U.S. patent application number 11/435699 was filed with the patent office on 2006-11-16 for outboard motor with cowling.
Invention is credited to Sakayuki Kimura, Hideaki Matsushita, Naoya Murai.
Application Number | 20060258235 11/435699 |
Document ID | / |
Family ID | 37419739 |
Filed Date | 2006-11-16 |
United States Patent
Application |
20060258235 |
Kind Code |
A1 |
Kimura; Sakayuki ; et
al. |
November 16, 2006 |
Outboard motor with cowling
Abstract
An outboard motor includes an engine having an air intake
device. A cowling has an internal space in which the engine is
disposed and an air intake opening through which ambient air is
introduced into the internal space. The internal space defines an
air intake passage connecting the air intake opening of the cowling
to the air intake device of the engine. An air/water separator is
disposed within the air intake passage for separating water from
the air. The air/water separator has a relative large volume so as
to temporarily hold water from a sudden flow of water that may flow
into the cowling air intake. Water accumulated in the separator is
drained from the cowling.
Inventors: |
Kimura; Sakayuki;
(Shizuoka-ken, JP) ; Murai; Naoya; (Shizuoka-ken,
JP) ; Matsushita; Hideaki; (Shizuoka-ken,
JP) |
Correspondence
Address: |
KNOBBE MARTENS OLSON & BEAR LLP
2040 MAIN STREET
FOURTEENTH FLOOR
IRVINE
CA
92614
US
|
Family ID: |
37419739 |
Appl. No.: |
11/435699 |
Filed: |
May 16, 2006 |
Current U.S.
Class: |
440/77 |
Current CPC
Class: |
F02M 35/168 20130101;
B63H 20/32 20130101 |
Class at
Publication: |
440/077 |
International
Class: |
B63H 20/32 20060101
B63H020/32; B63H 21/36 20060101 B63H021/36 |
Foreign Application Data
Date |
Code |
Application Number |
May 16, 2005 |
JP |
2005-143158 |
May 16, 2005 |
JP |
2005-143134 |
Claims
1. An outboard motor comprising an engine having an air intake
device, a cowling defining an internal space in which the engine
and air intake device are disposed, and an air intake opening
through which air from outside of the cowling is introduced into
the internal space, an air intake passage within the internal
space, the intake passage connecting the air intake opening of the
cowling to the air intake device of the engine, and an air/water
separator disposed within the air intake passage for separating
water from the air, the air/water separator being elongate in a
generally vertical direction and having a water discharge opening
arranged at a position vertically lower than a vertical center of
the engine.
2. The outboard motor according to claim 1, wherein the air/water
separator extends across a majority of the width of the
cowling.
3. The outboard motor according to claim 1, wherein the water
discharge opening extends through the cowling so that water is
discharged outside of the cowling.
4. An outboard motor comprising an engine having an air intake
device, a cowling defining an internal space in which the engine
and air intake device are disposed, and an air intake opening
through which air from outside of the cowling is introduced into
the internal space, an air intake passage within the internal
space, the intake passage comprising first and second passage
sections that extend generally parallel to each other and are
separated from each other by a partition, the first passage section
communicating with the air intake opening, the second passage
section communicating with a terminus of the air intake passage so
that air that enters the cowling through the air intake opening
flows through the first and second passage sections, through the
terminus and into an engine compartment defined within the cowling,
and an air/water separator is disposed within the air intake
passage for separating water from the air, the air/water separator
being elongate in a generally vertical direction.
5. The outboard motor according to claim 4, wherein air flows in a
first direction in the first passage section and air flows in a
second direction in the second passage section, and the first and
second flow directions generally oppose to each other.
6. The outboard motor according to claim 4, wherein the first and
second passage sections extend generally horizontally.
7. The outboard motor according to claim 6, wherein the first and
second passage sections extend in a generally fore-to-aft
direction, the air intake opening is positioned on one of a front
side or rear side of the cowling, and the air/water separator is
positioned on the other of the front side or rears side of the
cowling.
8. The outboard motor according to claim 4, wherein the air/water
separator communicates with both of the first and second passage
sections.
9. The outboard motor according to claim 8, wherein the air/water
separator is disposed at or adjacent a first side of the cowling
and the air intake passage terminus is disposed on a second side of
the cowling generally opposite the first side.
10. The outboard motor according to claim 9, wherein the air intake
opening is positioned on the second side.
11. An outboard motor comprising an engine having an air intake
device, a cowling defining an internal space in which the engine
and air intake device are disposed, and an air intake opening
through which air from outside of the cowling is introduced into
the internal space, an air intake passage within the internal
space, the intake passage connecting the air intake opening of the
cowling to the air intake device of the engine, an air/water
separator disposed within the air intake passage for separating
water from the air, the air/water separator extending generally
vertically and having a water discharge opening, a water discharge
valve disposed at the water discharge opening and being movable
between an open position and a closed position, a sensor adapted to
detect an operational condition of the outboard motor, and a
control device adapted to control the water discharge valve based
upon a signal of the sensor.
12. The outboard motor according to claim 11, wherein the air/water
separator functions as an air intake silencer for attenuating
intake air noise.
13. The outboard motor according to claim 11, wherein the air/water
separator comprises a water releasing section and a water receiving
section communicating with each other, at least the water releasing
section has the water discharge opening having the water discharge
valve.
14. The outboard motor according to claim 13, wherein the water
receiving section comprises a voluminous chamber.
15. The outboard motor according to claim 14, wherein the
voluminous chamber has a second water discharge opening that has no
water discharge valve and is always open.
16. The outboard motor according to claim 11, wherein the air
intake passage includes a plurality of air/water separators
arranged physically in series relative to one another.
17. The outboard motor according to claim 11, wherein at least a
portion of the air intake passage downstream of the air/water
separator comprises a supplemental air inlet port opening into the
internal space, the port having an air inlet valve adapted to
selectively open or close the port, the valve being controlled by a
control device that controls the air inlet valve based upon the
signal of the sensor.
18. The outboard motor according to claim 11, wherein the sensor
detects at least one of water invasion into the air intake passage,
deceleration of the outboard motor, an engine speed of the engine
and a shift position of a transmission of the outboard motor.
19. An outboard motor comprising an engine, a cowling enclosing the
engine, and a partition defining an air passage and an engine
compartment within the cowling, the partition having an aperture
through which the air passage communicates with the engine
compartment, the cowling having a first opening adapted so that air
from outside the cowling is introduced into the air passage through
the first opening, a portion of the air passage forming a water
receiving chamber adapted to accumulate and hold a flow of water
flowing through the air passage upstream of the chamber so that the
water does not flow through the air passage downstream of the
chamber.
20. The outboard motor according to claim 19, wherein the cowling
has a second opening communicating with the water receiving
chamber, the second opening configured so that water is discharged
therethrough.
21. The outboard motor according to claim 20, wherein the first
opening is positioned on one of a front side or rear side of the
cowling, and the second opening is positioned on the other of the
front side or rear side of the cowling.
22. The outboard motor according to claim 19, wherein the partition
divides the air passage into first and second paths, both of the
first and second paths communicating with the water receiver, the
first path communicating with the first opening, the second path
communicating with the engine compartment through the aperture of
the partition, and the aperture is positioned closer to the first
opening than to the water receiver.
23. The outboard motor according to claim 22, wherein the first and
second paths extend generally horizontally, and the water receiver
is generally vertically elongate.
24. The outboard motor according to claim 19, wherein the water
receiver chamber is interposed between the engine and a generally
vertically extending portion of the cowling.
25. An outboard motor comprising an engine having an air intake
device, a cowling defining an internal space that encloses the
engine and the air intake device, an air intake opening being
formed through the cowling and enabling air from outside the
cowling to be drawn into the internal space, the internal space
comprising an air intake passage connecting the air intake opening
of the cowling to the air intake device of the engine, and means
for separating water from air flowing through the air intake
passage, the means for separating water comprising a water releaser
positioned at a location vertically lower than a center of the
engine.
26. The outboard motor according to claim 25, wherein the water
releaser comprises an opening extending through a portion of the
cowling.
27. The outboard motor according to claim 25, wherein the engine
has an air silencer positioned upstream of the air intake device,
and the water releaser is disposed in the air silencer.
28. The outboard motor according to claim 27, wherein the water
releaser includes a discharge port, and a valve normally closing
the discharge port and opening the discharge port when a relatively
large volume of water enters the air silencer.
29. The outboard motor according to claim 25, wherein the water
separating means comprises a plurality of water separators disposed
in the air intake passage, and one of the water separators
comprises the water releaser.
Description
PRIORITY INFORMATION
[0001] This application is based on and claims priority under 35
U.S.C. .sctn. 119 to Japanese Patent Applications No. 2005-143134,
filed on May 16, 2005, and No. 2005-143158, filed on May 16, 2005,
the entire contents of which are hereby expressly incorporated by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention generally relates to an outboard motor with a
cowling, and more particularly relates to an outboard motor having
a cowling that encloses an engine and defines an air intake passage
through which the ambient air is introduced into the engine.
[0004] 2. Description of Related Art
[0005] Typically, outboard motors are mounted on a transom board of
an associated watercraft. Such an outboard motor typically has an
engine for powering a propulsion device such as, for example, a
propeller that generates thrust force for the watercraft. A cowling
typically surrounds the engine for protecting the engine.
[0006] The engine requires air for combustion. Thus, in prior
outboard motors, the cowling allows ambient air from outside the
cowling to enter an internal space thereof in which the engine is
positioned (i.e., engine room). On the other hand, it is
undesirable to have water enter the engine air intake. Thus,
cowlings typically attempt to block splashing water from entering
the internal space. In order to block the water from entering the
internal space, prior cowlings have a structure for separating
water from the air.
[0007] For example, JP-A-2004-239156 discloses such a water
separating structure. That is, the publication shows a cowling
having multiple walls that allow air to move over but hamper water
from surmounting the walls. The water thus can be separated from
the air so that only the air is introduced into the engine.
[0008] Once in a while, however, a relatively large wave may go
over the entire body of the outboard motor. When this happens, a
large amount of water can enter the water separating structure. A
conventional water separating structure likely cannot block such a
large amount of water; thus, some of the water may enter the engine
room, and the engine may intake water with the air.
SUMMARY OF THE INVENTION
[0009] A need thus exists for an outboard motor that can certainly
prevent water from entering an internal space of a cowling where an
engine is placed (i.e., engine room), even when a large quantity of
water suddenly impacts the cowling.
[0010] To address such needs, in accordance with one embodiment of
the present invention, an outboard motor includes an engine having
an air intake device. A cowling has an internal space in which the
engine is disposed and an air intake opening through which ambient
air is introduced into the internal space. The internal space
defines an air intake passage connecting the air intake opening of
the cowling to the air intake device of the engine. An air/water
separator is disposed within the air intake passage for separating
water from the air. The air/water separator extends generally
vertically.
[0011] In accordance with another embodiment of the invention, an
outboard motor comprising an engine having an air intake device is
provided. A cowling defines an internal space in which the engine
and air intake device are disposed. Air from outside of the cowling
is introduced into the internal space through an air intake
opening. An air intake passage is arranged within the internal
space, the intake passage connecting the air intake opening of the
cowling to the air intake device of the engine. An air/water
separator is disposed within the air intake passage for separating
water from the air. The air/water separator is elongate in a
generally vertical direction and has a water discharge opening
arranged at a position vertically lower than a vertical center of
the engine.
[0012] In accordance with another embodiment, the present invention
provides an outboard motor comprising an engine having an air
intake device, a cowling defining an internal space in which the
engine and air intake device are disposed, and an air intake
opening through which air from outside of the cowling is introduced
into the internal space. An air intake passage is arranged within
the internal space. The intake passage comprises first and second
passage sections that extend generally parallel to each other and
are separated from each other by a partition. The first passage
section communicates with the air intake opening. The second
passage section communicates with a terminus of the air intake
passage so that air that enters the cowling through the air intake
opening flows through the first and second passage sections,
through the terminus and into an engine compartment defined within
the cowling. An air/water separator is disposed within the air
intake passage for separating water from the air. The air/water
separator is elongate in a generally vertical direction.
[0013] In yet another embodiment, the present invention provides an
outboard motor comprising an engine having an air intake device. A
cowling defines an internal space in which the engine and air
intake device are disposed. An air intake opening is provided
through which air from outside of the cowling is introduced into
the internal space. An air intake passage is provided within the
internal space. The intake passage connects the air intake opening
of the cowling to the air intake device of the engine. An air/water
separator is disposed within the air intake passage for separating
water from the air, the air/water separator extending generally
vertically and having a water discharge opening. A water discharge
valve is disposed at the water discharge opening and is movable
between an open position and a closed position. A sensor is adapted
to detect an operational condition of the outboard motor. A control
device is adapted to control the water discharge valve based upon a
signal of the sensor.
[0014] In accordance with a still further embodiment of the present
invention, an outboard motor comprises an engine, a cowling
enclosing the engine, and a partition defining an air passage and
an engine compartment within the cowling. The partition has an
aperture through which the air passage communicates with the engine
compartment. The cowling has a first opening adapted so that air
from outside the cowling is introduced into the air passage through
the first opening. A portion of the air passage forms a water
receiving chamber adapted to accumulate and hold a flow of water
flowing through the air passage upstream of the chamber so that the
water does not flow through the air passage downstream of the
chamber.
[0015] In accordance with still a further embodiment, the present
invention provides an outboard motor comprising an engine having an
air intake device. A cowling defines an internal space that
encloses the engine and the air intake device. An air intake
opening is formed through the cowling and enables air from outside
the cowling to be drawn into the internal space. The internal space
comprises an air intake passage connecting the air intake opening
of the cowling to the air intake device of the engine. Means are
provided for separating water from air flowing through the air
intake passage, the means for separating water comprising a water
releaser positioned at a location vertically lower than a center of
the engine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] These and other features, aspects and advantages of the
present invention are now described with reference to the drawings
of preferred embodiments, which are intended to illustrate and not
to limit the present invention. The drawings include nine figures
in which:
[0017] FIG. 1 is a side elevational view of an outboard motor
configured in accordance with certain features, aspects and
advantages of a preferred embodiment, a transom of an associated
watercraft being shown in part;
[0018] FIG. 2 is a side elevational view of a power head of the
outboard motor of FIG. 1, the cowling being sectioned along a
longitudinal center plane extending vertically and fore to aft;
[0019] FIG. 3 is a front elevational, cross sectional view of the
cowling taken along the line 3-3 of FIG. 2;
[0020] FIG. 4 is a rear elevational, cross sectional view of the
cowling taken along the line 4-4 of FIG. 2;
[0021] FIG. 5 is a top plan, cross sectional view of the cowling
taken along the line 5-5 of FIG. 2;
[0022] FIG. 6 is a side elevational view of a power head of another
outboard motor embodiment, the cowling being sectioned along a
longitudinal center plane extending vertically and fore to aft;
[0023] FIG. 7 is a schematic side elevational view of a power head
of a further outboard motor embodiment, a camshaft drive mechanism,
a flywheel magneto and a flywheel magneto cover being omitted in
this figure;
[0024] FIG. 8 is a schematic side elevational view of a power head
of a still further outboard motor embodiment; and
[0025] FIG. 9 is a schematic side elevational view of an engine and
components positioned within a power head as in FIG. 8, showing
water invasion sensors.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0026] With reference to FIGS. 1 and 2, an overall structure of an
outboard motor 30 will be described below.
[0027] The outboard motor 30 preferably has a mount unit 32 and a
drive unit 34.
[0028] The mount unit 32 supports the drive unit 34 on a transom
board 36 of an associated watercraft 38 and places a marine
propulsion device such as, for example, a propeller 40 in a
submerged position with the watercraft 38 resting relative to a
surface of the body of water. The drive unit 34 preferably can be
tilted up (raised) or tilted down (lowered) relative to the
watercraft 38.
[0029] As used through this description, the terms "forward" and
"front" mean at or to the side where the mount unit 32 is located,
unless indicated otherwise or otherwise readily apparent from the
context used. Also, the terms "rear," "rearward" and "backward"
mean at or to the opposite side of the front side.
[0030] As used in this description, the term "horizontally" means
that the subject portions, members or components extend generally
parallel to the water surface when the watercraft 38 is
substantially stationary with respect to the water surface and when
the drive unit 34 is not tilted and is generally placed in the
position shown in FIG. 1. The term "vertically" means that
portions, members or components extend generally normal to those
which extend horizontally.
[0031] The arrow FWD indicates a forward direction in which the
outboard motor 30 moves forward together with the watercraft 38,
while the arrow RWD indicates a rearward direction in which the
outboard motor 30 moves rearward together with the watercraft
38.
[0032] As used in this description, the term "right side" means the
starboard side when the outboard motor 30 is mounted on the
watercraft 38. Also, the term "left side" means the port side when
the outboard motor 30 is mounted on the watercraft 38.
[0033] The mount unit 32 preferably includes a clamping bracket 44,
a swivel bracket 46, a tilt pin 48 and a steering shaft.
[0034] The clamping bracket 44 preferably includes a pair of
bracket arms that are transversely spaced apart from each other and
can be affixed to the transom board 36. The tilt pin 48 extends
generally horizontally and completes a hinge coupling between the
swivel bracket 46 and the clamping bracket 44. The tilt pin 48
extends through the clamping bracket 44 and the swivel bracket 46
in such a manner that the clamping bracket 44 supports the swivel
bracket 46 for pivotal movement about an axis of the tilt pin
48.
[0035] The swivel bracket 46 preferably carries the drive unit 34
for pivotal movement about an axis of the steering shaft which
extends generally vertically. The swivel bracket 46 is affixed to
the drive unit 34 by upper and lower mount members. The swivel
bracket 416 and the drive unit 34 thus can be tilted together about
the axis of the tilt pin 48 relative to the clamping bracket
44.
[0036] The drive unit 34 preferably includes a power head 54 and a
housing unit 56. The power head 54 is disposed atop the drive unit
34 and includes an internal combustion engine 58. In order to
protect the engine 58, the power head 54 includes a protective
cowling 60 that surrounds the engine 58.
[0037] The cowling 60 preferably includes a top cowling member 62
and a bottom cowling member 64. The illustrated top and bottom
cowling members 62, 64 preferably are made of an aluminum alloy or
synthetic resin. Preferably, the top cowling member 62 is
detachably coupled with the bottom cowling member 64 by a lock
mechanism. The top and bottom cowling members 62, 64 together
define an internal space 68 in which the engine 58 is placed.
Normally, water does not enter the internal space 68 through
coupling portions of the top and bottom cowling members 62, 64,
because the members 62, 64 are water-tightly coupled with each
other.
[0038] The engine 58 in the illustrated embodiment is a four stroke
engine, and generates the power for driving the propeller 40. The
engine 58 preferably has four cylinders extending generally
horizontally in the fore to aft direction of the outboard motor 30.
The respective cylinders are positioned in line. That is, one
cylinder is located above another cylinder except for the cylinder
positioned atop. Combustion chambers of the respective cylinders
are preferably located on a rear side of the engine 58. The engine
58 also has a crankshaft 66 extending generally vertically. It is
to be understood that other engine sizes and configurations (such
as V6 and rotary) can appropriately be employed.
[0039] The housing unit 56 preferably includes an upper casing (or
driveshaft housing) 70 and a lower casing 72. The illustrated upper
and lower casings 70, 72 are made of an aluminum alloy. The upper
casing 70 is disposed below the power head 54 and is coupled with
the power head 54. Preferably, a top end of the upper casing 70 is
coupled with the bottom cowling member 64 through an exhaust guide
74. The bottom cowling member 64 and the exhaust guide 74 together
form a tray that accepts the engine 58. The engine 58 is fixed to
the tray.
[0040] The lower casing 72 depends from the upper casing 70. A
driveshaft 78 extends generally vertically within the upper casing
70 and the lower casing 72. The upper casing 70 by itself or
together with the lower casing 72 journal the driveshaft 78. A top
end of the driveshaft 78 is coupled with a bottom end of the
crankshaft 66. The lower casing 72 journals a propulsion shaft 80
extending generally horizontally within the lower casing 72.
[0041] The driveshaft 78 and the propulsion shaft 80 are coupled
with each other for rotation through a transmission mechanism 82
which includes a forward-neutral-reverse mode change device. The
propeller 40 is connected to an end of the propulsion shaft 80.
Thus, the power generated by the engine 58 is transmitted to the
propeller 40 through the driveshaft 78, the transmission mechanism
82 and the propulsion shaft 80. The propeller 40 rotates to produce
the thrust that propels the associated watercraft 38.
[0042] With reference to FIGS. 2 and 5, the illustrated top cowling
member 62 has a pair of air intake openings 84R, 84L through which
ambient air from outside the cowling 60 enters the internal space
68 of the cowling 60. The respective air intake openings 84R, 84L
preferably are disposed at front top portions of the top cowling
member 62 on opposite sides of the longitudinal center plane LCP,
which extend vertically and in the fore to aft direction of the
outboard motor 30. The air intake opening 84R is positioned on the
right side of the cowling 60, while the air intake opening 84L is
positioned on the left side of the cowling 60.
[0043] In the illustrated embodiment, as shown in FIG. 2, the
engine 58 has a pair of air intake devices 90 defining external air
passages through which air is introduced into inner air passages of
the engine 58, which inner air passages are positioned downstream
of the external air passages. The inner air passages communicate
with combustion chambers of the respective cylinders. Preferably,
each air intake device 90 is bifurcated to be connected to the
associated inner air passages. In the illustrated embodiment, the
air intake devices 90 are positioned on a left side of the engine
58 (i.e., on the port side of the watercraft 38) and fixed
thereto.
[0044] An air silencer 92 preferably is coupled with upstream
portions of the air intake devices 90. The air silencer 92 defines
a plenum chamber configured to attenuate intake noise. The air
silencer 92 has an opening (not shown) through which the air in the
internal space 68 of the cowling 60 can enter the plenum chamber.
The plenum chamber also smoothes the air flow before delivering it
to the respective external air passages. The illustrated air
silencer 92 is positioned in front of the engine 58 and fixed
thereto.
[0045] Air from within the internal space 68 of the cowling 60 is
introduced into the air silencer 92. In the illustrated embodiment,
the air passes through air passages 93 defined in a partition unit
or duct unit 94 before entering the air silencer 92. That is, the
air entering the air intake openings 84R, 84L flows through the air
passages 93 of the partition unit 94 and enters the remainder part
of the internal space 68, which has no air duct. The air then
enters the air silencer 92.
[0046] The air passage 93 preferably is positioned atop the
internal space 68 of the cowling 60 so as to be placed generally
above the engine 58. The air passage 93 preferably includes
upstream passage sections (or upstream path) 96R, 96L and a
downstream passage section (or downstream path) 98. The partition
unit 94 and the passage sections 96R, 96L, 98 will be described in
greater detail below. The remainder part of the internal space 68
forms an engine room 100 in this embodiment.
[0047] Air entering the air silencer 92 goes to the respective
combustion chambers of the engine 58 through the external air
passages of the air intake devices 90 and the inner air passages of
the engine 58 for combustion of fuel. Fuel is also delivered to the
combustion chambers through a fuel supply system.
[0048] The upper and lower casings 70, 72 also define exhaust
passages of an exhaust system for the engine 58. Exhaust gases
discharged from the engine 58 pass through the exhaust guide 74 and
enter a portion of the exhaust system extending in the upper casing
70. All or most of the exhaust gases are eventually discharged to
an external location preferably under a surface of the water body
through the upper and lower casings 70, 72 and a boss of the
propeller 40.
[0049] With reference to FIGS. 2-5, a preferred structure of the
cowling 60 will be described below.
[0050] Preferably, upstream 96R, 96L and downstream 98 passage
sections extend generally horizontally and parallel to each other
in the fore to aft direction. The upstream passage section 96R
extends from the air intake openings 84R on the right side toward a
rear end of the cowling 60, while the upstream passage section 96L
extends from the air intake openings 84L on the left side also
toward the rear end of the cowling 60. The downstream passage
section 98 extends from the rear end of the cowling 60 toward a
front end of the cowling 60. The respective upstream passage
sections 96R, 96L preferably interpose the downstream passage
section 98 between them. The downstream passage section 98 in this
embodiment is positioned slightly higher than the upstream passage
sections 96R, 96L to avoid interference with a top portion of the
engine 58.
[0051] In the illustrated embodiment, the air passage 93 also
includes an air/water separator or water receiver 104 positioned in
the most rear end portion of the air passage 93. The air/water
separator 104 preferably comprises a relatively voluminous chamber
which communicates with all of the upstream and downstream passage
sections 96R, 96L, 98. Notably, air flow through the air passage
changes direction at an upper portion 138 of the separator 104 from
a fore-to-aft direction in passage sections 96R and 96L to an
aft-to-fore direction in passage section 98.
[0052] In general, air accompanied with water can flow through the
upstream passage sections 96R, 96L. The water can be released in
the air/water separator 104 so that the air proceeds to the
downstream passage 98 without the water. Further, if a large volume
of water enters the upstream passage sections 96 through the air
intake openings 84, the air/water separator 104 functions as a
water receiver to temporarily accept and accumulate the water.
[0053] In the illustrated embodiment, a water discharge opening 106
communicating with the air/water separator 104 is formed at a rear
portion of the top cowling member 62. The water discharge opening
106 is configured to release water that may have accumulated in the
separator 104.
[0054] In order to ensure a sufficient capacity of the chamber, the
air/water separator 104 preferably extends in a transverse
direction across a majority of the width of the cowling 60 as shown
in FIG. 4. Also, the water discharge opening 106 preferably is
positioned lower than a hypothetical center plane 108 of the engine
58 in a vertical direction so as to have a sufficient depth. For
purposes of this discussion, the center 108 of the engine 58 is
generally equally distant from the top 110 and bottom 112 of the
engine 58. In other words, the water discharge opening 106 is
positioned lower than a center of the cowling 60 in the vertical
direction which is positioned at generally equal distances from the
top and bottom of the cowling 60.
[0055] In the illustrated embodiment, the engine 58 has a camshaft
drive mechanism and a flywheel magneto atop thereof. A top end of a
flywheel magneto cover defines the top 110 of the engine 58.
[0056] Preferably, the illustrated partition unit 94, together with
the top cowling member 62, forms the upstream passage section 96R,
96L, the downstream passage section 98 and the air/water separator
104. The partition unit 94 is preferably made of synthetic resin or
sheet metal. In order to form the sections 96R, 96L, 98, 104, the
partition unit 94 preferably has a plurality of wall portions
unitarily connected to each other. The wall portions in this
embodiment includes passage bottom wall portions 116R, 116C, 116L,
passage side wall portions 118R, 118L, a chamber front wall portion
120, a chamber bottom wall portion 122 and chamber side wall
portions 124R, 124L.
[0057] The passage bottom wall portion 116R, the passage side wall
portion 118R and the top cowling member 62 together form the
upstream passage section 96R. The passage bottom wall portion 116R
is attached to an upper right side wall 128R of the top cowling
member 62, while the passage side wall portion 118R is attached to
a top wall 130 of the top cowling member 62. The passage bottom
wall portion 116L, the passage side wall portion 118L and the top
cowling member 62 together form the upstream passage section 96L.
The passage bottom wall portion 116L is attached to an upper left
side wall 128L of the top cowling member 62, while the passage side
wall portion 118L is attached to a top wall 130 of the top cowling
member 62. The passage bottom wall portion 116C, the passage side
wall portion 118R and the passage side wall portion 118L together
form the downstream passage section 98.
[0058] With continued reference to FIGS. 2 and 5, the passage
bottom wall portion 116C has an opening 134 through which the
downstream passage section 98 communicates with the engine room
100. The opening 134 preferably is positioned adjacent to the air
intake openings 84R, 86L. That is, the opening 134 is positioned
closer to the air intake openings 84R, 84L than to the air/water
separator 104. This is advantageous because water separated from
the air is unlikely to proceed far enough up the passage section 98
to reach the opening 134, even if it may drift as moisture or mist
in a rear portion of the downstream passage section 98. The opening
134 preferably has a rectangular shape in the top plan view of FIG.
5.
[0059] The chamber front wall portion 120, the chamber bottom wall
portion 122, the chamber side wall portions 124R, 124L and the top
cowling member 62 together form the air/water separator 104. That
is, the chamber bottom wall portion 122 and the chamber side wall
portions 124R, 124L are attached to a rear wall 136 of the top
cowling member 62 to define the chamber of the air/water separator
104.
[0060] Because the air/water separator 104 in the illustrated
embodiment has a sufficient width and depth to provide sufficient
capacity to hold water from a large wave impinging on the inlets
84R, 84L, the chamber front wall portion 120 can approach to the
rear wall 136 as close as possible, thus providing a relatively low
profile or thickness. Thus, even though a space between a rear
surface of the engine 58 and the rear wall 136 of the top cowling
member 62 is narrow, the voluminous chamber of the air/water
separator 104 can be readily provided.
[0061] In the illustrated embodiment, the chamber bottom wall
portion 122 is placed at about the same level as the water
discharge opening 106. The water discharge opening 106 thus is
positioned at the bottom end of the chamber of the air/water
separator 104. Thus, normally, no water is retained in the
air/water separator 104, although it may take some time for water
to drain from the separator when a large volume of water enters the
air/water separator 104.
[0062] As best shown in FIG. 5, the upstream passage sections 96R,
96L and the downstream passage section 98 communicate with the
air/water separator 104 and also communicate with each other
through an upper portion 138 of the air/water separator 104.
[0063] As thus constructed, when the engine 58 operates, ambient
air is introduced into the upstream passage sections 96R, 96L
through the air intake openings 84R, 84L. The air moves to the rear
end of the upstream passage sections 96R, 96L. Because the air is
light, it turns rightward or leftward and moves into the downstream
passage sections 98 without falling into the chamber of the
air/water separator 104. The air then moves toward the front end of
the downstream section 98, and moves further into the engine room
100 through the opening 134. The air eventually is introduced into
the plenum chamber of the air silencer 92, and finally proceeds to
the respective combustion chambers through the external air
passages of the air intake devices 90 and the inner air passages of
the engine 58.
[0064] Splashing water may enter the upstream passage sections 96R,
96L through the air intake openings 84R, 84L. The water moves to
the rear end of the upstream passage sections 96R, 96L together
with the ambient air. Because the water is heavier than the air, it
does not move into the downstream passage section 98, but falls
into the chamber of the air/water separator 104 by its own weight.
Thus, the water is separated from the air in the air/water
separator 104. Water within the separator 104 is discharged outside
through the water discharge opening 106.
[0065] In the event that a relatively large wave surges on the
outboard motor 30 and goes over the cowling 60, a large volume of
water may enter the upstream passage sections 96R, 96L through the
air intake openings 84R, 84L. The water moves to the rear end of
the upstream passage sections 96R, 96L and falls into the chamber
of the air/water separator 104. Because the air/water separator 104
has a relatively large capacity as described above, the entire
volume of the water can be received within the air/water separator
104. That is, the air/water separator 104 acts as a water receiver.
Afterwards, the water drains from the separator through the water
discharge opening 106. Thus, the engine and other components
including electrical components are protected from the water, and
functional troubles due to rust or adhering are avoided.
[0066] In the illustrated embodiment, the water is separated from
the air in a top area of the air/water separator 104 because the
upstream and downstream passage sections 96R, 96L, 98 are connected
to each other in the top area of the air/water separator 104. This
is advantageous because the capacity of the air/water separator 104
can be fully used. However, in another embodiment, the upstream and
downstream passage sections 96R, 96L, 98 can be connected in
another area of the air/water separator 104 such as, for example, a
mid area thereof in the vertical direction.
[0067] The number of the air intake openings 84R, 84L and the water
discharge opening 106 can be altered in other embodiments. For
example, the cowling can have only one air intake opening and two
water discharge openings.
[0068] The arrangement of the partition unit 94 and the positions
of the air intake openings 84R, 84L and the water discharge opening
106 can also be changed in other embodiments. For example, openings
can be positioned on one or more lateral sides of the cowling. The
arrangement of the partition unit 94 is changed in accordance with
the positions of the openings. Also, the air intake openings 84R,
84L can be positioned at a rear portion of the cowling 60.
[0069] With reference to FIG. 6, another outboard motor 30A having
a modified top cowling member 62A will be described below.
Reference numerals 54A and 60A indicate a power head and a cowling
having the modified top cowling member 62A. The same portions,
sections and members as those which have been already described
above will be assigned with the same reference numerals or symbols
(or the same reference numerals together with the letter A), and
will not be repeatedly described unless there is any necessity. In
addition, the terms "front" and "rear" in the first embodiment
should read as "rear" and "front," respectively, in this
embodiment.
[0070] In this embodiment, the air intake openings 84R, 84L are
positioned at rear top portions of the top cowling member 62A,
while the water discharge opening 106 is positioned at a portion of
the front wall 136 of the top cowling member 62A. Also, the
partition member 94 is entirely turned so that the air/water
separator 104 is positioned in front of the engine 58. The
structure of the partition member 94 is substantially the same as
in the embodiments discussed above.
[0071] Preferably, the air/water separator 104 separates water from
the air entering the internal space 68 of the cowling 60A through
the air intake openings 84R, 84L in a manner similar to that
described above.
[0072] In the event that a relatively large wave surges on the
outboard motor 30A and goes over the cowling 60A, the air/water
separator 104 acts as a water receiver that can receive the water
also in a manner as described above. Since the air intake openings
84R, 84L are positioned on the rear side of the outboard motor 30A,
a following wave can rush on the cowling 60A when the outboard
motor 30A starts moving backward with the transmission in the
reverse position after a sudden stop of its forward movement. Also,
in some fishing methods, the watercraft 38 moves backward while
taking fishes. In such conditions, a wave can rush onto the cowling
60A. Under these conditions, the air/water separator 104 acts as a
water receiver in a manner as described above.
[0073] With reference to FIG. 7, another embodiment of an outboard
motor 30B having a power head 54B will be described below. The same
portions, sections and members as those which have been already
described above will be assigned with the same reference numerals
or the same reference numerals with the letter B, and will not be
repeatedly described unless there is any necessity.
[0074] The top cowling member 62B in this embodiment includes a
lower section 150 and an upper section 152. The upper section 152
is positioned above the lower section 150 and is fixed thereto. The
upper section 152 entirely covers a top wall 154 of the lower
section 150. Alternatively, the lower and upper sections 150, 152
can be unitarily formed with each other. In this alternative, the
top wall 154 can be a partition separately prepared from the lower
and upper sections 150, 152 and attached to the inner surface of
the top cowling member 62B.
[0075] The upper section 152 of the top cowling member 62B
preferably has a single air intake opening 84 which is oriented
rearward. In one variation, the intake opening 84 can be oriented
sideward, or rearward and sideward. The partition 154 divides the
internal space of the cowling 60B into an air/water separating room
156 and the engine room 100.
[0076] An air silencer 92 preferably is coupled with upstream ends
of the air intake devices 90. A majority of the air silencer 92
preferably is situated within the engine room 100. The illustrated
air silencer 92 has a neck 158 extending upward from the rest of
the air silencer 92. A top portion of the neck 158 extends beyond
the top wall or partition 154 into the air/water separating room
156 and has an air inlet opening 159. Preferably, the neck 158 is
spaced apart from the air intake opening 84 (most preferably as far
as possible) so that water entering the air/water separating room
156 does not directly enter the air silencer 92.
[0077] In the illustrated embodiment, the air/water separating room
156 and the plenum chamber of the air silencer 92 defines an air
intake passage 160 through which the ambient air moves from the air
intake opening 84 to the air intake devices 90.
[0078] The air silencer 92 preferably has a water discharge opening
164 at a bottom end 166. A valve mechanism 168 selectively opens or
closes the opening 164. Preferably, the valve mechanism 168
includes an electromagnetic valve member 170 adapted to move
between a closed position where the valve member 170 closes the
opening 164 and an opened position where the valve 170 opens the
opening 164. Normally, the valve member 170 stays at the closed
position.
[0079] The outboard motor 30B preferably has a control device 174
and at least one operational condition detecting sensor 176. The
control device 174 is adapted to control movement of the valve
member 170 based upon a signal provided from the operational
condition detecting sensor 176.
[0080] A modern outboard motor typically has an ECU (electronic
control unit) for controlling operations of the engine and other
devices such as, for example, a shift device of the transmission
mechanism. The illustrated outboard motor 30B can use such an ECU
as the control device 174. In another embodiment, the outboard
motor 30B can have its own dedicated control device 174 for
controlling the valve member 170. A micro-computer is applicable as
the control device 174.
[0081] In one embodiment, the operational condition detecting
sensor 176 comprises a water invasion sensor such as, for example,
a water pressure sensor. The water pressure sensor preferably is
positioned in the air/water separating room 156. More preferably,
the water pressure sensor is placed adjacent to the air intake
opening 84. The water pressure sensor can generate a signal when a
relatively large volume of water enters the air/water separating
room 156 and the water pushes an operator of the sensor. An example
of an embodiment of a water pressure sensor will be described below
with reference to FIG. 9. The water invasion sensor is advantageous
because it can quickly detect when a large volume of water enters
the air/water separating room 156.
[0082] Other sensors can be provided in addition to the water
invasion sensor, or can replace the water invasion sensor. For
example, a velocity sensor of the outboard motor 30 B or the
watercraft 38, an engine speed sensor of the engine 58, a shift
position sensor of the transmission mechanism or the like can be
provided.
[0083] The velocity sensor can be used for detecting deceleration
of the outboard motor 30B. The engine speed sensor can be used for
detecting an engine speed of the engine 58. The shift position
sensor can be used for detecting a shift position, i.e., forward,
reverse or neutral position, of the shift mechanism. Sensors
directed to these settings because, in general, a relatively large
wave is likely to surge on the outboard motor when the outboard
motor or the watercraft decelerates, when the engine speed rapidly
decreases or when the shift mechanism is changed to the reverse
position from the forward position.
[0084] The control device 174 preferably has a reference velocity
ratio that is predetermined. The control device 174 determines that
the outboard motor 30B is decelerating if a velocity ratio
calculated from a signal given by the velocity sensor becomes less
than the reference velocity ratio.
[0085] The control device 174 preferably has a reference engine
speed ratio that is predetermined. The control device 174
determines that the engine power is decreasing if an engine speed
ratio calculated from a signal given by the engine speed sensor
becomes less than the reference engine speed ratio. Mostly, when
the engine power decreases, the outboard motor 30B decelerates.
[0086] The control device 174 can use a plurality of signals given
by two or more sensors for more certainly determining the
operational condition of the outboard motor 30A. For example, if
the control device 174 uses both of the signals given by the
velocity sensor and the engine speed sensor, the deceleration of
the outboard motor 30A can be determined without any errors or with
less chance of error.
[0087] Although not shown, the cowling 60B in this embodiment
preferably has water drains. For example, the upper section 152 of
the top cowling member 62B preferably has one or more drains
immediately above the top wall or partition 154. In addition, the
bottom cowling member 64 preferably has one or more drains at a
bottom thereof.
[0088] As thus constructed, when the engine 58 is running, ambient
air is drawn into the air/water separating room 156 through the air
intake opening 84. The air moves to the neck 158 of the air
silencer 92 projecting into the air/water separating room 156
beyond the top wall or partition 154 and enters the plenum chamber
of the air silencer 92. The air proceeds to the respective
combustion chambers through the external air passages of the air
intake devices 90 and the inner air passages of the engine 58.
[0089] Similarly to the embodiments discussed above, splashing
water may enter the air/water separating room 156 through the air
intake opening 84. The water, however, is most likely to
immediately fall onto the top wall or partition 154 by its own
weight. Only the air can move to the air inlet opening 159 of the
air silencer 92. That is, the water is separated from the air and
generally will not enter the plenum chamber of the air silencer 92.
The water is discharged outside through the water drains of the
upper section 152 of the top cowling member 62B.
[0090] In the event that a relatively large wave surges on the
outboard motor 30B and goes over the cowling 60B, a large volume of
water enters the air/water separating room 156 through the air
intake opening 84. Such a large volume of water may advance over
the neck 158 of the air silencer 92 and enter the plenum chamber
thereof through the air inlet opening 159. Because the air silencer
92 has a sufficient capacity for the purpose of attenuating noise
and smoothing the air flow, the air/water separating room 156 can
receive the entire volume of the water. That is, the plenum chamber
of the air silencer 92 acts as a water receiver in this
embodiment.
[0091] In this condition, the water invasion sensor (e.g. water
pressure sensor) as the operational condition detecting sensor 176
senses the water invasion into the air/water separating room 156
and sends a signal to the control device 174. In another
embodiment, otherwise or in addition to the detecting operation of
the water invasion sensor and prior to occurrence of the above
condition, the velocity sensor, the engine speed sensor or the
shift position sensor as the operational condition detecting sensor
176 may sense an operational condition in which such a wave surge
is likely and send a signal to the control device 174.
[0092] The control device 174 determines that the large volume of
water has or will enter the air/water separating room 156 based
upon at least one of the signals and controls the valve member 170
to open the water discharge opening 164. That is, the control
device 174 gives an open command to the valve member 170. Thus, the
water in the plenum chamber of the air silencer 92 goes down to the
bottom cowling member 64 and is immediately discharged outside
through the drains of the bottom cowling member 64.
[0093] In one embodiment, the control device 174 returns the water
discharge valve 160 to the initial position, i.e., the closed
position after a certain time period elapses. For example, the
control device 174 can give a close command to the valve member 170
when a preset time elapses after the control device 174 has given
the open command to the valve member 174. In an additional
embodiment, the control device 174 can give the close command to
the valve member 170 when the water invasion sensor no longer
provides the signal indicative of the water invasion.
[0094] With reference next to FIGS. 8 and 9, a still further
outboard motor 30C having a further modified power head 54C will be
described below. The same portions, sections and members as those
which have been already described above will be assigned with the
same reference numerals or the same reference numerals with the
letter C, and will not be repeatedly described unless there is any
necessity.
[0095] The arrows in the solid line indicate flow of the air. The
arrows in the phantom line indicate flow of a large volume of water
rushing into the air intake passage 160C.
[0096] In this embodiment, a four stroke, four cylinder engine 58
is positioned in the engine room 100 of a cowling 60C of the
outboard motor 30C similarly to the embodiments described above. An
air silencer 92 is mounted on the engine 58. The plenum chamber of
the air silencer 92 communicates with the respective external air
passages of the intake devices 90.
[0097] The air intake opening 84 in this embodiment is oriented
rearward. The air intake passage 160C connecting the air intake
opening 84 and the plenum chamber of the air silencer 92 in this
embodiment has a labyrinth structure to effectively separate water
from the ambient air. In other words, the air intake passage 160C
includes multiple sets of air/water separators. A plurality of
partition members form the air/water separators. For example, a
transverse partition 188 extends generally transversely within the
internal space of the cowling 60C to separate the engine room 100
from the remainder part.
[0098] Although any number of air/water separators can be provided,
three air/water separators 190, 192, 194 are formed in the
illustrated embodiment. The air/water separator 190 is preferably
positioned close to the air intake opening 84 to define a first
stage of the multiple air/water separators.
[0099] The air/water separator 192 is preferably positioned
downstream of the first air/water separator 190 to define a second
stage of the multiple air/water separators. The first and second
air/water separators 190, 192 are located above the transverse
partition 188. That is, the first and second air/water separators
190, 192 are positioned above the engine 58. In the illustrated
embodiment, a vertical partition 196 extending generally vertically
from the transverse partition 188 separates the first and second
air/water separators 190, 192 from each other.
[0100] The air/water separator 194 is preferably positioned
downstream of the second air/water separator 190 and generally
below the second air/water separator 192. The air/water separator
194 defines a third stage of the air/water separators. The third
air/water separator 194 is located next to the air silencer 92.
[0101] The first air/water separator 190 has an air inlet 200
spaced apart from the transverse partition 188 for a certain
distance in the vertical direction. A first air path 202 extends
upward from the air inlet 200 and extends forward. The first air
path 202 then turns downward to the second air/water separator 190.
The first air path 202 preferably has an air outlet 204 which is
positioned lower than the air inlet 200. Because of such locations
of the inlet 200 and outlet 204, water hardly flows backward even
though a large volume of water rushes into the second air/water
separator 192 through the first air/water separator 190.
[0102] The second air/water separator 192 preferably includes a
water discharge port 206 formed in the transverse partition 188 in
front of the vertical partition 196, a generally L-shaped partition
208 and another water discharge port 210. The L-shaped partition
208 preferably is positioned in front of the air outlet 204 of the
first air/water separator 190 (i.e., the air inlet of the second
air/water separator 192). The L-shaped partition 208 forms a second
air path 212 squeezed upward to be spaced apart from the transverse
partition 188.
[0103] A top end 214 of a portion of the third air/water separator
194 preferably extends upward beyond the transverse partition 188
into the second air/water separator 192. A front end of the
L-shaped partition 208 is positioned at a location in front of the
top end 214 of the third air/water separator 194. The water
discharge port 210 is preferably positioned in front of the top end
214 of the third air/water separator 194 and is formed between a
forward end of the transverse partition 188 and a relatively large
vertical partition 216.
[0104] Because of such structures of the first and second air/water
separators 190, 192, water can be separated from the air entering
the air intake opening 84 due to its own weight before the air
enters the air inlet 200 of the first air path 202. Such separated
water preferably is drained through the air intake opening 84 or
other water drains which are not shown.
[0105] The air, however, can be accompanied with water which has
not been separated in the first air/water separator 192 and enters
the second air/water separator 192. The air flows downward when it
enters the second air/water separator 192 and then flows upward and
goes forward within the second air path 212. In moving through this
winding path, most of the remaining water is separated from the air
and is drained through the water discharge port 206. Even though
some water can further follow the air toward the third air/water
separator 194, the water due to its weight will likely pass by the
protruding top end 214 of the third air/water separator 194 and
proceed to the water discharge port 210 from which it is
discharged.
[0106] The third air/water separator 194 in this embodiment mostly
works as a water receiver under a condition that a large volume of
water enters the air intake passage 160C rather than working as an
air/water separator under a normal condition. For this purpose, the
third air/water separator 194 preferably includes a water releasing
section 220 and a water receiving section 222. The water releasing
section 220 and the water receiving section 222 preferably
communicate with each other. Preferably, the water receiving
section 222 is positioned downstream of the water releasing section
220 and communicates with the plenum chamber of the air silencer 92
through an air path 224.
[0107] Preferably, the water releasing section 220 extends
generally vertically and is generally aligned with the top end 214,
which extends into the second air/water separator 192. In other
words, the water releasing section 220 defines a straight path 226
extending generally straight top to bottom. The water releasing
section 220 has an air inlet 228 atop of the straight path 226 and
a water discharge opening 164C at a bottom of the straight path
226. The air inlet 228 is also an air outlet of the second
air/water separator 192. A mid portion of the water releasing
section 220 in the vertical direction is coupled with a mid portion
of the air silencer 92 in the vertical direction through an air
path 230 so that the straight path 226 and the plenum chamber of
the air silencer 92 communicate with each other.
[0108] The water discharge opening 164C preferably has a water
discharge valve 168 as has been described above with the second
embodiment shown in FIG. 7. An electromagnetic member 170 of the
water discharge valve 168 normally closes the water discharge
opening 164C as indicated by the dotted line and is movable to the
open position as indicated by the solid line under control of the
control device 174.
[0109] Preferably, the water receiving section 222 extends
generally vertically and has a voluminous chamber 234. That is, the
voluminous chamber 234 has a relatively large capacity that can
temporarily receive a large volume of water. The water receiving
section 222 has a water discharge opening 236 at a bottom of the
water receiving section 222. Preferably, no water discharge valve
closes the water discharge opening 236. That is, the water
discharge opening 236 is always open. In another embodiment, a
water discharge valve may selectively close the opening 236.
[0110] Preferably, air path 224 is positioned higher than air path
230. More preferably, the air path 224 is located at a top end of
the water receiving section 222. As such, water in the voluminous
chamber 234 most likely will not flow into to the plenum chamber of
the air silencer 92 even if a large volume of water rushes into the
voluminous chamber 234.
[0111] In the illustrated embodiment, the air silencer 92
preferably has an air inlet opening 238 at its top end 240. The air
inlet opening 238 has an air inlet valve 242 formed with an
electromagnetic valve member 244 which is similar to the
electromagnetic valve member 170 of the water discharge valve 168.
The electromagnetic valve member 244 of the air inlet valve 242
normally closes the air inlet opening 238 as indicated by the
broken line and is movable to the open position indicated by the
solid line under control of the control device 174. Preferably, the
opening 238 is not aligned with, and is spaced from, water
discharge port 206, and that is no possibility that water flowing
through the port 286 will flow onto or into the opening 238.
[0112] The air inlet valve 242 is preferably movable together with
the water discharge valve 168. That is, when the water discharge
valve 168 is placed at the closed position, the air inlet valve 242
is also placed at the closed position. Meanwhile, when the water
discharge valve 168 is placed at the open position, the air inlet
valve 242 is also placed at the open position.
[0113] The air inlet valve 242 can allow the air in the engine room
100 to enter the plenum chamber of the air silencer 92 when the air
inlet valve 242 opens. When the voluminous chamber 234 is partially
or completely filled with water rushing thereinto, air may not be
able to flow through the chamber 234 and into can be the air
silencer 92. Thus, engine operation can be restrained unless
sufficient intake air is introduced immediately. The air inlet
opening 238 is useful to immediately deliver the air to the engine
58 through the plenum chamber of the air silencer 92.
[0114] As thus constructed, under a normal condition, the air in
the second air/water separator 192 enters the straight path 226 of
the water releasing section 220 through the air inlet 228. Because
the water discharge valve 168 closes the water discharge opening
164C under the normal condition, the air goes to the voluminous
chamber 234 of the water receiving section 222 through the air path
230. The air further moves to the plenum chamber of the air
silencer 92 and goes to the engine 58 through the air intake
devices 90.
[0115] Under the normal condition, the air inlet valve 242 closes
the air inlet opening 238. Thus, the air silencer 92 does not
directly introduce air from the engine room 100 into its plenum
chamber. This is advantageous because air within the engine room
100 is warmed by the heat of the engine 58 and such warmed air can
decrease the charging efficiency of the engine 58.
[0116] Under an emergency condition as discussed above, when a
large volume of water rushes into the air intake passage 160C
through the air intake opening 84, the water can flow through the
first and second air/water separators 190, 192 and can move to the
third air/water separator 194 as indicated by the dotted line
arrows, because the first and second air/water separators 190, 192
may not be able to block such a large volume water invasion.
[0117] In case of the emergency condition discussed above, at least
one of the operational condition detecting sensors 176, preferably
the water invasion sensor, detects the state and sends a signal to
the control device 174. The control device thus controls the water
discharge valve 168 to move to the open position. At least a part
of the water is discharged to the bottom of the bottom cowling
member 64 through the water discharge opening 164C.
[0118] The remainder part of the water, however, may further move
into the voluminous chamber 234 of the water receiving section 222.
Because of the large capacity of the chamber 234, the water can
stay in the voluminous chamber 234 for a while and does not flow
over to the plenum chamber of the air silencer 92. The water in the
voluminous chamber 234 can be drained through the water discharge
opening 236 to the bottom of the bottom cowling member 64.
[0119] The water rushing into the voluminous chamber 234 may close
the air path 230 for a moment. In this embodiment, however, the air
inlet valve 242 opens the air inlet opening 238 of the air silencer
92 simultaneously when the water discharge valve 168 opens the
water discharge opening 164C. Thus, the air in the engine room 100
can be introduced into the plenum chamber of the air silencer 92 as
an emergency intake air source. As such, the engine 58 is not
choked for intake air.
[0120] The water in the bottom cowling member 64 is drained outside
of the outboard motor 30C through drain holes which are not shown
in FIG. 8.
[0121] With reference to FIG. 9, a preferable example of an
embodiment having a water pressure sensor (i.e., water invasion
sensor) is shown.
[0122] In the illustrated embodiment, a set of water pressure
sensor units 250, 252 are provided. One water invasion sensor unit
250 preferably is positioned in front of the air intake opening 84.
The other water invasion sensor unit 252 is preferably positioned
at the air inlet 200 of the first air/water separator 190.
[0123] Each water invasion sensor unit 250, 252 preferably includes
a sensor body 254 which can be a movable contact, and a fixed
contact 256. The sensor body (i.e., the movable contact) 254 has a
shaft 258 attached to a partition member for pivotal movement about
an axis thereof so that the sensor body 254 can swing about the
axis. The fixed contact 256 is attached to the partition member in
the sphere of the swing movement of the sensor body 254. The sensor
body 254 preferably has a certain area that can receive a water
pressure. When the sensor body (i.e., the movable contact) 254
contacts the fixed contact 256, a signal indicative of the water
invasion is generated.
[0124] Various kinds of control strategies are practicable using
the water pressure sensor units 250, 252. For example, in one
control strategy, the control device 174 does not determine that
the water rushes into the air intake passage 160c unless both of
the signals from the water pressure sensor units 250, 252 indicate
such a flood of water. In another control strategy, the control
device 174 determines the water invasion based upon either one of
the signals.
[0125] The control device 174 can operate the water discharge valve
168 and the air inlet valve 242 in a multistage control strategy.
For example, in one control strategy, when only the water pressure
sensor unit 250 generates the water invasion signal and the water
pressure sensor unit 252 does not generate the water invasion
signal because a volume of water is not so large, the control
device 174 operates the water discharge valve 168 and the air inlet
valve 242 to a half way of the respective open degrees. When both
of the water pressure sensor units 250, 252 generate the respective
water invasion signals because a volume of water is so large, the
control device 174 fully operates the water discharge valve 168 and
the air inlet valve 242.
[0126] The number of the sensor units does not limit the scope of
this invention. For example, a single sensor is applicable. Three
or more sensors also are applicable. Additionally, although the
above control strategy embodiments have employed inputs from two
water pressure sensors, other control strategy embodiments may
weigh sensor inputs indicating other conditions as discussed above.
For example, a velocity sensor, engine speed sensor, transmission
sensor, or the like can be considered alone or in conjunction with
other sensors, and with water pressure sensors. Such sensor inputs
can also be considered by the control device 174 in controlling the
valves 168, 242. For example, the sensor input of one of the
non-water pressure sensors may trigger partial opening of the
valves 168, 242, and an additional reading from a water pressure
sensor may trigger complete opening of the valves.
[0127] The structure of the sensor unit does not limit the scope of
this invention. Any other pressure sensors such as, for example, a
sensor which does not pivot only by an air pressure but pivots by a
water pressure can replace the sensor unit discussed above. Also,
other types of sensors such as, for example, a piezoelectric
pressure sensor, an infrared sensor or a waterdrop sensor can
replace the sensor unit.
[0128] Although this invention has been disclosed in the context of
certain preferred embodiments, it will be understood by those
skilled in the art that this invention extends beyond the
specifically disclosed embodiments to other alternative embodiments
and/or uses of the invention and obvious modifications and
equivalents thereof. It is also contemplated that various
combinations or sub-combinations of the specific features and
aspects of the embodiments may be made and still fall within the
scope of the invention. It should be understood that various
features and aspects of the disclosed embodiments can be combined
with or substituted for one another in order to form varying modes
of the disclosed invention. Thus, it is intended that the scope of
the present invention herein disclosed should not be limited by the
particular disclosed embodiments described above, but should be
determined only by a fair reading of the claims that follow.
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