Information
-
Patent Grant
-
6485342
-
Patent Number
6,485,342
-
Date Filed
Friday, August 17, 200123 years ago
-
Date Issued
Tuesday, November 26, 200222 years ago
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Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
-
International Classifications
-
Abstract
An outboard motor is provided, the motor including a V-multicylinder engine arranged horizontally and an intake silencer arranged above the engine. The V engine has an engine block including cylinder blocks extending in a V configuration, forming an opening to the rear of the outboard motor. The intake silencer is arranged above the engine block to match the shape of the V engine. The intake silencer has two inlets opening rearwards of the outboard motor and one outlet positioned between the inlets for introducing air to combustion chambers of the cylinder heads. The two inlets are positioned above the cylinder blocks in a V configuration, respectively.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an improved outboard motor with an intake silencer.
2. Description of the Related Art
Intake noise caused by outboard motors without intake silencers or outboard motors with intake openings directed to the hulls to which they are mounted, is transmitted directly to operators. To prevent it, outboard motors have been provided with intake silencers in the passage of intake air to reduce intake noise. An outboard motor with such an intake silencer is disclosed, for example, in Japanese Patent Laid-Open Publication No. HEI-8-310487.
This outboard motor has an intake silencer interposed in the induction system of an engine. The induction system has a throttle body arranged in the laterally and generally middle part in the front portion of an engine room in the outboard motor, and takes air in from both right and left sides of the throttle body. Thus the total cross-sectional area of two intake openings of the intake silencer is greater than the cross-sectional area of the intake air passage of the throttle body, securing a sufficient amount of intake air.
The above conventional intake silencer is arranged to face the hull (in the front portion of the outboard motor in the advancing direction), and the intake openings face upwards in the vertical direction, so that intake noise is directly transmitted to an operator, resulting in an unsatisfactory endeavor in the reduction of intake noise.
SUMMARY OF THE INVENTION
The present invention was made with the above points in mind and it is accordingly an object of the present invention to provide a V-engine-mounted outboard motor in which intake noise is prevented from being directly transmitted to an operator without making the outboard motor larger.
According to the present invention, there is provided an outboard motor comprising: a V engine arranged in a horizontal direction, the engine comprising: an engine block comprising two cylinder blocks extending in a V configuration, forming an opening to the rear of the outboard motor, and a skirt integrally formed with the cylinder blocks and housing a crankshaft arranged vertically; and two cylinder heads having a plurality of combustion chambers, being provided at the rear ends of the cylinder blocks; and an intake silencer comprising: two inlets positioned above the cylinder heads and opening rearwards of the outboard motor for taking air in; and one outlet positioned between the two inlets for letting the inlet air out to supply it to the combustion chambers.
Thus in the present invention, the V configuration of the V engine mounted to the outboard motor is utilized to sufficiently secure the volume of an expansion chamber and the opening of the intake silencer while making the lateral dimension of the intake silencer smaller than that of the opening end of the V configuration. The two inlets open rearwards of the outboard motor so as to prevent intake noise from being directly transmitted to an operator, thereby increasing the noise dampening effect of the intake silencer. Further, since upper space of the engine block is utilized to arrange the intake silencer therein, the dimension of the outboard motor in the back and forth direction is made smaller, making the outboard motor compact. Furthermore, since the two inlets are provided, a cross-sectional area of each inlet is made smaller, saving space.
The outboard motor further comprises a transmission system for transmitting drive force from the crankshaft to a camshaft for opening or closing intake valves and exhaust valves provided in the combustion chambers, the transmission system being provided between the engine block and the intake silencer.
Thus, since the intake silencer is arranged above the transmission system provided above the engine block, space above the transmission system is usable, making the outboard motor compact.
It is preferred that a throttle body connected to the outlet of the intake silencer be arranged between the cylinder heads extending in a V configuration above the camshaft of the transmission system so that space is efficiently utilized without waste. The outlet of the intake silencer is connected to the throttle body via a grommet in an embodiment, for example.
In the present invention, the intake silencer has a body with a top wall configured flat. Thus the height of the intake silencer is made smaller, resulting in the smaller height of the outboard motor.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the present invention will be described below, by way of example only, with reference to the accompanying drawings, in which:
FIG. 1
is a partly sectional view of an outboard motor according to the present invention;
FIG. 2
is a perspective view of an intake silencer as shown in
FIG. 1
;
FIG. 3
is a horizontal sectional view of an upper portion of the outboard motor in
FIG. 1
;
FIG. 4
is a rear view of the outboard motor in
FIG. 3
with an engine cover omitted, showing the relationships in height between the intake silencer, cylinder head covers, and an intake manifold; and
FIG. 5
is a sectional view taken along line
5
—
5
in FIG.
4
.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In an embodiment as shown in the drawings, Fr denotes a forward direction as an advancing direction of the ship and Rr denotes a rearward direction.
Referring to
FIGS. 1 and 3
, an outboard motor
1
of the present invention has an engine
4
housed in an engine room
3
defined by an engine cover
2
constituting the contour of the motor
1
. The engine
4
is a V-engine in a plan view with two cylinder blocks
5
extending right and left in the rearward direction, forming an opening (See FIG.
3
). Each cylinder block
5
has a plurality of generally horizontal cylinders
5
a
arranged in the vertical direction. A piston
5
b
is fitted into each cylinder
5
a.
A cylinder head
6
is connected to the rear end of each cylinder block
5
. A cylinder head cover
7
is connected to the rear end of the cylinder head
6
. A plurality of combustion chambers communicating with the horizontal cylinders
5
a
are formed between the cylinder head
6
and the cylinder block
5
.
The cylinder blocks
5
integrally have a skirt
8
in the front portion. The skirt
8
houses a crankshaft
8
a
extending in the vertical direction. The cylinder blocks
5
together with the skirt
8
constitute an engine block
9
.
The skirt
8
is connected at its front end (in the forward portion of the outboard motor) to a crankcase
10
. A generator
11
is mounted on an upper front part of the crankcase
10
.
A bottom block
12
of the engine
4
is supported on a mounting case
14
provided inside an under cover
13
. The lower end
8
b
of the crankshaft
8
a
extends vertically downwards below the under cover
13
and is connected to the top end of a drive shaft
15
extending vertically through an extension case not shown. The lower end of the drive shaft
15
is connected to a gear box not shown for driving a screw.
In the figure, reference numeral
16
denotes an oil pan provided below the bottom block
12
,
17
denotes a stern bracket for mounting the outboard motor to a stern, and
17
a
denotes a tilt shaft for supporting the outboard motor rotatably.
An exhaust pipe
18
is provided on the side of the cylinder head
6
, extending downwards. The top end of the crankshaft
8
a
projects from the top surface of the crankcase
10
of the engine block
9
. To the top end, a camshaft drive pulley
19
for driving a camshaft
37
is fixed. A camshaft driven pulley
20
is provided above the cylinder head
6
. A timing belt
22
is wound around the drive pulley
19
and the driven pulley
20
through a middle pulley
21
.
Rotation of the crankshaft
8
a
causes the camshaft
37
to rotate through the drive pulley
19
, belt
22
and driven pulley
20
.
Above the drive pulley
19
, a generator drive pulley
23
for driving the generator
11
is fixed to the upper end of the crankshaft
8
a.
The drive pulley
23
is connected to a generator pulley
24
provided above the generator
11
through a belt
25
. The generator
11
is driven through the rotation of the crankshaft
8
a.
Above the generator pulley
24
, a belt cover
26
is provided.
The intake silencer
50
according to the present invention is arranged between a transmission system comprising the belt and pulleys
19
to
23
, and an upper cover
2
b
of the engine cover
2
.
The intake silencer
50
has an expansion chamber
51
inside and also has two inlets
54
,
54
and one outlet
52
(See
FIG. 2
) to be described later. The intake silencer
50
is connected at the outlet
52
to a throttle body
27
via a grommet
28
. The throttle body
27
communicates with an intake manifold
29
to distribute and supply fuel to the combustion chambers
5
c
as will be described later.
The engine cover
2
has a rear cover
2
a,
the upper cover
2
b,
a front cover
2
c
and right and left covers
2
d,
2
d
(see FIG.
3
). The lower end of the engine cover
2
is put on the top end of the under cover
13
to be joined. The engine cover
2
is formed with a recess
2
e
in a rear top surface. The recess
2
e
has an air inlet opening
2
f
for letting air in. The air inlet opening
2
f
lies in the same plane and communicates with an upper end opening
30
a
of an air intake guide
30
provided between the inside of the rear cover
2
a
of the engine cover
2
and the rear surface (outer surface) of the intake manifold
29
. A lower end opening
30
b
of the intake guide
30
communicates with a rear portion of the engine room
3
. The upper part of the recess
2
e
including the air inlet opening
2
f
is covered with a top cover
31
.
The front cover
2
c
of the engine cover
2
has a labyrinth passage
33
configured to prevent water invasion by means of an upper and lower vertical walls spaced back and forth. A front lower part of the front cover
2
c
formed with the labyrinth passage
33
is covered by a front cover
34
including a plurality of air inlet slits
35
. An upper front part of the front cover
2
c
is formed with a recess
2
g.
The recess
2
g
has an air inlet opening
2
h.
Air enters from the slits
35
in the front cover
34
, passes through the labyrinth passage
33
to be introduced into the space below the generator and is further taken in through the upper openings
2
h,
26
a
to be supplied to the generator
11
, thereby cooling it.
FIG. 2
shows on an enlarged scale the intake silencer
50
of FIG.
1
. The intake silencer
50
has a body
53
with a dimension larger in the lateral direction (in the width direction of the outboard motor) in this embodiment. The body
53
has the expansion chamber
51
inside as shown in FIG.
1
. The body
53
also has on the right and left in the rear thereof two inlets
54
,
54
projecting rearwards in obliquely outward directions in a symmetrical relationship. The outlet
52
as illustrated in
FIG. 1
is positioned between the two inlets
54
,
54
and is arranged to project rearwards.
A top wall of the body
53
of the intake silencer
50
is configured to be substantially flat as shown in FIG.
1
and
FIG. 5
to be described later, so that the intake silencer
50
has a smaller height, thereby reducing the height of the outboard motor.
The body
53
has a plurality of mounting stays
55
having respective mounting holes
55
a
in the four peripheral corners. The body
53
also has at its front an extension
56
constituting part of the belt cover
26
as shown in FIG.
1
.
FIG. 3
is a horizontal cross-sectional view of an upper part of the outboard motor as shown in FIG.
1
.
The inlets
54
,
54
on the right and left of the intake silencer
50
are positioned above the V cylinder heads
6
,
6
extending rearwards Rr of the outboard motor
1
.
The outlet
52
positioned between the right and left inlets
54
,
54
is connected to the throttle body
27
via the grommet
28
. The throttle body
27
is connected to an inlet of the intake manifold
29
. The intake manifold
29
has six intake pipes
29
a
(only two shown in
FIG. 3
) extending from the right and left of a recessed surface of the front part thereof, to supply fuel to the combustion chambers
5
c
(See
FIG. 1
) of the cylinder heads
6
,
6
. On the outer side of each cylinder head
6
are provided a plurality of exhaust manifolds
18
a
which are connected to the exhaust pipe
18
as shown in FIG.
1
.
In the figure, reference numeral
36
denotes a wall means formed with material such as rubber providing sealing for partitioning the engine room
3
into the front and rear portions.
FIG. 4
shows the intake manifold
29
from the rear view of the outboard motor as shown in
FIG. 3
with the engine cover omitted for convenience in description.
The intake manifold
29
is arranged rearwards of the right and left cylinder head covers
7
,
7
. The intake silencer
50
is arranged above the engine block of the engine
4
. The inlets
54
,
54
of the intake silencer
50
open in the same direction as the direction of the cylinder heads
6
,
6
(cylinder head covers
7
,
7
) extending in the rearward direction.
In
FIG. 5
, the engine
4
as shown in this embodiment is a V-
6
engine with three cylinders
5
a,
5
a,
5
a
arranged vertically. In the figure, an ignition plug
39
is shown in the uppermost combustion chamber
5
c.
Two intake valves
40
,
40
are shown in the middle combustion chamber
5
c.
Two exhaust valves
41
,
41
are shown in the lowermost combustion chamber
5
c.
The camshaft
37
extends vertically through the cylinder head
6
. The top end of the camshaft
37
is connected to the camshaft pulley
20
. The camshaft
37
is rotated through the rotation of the crankshaft
8
a
as shown in FIG.
1
. The rotation of the camshaft
37
causes cams to move a plurality of valve rocker arms
38
a
supported on rocker arm shafts
38
, thereby opening or closing the intake and exhaust valves
40
,
41
. The outside of the camshaft
37
and the valve rocker arm shafts
38
are covered with the cylinder head cover
7
.
Obviously, various minor changes and modifications of the present invention are possible in the light of the above teaching. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described above.
Claims
- 1. An outboard motor comprising:a V engine arranged in a horizontal direction, the engine having an engine block provided with two cylinder blocks extending in a V configuration and forming therebetween an opening which opens to the rear of the outboard motor, a skirt integrally formed with the cylinder blocks and housing a crankshaft arranged vertically, and two cylinder heads provided on ends of the cylinder blocks to define a plurality of combustion chambers; and an intake silencer having two inlets positioned above the cylinder heads and forming an opening therebetween which opens rearwards of the outboard motor for taking air in, and one outlet positioned between the two inlets for letting the inlet air out to supply it to the combustion chambers.
- 2. An outboard motor according to claim 1; further comprising a transmission system for transmitting a drive force from the crankshaft to a camshaft for opening or closing intake valves and exhaust valves provided in the combustion chambers, the transmission system being provided between the engine block and the intake silencer.
- 3. An outboard motor according to claim 2; further comprising a throttle body connected to the outlet of the intake silencer and arranged between the cylinder and above the camshaft.
- 4. An outboard motor according to claim 3; further comprising a grommet for connecting the outlet of the intake silencer to the throttle body.
- 5. An outboard motor according to claim 2; wherein the transmission system has a driving pulley driven by the crankshaft, a driven pulley connected to the camshaft, and a belt entrained around the driving and driven pulleys.
- 6. An outboard motor according to claim 5; further comprising a second driven pulley driven by the crankshaft and a second belt entrained around the driving pulley and the second driven pulley; wherein the intake silencer has a body with an extension portion serving as a belt cover for covering a portion of the second belt.
- 7. An outboard motor according to claim 1; wherein the intake silencer has a body with a substantially flat top wall.
- 8. An outboard motor comprising: a engine cover defining an engine room and having an air intake opening; an engine disposed in the engine room; an air intake guide disposed within the engine cover and having one end communicating with the air intake opening of the engine cover and another end opening into the engine room; an intake silencer comprising at least one inlet positioned above the engine and facing in a rearward direction of the outboard motor for taking air in, and an outlet positioned in the rearward direction of the engine; and a throttle body connected to the outlet for supplying the inlet air to the engine.
- 9. An outboard motor according to claim 8; wherein the engine has two cylinder blocks arranged to form an opening which opens in the rearward direction of the outboard motor.
- 10. An outboard motor according to claim 9; wherein the intake silencer has an inlet for each of the two cylinder blocks, the inlets being positioned above the cylinder blocks and oriented to form an opening in the rearward direction of the outboard motor, and the outlet is positioned between the two inlets.
- 11. An outboard motor according to claim 8; wherein the air intake opening is provided in an upper portion of the engine cover, and the air intake guide has a first opening connected to the air intake opening, a second opening in the engine room for discharging air, and a main body connecting the first and second openings and extending downward from the air intake opening into the engine room.
- 12. An outboard motor according to claim 11; wherein the main body of the air intake guide has an upper portion in contact with an inner surface of the engine cover and a lower portion spaced from the inner surface of the engine cover.
- 13. An outboard motor according to claim 8; wherein the engine cover has a recessed portion in which the air intake opening is formed; and further comprising a top cover member covering the recessed portion and having one or more openings in communication with the air intake opening.
- 14. An outboard motor comprising: a V-type engine having a plurality of cylinder blocks arranged to form a V-shaped opening which opens in a rearward direction of the outboard motor, a skirt integrally formed with the cylinder blocks for housing a crankshaft therein, and a plurality of cylinder heads each provided at an end of a respective cylinder block to jointly define therewith a plurality of combustion chambers; and an intake silencer comprising an inlet for each of the cylinder blocks, the inlets being positioned above the cylinder heads and oriented to form an opening in the rearward direction of the outboard motor for taking in air, and an outlet positioned between two of the inlets for letting out the inlet air to supply it to the combustion chambers.
- 15. An outboard motor according to claim 14; further comprising a transmission system for transmitting a drive force from the crankshaft to a camshaft for opening or closing intake valves and exhaust valves provided in the combustion chambers, the transmission system being provided between the engine and the intake silencer.
- 16. An outboard motor according to claim 15; wherein the transmission system has a driving pulley driven by the crankshaft, a driven pulley connected to the camshaft, and a belt entrained around the driving and driven pulleys.
- 17. An outboard motor according to claim 16; further comprising a second driven pulley driven by the crankshaft and a second belt entrained around the driving pulley and the second driven pulley; wherein the intake silencer has a body with an extension portion serving as a belt cover for covering a portion of the second belt.
- 18. An outboard motor according to claim 15; further comprising a throttle body connected to the outlet of the intake silencer and arranged above the camshaft.
- 19. An outboard motor according to claim 18; further comprising a grommet for connecting the outlet of the intake silencer to the throttle body.
- 20. An outboard motor according to claim 14; wherein the intake silencer has a body with a substantially flat top wall.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2000-255413 |
Aug 2000 |
JP |
|
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
6149477 |
Toyama |
Nov 2000 |
A |
Foreign Referenced Citations (1)
Number |
Date |
Country |
08310487 |
Nov 1996 |
JP |