Note: Descriptions are shown in the official language in which they were submitted.
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TITLE: Sensor Arrangement Structure for Personal
watercraft
FIELD OF THE INVENTION
This invention relates to a sensor arrangement
structure for an engine for a personal watercraft.
BACKGROUND OF THE INVENTION
Conventionally, a personal watercraft is known
wherein an engine for driving a jet propulsion pump is
provided in a watercraft body surrounded by a hull and a
deck.
In a personal watercraft of the type described,
an intake duct for supplying air into the watercraft body
is provided. From an opening of the intake duct on the
inner side of the watercraft body, water is sometimes
admitted in the form of droplets into the watercraft body
together with air. If an engine controlling sensor is
splashed with the water, then there is the possibility
that a wrong signal may be inputted from the sensor to a
control apparatus for the engine and cause the engine to
operate inappropriately.
In order to eliminate such a disadvantage as
just described, a personal watercraft has already been
proposed wherein an engine controlling sensor is disposed
above an opening of an intake duct on the inner side of a
watercraft body (Japanese Patent Laid-Open No. Hei 10-
318014).
With the personal watercraft described above,
since the engine controlling sensor is provided above the
opening of the intake duct on the inner side of the
watercraft body, even if water is introduced in the form
of droplets into the space in the watercraft body when
the atmospheric air outside the watercraft body is
introduced into the space in the watercraft body through
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the intake duct during traveling of the personal
watercraft, the water is less likely to splash the
sensor, and the engine is likely to operate
appropriately.
Since usually a personal watercraft of the type
described is frequently utilized for leisure, such a
situation that some water enters the inside of the
watercraft body occurs frequently.
Further, a personal watercraft frequently
undergoes sudden turn or violent rolling because it is in
most cases utilized for leisure.
In such a situation as just described, in the
conventional personal watercraft described above, since
the engine controlling sensor is merely disposed above
the opening of the intake duct on the inner side of the
watercraft body, if the personal watercraft turns
suddenly or rolls violently in a state wherein some water
is admitted in the watercraft body, then the water in the
watercraft body is excited and is likely to splash the
engine controlling sensor. Therefore, the conventional
personal watercraft described above still has the
possibility that the engine may be hindered from
operating appropriately.
In other words, the prior art described above
does not present a sufficient countermeasure for
prevention of the engine controlling sensor from being
splashed with water. .
The object of the present invention resides in
solution of such a problem as described above and
provision of a sensor arrangement structure for an engine
for a personal watercraft which takes a sufficient
countermeasure for prevention of an engine controlling
sensor from being splashed with water so that the engine
operates appropriately.
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SUMMARY OF THE INVENTION
In order to attain the object described above,
according to the present invention, a sensor arrangement
structure for an engine for a personal watercraft is
characterized in that an engine for driving a jet
propulsion pump is provided in a watercraft body
surrounded by a hull and a deck, that a throttle body and
a surge tank contiguous to the throttle body are provided
on an intake side of the engine, that a horizontal
partition assembly extending iri a forward and backward
direction and extending in a substantially horizontal
direction at an upper potion of the engine is formed from
the throttle body and the surge tank, and that a sensor
for controlling the engine is disposed above the
horizontal partition assembly.
According to an aspect of the invention, the
sensor arrangement structure for an engine for a personal
watercraft according to the above is characterized in
that the engine is provided with a supercharger which
communicates with the surge tank through an intercooler
and a supercharged pressure sensor and/or a temperature
sensor of air of the supercharger is provided above the
surge tank, and the intercooler is disposed just below
the surge tank.
According to another aspect of the invention,
the sensor arrangement structure for an engine for a
personal watercraft according to the above is
characterized in that an intake pressure sensor for
detecting an intake pressure of the throttle body on the
downstream side of the throttle is disposed rather near
to a head cover of the engine between the head cover and
the surge tank.
According to yet another aspect of the
invention, the sensor arrangement structure for an engine
for a personal watercraft according to the above is
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characterized in that the intake pressure sensor is
attached to the head cover in such a state that the
intake pressure sensor is spaced away from an upper face
of the throttle body.
According to yet another aspect of the
invention, the sensor arrangement structure for an engine
for a personal watercraft according to any one of the
above is characterized in that an opening which is closed
up with a removable lid member is provided in an upper
portion of the deck, and the sensor is exposed to the
opening.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention are
shown in the drawings, wherein:
FIG. 1 is a schematic side elevational view
showing an embodiment of a personal watercraft in which
an embodiment of a sensor arrangement structure for a
personal watercraft according to the present invention is
employed.
FIG. 2 is a plan view of the same.
FIG. 3 is a partial enlarged sectional view
(partly omitted sectional view) taken along line III-III
of FIG. 1.
FIG. 4 is a view principally showing an engine
20 and is a partial enlarged sectional view (partly
omitted sectional view) taken along line IV-IV of FIG. 1.
FIG. 5 is a schematic perspective view of the
engine 20 as viewed from obliquely rearwardly.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the following, preferred embodiments of the
present invention are described with reference to the
drawings.
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FIG. 1 is a schematic side elevational view
showing an embodiment of a personal watercraft which
employs an embodiment of a sensor arrangement structure
for an engine for a personal watercraft according to the
present invention, FIG. 2 is a plan view of the same, and
FIG. 3 is a partial enlarged sectional view (partly
omitted sectional view) taken along line III-III of FIG.
1.
As shown in the figures (principally in FIG.
1), this personal watercraft 10 is a small watercraft of
the saddle type, and a driver can sit on a seat 12 on a
watercraft body 11 and grip a steering handle 13 with a
throttle level to steer the personal watercraft 10.
The watercraft body 11 has a floating body
structure wherein a hull 14 and a deck 15 are joined
together such that a space 16 is formed in the inside
thereof. In the space 16, an engine 20 is mounted on the
hull 14, and a jet pump (jet propulsion pump) 30 as
propulsion means which is driven by the engine 20 is
provided at a rear portion of the hull 14.
An intake duct 18, 19 for supplying intake air
into the watercraft body (space 16) is provided on the
watercraft body 11.
The jet pump 30 has a passage 33 extending from
an intake 17 open to the watercraft bottom to a jet
outlet 31 and a nozzle 32 open to the rear end of the
watercraft body and an impeller 34 disposed in the
passage 33, and a shaft 35 of the impeller 34 is
connected to an output power shaft 20a of the engine 20.
Accordingly, if the impeller 34 is driven to rotate by
the engine 20, then water taken in from the intake 17 is
jetted from the nozzle 32 through the jet outlet 31 so
that the watercraft body 11 is propelled. The driving
speed of the engine 20, that is, the propelling force by
the jet pump 30, is operated by a turning operation of a
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throttle lever 13a (refer to FIG. 2) of the steering
handle 13 described above. The nozzle 32 is operatively
associated with the steering handle 13 by an operation
wire not shown such that it is pivoted by an operation of
the steering handle 13, and the advancing direction can
be changed thereby.
It is to be noted that reference numeral 40
denotes a fuel tank, and 41 an accommodation chamber.
FIG. 4 is a view principally showing the engine
20 and is a partial enlarged sectional view (partly
omitted sectional view) taken along line IV-IV of FIG. 1.
FIG. 5 is a schematic perspective view of the engine 20
as viewed from obliquely rearwardly.
The engine 20 is a DOHC in-line 4-cylinder 4
cycle engine and is disposed such that a crankshaft
(refer to the output power shaft 20a) thereof extends in
the forward and backward direction of the body 11 as
shown in FIG. 1. Further, as can be seen apparently from
FIG. 4, the engine 20 is carried on the watercraft body
11 in a state wherein a vertical axis (center axis)
thereof is inclined in the counterclockwise direction as
viewed in front elevation (FIG. 4).
As shown in FIG. 4, an intake opening (intake
port) 21 is disposed on the left side of the engine 20
with respect to the advancing direction of the watercraft
body 11, and an exhaust opening (exhaust port) 24 is
disposed on the right side of the engine 20. Four such
intake openings (intake ports) 21 and four such exhaust
openings (exhaust ports) 24 are disposed along the
forward and backward direction of the engine 20.
A throttle body 22 and a surge tank (intake
chamber) 23 which communicate with the intake opening 21
are connected to the intake opening 21. The throttle
body 22 and the surge tank 23 form a horizontal partition
assembly A which extends in the forward and backward
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direction (refer to FIG. 5) and extends in a
substantially horizontal direction at an upper portion of
the engine 20.
An intercooler 50 is connected to and disposed
just below the surge tank 23. Reference numerals 52 and
53 denote mounting brackets for mounting the intercooler
50 on the engine 20.
As shown in FIGS. 4 and 5, the intercooler 50
includes a case 51 having an intake entrance 51i
connected for communication by a pipe 72 to a compressor
section 71 of a supercharger (turbocharger) 70 disposed
immediately rearwardly of the engine 20 and an exit 510
connected to an intake entrance 23a of the surge tank 23
by a tube 51c, and a cooling unit 60 (refer to FIG. 4)
accommodated in the case 51 and serving as a heat
exchanging unit.
Referring to FIG. 5, reference numerals 91 and
92 denote cooling water hoses connected to the
intercooler 50.
Meanwhile, as shown in FIG. 4, an exhaust
manifold 25 (refer to FIG. 1) is provided at the exhaust
opening 24 of the engine 20 such that it extends in the
direction of the arrangement of the exhaust opening 24,
that is, in the forward and backward direction of the
engine 20, and an exhaust exit 250 (refer to FIG. 5)
provided at a rear end of the exhaust manifold 25 is
connected to a turbine portion 73 of the supercharger 70.
It is to be noted that exhaust gas having
rotated the turbine in the turbine portion 73 passes
successively through an exhaust pipe 74, a back flow
preventing chamber 75 for preventing backflow of water
upon upsetting (admission of water into the supercharger
70 and so forth), a water muffler 76 and an exhaust-
drainage pipe 77 and is discharged into a water stream
formed by the jet pump 30 as seen in FIGS. 1 and 2.
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As shown in FIGS. 4 and 5, a sensor 80 for air
supplied from the supercharger 70 through the intercooler
50 is provided at an upper portion of the surge tank 23
(accordingly, at an upper portion of the horizontal
partition assembly A). The sensor 80 is disposed above
the throttle body 22 (accordingly, above the horizontal
partition assembly A) as can be seen apparently from
FIGS. 4 and 5. The sensor 80 is communicated with the
inside of the surge tank 23 by a pipe 80a and is
electrically connected to an engine control circuit (not
shown). The sensor 80 may be formed as a supercharged
pressure sensor for detecting the pressure of air
(supercharged pressure) in the surge tank 23 or may
alternatively be formed as a temperature sensor for
detecting the temperature of air in the surge tank 23.
The sensor 80 may otherwise be formed as a supercharged
pressure and temperature sensor which detects not only
the pressure of air (supercharged pressure) in the surge
tank 23 but also the temperature of the air. Further,
while a single sensor 80' is shown in the figures, it is
possible to provide a supercharged pressure sensor for
detecting the pressure of air (supercharged pressure) in
the surge tank 23 and a temperature sensor for detecting
the temperature of air in the surge tank 23 separately
from each other (i.e., to provide totaling two sensors)
at an upper portion of the surge tank 23.
An intake pressure sensor 81 for detecting the
intake pressure on the downstream side with respect to a
throttle (throttle valve) 22a in the throttle body 22 is
disposed rather near to a head cover 26 of the engine 20
between the head cover 26 and the surge tank 23. The
sensor 81 is attached to the head cover 26 by a mounting
member 82 and is disposed above the throttle body 22
(accordingly, above the horizontal partition assembly A)
as can be seen apparently from FIGS. 4 and 5. Further,
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the intake pressure sensor 81 is attached by the mounting
member 82 in a state wherein it is spaced away from an
upper face of the throttle body 22. The sensor 81 is
communicated with the inside of an intake path on the
downstream side with respect to the throttle valve 22a of
the throttle body 22 by a pipe 81a and is electrically
connected to the engine control circuit (not shown).
Such engine controlling sensors 80 and 81 as
described above are provided at positions higher than
watercraft body inside openings 18a and 19a of the intake
ducts 18 and 19 as can be seen apparently from FIG. 1.
Further, an opening 15a is provided at an upper
portion of the deck 15 as shown in FIG. 4, and the
sensors 80 and 81 are exposed to the opening 15a. The
opening 15a of the deck 15 is opened by removing the seat
12 serving as a lid member removably mounted on the
watercraft body 11 from the watercraft body 11.
~nlith the sensor arrangement structure for an
engine for a personal watercraft having such a
configuration as described above, the following operation
and effects are achieved.
(a) The sensor arrangement structure for an engine for a
personal watercraft is structured such that an engine 20
for driving a jet propulsion pump 30 is provided in a
watercraft body 11 surrounded by a hull 14 and a deck 15,
that a throttle body 22 and a surge tank 23 contiguous to
the throttle body 22 are provided on an intake side of
the engine 20, that a horizontal partition assembly A
extending in a forward and backward direction and
extending in a substantially horizontal direction at an
upper portion of the engine 20 is formed from the
throttle body 22 and the surge tank 23, and that a sensor
80, 81 for controlling the engine is disposed above the
horizontal partition assembly A. Therefore, even if the
personal watercraft 10 turns suddenly or rolls violently
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in a state wherein some water is admitted in the
watercraft body 11 and the water in the watercraft body
11 is excited and tends to move toward the sensor 80, 81,
the water is in most cases hindered by the horizontal
partition assembly A formed from the throttle body 22 and
the surge tank 23 in such a state that it extends in a
forward and backward direction and extends in a
substantially horizontal direction above the engine 20,
and is less likely to splash the sensor 80, 81.
Accordingly, such a situation that the sensor
80, 81 for controlling the engine becomes wet with water
is less likely to occur, and such a situation that a
wrong signal is inputted from the sensor 80, 81 to a
control apparatus for the engine is less likely to occur.
Therefore the engine 20 is likely to operate
appropriately.
(b) The engine 20 is provided with a supercharger 70
which communicates with the surge tank 23 through an
intercooler 50 and a supercharged pressure sensor (and/or
a temperature sensor) 80 of air of the supercharger 70 is
provided above the surge tank 23, and the intercooler 50
is, disposed just below the surge tank 23. Therefore,
even if the water in the watercraft body 11 is excited
and tends to move toward the sensor 80, it is hindered
also by the intercooler 50 disposed just below the surge
tank 23 and is less likely to splash the supercharged
pressure sensor (and/or a temperature sensor) 80.
Accordingly, such a situation that the sensor
80 for controlling the engine with a supercharger becomes
wet with water is less likely to occur, and such a
situation that a wrong signal is inputted from the sensor
80 to the control apparatus for the engine with a
supercharger is less likely to occur. Therefore the
engine with a supercharger is likely to operate
appropriately.
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(c) An intake pressure sensor 81 for detecting an intake
pressure of the throttle body 22 on the downstream side
of the throttle valve 22a is disposed rather near to a
head cover 26 of the engine 20 between the head cover 26
and the surge tank 23. Therefore, the intake pressure
sensor 81 is disposed at a high position at the
substantially center in the widthwise direction of the
watercraft body.
Accordingly, even if the water in the
watercraft body 11 is excited and tends to move toward
the intake pressure sensor 81, such a situation that the
intake pressure sensor 81 becomes wet with water is less
likely to occur, and such a situation that a wrong signal
from the intake pressure sensor 81 is inputted to the
control apparatus for the engine 20 is less likely to
occur. Therefore the engine 20 is likely to operate
appropriately.
Particularly, a personal watercraft of the type
described is utilized principally for leisure, it turns
quickly or rolls over a great amount (rocks in the
clockwise direction or the counterclockwise direction in
FIG. 4) or may be upset in an extreme case. Also in such
an instance, with the sensor arrangement structure of the
present embodiment, since water admitted in the
watercraft body 11 is less likely to splash the sensor
80, 81, particularly the intake pressure sensor 81
disposed at a high position at the substantially center
in the widthwise direction of the watercraft body,
appropriate operation of the engine 20 can be achieved.
(d) The intake pressure sensor 81 is attached to the head
cover 26 in such a state that the intake pressure sensor
81 is spaced away from an upper face of the throttle body
22. Therefore, even if the intake pressure sensor 81
should be splashed with water or some water should stay
on the upper face of the throttle body 22, the water is
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retracted (removed) rapidly from around the intake
pressure sensor 81.
Accordingly, even if the intake pressure sensor
81 should become wet with water, this state is eliminated
in a short time, and a situation wherein there is the
possibility that a wrong signal may be inputted from the
intake pressure sensor 81 to the control apparatus for
the engine is likely to be eliminated in a short time,
and the engine 20 is likely to operate appropriately.
Further, since the intake pressure sensor 81 is
attached to the head cover 26, the intake pressure sensor
81 can be attached readily in a state wherein it is
spaced away from the upper face of the throttle body 22
with certainty.
(e) An opening 15a which is closed up with an openable
and closeable lid member 12 is provided in an upper
portion of the deck 15, and the sensor 80, 81 is exposed
to the opening 15a. Therefore, if the lid member 12 is
opened, then a checking operation of the sensor 80, 81
and an upper portion of the engine 20 can be performed
readily.
(f) Since an intake duct 18, 19 for supplying intake air
into the watercraft body 11 is provided on the watercraft
body 11 and the sensor 80, 81 is provided at a position
higher than a watercraft body inner side opening 18a, 19a
of the intake duct 18, 19, when the atmospheric air
outside the watercraft body 11 is introduced into the
space 16 in the watercraft body 11 through the intake
duct 18, 19 during traveling of the personal watercraft
10, even if it is introduced in together with water (for
example, in the form of droplets), such a situation that
the water splashes the sensor 80, 81 is less likely to
occur.
Accordingly, such a situation that the sensor
80, 81 for controlling the engine becomes wet with water
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is further less likely to occur, and such a situation
that a wrong signal is inputted from the sensor 80, 81 to
the control apparatus for the engine 20 is further less
likely to occur. Therefore the engine 20 operates
further appropriately.
According to the present invention, a sensor
arrangement structure for an engine for a personal
watercraft is structured such that an engine for driving
a jet propulsion pump is provided in a watercraft body
surrounded by a hull and a deck, that a throttle body and
a surge tank contiguous to the throttle body are provided
on an intake side of the engine, that a horizontal
partition assembly extending in a forward and backward
direction and extending in a substantially horizontal
direction at an upper portion of the engine is formed
from the throttle body and the surge tank, and that a
sensor for controlling the engine is disposed above the
horizontal partition assembly. Therefore, even if the
personal watercraft turns suddenly or rolls violently in
a state wherein some water is admitted in the watercraft
body and the water in the watercraft body is excited and
tends to move toward the sensor, the water is in most
cases hindered by the horizontal partition assembly
formed from the throttle body and the surge tank in such
a state that it extends in a forward and backward
direction and extends in a substantially horizontal
direction above the engine, and is less likely to splash
the sensor.
Accordingly, such a situation that the sensor
for controlling the engine becomes wet with water is less
likely to occur, and such a situation that a wrong signal
is inputted from the sensor to a control apparatus for
the engine is less likely to occur. Therefore the engine
is likely to operate appropriately.
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According to an embodiment of the invention,
the sensor arrangement structure for an engine for a
personal watercraft according to the above is structured
such that the engine is provided with a supercharger
which communicates with the surge tank through an
intercooler and a supercharged pressure sensor and/or a
temperature sensor of air of the supercharger is provided
above the surge tank, and the intercooler is disposed
just below the surge tank. Therefore, even if the water
in the watercraft body is excited and tends to move
toward the sensor, it is hindered also by the intercooler
disposed just below the surge tank and is less likely to
splash the supercharged pressure sensor and/or the
temperature sensor.
Accordingly, such a situation that the sensor
for controlling the engine with a supercharger becomes
wet with water is less likely to occur, and such a
situation that a wrong signal is inputted from the sensor
to the control apparatus for the engine with a
supercharger is less likely to occur. Therefore the
engine with a supercharger is likely to operate
appropriately.
According to another embodiment of the
invention, the sensor arrangement structure for an engine
for a personal watercraft according to the above is
structured such that an intake pressure sensor for
detecting an intake pressure of the throttle body on the
downstream side of the throttle valve is disposed rather
near to a head cover of the engine between the head cover
and the surge tank. Therefore, the intake pressure
sensor is disposed at a high position at the
substantially center in the widthwise direction of the
watercraft body.
Accordingly, even if the water in the
watercraft body is excited and tends to move toward the
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intake pressure sensor, such a situation that the intake
pressure sensor becomes wet with water is less likely to
occur, and such a situation that a wrong signal from the
intake pressure sensor is inputted to the control
apparatus for the engine is less likely to occur.
Therefore the engine is likely to operate appropriately.
According to another embodiment of the
invention, the sensor arrangement structure for an engine
for a personal watercraft according to the above is
structured such that the intake pressure sensor is
attached to the head cover in such a state that the
intake pressure sensor is spaced away from an upper face
of the throttle body. Therefore, even if the intake
pressure sensor should be splashed with water or some
water should stay on the upper face of the throttle body,
the water is retracted (removed) rapidly from around the
intake pressure sensor.
Accordingly, even if the intake pressure sensor
should become wet with water, this state is eliminated in
a short time, and a situation wherein there is the
possibility that a wrong signal may be inputted from the
intake pressure sensor to the control apparatus for the
engine is likely to be eliminated in a short time, and
the engine is likely to operate appropriately.
Further, since the intake pressure sensor is
attached to the head cover, the intake pressure sensor
can be attached readily in a state wherein it is spaced
away from the upper face of the throttle body with
certainty.
According to another embodiment of the
invention, the sensor arrangement structure for an engine
for a personal watercraft according to the above is
structured such that an opening which is closed up with a
removable lid member is provided in an upper portion of
the deck, and the sensor is exposed to the opening.
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Therefore, if the lid member is opened, then a checking
operation of the sensor can be performed readily.
Although various preferred embodiments of the
present invention have been described herein in detail,
it will be appreciated by those skilled in the art, that
variations may be made thereto without departing from the
spirit of the invention or the scope of the appended
claims.
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