be mixed with fuel sprayed from one or more fuel
injectors 101.
[0064] As seen from FIGS. 9 and 10, the intake box 105 is
positioned behind the flywheel casing 79 and to one side of the
longitudinal axis opposite the side on which the water trap 63 is
located. At this location, the inlet 106a of the intake box 106 is
located next to the lower end of the rear intake duct 26. At this
location, fresh air can enter the intake box while experiencing
minimal heating. In addition, the flywheel casing 79 generally
insulates the intake box from the engine so as to reduce the
heating effect of the intake air from the intake duct 26 into the
intake box 106, as well as to inhibit air flow from the front
intake duct 25 across the engine 10 to the intake duct 106.
Consequently, the induction system intakes less air heated by the
engine and more fresh air flowing through the rear intake duct
26.
[0065] In addition, the coupling between the impeller shaft 19 and
the output shaft of the engine 10 is enclosed within the casing 79.
As a result, the rotating components within the engine compartment
tend to splatter less water about the engine compartment.
[0066] Turning now to FIGS. 12 through 14, there is depicted a
small watercraft or jet boat 110, incorporating another embodiment
of an air intake system constructed in accordance with the present
invention. As viewed from the bow to the stern, the hull 112 of the
jet boat 110 includes floor 113a and a bench-type seat 114 located
forward of an aft end 111 of the watercraft. A steering handle is
positioned forward of the bench-type seat, and controls the
steering of the watercraft in a conventional manner well known to
those skilled in the art. A deck section 113 is fixed to the hull
112 around the peripheral edges in a manner well known to those
skilled in the art. As can best be seen from FIG. 14, the engines
10 are skewed by approximately 10 degrees from vertical.
[0067] A maintenance opening 113b is provided in the deck section
113 to provide access to the engine chamber 13. An engine hatch
120, attached to the deck by a rear hinge 120a, closes the
maintenance opening 113b in a watertight manner. Two storage boxes
121, 122 are positioned in the engine chamber.
[0068] A storage chamber 119, located underneath the bench-type
seat 114, is formed between front dividing wall 117 and rear
dividing wall 118, and contains a fuel tank 116. Two storage boxes
121, 122, are located within the engine chamber 13 and are disposed
alongside the outer side of each engine 10. A battery 123 is
positioned within one of the storage boxes 121. Electrical engine
control components 124 well known to those skilled in the art, such
as computer control circuits, are located in the opposite storage
box 122.
[0069] On one side of each engine 10 an exhaust system is provided.
In this exhaust system, exhaust pipes 130 extend from the side of
the engines and downward into an exhaust-air merging pipe 131. The
exhaust-air merging pipe extends rearwardly and connects to a front
end of a water lock or trap 63. The water lock 63 inhibits a
reverse flow of water toward the engine. In the rear end of the
water lock 63, a through-hull exhaust pipe 64 is connected. This
exhaust pipe 64 extends upwardly and across the hull and over the
pump chamber, and is connected to a pump chamber of the watercraft
to exhaust at this location.
[0070] In the embodiment depicted in FIGS. 12 through 14, the
engines 10 are cooled by a liquid cooling system comprising water
jackets 133, coolant inlet ports 134, water ports 135, coolant
hoses 136, and coolant drain ports 137. In operation, cooling water
is pumped into the water ports 135 and travels through the cooling
hoses into coolant inlet ports 134. This flow of cooling water
travels into the water jackets 133, and comes in contact with the
cylinder block 10b, the cylinder heads 10c, and the engine exhaust
pipe 130. The cooling water than travels into the exhaust pipe,
travels through the water lock 63, and is discharged out of the jet
boat through the through-hull exhaust pipe 64.
[0071] The intake air system comprises intake pipes 140 connected
to air inlets of the engines 10. The opposite ends of these intake
pipes 140 are connected to an intake air merging pipe 141. The
intake air merging pipe extends rearwardly and through the bulkhead
15, and connects to an intake air port 141a which is open to the
propulsion chamber 14. An air inlet port 142 is provided in the
upper deck 113 which allows outside air to travel into the
propulsion chamber 14. A cover 143, located over the air inlet port
142, prevents water from entering the propulsion chamber.
[0072] FIG. 15 depicts the jet boat of FIG. 12 through 14,
incorporating an additional embodiment of the present invention. In
this embodiment, the engines 10 are positioned such that the
cylinders of the engines 10 are skewed by approximately 10 degrees
left and right, respectively, from vertical, thus forming a
V-shape. This embodiment provides for increased separation between
the engines, facilitating maintenance and removal of the engines,
if required. The increased spacing between the exhaust system of
one engine and the induction system of the other engine will
further reduce the temperature of the air used to form the fuel/air
charge.
[0073] Accordingly, although this invention has been described in
terms of certain preferred embodiments, other embodiments apparent
to those of ordinary skill in the art are also within the scope of
this invention. Of course, a watercraft need not include all of
these features to appreciate some of the aforementioned advantages
associated with the present watercraft. Accordingly, the scope of
the invention is intended to be defined only by the claims that
follow.
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