JP4055720B2 - 4-cycle engine mounted on snow vehicles - Google Patents

Description

  The present invention relates to a four-cycle engine mounted on a snow vehicle.

  Conventionally, an engine mounted on a small snow vehicle such as a snowmobile has a relatively simple structure, a lightweight, compact and powerful two-cycle.

  Recently, however, the 4-cycle engine has been promoted with the aim of improving exhaust gas regulations and fuel efficiency. Compared to the high-power and compact 2-cycle engine, the 4-cycle engine that requires camshaft and oil lubrication is It tends to be large.

  Therefore, in order to make the body and engine hood shape of a snow vehicle equipped with a 4-cycle engine the same size as when a 2-cycle engine is installed, the layout of the oil pan shape, intake, exhaust and related accessories is devised. Is indispensable.

  By the way, in order to improve the steerability of snow vehicles, to lower the center of gravity when the engine is installed, lower the engine position to the same level as the steering tie rod, and to set the center of gravity to the center of the vehicle, push the engine to the steering post Is desirable.

  However, when the engine of a snow vehicle is replaced with a 4-cycle engine from a 2-cycle engine, the case where the crank center of the 4-cycle engine is set at the same position as the crank center of the previous 2-cycle engine is considered 4 There is an oil pan at the bottom of the cycle engine, and the overall height of the engine is higher than that of the 2-cycle engine, so when placing the engine so that the cylinder faces upright, the engine interferes with the steering rod, or the cylinder head or throttle body There may be a problem that may interfere with the engine hood.

  In addition, a two-cycle engine of a snow vehicle requires a large-capacity expansion chamber in order to improve performance, and this chamber is usually routed on the side opposite to the drive clutch and connected to a muffler. The exhaust system is arranged in order to maintain the handling space and to balance the left and right weights. A flywheel magneto, chamber, and muffler are placed on the opposite side of the heavy clutch. To do.

  The present invention has been made paying attention to the above-mentioned problems of the prior art. A four-cycle engine can be mounted on a snow vehicle without interfering with the engine hood and with a low center of gravity, and the center of gravity of the engine is set to the center of gravity of the vehicle body. An object of the present invention is to provide a four-cycle engine mounted on a snow vehicle that can be brought close to and lowered in the center of gravity to improve running performance.

The present invention relates to a four-cycle engine mounted on a snow vehicle.
The present invention relates to a four-cycle engine mounted on a snow vehicle having an engine hood that is disposed in front of the seat, has an engine hood positioned in front of the steering shaft, and has an engine room that is covered by the engine hood. The cycle engine is mounted on the vehicle body with the crankshaft along the vehicle body width direction and the center axis of the cylinder inclined backward with respect to the vehicle body vertical direction line, and is installed in the oil pan of the 4-cycle engine. An oil strainer is accommodated, and the oil pan is positioned at the bottom of the engine room so that the suction port of the oil strainer is located behind the cylinder center axis and below the axis of the drive wheel at the front of the crawler in a side view. The steering shaft and the 4-cycle engine are arranged adjacent to each other in the vicinity. Between, and is arranged a throttle body and the air cleaner box constituting the intake system at a position higher than the cylinder head upper portion through the intake pipe provided obliquely upward and rearward from the intake port of the cylinder head, the air cleaner box Is a four-cycle engine mounted on a snow vehicle, characterized in that at least a part is located on the cylinder head and is wrapped on the engine in plan view .

  In the present invention, the four-cycle engine can be of a double overhead cam type.

  In the present invention, the water pump can be disposed on the front side of the four-cycle engine.

  In the present invention, the front part of the crankcase may be provided with an oil filter.

According to the present invention, since the four-cycle engine is tilted backward, the overall engine height can be greatly reduced compared with the upright engine, and interference with the engine hood can be avoided.
Also, by tilting the 4-cycle engine backward in the engine hood at the front of the vehicle body, the center of gravity of the engine can be brought closer to the center of the vehicle body, and the position of the center of gravity can be lowered by lowering the cylinder head position. This improves the driving performance of snow vehicles.
Further, the front of the engine is widened by the rearward tilt of the engine, and the exhaust pipe can be arranged with a degree of freedom, and the height of the engine hood can be further reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a front side view enlarged explanatory view of a snow vehicle equipped with a four-cycle engine applied to an embodiment of the present invention, FIG. 2 is an overall side view explanatory view of the snow vehicle, and FIG. FIG. 4 is an enlarged detailed explanatory view of FIG. 3, FIG. 5 is a front explanatory view of a snow vehicle, FIG. 6 is an explanatory view of battery arrangement taken along line VI-VI in FIG. FIGS. 8A and 8B are an external side view and a front view of the 4-cycle engine, and FIG. 8 is a plan view of the 4-cycle engine.

As shown in FIGS. 1 to 4, the snow vehicle according to the embodiment includes a three-cylinder (an example of a multi-cylinder) four-cycle engine 16 in an engine hood 14 positioned in front of the seat seat 12 at the front portion 10 f of the vehicle body 10. Is housed and mounted.
A headlamp 20 is provided in front of the uppermost portion of the engine hood 14 (in the embodiment, the bulging portion 18 bulging upward).

The four-cycle engine 16 is a rear-tilt engine in which the crankshaft 22 is along the vehicle body width direction and the center axis 24c of the cylinder 24 is inclined rearward by an angle α with respect to the vehicle body vertical direction line 10c. At least a part of the intake system 34 of the engine 16 including the air cleaner box 30 and the throttle body 32 connected to the rear intake port 28 (in the embodiment, the front part 30a of the air cleaner box 30 and the upper part of the throttle body 32) is the outermost part of the engine hood 14. It is housed behind the headlamp 20 in the space of the upper bulging portion 18.
Then, exhaust is led to the front of the cylinder 24 by an exhaust system 38 connected to an exhaust port 36 in front of the cylinder head 26.

  Here, the structure of the snow vehicle will be described in more detail.

As shown in FIGS. 2 and 3, the snow vehicle according to the embodiment is rotated so that a pair of left and right steering sleds (skis) 40 are directed in the left-right direction below the front portion 10f of the vehicle body 10 extending in the front-rear direction. On the other hand, a crawler 44 that circulates the track belt 42 is disposed below the rear part 10r of the vehicle body on which the seat 12 is placed.
The crawler 44 includes a drive wheel 44a disposed at the front end of the vehicle body rear portion 10r, a driven wheel 44b disposed at the rear end, a plurality of intermediate wheels 44c, a suspension mechanism 44d that suspends and cushions them, and each wheel. And a track belt 42 that wraps around and circulates.

  The vehicle body 10 has a monocoque frame structure, and a vehicle body front portion (engine mount frame) 10f on which the four-cycle engine 16 is mounted has a shape that is gradually squeezed toward the front in plan view and has an upper portion. It has a general ship bottom shape that is open, and the upper hood 10f1 is covered with an engine hood 14 to close the interior of the engine room 46. The peripheral edge of the upper opening 10f1 has a slightly gently wavy shape.

  Further, in the vehicle body front portion 10f, as mainly shown in FIG. 2, the inner bottom surface of the engine room 46 is formed at the center portion in the vehicle width direction and the center portion 48 in the front-rear direction (referred to as main portion). The four-cycle engine 16 is fixed and mounted by floating via a bracket 16c at the lower front portion thereof, positioned on the main portion 48 so that the engine oil pan 16a is adjacent to the bottom of the portion 48.

Further, the central portion in the vehicle width direction of the inner bottom surface of the engine room 46 is a slope that gently rises at the front portion 48 a of the main portion 48.
From the left and right side positions of the main portion 48 to the front portion, the sled 40 protrudes upward in the engine room 46 so that the sled 40 does not hit the vehicle body even when the steering sled 40 swings and cushions (lower in the front portion 10f of the vehicle body). The sled house part 50 is recessed.
The front portion 50a of the sled house portion 50 is recessed upward and higher than the vicinity of the main portion 48, and accommodates the suspension mechanism and steering mechanism 40a of the sled 40 therein (see FIG. 4). .
Further, the rear side of the main portion 48 on the bottom surface is a crawler house portion 52 that accommodates the front portion of the crawler 44 (near the driving wheel 44a) protruding upward from the main portion 48.

  A steering shaft (also referred to as a steering post) 54 protrudes slightly rearward from the rear portion of the engine hood 14 and immediately before the seat 12, and a bar-like steering handle for steering is provided at the upper end of the steering shaft 54. 56 is provided.

  A lower end portion of the steering shaft 54 is rotatably supported by the vehicle body adjacent to the crawler house portion 52. A link mechanism (not shown) is connected to the lower end portion of the steering mechanism 40a that swings and steers the sled 40 left and right. The steering force is transmitted with.

As shown in FIGS. 1 to 8, the rearwardly tilted four-cycle engine 16 mounted in the engine room 46 in the engine hood 14 has an oil pan 16a at the bottom of the lower crankcase 58. In the oil pan 16a, an oil strainer 16b is accommodated in an oil suction port.
Further, the movement of the piston 24a that reciprocates in the cylinder 24 above the engine crankcase 58 is converted into the rotational movement of the crankshaft 22 through the connecting rod 58a.
Then, the cylinder head 26 provided in the cylinder 24 top, intake valve 60a and exhaust valve 62 a and the valve operating mechanism 60b for opening and closing the intake port 28 and exhaust port 36 leading to 24 the combustion chamber cylinder. 62b is disposed.
Thus, the engine of the embodiment is a double overhead cam type four-cycle engine.

Above the crankcase 58, a water pump 64 is disposed at the front of the engine cylinder 24, and an alternator 66 is disposed at the rear of the engine cylinder 24. Driven pulleys 64a and 66a are respectively provided. A timing belt 68 is wound around these and a drive pulley 22a provided on the crankshaft 22 outside the crankcase 58, and is driven by the rotation of the crankshaft 22.
The positional relationship among the water pump 64, the alternator 66, and the crankshaft 22 has a substantially inverted triangular shape in a side view, and the upper path of the timing belt 68 is substantially parallel to the mating surface of the cylinder head 26 and the cylinder 24. .

  A substantially cylindrical oil filter 70 is erected at a front portion of the crankcase 58 so that its central axis is inclined obliquely forward and upward, and the upper end position of the oil filter 70 in the side view is the position of the water pump 64. It almost coincides with the position of the lower edge.

A bulging portion 18 protruding upward is formed at the uppermost portion of the engine hood 14, and a single headlamp 20 is provided at the front portion of the bulging portion 18, while the vehicle is provided at the rear portion of the bulging portion 18. An instrument panel 72 for displaying the state is provided, and at least a part of the intake system 34 is accommodated in a space 74 sandwiched between the headlamp 20 of the bulging portion 18 and the instrument panel 72.
Further, a fairing 19 for avoiding the wind of the driver is formed on the engine hood 14 so as to be wider rearward than the steering handle 56 so as to cover the bulging portion 18.

In the intake system 34 of the embodiment, the air cleaner box 30 is divided into two front and rear (a front box 30a and a rear box 30b) at a position sandwiching the throttle body 32, and the front box 30a and the upper part of the throttle body 32 are viewed from the side. It wraps around the bulging portion 18.
The front box 30 a is located on the cylinder head 26 (on the cylinder head cover 26 a) and is wrapped on the engine 16 in plan view, and the rear box 30 b is located in a space on the drive sprocket shaft 84.
In the intake system 34, the intake air flows from the rear box 30b to the front box 30a, and the air-fuel mixture flows obliquely downward and forward from the throttle body 32 to the intake pipe 32a and further to the intake port 28 of the engine 16.

1 and FIGS. 4 to 5, the exhaust system 38 is located in front of the engine 16 and connected to the exhaust port 36 in the front part of the cylinder head 26, and via an exhaust pipe 76. The exhaust muffler 78 connected to the outlet side of the exhaust manifold 74 is disposed in the engine room 46 covered with the engine hood 14, and the muffler 78 is placed on the main portion front portion 48a in the embodiment. ing.
The exhaust outlet pipe 80 of the muffler 78 penetrates the lower portion of the vehicle body 10 and the opening 80a is provided at the vehicle width direction central portion (indicated by the symbol SC) of the lower surface portion of the vehicle body 10, and the exhaust of the engine 16 is exhausted from the opening 80a. Is discharged downward toward the outside of the vehicle body.

A muffler 78 is positioned below the engine cylinder 24, and an exhaust pipe 76 connected to the exhaust manifold 74 extends forward and downward toward the muffler 78.
The exhaust manifold 74 has a plurality of inlet side portions corresponding to a plurality of exhaust ports 36 of the four-cycle engine 16 (three cylinders in the embodiment, three locations), and the outlet side portion connected to the exhaust pipe 76 is collectively. And this collective part is a forward drop.

Further, the muffler 78 is a substantially cylindrical body, and the cylindrical body shaft 78a extends along the vehicle width direction, and the exhaust is bent in a substantially C shape on the surface portion on one side in the vehicle width direction (the vehicle body left side in the embodiment). The outlet side of the pipe 76 is connected, and the exhaust from the four-cycle engine 14 is introduced into the muffler 78 via the exhaust pipe 76.
The muffler 78 is biased and installed on the other side in the vehicle width direction (right side of the vehicle body in the embodiment), thereby ensuring a space for arranging the exhaust pipe 76 with a space from the inner wall of the engine room 46. is doing.

Further, in the engine hood 14, the four-cycle engine 16 is arranged such that the center position 16C in the crankshaft 22 direction is biased to one side with respect to the center position SC in the vehicle width direction (see FIG. 4).
Further, in the engine hood 14, a clutch device 82 is disposed on one side in the vehicle width direction (the left side of the vehicle body in the embodiment) across the four-cycle engine 14, and a battery 86 is disposed on the other side in the vehicle width direction. ing.

The clutch device 82 includes a drive clutch pulley 82a installed at the output end of the engine crankshaft, a driven clutch pulley 82b installed at the opposite end of the sprocket 84a in the crawler drive sprocket shaft 84, and a V-belt 8 having a V-shaped cross section. 2 c is also used as a V-belt transmission.

  In addition, it is preferable to install an electrical component 90 such as an ECU or a CDI unit in the battery holder portion 88 that houses and places the battery 86 so as not to rattle.

  As shown in FIGS. 4 and 6, the battery holder 88 is formed of a metal fitting having an L-shaped cross section, and as shown in FIG. 6A, the electrical component 90 is installed back-to-back with the battery 86. , (B), the electrical component 90 can be installed above the battery 86.

  As described above, according to the present embodiment, a part of the intake system above the engine 16 is disposed behind the headlamp 20 at the uppermost portion (the bulging portion 18) in the engine hood 14 with the four-cycle engine 16 tilted backward. Since it is housed, the overall engine height can be greatly reduced compared to an upright engine, and interference with the engine hood 14 and the headlamp 20 can be avoided.

  Further, by tilting the four-cycle engine 16 backward in the engine hood 14 at the front of the vehicle body, the center of gravity of the engine 16 can be brought closer to the center of the vehicle body, and the position of the center of gravity is lowered by a decrease in the position of the cylinder head 26. , The maneuverability is improved and the driving performance of snow vehicles can be improved.

  Further, when the engine 16 is tilted backward, the front of the engine becomes wider, and the engine hood 14 can be further reduced in height by being arranged with a degree of freedom such as an exhaust pipe. Further, even if the intake system 34 connected to the rear part of the engine is installed above the engine 16, the intake system can be accommodated behind the headlamp 20 at the top of the engine hood 14, so that space efficiency is improved and the overall height of the engine hood is increased. There is no need to make any changes or modifications.

An upward bulging portion 18 is formed at the top of the engine hood 14, a headlamp 20 is provided at the front of the bulging portion 18, and an instrument panel 72 for displaying the vehicle state is provided at the rear of the bulging portion 18. Each is provided, and at least a part of the intake system 34 can be accommodated in a space sandwiched between the headlamp 20 of the bulging portion 18 and the instrument panel 72.
In this way, at the uppermost part of the engine hood 14 where the headlamp 20 and the instrument panel 72 are to be disposed, a part of the intake system is accommodated in the space behind the headlamp 20 which is an empty space, and the intake system is efficiently space-efficient. The shape of the engine hood 14 can be lowered.

Further, an engine hood includes an exhaust manifold 74 that connects the exhaust system 38 to the exhaust port 36 in front of the cylinder head 26, and an exhaust muffler 78 that is positioned in front of the engine and that is connected to the outlet side of the exhaust manifold 74 via the exhaust pipe 76. 14, the opening 80 a of the exhaust outlet pipe 80 from the muffler 78 is provided at the center position in the vehicle width direction of the lower surface of the vehicle body, and the exhaust gas is discharged from the opening 80 a toward the outside of the vehicle body. Therefore, the exhaust sound can be emitted from the center of the vehicle width direction on the underside of the car body, and the exhaust sound is divided into two sides from the lower side of the car body and at the front part of the car body. It will not be a nuisance to the elderly.
In addition, since it is at the center of the vehicle width, the exhaust noise during driving is the same on the left and right sides of the vehicle body, and by setting it downward, it is possible to expect a noise reduction effect due to snow splashed on the snow surface or steering sled.

  Further, since the muffler 78 is positioned below the engine cylinder 24 and the exhaust pipe 76 connected to the exhaust manifold 74 extends forward and downward toward the muffler 78, the exhaust pipe 76 and the muffler 78 are lowered forward from the engine 16. Thus, the shape is in line with the shape of the engine hood 14 that is lowered forward to improve aerodynamic performance.

  The muffler 78 is a substantially cylindrical body. When the cylindrical body axis is along the vehicle width direction and connected to one side in the vehicle width direction, exhaust from the engine 16 is introduced into the muffler 78 via the exhaust pipe 76. Thus, the muffler 78 can be accommodated in the engine hood 14 without taking the length in the front-rear direction.

  In the engine hood 14, the four-cycle engine 16 is arranged such that the center position in the crankshaft direction is deviated to one side with respect to the center position in the vehicle body width direction, and the battery 86 is arranged on the other side to provide space utilization efficiency. Has improved.

  Further, in the engine hood 14, the clutch device 82 is disposed on one side in the vehicle width direction with the engine 16 in between, and the battery 86 is disposed on the other side in the vehicle width direction. Can be easily done.

  In addition, since the electrical components are installed in the battery holder portion 88 on which the battery 86 is placed, for example, an electrical component 90 such as an ECU or a CDI unit can be installed in the battery holder portion 88 to achieve a better weight balance, and the engine Since the electrical components can be disposed immediately beside the 16, lead wires to the engine 16 can be shortened, and wiring can be easily performed.

It is front part side expansion explanatory drawing of the snow vehicle carrying the 4-cycle engine applied to embodiment of this invention. It is a whole side view explanatory drawing of the snow vehicle. It is a whole top view explanatory drawing of the snow vehicle. FIG. 4 is an enlarged detailed explanatory diagram of FIG. 3. It is front view explanatory drawing of a snow vehicle. It is arrangement | positioning explanatory drawing of the battery which looked at the VI-VI line cross section of FIG. (A), (b) is an external side view and a front view of the 4-cycle engine. It is a top view of a 4-cycle engine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle body 10c Vehicle body vertical direction line 14 Engine hood 16 Four cycle engine 16a Oil pan 16b Oil strainer 18 Swelling part 22 Crankshaft 24 Cylinder 24c Cylinder center axis 28 Intake port 30 Air cleaner box 32 Throttle body 34 Intake system 36 Exhaust port 38 Exhaust Series 78 muffler

Claims (4)

In a four-cycle engine mounted on a snow vehicle having an engine hood positioned in front of the steering shaft and having an engine hood positioned in front of the seat shaft and having an engine room covered by the engine hood,
The 4-cycle engine is mounted on the vehicle body with the crankshaft extending along the vehicle body width direction and the center axis of the cylinder inclined backward with respect to the vehicle body vertical direction line. An oil strainer is housed in the engine room so that the oil strainer suction port is located behind the cylinder center axis and below the axis of the drive wheel at the front of the crawler in a side view. Positioned adjacent to the bottom and higher than the upper end of the cylinder head via an intake pipe provided between the steering shaft and the four-cycle engine and obliquely upward and rearward from the intake port of the cylinder head throttle body and air cleaner box constituting the intake system is disposed, the air cleaner ball 4-cycle engine box is mounted on a snowmobile, characterized in that wrapping the engine in plan view at least partially located on the cylinder head.   The four-cycle engine mounted on a snow vehicle according to claim 1, wherein the four-cycle engine is of a double overhead cam type.   The four-stroke engine mounted on a snow vehicle according to claim 1, wherein the water pump is disposed in front of the four-stroke engine.   The four-cycle engine mounted on a snow vehicle according to claim 1, wherein an oil filter is disposed at a front portion of the crankcase.

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