Title:
Outboard motor with cowling
Kind Code:
A1


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)
Application Number:
11/435699
Publication Date:
11/16/2006
Filing Date:
05/16/2006
Primary Class:
International Classes:
B63H20/32; B63H21/36
View Patent Images:



Primary Examiner:
VENNE, DANIEL V
Attorney, Agent or Firm:
KNOBBE MARTENS OLSON & BEAR LLP (IRVINE, CA, US)
Claims:
What is claimed is:

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

This application is based on and claims priority under 35 U.S.C. § 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

1. Field of the Invention

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.

2. Description of Related Art

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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

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:

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;

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;

FIG. 3 is a front elevational, cross sectional view of the cowling taken along the line 3-3 of FIG. 2;

FIG. 4 is a rear elevational, cross sectional view of the cowling taken along the line 4-4 of FIG. 2;

FIG. 5 is a top plan, cross sectional view of the cowling taken along the line 5-5 of FIG. 2;

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;

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;

FIG. 8 is a schematic side elevational view of a power head of a still further outboard motor embodiment; and

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

With reference to FIGS. 1 and 2, an overall structure of an outboard motor 30 will be described below.

The outboard motor 30 preferably has a mount unit 32 and a drive unit 34.

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.

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.

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.

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.

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.

The mount unit 32 preferably includes a clamping bracket 44, a swivel bracket 46, a tilt pin 48 and a steering shaft.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

With reference to FIGS. 2-5, a preferred structure of the cowling 60 will be described below.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

With reference to FIG. 9, a preferable example of an embodiment having a water pressure sensor (i.e., water invasion sensor) is shown.

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.

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.

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.

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.

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.

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.

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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