Information
-
Patent Grant
-
6331127
-
Patent Number
6,331,127
-
Date Filed
Tuesday, February 8, 200024 years ago
-
Date Issued
Tuesday, December 18, 200122 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Knobbe, Martens, Olson & Bear, LLP
-
CPC
-
US Classifications
Field of Search
-
International Classifications
-
Abstract
An engine for a watercraft includes a cooling system having a coolant supply. The coolant supply supplies an engine coolant jacket with a flow of coolant that is controlled by a temperature dependent flow control valve. The coolant supply also supplies an exhaust conduit coolant jacket independently of the engine coolant jacket.
Description
RELATED APPLICATIONS
This application is based on Japanese Patent Application No. 10-238785, filed Aug. 25, 1998.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a marine engine, and more particularly to a cooling system employed in a marine engine.
2. Description of the Related Art
Personal watercraft, like other applications that use internal combustion engines as prime movers, are experiencing considerable public and governmental pressure to improve not only their performance, but also their exhaust emissions level. For example, due to the emissions generated by two-stroke powered watercraft, certain recreational areas have banned the operation of such watercrafts. These bans have decreased the popularity of personal watercraft, and have caused manufacturers of these types of watercraft to consider fuel injected engines to power their watercraft and/or other means to reduce emission levels.
Fuel injected engines are known to provide a significantly enhanced performance, power output, and emissions as compared to carburated engines. All even more significant improvement is achieved through direct cylinder injection. Direct cylinder injection may be accompanied by stratification or lean burning operation to further fuel economy and emission control.
The benefits of fuel injection are further enhanced through the control of the engine block temperature during operation. For example, it has been known to employ a thermostat within the cooling system of a watercraft so as to control the flow of coolant through the cooling system of a watercraft.
SUMMARY OF THE INVENTION
A need therefore exists for a marine engine having a cooling system which can accurately control the temperature of the engine block during operation. Additionally, it is desirable to cool the engine block as well as other components simultaneously, during operation. For example, it is desirable to provide a cooling system for a marine engine which precisely controls the temperature of the engine block during operation, but does not allow the exhaust system to become overheated.
According to one aspect of the present invention, a marine engine for a watercraft includes an engine body defining a combustion chamber and a coolant jacket therein. The watercraft includes an exhaust conduit communicating with the combustion chamber and extending to an exhaust discharge arranged to discharge exhaust gases flowinig through the exhaust conduit to the atmosphere. The exhaust conduit also includes a coolant jacket in thermal communication with at least a portion thereof. The watercraft includes a coolant supply configured to generate pressurized coolant, a cooling system having a first coolant flow path extending from the coolant supply, through the engine coolant jacket and through a temperature dependent flow control valve, and a second coolant flow path extending from at least one of the coolant supply and a portion of the first coolant flow path upstream from the temperature dependent flow control valve.
By providing a first coolant path for supplying coolant to the coolant jacket of the engine body and having a temperature dependent flow control valve, and a second cooling path for supplying coolant to the exhaust conduit coolant jacket, the present aspect of the invention allows the engine body to be controlled to a desired operating temperature while allowing the exhaust system to receive a supply of coolant, independently of the flow of coolant through the temperature dependant flow control valve.
One aspect of the present invention is the realization that when a thermostat is used in a cooling system to maintain a temperature of a component of the engine to a specified range by varying the flow of coolant therethough, other components receiving coolant from the cooling system can be adversely affected by adjustments to the flow rate of the coolant. For example, it has been found that in a watercraft engine that directs coolant flowing out of the engine block coolant jacket through a thermostat, into the exhaust manifold coolant jacket, the fluctuations in the coolant flow rate causes undesirable fluctuations in the temperature of the exhaust system. In fact, it has been found that such exhaust systems have cyclically overheated and cooled under certain operating conditions, due at least in part to the variations in the coolant flow rate caused by the thermostat. Such fluctuations have been found to adversely affect exhaust systems due to the heat cycling. Therefore, by providing the exhaust conduit coolant jacket with a coolant supply path independent from the engine thermostat the present aspect of the invention reduces the effect on the coolant flow rate through the exhaust conduit coolant jacket caused by the thermostat.
Further aspects, features and advantages of the present invention will become apparent from the detailed description of the preferred embodiment which follows.
BRIEF DESCRIPTION OF THE DRAWINGS
The above mentioned and other features of the invention will now be described with reference to the drawings of the preferred embodiment of a marine engine. The illustrated embodiment of the engine is intended to illustrate, but not to limit, the invention. The drawings contain the following figures:
FIG. 1
is a side elevational view of a personal watercraft constructed in accordance with a first embodiment of the invention, with a partial cut-away view of the internal components;
FIG. 2
is a cross-sectional view along line
2
.—
2
. of the watercraft shown in
FIG. 1
with certain components omitted;
FIG. 3
is a schematic representation of the fuel delivery and induction systems of the engine shown in
FIG. 2
;
FIG. 4
is a side elevational view of the cooling system included in the watercraft shown in
FIG. 1
;
FIG. 5
is a schematic representation of the cooling system shown in
FIG. 4
; and
FIG. 6
is a partial cross-sectional view of a flywheel, flywheel cover and an oil pump included in the engine shown in FIG.
1
.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION
An improved engine for a personal watercraft is disclosed herein. The engine includes a cooling system for cooling the engine provided within the watercraft, which allows an engine body of the engine to be controlled to a desired temperature, while reducing the risk that the exhaust system temperatures may exceed a desired operating range. Thus, the engine performance is enhanced while adverse heat cycling of the exhaust system is prevented.
Although the present engine is illustrated in connection with a personal watercraft, the illustrated engine can be used with other types of watercraft as well, such as, for example, and without limitation, small jet boats and the like. Additionally, although the present engine includes a direct cylinder injection fuel delivery system, the cooling system according to the present invention can be used with fuel delivery systems other than direct cylinder injection (e.g., induction system injection, and carburation). Before describing the cooling system and its arrangement within a watercraft, an exemplary personal watercraft
10
will first be described in general details to assist the reader's understanding of the environment of use and the operation of the cooling system flow.
With initial reference to
FIGS. 1-3
, the watercraft
10
includes a hull
14
formed of a lower hull section
16
and an upper hull section
18
. The hull sections
16
and
18
are formed of a suitable material, such as, for example, a molded fiberglass reinforced resin (e.g., SMC). The lower hull section
16
and the upper hull section
18
are fixed together around the peripheral edges or gunnels
20
in any suitable manner.
As viewed in a direction from bow to stern of the watercraft
10
, the upper hull section
18
includes a bow portion
22
, a control mast portion
24
. and a rider's area
26
. The bow portion
22
slopes upwardly towards the control mast
24
and includes at least one air duct
28
through which air enters the hull
14
. A hatch cover
30
desirably extends above an upper inlet
32
of the air duct
28
to inhibit an influx of water into the hull
14
.
As seen in
FIG. 1
, the air duct
28
terminates at a lower end opening
34
located near a lower surface
36
of lower hull section
16
.
A fuel tank
38
is located within the hull
14
beneath the hatch cover
30
. Conventional means, such as, for example. straps, secure the fuel tank
38
to the lower hull section
16
. A fuel filler hose (not shown) preferably extends between fuel tank
38
and a fuel cap assembly arranged on the bow portion
22
of the upper portion
18
, to the side and in front of the control mast
24
. In this manner, the fuel tank
38
can be filled from outside the hull
14
with the fuel passing, through the fuel filler hose into the fuel tank
38
.
The control mast
24
extends from the bow portion
22
and supports a handlebar assembly
40
. The handlebar assembly
40
controls the steering of the watercraft
10
in a conventional manner. The handlebar assembly also carries a variety of controls of the watercraft
10
, such as, for example, a throttle control, a start switch, and a lanyard switch.
The rider's area
26
lies behind the control mast
24
and includes a seat assembly
42
. In the illustrated embodiment. the seat assembly
42
has a longitudinally extending straddle-type shape that can be straddled by an operator and by at least one, two, or three passengers. The seat assembly
42
is, at least in principal part, formed by a seat cushion
44
supported by a raised pedestal
46
. The raised pedestal has an elongated shape and extends longitudinally along the center of the watercraft
10
. The seat cushion
44
desirably is removably attached to the top surface of the pedestal
46
and covers the entire upper end of the pedestal
46
for the rider and passenger's comfort.
In the illustrated embodiment, the seat cushion
44
has a single piece construction. Alternatively, the seat cushion
44
may be formed in sectional pieces which are individually attached to the seat pedestal
50
. In this manner. one sectional piece of the seat cushion
44
can be removed to expose a portion of the watercraft beneath the seat cushion
44
, without requiring removal of the other sectional piece(s). For instance, a rear sectional piece of the seat cushion
44
can be removed to gain access to a storage compartment located beneath the seat without requiring removal of a front sectional piece of the seat cushion
44
.
As shown in
FIG. 2
, an access opening
48
is located on an upper surface of the pedestal
46
. The access opening
48
opens into an engine compartment
50
formed within the hull
14
. The seat cushion
44
normally covers and seals the access opening
48
. When the seat cushion
44
is removed, the engine compartment
50
is accessible through the access opening.
As shown in FIG.
1
. the seat pedestal
46
also desirably includes at least one air duct
52
located behind the access opening
48
. The air duct
52
communicates with the atmosphere through an upper end port
54
located within a space between the pedestal
46
and the seat cushion
44
and rearward from the access opening
48
. The rear air duct
52
terminates in a lower end opening
56
.
As shown in
FIG. 1
, the hull
14
preferably includes a divider wall or “bulkhead”
58
mounted rearward from the access opening
48
. The bulkhead
58
cooperates with the seat pedestal
46
so as to define a propulsion unit chamber
60
arranged rearward from the engine compartment
50
.
The rear air duct
52
terminates at a position within the propulsion unit chamber
60
. Air can pass through the rear duct
54
in both directions.
As shown in
FIG. 2
, a bulwark
62
extends outwardly along each side of the watercraft
10
. A footwell
64
is defined between the side of the pedestal
46
and the corresponding bulwark
62
. In the illustrated embodiment, the footwells
64
extend entirely along the length of the seat assembly
42
and open into a rear deck
66
(
FIG. 1
) that is located at the aft end of the watercraft
10
above the transom. The footwells
64
, however, can be closed at their aft end with a suitable drainage system provided.
The hull
14
is configured such that the watercraft
10
has sufficient buoyancy to float in a body of water in which the watercraft
10
is operated, regardless of the orientation of the hull
14
in the water. That is, as appreciated from
FIG. 1
, line L represents the water surface level relative to the watercraft
10
when the watercraft
10
is at rest in a body of water. In contrast., line L
1
represents the water surface level relative to the watercraft
10
when the watercraft
10
is capsized in a body of water.
The lower hull section
16
is designed such that the watercraft
10
planes or rides on a minimum surface area at the aft end of the lower hull
16
in order to optimize the speed and handling of the watercraft
10
when up on plane. For this purpose, the lower hull section
16
generally has a V-shaped configuration, as apparent from
FIG. 2
, formed by a pair of inclined sections that extend outwardly from a keel of the hull to the hull's sidewalls at a dead rise angle. The inclined sections also extend longitudinally from the bow toward the transom of the lower hull
16
. The sidewalls are generally flat and straight near the stern of the hull and smoothly blend towards the longitudinal center of the watercraft at the bow. The lines of intersection between the inclined sections and the corresponding sidewalls form the outer chines of the lower hull section
16
.
Toward the transom of the watercraft, the inclined sections of the lower hull
16
extend outwardly from a recessed channel or tunnel
68
that extends upwardly toward the upper hull portion
18
. The tunnel generally has a parallelepiped shape and opens through the transom of the watercraft
10
.
As shown in
FIG. 1
, a jet pump unit
70
is mounted within the tunnel
68
. An inlet
72
to the jet pump unit
70
is formed in the lower surface of the lower hull section
16
which opens into a gullet of an intake duct leading to the jet pump unit
70
. As shown in
FIG. 4
, the intake duct leads to an impeller housing, assembly in which an impeller
74
of the jet pump unit
70
operates. The impeller housing assembly also acts as a pressurization chamber and delivers the water flow from the impeller housing to a discharge nozzle
76
.
A steering nozzle
78
is supported at a downstream end of the discharge nozzle
76
by a pair of vertically extending pivot pins. In an exemplary embodiment, the steering nozzle
78
has an integral lever on one side that is coupled to the handlebar assembly
40
, through, for example, a bowden-wire actuator, as known in the art. In this manner, the operator of the watercraft can move the steering nozzle
78
to affect directional changes of the watercraft
10
.
A ride plate covers a portion of the tunnel behind the inlet opening
70
to close the jet pump unit
66
within the tunnel. In this manner, the lower opening of the tunnel is closed to provide a plane surface for the watercraft
10
.
As shown in
FIG. 4
, an impeller shaft
80
supports the impeller
74
within the impeller housing of the jet pump unit
70
. The aft end of the impeller shaft
80
is suitably supported and journaled within the compression chamber of the jet pump unit
70
in a known manner. The impeller shaft
80
extends forwardly through a front wall of the tunnel, which is, in the illustrated embodiment, defined by the bulkhead
58
. As shown in
FIG. 1
, the impeller shaft
80
is supported by a bearing
82
mounted to the bulkhead
58
.
With reference to
FIG. 1
, the watercraft
10
may include a bilge system for removing water from the engine compartment
50
of the watercraft
10
. The bilge system includes a water pick-up
84
located on the lower surface of the engine compartment
50
, and at the aft end of the engine compartment
50
adjacent the bulkhead
58
. The bilge system may employ a Venturi-type pump by utilizing a reduced pressure area formed within the jet pump unit
70
. For this purpose, a bilge hose may connect water pick up
84
to the jet pump unit
70
. The bilge system can alternatively include a mechanical bilge pump driven by an electric motor.
An internal combustion engine
86
of the watercraft
10
powers the impeller shaft
80
to drive the impeller
74
of the jet pump unit
70
. As seen in
FIGS. 1 and 2
, the engine
86
is positioned within the engine compartment
50
and is mounted behind the control mast
24
, beneath the seat assembly
42
. In the illustrated embodiment, the engine
86
is arranged at a longitudinal position that is generally beneath the access opening
48
formed on the upper surface of the seat pedestal
46
.
With reference to
FIGS. 1 and 2
. vibration absorbing engine mounts
88
secure the engine
86
to the lower surface of the lower hull section
16
. As best seen in
FIG. 2
, the engine mounts
88
are attached to the engine
86
by a first set of brackets
90
and to the lower surface of the lower hull portion
16
by a second set of brackets
92
. These lower brackets
92
are arranged to support the engine
86
at a distance above the lower surface of the lower hull section
16
, and at a desired location within the engine compartment
50
.
In the illustrated embodiment, the engine
86
includes two in-line cylinders and operates on a two-stroke, crankcase compression principle. The engine
86
is positioned such that the row of cylinders is generally parallel to the longitudinal axis of the watercraft
10
, running bow to stern. The axis of each cylinder is generally inclined relative to a vertical central plane of the watercraft
10
, in which the longitudinal axis of the watercraft
10
lies. This engine type, however, is merely exemplary. Those skilled in the art will readily appreciate that the present cooling system
12
can be used with a variety of engine types having other numbers of cylinders, having other cylinder arrangements (e., vertical), and operating on other combustion principals (e.g., four stroke and rotary principals).
As best seen in
FIG. 2
, a cylinder block
96
and a cylinder head
98
desirably form the cylinders of the engine
86
. As shown in
FIG. 3
, a piston
100
reciprocates within each cylinder of the engine
86
. The pistons drive, an output shaft
102
, such as a crankshaft, is driven in a known manner. A connecting rod
104
links the corresponding piston
100
to the crankshaft
102
. The corresponding cylinder bore, piston and cylinder head of each cylinder forms a variable volume chamber, which defines a combustion chamber therein.
The output shaft
102
desirably is journaled within a crankcase
106
. A plurality of individual crankcase chambers
108
to the engine
86
are formed within the crankcase
106
by dividing walls and sealing disks, and are thereby sealed from one another with each crankcase chamber communicating with a dedicated variable volume chamber. Each crankcase chamber
108
also communicates with an induction system
110
(which is described below in detail). Because the internal details of the engine
86
desirably are conventional, a further description of the engine construction is not believed necessary to understand and practice the invention.
As shown in
FIG. 6
, the output shaft
102
carries a flywheel assembly
112
on a front end
130
of the output shaft
102
at a position forward of the row of cylinders. The flywheel assembly
112
includes a flywheel magneto
114
. A cover
116
, as also shown in
FIG. 1
, is attached to a front opening
117
of the crankcase
106
to enclose the flywheel assembly
112
.
As illustrated in
FIG. 6
, the flywheel magneto
114
is generally annular in shape and is fixed to a boss
115
which forms a hub for the flywheel magneto
114
. The boss
115
is fixed to the front end
130
via a bolt
132
threadedly engaged with the front end
130
such that the flywheel magneto
114
rotates with the output shaft
102
.
In contrast, a stator
118
having coils
120
,
122
is mounted to a boss
124
protruding from an inner surface
126
of cover
116
, via a plurality of bolts
128
, so as to remain stationary relative to flywheel magneto
114
.
Constructed as such, the flywheel assembly
112
forms an electric generator for supplying the watercraft
10
with an electric current. Alternatively, the watercraft
10
may include a generator mounted externally of the engine
86
, and driven by a pulley system.
With reference to
FIGS. 1 and 4
, an exhaust system is provided to discharge exhaust by-products from the engine
86
to the atmosphere and/or into the body of water in which the watercraft
10
is operated. The exhaust system is formed of an exhaust conduit
133
which communicates with the combustion chambers defined in the engine body and is configured to discharge the exhaust gases to the atmosphere.
The exhaust conduit
133
includes an exhaust manifold
134
affixed to the side of the cylinder block
96
to receive exhaust gases from the variable volume chambers through exhaust ports in a well known manner.
At an outlet end, the exhaust manifold
134
communicates with a C-shaped pipe section
136
. The C-shaped pipe
136
includes an inner tube
138
that communicates directly with the discharge end of the exhaust manifold
134
. An outer tube
140
surrounds the inner tube
138
to form a coolant jacket
142
between the inner tube
138
and the outer tube
140
. As shown in
FIG. 4
, the coolant jacket
142
includes an inlet
144
for receiving coolant.
The C-shaped pipe
136
includes an expansion chamber
146
. In the illustrated embodiment, the expansion chamber
146
has a tubular shape. The coolant jacket
142
extends over the expansion chamber
146
and the exhaust manifold
134
.
A discharge end
148
of the expansion chamber
146
tapers so as to reduce in cross-section and forms a downwardly turned portion. The inner tube
138
terminates at the discharge end
148
such that the water flowing through the water jacket
142
merges with the exhaust gas flowing through the inner tube
138
at the discharge end
148
.
A connector
150
, preferably formed from a flexible pipe, is connected to the discharge end
148
and extends rearward along one side of the watercraft hull tunnel
68
.
The connector
150
connects to an inlet section of the water trap device
152
lying on the same side of the tunnel
68
.
The water trap device
152
has a sufficient volume to retain water and to preclude the backflow of water to the expansion chamber
146
and the engine
86
. Internal baffles within the water trap device
152
help control water flow through the exhaust system.
An exhaust pipe
154
extends from an outlet section of the water trap device
152
and wraps over the top of the tunnel
68
to a discharge end
156
. The discharge end
156
desirably opens into the tunnel
68
in an area that is close to or below the water line L.
As seen in
FIGS. 2 and 3
, the induction system
110
is located on a side of the engine
86
opposite the exhaust system and supplies air to the variable volume chambers within the engine
86
. In the illustrated embodiment, the induction system
110
includes an air intake silencer
158
which is connected to the variable volume chambers through a number of intake runners
160
corresponding to the number of cylinders within the engine
86
. In the illustrated embodiment, there are two intake runners
160
.
As shown in
FIG. 3
, the intake silencer
158
communicates with a plurality of throttle devices
162
. The engine
86
desirably includes a number of throttle devices
162
equal in number to the number of cylinders within the engine
86
.
In the illustrated embodiment, the throttle devices
162
are throttle valves. The throttle shaft supports a butterfly-type valve plate
164
within a throat
166
of the throttle device
162
.
Each throttle device
162
communicates with an intake manifold through one of the intake runners
160
. The intake manifold is attached to the crankcase
106
and/or cylinder block
96
to place each intake runner
160
in communication with one of the crankcase chambers. In the illustrated embodiment, the intake runner
160
desirably has an arcuate shape with a portion of the runner
160
extending generally transverse to a rotational axis of the crankshaft
102
and a longitudinal axis of the watercraft
10
. As a result, the throttle device
162
and intake silencer
158
are distanced from the cylinder block and the cylinder head assemblies
96
,
98
.
A check valve (e.g., a reed valve) is disposed within each intake runner
160
at the junction between the intake manifold and the crankcase
106
. In the illustrated embodiment, a reed valve assembly
168
includes a pair of reed valves
170
which open upon upward movement of the piston
100
to permit an influx of air into the corresponding crankcase chambers and which close upon downward movement of the piston
100
, to inhibit reverse air flow from the crankcase chamber into the intake manifold.
The fuel delivery system of the illustrated embodiment is designed for direct cylinder injection of fuel through fuel injectors
172
. However, the present cooling system can be used with other types of charge formers and arrangements of charge formers within the engine (e.g., intake passage injection) as well.
The engine
86
desirably includes the same number of fuel injectors
172
as the number of cylinders. In the illustrated embodiment, the fuel injectors
172
spray fuel directly into the cylinders defined in the cylinder block
96
so as to operate under the direct injection principal.
As shown in
FIG. 3
, a fuel supply line
174
extends from the fuel tank
38
to the vapor separator assembly
176
. A low pressure fuel pump
178
and a fuel filter
179
are provided along the fuel supply line
174
, between the fuel tank
89
and the vapor separator assembly
176
. A fuel filter outlet pipe
175
connects the fuel filter
179
with the fuel bowl
180
.
As shown in
FIG. 1
, the vapor separator assembly
176
is preferably mounted directly to the engine
86
via a plurality of elastic members
181
. By mounting the vapor separator assembly
176
directly to the engine
86
with the elastic members
181
, vibration conducted to the vapor separator assembly
176
is attenuated.
The low pressure fuel pump
178
can either be mechanically or electrically driven. For instance, in the illustrated embodiment, the low pressure fuel pump
178
is diaphragm pump operated by the changing pressure within one of the crankcase chambers, via a pressure line
177
. The pump, however, can be an impeller pump driven by an electric motor.
With reference to
FIG. 3
, the vapor separator assembly
176
includes a vapor separator as well as a high pressure pump
184
which is positioned within the housing of the vapor separator assembly
176
. The housing defines an inner cavity which forms the fuel bowl
180
. The housing can have a sloped bottom surface to ftinel the fuel towards an influent port
182
which is generally positioned at the bottom of the fiel bowl
180
.
The housing also defines an inlet port
188
, a return port
190
, and a vapor discharge port
192
. The vapor discharge port
192
is positioned to the side of the inlet port
188
at a position proximate to the upper end of the housing. A breather conduit
191
allows excess vapor to vent to the atmosphere. Alternatively the breather conduit
191
could be routed to return vapor to the fuel tank
38
. Preferably, the breather conduit
191
includes an anti-back flow device
193
for preventing the influx of water into the fuel system when the watercraft
10
is capsized.
The inlet port
188
connects the fuel supply line
174
to the fuel bowl
180
. A needle valve
194
operates at a lower end of the intake port
188
to regulate the amount of fuel within the fuel bowl
180
. A float
196
within the fuel bowl
180
actuates the needle valve
194
. The float
196
includes a buoyant body supported by a pivot arm
198
.
The pivot arm
198
is pivotally attached to an inner flange within the housing by a pivot shaft
200
at a point proximate to the lower end of the housing inlet port
188
. The pivot arm also supports the needle valve
194
in a position lying directly beneath a valve seat formed on the lower end of the inlet port
188
. Movement of the pivot arm
198
causes the needle valve
194
to open and close the inlet port
188
by either seating against or moving away from the valve seat, depending on the rotational direction of the pivot arm
198
.
In the illustrated embodiment. the pivot arm
198
rotates about a pivot shaft
200
which extends in a direction generally transverse to the longitudinal axis as well as the direction of travel of the watercraft
10
. This orientation of the pivot shaft
200
generally isolates the function of the float
196
from turning movements of the watercraft
10
. That is, the movement of the watercraft
10
when turning does not cause the float
196
to rotate about the pivot shaft
200
. The pivot shaft
200
, alternatively, may be arranged so as to extend it in a direction generally parallel to the direction of travel in order to isolate the float
196
from movements produced when the watercraft
10
accelerates or decelerates.
In operation, the low pressure portion of the fuel delivery system operates to maintain a preselected amount of fuel within the fuel bowl
180
. For or example, the low pressure fuel pump
178
draws furl through a stand pipe in the fuel tank
38
. The fuel is pressurized by the low pressure fuel pump
178
, and is thereby urged through the fuel filter
179
and the fuel filter outlet pipe
175
.
When the fuel bowl
180
contains a low level of fuel, the float
196
floats in a lower position, as shown in FIG.
3
. The needle valve
194
is opened by the float
196
in this lower position and fuel flows from the fuel filter outlet pipe
175
and into the fuel bowl
180
.
When the fuel bowl
180
contains a preselected amount of fuel, the float
196
rises to a level where it causes the needle valve
194
to seat against the valve seat at the lower end of the inlet port
188
. The preselected amount of fuel desirably lies below the inlet port
188
, the return port
190
, and the vapor discharge port
192
. As such the low pressure portion of the fuel delivery system maintains a predetermined amount of fuel in the fuel bowl
180
as a reservoir for the high pressure portion of the fuel delivery system.
The high pressure portion of the fuel delivery system is designed to pressurize fuel from the fuel bowl
180
, and deliver the pressurized fuel to the fuel injectors
172
. In the illustrated embodiment, the high pressure pump
184
is integrated into the vapor separator housing assembly
176
. The high pressure pump
184
includes an influent port
182
which communicates with the fuel bowl
180
through a fuel strainer
202
. The fuel strainer
202
lies generally at the bottom of the fuel bowl
180
.
The high pressure pump
184
may include an electric motor which drives an impeller shaft of the high pressure pump
184
. The impeller shaft supports an impeller that rotates in a pump cavity. In an exemplary embodiment, the pump is a centrifugal pump; however, other types of pumps, such as rotary vein pumps, can be used as well. Alternatively, the high pressure fuel pump
184
may be driven directly by the crankshaft
102
.
The vapor separator assembly
176
desirably includes a lid which is removably attached to a base portion of the housing by a plurality of conventional fasteners. A seal extends around the periphery of the housing at the joint between the lid and the housing base.
As shown in
FIG. 3
, the high pressure pump
184
communicates with a fuel rail or manifold
206
via a conduit
204
. A check valve (not shown) is disposed within the conduit
204
to prevent a back flow of fuel from the fuel rail
206
.
The fuel rail
206
has an elongated shape. An inlet port of the fuel rail
206
communicates with the conduit
204
which carries fuel from the high pressure pump
184
. The inlet port opens into a manifold chamber which extends along the length of the fuel rail
206
.
The fuel rail
206
communicates with each fuel injector
172
. In particular, the manifold chamber of the fuel rail
206
communicates with each a plurality of supply ports defined along the length of the fuel rail
206
. Each supply port receives an inlet end of the corresponding fuel injector
172
.
In the illustrated embodiment, the fuel rail lies generally parallel to the direction of travel of the watercraft
10
, and also to the longitudinal axis of the watercraft
10
and the rotational axis of the crankshaft
102
. The conduit
204
is desirably attached to the forward end of the fuel rail
206
. such that fuel flows through the fuel rail
206
in the direction from bow to stern in order to utilize the momentum of the fuel toward the watercraft stern to increase the pressure within the fuel rail
206
. As a result, a smaller size high pressure pump
184
can be used. Alternatively, the conduit can be attached to a rear portion of the fuel rail
206
, so that the fuel flows in the opposite direction, i.e., stern to bow, but this would require a larger size high pressure fuel pump.
A fuel return line
208
extends between an outlet port of the fuel rail
206
and the fuel bowl
180
of the vapor separator assembly
176
. The return line
208
completes the flow loop defined by the high pressure side of the fuel supply system to generally maintain a constant flow of fluid through the fuel rail
206
. The constant fuel flow through the high pressure side of the fuel delivery system inhibits heat transfer to the fuel and thus produces fuel vaporization in the fuel rail
206
.
A pressure regulator
210
is positioned along the return line
208
. The pressure regulator
210
generally maintains a desired fuel pressure at the fuel injectors
172
sufficient for direct cylinder injection. The regulator
210
regulates pressure by dumping excess fuel back to the vapor separator assembly
176
, as known in the art.
In operation, the high pressure fuel pump
184
draws fuel from the fuel bowl
180
, through the strainer
202
and through the influence port
182
. The high pressure fuel pump
184
then pressurizes the fuel and thereby pushes the fuel to the fuel rail
206
. The fuel within the fuel rail
206
is maintained at a desired pressure by the interaction between the high pressure fuel pump
184
and the pressure regulator
210
. The fuel injectors
172
are selectively operated to inject the pressurized fuel from the fuel rail
206
, directly into the cylinders.
A control system manages the operation of the engine
86
. The control system includes an electronic control unit (ECU)
212
that receives signals from various sensors regarding a variety of engine functions. As shown in FIG.
1
. ECU
212
is mounted within the hull
14
, via a support member
211
fixed to the lower hull section
16
.
As schematically illustrated in
FIG. 3
, a crank sensor
214
is positioned adjacent a peripheral edge of the flywheel
196
. The crank sensor
214
is electronically connected with the ECU
212
via an engine data line
213
. A throttle position sensor
216
is mounted to the throttle valve
162
so as to sense a position thereof. The throttle position sensor
216
is electronically connected to the ECU
212
via a throttle data line
217
.
In operation, the crank position sensor
214
senses the angular position of the crankshaft
102
and also the speed of its rotation. The sensor
214
produces a signal indicative of an angular orientation and speed, and directs the signal to the ECU
212
via the engine speed data line
213
. The throttle position sensor
216
produces a signal indicative of the throttle valve position and directs the signal to the ECU
212
via the throttle data line
217
.
The ECU
212
receives the signals from the sensors
214
and
216
to control injection timing and duration, as well as spark timing. For this purpose, the ECU
212
communicates with each fuel injector
172
, and specifically the solenoid
218
used with each fuel injector
172
, via a fuel injector control line
219
. The FCU
212
controls the operation of the solenoid
218
in order to manage fuel injection timing and duration, the latter affecting the fuel/air ratio of the produced fuel charge.
The desired stociometric fuel/air ratio will depend upon the amount of air flow into the engine
86
, which is a function of the opening degree of the throttle valve
162
. This information is stored within a memory device with which the ECU
212
communicates.
The ECU
212
thus processes the information signal received from the throttle valve sensor
162
and determines the amount of fuel to be injected for the sensed operating condition of the engine. The ECU
212
also uses the information from the crankshaft sensor
214
to determine the point during the engine's revolution to initiate fuel injection.
The control system also includes an ECU
220
for controlling ignition timing. For this purpose, the ECU
220
controls a capacitor discharge ignition unit and the firing of the spark plums
222
. File ECU
220
desirably controls the discharge of one ignition coil for each spark plug
212
.
The flywheel assembly
112
powers one or more charging coils (schematically illustrated as part of the ECU
220
) which increases the voltage of the charge eventually delivered to the spark plugs
222
. The generator formed by the flywheel assembly
112
also charges one or more batteries (not shown), as known in the art.
The arrangement of the components of the engine
86
. Engine control system, fuel supply system, and exhaust system are illustrated in
FIGS. 1-3
. The vapor separator
176
desirably lies between the front end of the engine
86
and the main fuel tank
38
, and a space in front of the flywheel. The vapor separator
176
thus lies in an air flow stream between the air ducts
28
and
52
and near the air flow into the induction system. The air flow over the vapor separator
176
tends to cool the fuel flowing, therethrough.
With reference to
FIG. 4
, and in accordance with the present invention, the engine
86
includes a liquid cooling system
12
having a cooling supply
230
. As shown in
FIG. 4
, a coolant supply
230
is formed in the propulsion unit
70
downstream from the impeller
74
. Due to the rotation of the impeller
74
during operation of the watercraft
10
, the coolant supply
230
is comprised of a high pressure area within the propulsion unit
70
. However, it is conceived that other types of watercraft may form coolant supplies in other ways (e.g., a mechanical water pump separate from the propulsion unit or an electrically driven coolant pump). Additionally, a single-engine watercraft with multiple propulsion units or a multiple engine watercraft may form a coolant supply with more than one pump.
For example, a single-engine watercraft may include two propulsion units, each having a high pressure area formed therein via the rotation of an impeller. Similarly, a multiple engine watercraft may include one or more propulsion units driven by each engine. Although the cooling systems of such watercraft may include coolant supply lines connected to each of the propulsion units, the term “coolant supply” is intended to include a coolant supply formed by one or a plurality of propulsion units, or any combination of propulsion units and other mechanically or electrically driven coolant pumps.
As shown in
FIG. 4
, and schematically in
FIG. 5
, the cooling system
12
includes an engine coolant flow path
232
having by an engine coolant jacket
233
and a discharge portion
234
.
The engine coolant jacket is connected to the coolant supply
230
via an engine coolant supply line
235
which is connected to the coolant supply via an inlet
236
. At a downstream end, the engine coolant supply line
235
is connected to the engine coolant jacket
233
formed within the engine
86
.
The engine coolant jacket
233
includes a cylinder block coolant jacket
238
in thermal communication with the cylinder block
96
and a cylinder head coolant jacket
240
in thermal communication with the cylinder head
98
. The cylinder block coolant jacket
238
is in fluid communication with the cylinder head coolant jacket
240
.
The cylinder head coolant jacket
240
includes an outlet
242
which leads to the discharge portion
234
. The discharge portion
234
includes a temperature dependent flow control valve
244
and a discharge port
248
. In the illustrated embodiment, the temperature dependent flow control valve
244
is a thermostat which is configured to open and close according to preselected temperatures.
As shown in
FIG. 5
, a relief valve
246
is connected to the outlet
242
via a relief valve line
245
, in parallel with the temperature dependent flow control valve
244
. In the illustrated embodiment, the relief valve
246
is configured to discharge water from the outlet
242
when a pressure of the water flowing through the outlet
242
is above a predetermined pressure.
As shown in
FIG. 5
, the temperature dependent flow control valve
244
and the relief valve
246
are connected to the discharge port
248
which discharges coolant to the atmosphere and/or the body of water in which the watercraft
10
is operated. Alternatively, the temperature dependent flow control valve
244
and the relief valve
246
may be connected to other portions of the cooling or exhaust systems, so as to eventually discharge the coolant flowing therethrough to the atmosphere.
In operation, pressurized water from coolant source
230
flows into inlet
236
, engine coolant supply line
235
and into the engine coolant jacket
233
. The water flowing through the engine coolant jacket
233
absorbs heat from the cylinder and head blocks
96
and
98
, to thereby cool the engine
86
.
In the illustrated embodiment, water from the propulsion device
70
is used as coolant. Coolant first enters the cylinder block coolant jacket
238
, then the cylinder head coolant jacket
240
, before being discharged through the discharge
242
. Water leaving the discharge
242
enters the temperature dependent flow control valve
244
, which, in the illustrated embodiment, is a thermostat.
When the temperature of the water flowing into the temperature dependent flow control valve
244
is within the predetermined operating range, i.e., above a predetermined threshold temperature, the temperature dependent flow control valve
244
remains open, allowing coolant to flow through the valve
244
and into the discharge port
248
. In contrast, when the temperature of the water flowing into the valve
244
is below an operating temperature, i.e., below a predetermined threshold temperature, the valve
244
closes, thereby preventing water from flowing through the engine coolant jacket flow path
232
. In such a state, the cylinder block
86
and the head block
98
will increase in temperature during normal operation of the engine
86
. However, if the pressure in the discharge
242
reaches a predetermined threshold, the relief valve
246
allows water to flow, parallel to the valve
244
, and into the discharge port
248
.
With reference to
FIGS. 4 and 5
, the liquid cooling system
12
also includes an exhaust conduit coolant flow path
250
. As shown in
FIG. 5
, the exhaust coolant jacket flow path
250
includes an exhaust conduit coolant jacket
142
and an exhaust coolant discharge portion
143
.
In the illustrated embodiment, the exhaust conduit coolant jacket
142
is connected to the coolant supply
230
via an exhaust coolant supply line
252
, which communicates with the coolant supply through an inlet
254
.
The exhaust conduit coolant jacket
142
preferably includes an exhaust manifold coolant jacket
258
in thermal communication with the exhaust manifold
134
and an exhaust pipe coolant jacket
260
in thermal communication with the C-shaped pipe
136
and the expansion chamber
146
.
The exhaust manifold coolant jacket
258
is in fluid communication with the exhaust pipe coolant jacket
260
, so that coolant flowing out of the exhaust manifold coolant jacket
258
is directed into the exhaust pipe coolant jacket
260
. A downstream end of the exhaust conduit coolant jacket
142
is connected to the exhaust coolant discharge portion
143
.
The exhaust coolant discharge portion
143
includes at least one of the exhaust conduit
133
, a telltale port
264
and a drain
270
. However, the exhaust coolant discharge portion
143
preferably includes each of the exhaust conduit
133
, the telltale port
264
and the drain
270
.
As described above with respect to the exhaust system, the exhaust conduit
133
forms a discharge of the exhaust conduit coolant jacket
260
at the terminal end
148
of the exhaust conduit coolant passage
142
, as shown in FIG.
4
. At the terminal end
148
, the exhaust pipe coolant jacket
260
opens into the exhaust conduit
133
, which terminates at the exhaust discharge
156
.
In the illustrated embodiment, the exhaust pipe coolant jacket
260
includes a discharge
262
which leads to a telltale port
264
provided on hull
14
of the watercraft
10
. The telltale port
264
is preferably arranged so as to discharge a stream of coolant in a manner that is easily seen by the operator. Arranged as such, the operator is able to verify that coolant is flowing through the cooling system
12
.
A discharge
268
communicating with the exhaust pipe coolant jacket leads directly to a drain
270
which discharges the coolant directly to the atmosphere, above or below the water line of the watercraft
10
.
During operation of the watercraft
10
, the exhaust conduit cooling flow path
250
receives a supply of pressurized coolant, e.g., pressurized water, from propulsion device
70
. Pressurized water enters the inlet
252
, flows through supply line
254
, into the exhaust manifold coolant jacket
258
and into the exhaust pipe coolant jacket
260
. The water flowing through the jackets
258
and
260
absorbs heat from the exhaust gasses flowing through the exhaust conduit
133
. The water then flows out through at least one of the discharges
148
,
262
, and
268
. Preferably the discharges
262
and
268
are preferably configured such that the remaining flow of coolant in the exhaust coolant flow path
250
is appropriate, as is known in the art.
For example, as the flow rate of coolant through the discharges
268
and
262
are increased, the flow rate of coolant through the terminal end
148
will be reduced. As is known in the art, there is a maximum flow rate of coolant through the terminal end
148
into the exhaust conduit
133
. Therefore, by appropriately configuring discharges
268
and
262
, the flow rates therethrough can be controlled so as to achieve an appropriate flow rate through the terminal end
148
.
As shown in
FIGS. 4 and 5
, the liquid cooling system
12
may optionally include a cylinder block coolant bypass line
274
extending from the cylinder block coolant jacket
238
to the exhaust manifold coolant jacket
258
, and/or a cylinder head coolant bypass line
278
extending from the cylinder head coolant jacket
240
to the exhaust manifold cooling jacket
258
. Arranged as such, the bypass supply lines
274
and
278
allow coolant to flow out of the cylinder block coolant jacket
238
and/or cylinder head coolant jacket
240
regardless of the operation of temperature dependent flow control valve
244
.
Accordingly, the exhaust conduit coolant jacket
142
may be configured to receive coolant from at least one of the coolant supply line
254
the cylinder block coolant bypass line
274
, and the cylinder head coolant bypass line
278
, while the flow therethrough will remain independent of the flow of coolant through the temperature dependent flow control valve
244
.
As shown in
FIGS. 4 and 5
, the liquid cooling system
12
may also include an oil pump coolant flow path
279
. In the illustrated embodiment, the oil pump coolant flow path
279
includes an inlet
280
connected to the coolant supply
230
, and an oil pump coolant supply line
282
connecting the inlet
280
with an oil pump coolant jacket
284
.
The oil pump coolant jacket
284
is in thermal communication with an oil pump
286
. As shown in
FIG. 6
, the oil pump cooling jacket
284
is formed in an outer surface
285
of the flywheel cover
116
. In the illustrated embodiment, the oil pump cooling jacket
284
is annular in shape and centered around an aperture
296
formed in the outer surface
285
.
As shown in
FIG. 6
, the oil pump
286
is mounted to the outer surface
285
of the flywheel cover
116
by least one bolt
298
. The oil pump
286
is arranged such that a drive shaft
300
of the oil pump
286
passes through the aperture
296
and is generally axially aligned with the crankshaft
102
.
The drive shaft
300
of the oil pump
286
is connected to the bolt
132
. The bolt
132
includes recess
302
formed in its head. A releasable coupling
304
releasably engages the drive shaft
300
with the recess
302
via a projection
305
.
Arranged as such, the oil pump cooling jacket
284
primarily cools the oil pump
286
during operation of the watercraft
10
. Additionally, in the illustrated embodiment, the oil pump cooling jacket
284
provides cooling for the flywheel assembly
112
as well.
An intermediate supply line
288
connects the oil pump coolant jacket
284
with a vapor separator coolant jacket
290
which is in thermal communication with the vapor separator assembly
176
. Although the internal details of the vapor separator coolant jacket
290
are not shown, such coolant jackets are well known in the art and a further description is not believed necessary to understand and practice the invention. The vapor separator coolant jacket
290
includes a discharge line
292
which is connected to the coolant discharge
294
which discharges coolant to the atmosphere.
Alternatively, as shown in
FIG. 5
, the vapor separator coolant jacket
290
may be supplied with coolant independently of the oil pump coolant jacket
284
. Accordingly, a vapor separator coolant path
308
extending between the coolant supply
230
and the vapor separator coolant jacket
290
may be provided. In the illustrated embodiment, the vapor separator coolant path
308
includes a vapor separator coolant supply line
310
connecting the coolant supply
230
with the vapor separator coolant jacket
290
.
Optionally, an exhaust manifold coolant bypass line
306
may be provided to connect the exhaust manifold coolant jacket
258
with the oil pump coolant jacket
284
. As such, coolant flowing through exhaust manifold coolant jacket
258
, is directed into the oil pump coolant jacket
284
.
In operation, water flows into the inlet
280
, through the supply line
282
, into the oil pump coolant jacket
284
, and the vapor separator coolant jacket
290
. After passing through the coolant jackets
284
and
290
, the coolant is then discharged through coolant discharge
294
. If the vapor separator coolant flow path
310
is included, then the vapor separator coolant jacket
290
may receive a flow of coolant from the oil pump coolant jacket
284
and/or the vapor separator coolant supply line
310
.
As set forth above, the exhaust conduit coolant jacket
142
may be supplied with coolant from at least one of the coolant supply
230
and a portion of the engine coolant jacket
236
that is upstream from the temperature dependent flow control valve
244
. Therefore, the flow of coolant through the engine exhaust conduit coolant flow path
272
is generally independent of the flow of coolant through the temperature dependent flow control valve
244
. This provides an important advantage.
For example, during operation, the temperature dependent flow control valve
244
may open and close depending on the temperature of coolant flowing therethrough. As discussed above, the coolant flowing through the temperature dependent flow control valve
244
is directed from the coolant supply and through the engine coolant jacket
236
. Therefore, if the exhaust conduit coolant jacket
142
were fed with coolant flowing out from the temperature dependent flow control valve
244
, the temperature of the exhaust conduit
136
could not influence the operation of the valve
244
.
One aspect of the present invention is the realization that exhaust systems used on modern watercraft have become overheated and have been subjected to adverse heat cycling due to the use of control devices for controlling the flow of coolant through the engine coolant jackets. For example, as a flow control device which controls the flow of coolant through an engine coolant jacket, such as the temperature dependent flow control valve
244
, opens and closes to control the temperature of the engine, such as the engine
86
, the flow of water out from the valve
244
varies. Therefore, if a downstream device, such as exhaust conduit
133
, is cooled only with water flowing out of the valve
244
, the flow of water through a water jacket formed on that device, will not necessarily correspond to the temperature of that device.
It has been found that watercraft which cool the exhaust system with water flowing out of a temperature dependent flow control device, have caused damage to their exhaust systems. Therefore, by providing the exhaust conduit coolant jacket with a supply of coolant independent of the temperature dependent flow control valve
244
, the present invention reduces the risk that the exhaust conduit
136
will be subjected to overheating and/or adverse heat cycling due to the variations in coolant flow caused by a temperature dependent flow control valve.
Although this invention has been described in terms of a certain preferred embodiment, other embodiments apparent to those of ordinary skill in the art are also within the scope of this invention. Accordingly, the scope of the invention is intended to be defined only by the claims that follow.
Claims
- 1. A watercraft comprising a propulsion system including an engine, the engine having a body defining at least one combustion chamber therein and having at least one coolant jacket therein, an exhaust conduit communicating with the at least one combustion chamber and extending to an exhaust discharge arranged to discharge exhaust gases from the at least one combustion chamber through the exhaust conduit and to the atmosphere, the exhaust conduit having a coolant jacket in thermal communication with at least a portion thereof, a coolant supply configured to generate pressurized coolant, a cooling system defining a first coolant flow path extending from the coolant supply, in a downstream direction, through the engine coolant jacket, through a temperature dependent flow control valve, and to the atmosphere, a second coolant flow path having an inlet end connected to at least one of the coolant supply and a portion of the first coolant flow path upstream of the temperature dependent flow control valve, the second coolant flow path communicating with the exhaust conduit coolant jacket and discharging coolant to the atmosphere, the second coolant flow path not being connected to any portion of the first coolant flow path downstream of the temperature dependent control valve.
- 2. A watercraft as set forth in claim 1, wherein the first coolant flow path comprises a first coolant line extending from the coolant supply to the engine coolant jacket, through the engine coolant jacket, and through the temperature dependent flow control valve, and a second coolant line extending from the temperature dependent flow control valve to at least one of an exterior of the watercraft and an interior of the exhaust conduit.
- 3. A watercraft as set forth in claim 1, wherein the portion of the first coolant flow path is upstream of the engine coolant jacket.
- 4. A watercraft as set forth in claim 1, wherein the engine coolant jacket comprises a cylinder block coolant jacket, the watercraft additionally comprising a third coolant flow path extending from the cylinder block coolant jacket to the exhaust conduit coolant jacket.
- 5. A watercraft as set forth in claim 4, wherein the exhaust conduit coolant jacket comprises an exhaust manifold coolant jacket, the second coolant flow path extending from the cylinder block coolant jacket to the exhaust manifold cooling jacket.
- 6. A watercraft as set forth in claim 1, wherein the engine coolant jacket comprises a cylinder head coolant jacket, the watercraft additionally comprising a third coolant flow path extending from the cylinder head coolant jacket to the exhaust conduit coolant jacket.
- 7. A watercraft as set forth in claim 6, wherein the exhaust conduit coolant jacket comprises an exhaust manifold coolant jacket, the second coolant flow path extending from the cylinder head coolant jacket to the exhaust manifold cooling jacket.
- 8. A watercraft as set forth in claim 7, wherein the engine coolant jacket additionally comprises a cylinder block coolant jacket, the watercraft additionally comprising a fourth coolant line extending from the cylinder block coolant jacket to the exhaust conduit coolant jacket.
- 9. A watercraft as set forth in claim 8, wherein the fourth coolant line extends from the cylinder block coolant jacket to the exhaust manifold conduit coolant jacket.
- 10. A watercraft as set forth in claim 1 additionally comprising a relief valve provided in the first coolant flow path and connected in parallel with the temperature dependent flow control valve.
- 11. A watercraft comprising a propulsion system including an engine, the engine having a body defining at least one combustion chamber therein and having at least one coolant jacket therein, an exhaust conduit communicating with the at least one combustion chamber and extending to an exhaust discharge arranged to discharge exhaust gases from the at least one combustion chamber through the exhaust conduit and to the atmosphere, the exhaust conduit having a coolant jacket in thermal communication with at least a portion thereof, a coolant supply configured to generate pressurized coolant, a cooling system defining a first coolant flow path extending from the coolant supply, in a downstream direction, through the engine coolant jacket, and through a temperature dependent flow control valve, a second coolant flow path extending from at least one of the coolant supply and a portion of the first coolant flow path upstream of the temperature dependent flow control valve, the second coolant flow path communicating with the exhaust conduit coolant jacket, an oil pump configured to generate pressurized oil for the engine and having a oil pump coolant jacket, and a third coolant flow path extending from at least one of the coolant supply and the first coolant flow path at a position upstream of the temperature dependent flow control valve, and extending to the oil pump coolant jacket.
- 12. A watercraft as set forth in claim 11 additionally comprising a fourth coolant flow path extending from the exhaust conduit coolant jacket to the oil pump coolant jacket.
- 13. A watercraft as set forth in claim 11 additionally comprising a flywheel cover mounted to an end of the engine, the oil pump cooling jacket comprising a coolant passage defined in the flywheel cover.
- 14. A watercraft as set forth in claim 1 additionally comprising a fuel vapor separator having a vapor separator coolant jacket and a third coolant flow path extending from at least one of the coolant supply and the first coolant flow path at a position upstream from the temperature dependent flow control valve, and extending to the vapor separator coolant jacket.
- 15. A watercraft as set forth in claim 14 additionally comprising an oil pump having an oil pump coolant jacket, and a fourth coolant flow path extending from the oil pump coolant jacket to the vapor separator coolant jacket.
- 16. A watercraft comprising a propulsion system wherein the propulsion system comprises an engine including a body defining at least one combustion chamber therein and having at least one coolant jacket therein, an exhaust conduit communicating with the least one combustion chamber and extending to an exhaust discharge arranged to discharge exhaust gases from the at least one combustion chamber through the exhaust conduit and to the atmosphere, the exhaust conduit having an exhaust conduit coolant jacket in thermal communication with at least a portion thereof, a coolant supply configured to generate pressurized coolant, a cooling system defining a first coolant flow path extending from the coolant supply, in a downstream direction, through the engine coolant jacket, and through a temperature dependent flow control device, and means for supplying the exhaust conduit coolant jacket with coolant from the coolant supply independently from the temperature dependent flow control device and for discharging coolant from the exhaust conduit coolant jacket independently from an entire portion of the first coolant supply path downstream from the temperature dependent flow control valve.
- 17. A watercraft comprising a propulsion system wherein the propulsion system comprises an engine including a body defining at least one combustion chamber therein and having at least one coolant jacket therein, an exhaust conduit communicating with the least one combustion chamber and extending to an exhaust discharge arranged to discharge exhaust gases from the at least one combustion chamber through the exhaust conduit and to the atmosphere, the exhaust conduit having an exhaust conduit coolant jacket in thermal communication with at least a portion thereof, a coolant supply configured to generate pressurized coolant, a cooling system defining a first coolant flow path extending from the coolant supply, in a downstream direction, through the engine coolant jacket, and through a temperature dependent flow control device, means for supplying the exhaust conduit coolant jacket with coolant from the coolant supply independently from the temperature dependent flow control device, an oil pump configured to generate pressurized oil for the engine, the oil pump including an oil pump coolant jacket, and means for supplying coolant to the oil pump coolant jacket.
- 18. A watercraft as set forth in claim 16 additionally comprising a fuel vapor separator having a vapor separator coolant jacket, and means for supplying coolant to the vapor separator coolant jacket.
US Referenced Citations (7)
Foreign Referenced Citations (7)
Number |
Date |
Country |
7-156885 |
Jun 1995 |
JP |
9-041963 |
Feb 1997 |
JP |
9-041965 |
Feb 1997 |
JP |
9-041966 |
Feb 1997 |
JP |
9-254882 |
Sep 1997 |
JP |
9-317426 |
Dec 1997 |
JP |
10-238358 |
Sep 1998 |
JP |