JP2003176759A - Engine intake controller for motorcycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To certainly reduce intake resistance in a high engine speed range to improve high speed output performance, while securing low speed output performance of a parallel multicylinder engine of a motorcycle. <P>SOLUTION: A plurality of throttle bodies 18 each having an upward upstream end are connected to the rear face of a forward-inclined cylinder head 9 of the parallel multicylinder engine E of the motorcycle. The inside of an air cleaner 17 connected to the upstream ends of the throttle bodies 18 is formed with a plurality of passages 33a, 33b respectively extending in the back-and-forth direction of the motorcycle in parallel to each other, and communicating an air intake port 28 of the air cleaner 17 with the plurality of throttle bodies 18. An intake control valve 35 opening/closing at least one passage 33b of the plurality of passages 33a, 33b is provided in the air cleaner 17. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a body frame,
In a motorcycle equipped with a parallel multi-cylinder engine in which a cylinder block and a cylinder head are tilted forward, the intake system of the parallel multi-cylinder engine is controlled in accordance with its operating state so as to extend from a low speed range to a high speed range. The present invention relates to an engine intake control device for a motorcycle that exhibits good output performance.

[0002]

2. Description of the Related Art Conventionally, as an intake control device for a motorcycle, a relief valve that automatically opens due to a pressure difference between the front and rear when an intake amount exceeds a predetermined value is attached to an air intake of an air cleaner of an intake system. This relief valve provided with a small vent hole is already known as disclosed in Patent Document 1.

[0003]

[Patent Document 1] JP-A-58-155270

[0004]

In the engine intake control device disclosed in Patent Document 1, the intake air amount is controlled by the relief valve in the low speed range of the engine during the rapid acceleration operation of the engine in which the throttle valve is rapidly opened. By limiting with the pores, leaning of the air-fuel mixture sucked by the engine is suppressed to improve the acceleration performance, and when the engine enters the high speed range, the relief valve opens as the intake amount increases above a certain value. It is designed to reduce the intake resistance.

However, in the above-mentioned device, since the relief valve is spring-biased in the valve closing direction, the spring load thereof becomes the valve opening resistance of the relief valve, and the intake resistance corresponding thereto remains.

The present invention has been made in view of the above circumstances, and it is possible to reliably reduce the intake resistance in the high speed rotation range of the engine and to contribute to the improvement of the output performance of the motorcycle. An object is to provide a control device.

[0007]

In order to achieve the above object, the present invention mounts a parallel multi-cylinder engine in which a cylinder block and a cylinder head are tilted forward on a vehicle body frame, and on the back surface of the cylinder head, Engine intake control of a motorcycle in which a plurality of throttle bodies corresponding to each cylinder are connected with their upstream ends facing upward, and an air cleaner for purifying the air flowing into these throttle bodies is installed above the engine. In the device, a plurality of passages are formed in the air cleaner, the passages extending in the front-rear direction of the vehicle and arranged in parallel with each other to communicate between the air intake port of the air cleaner and the plurality of throttle bodies,
A first feature is that the air cleaner is provided with an intake control valve that opens and closes at least one of the plurality of passages.

The plurality of passages are the small cross sectional area passage 33a and the large cross sectional area passage 33b in the embodiment of the present invention described later.
The one passage corresponds to the large cross-section passage 33b.

According to the first feature described above, in the low speed rotation range of the engine, the intake control valve is held in a state in which at least one of the plurality of passages is closed, so that the intake air amount when the throttle valve is rapidly opened. Can be restricted by another passage to suppress lean dilution of the intake air-fuel mixture of the engine and improve the acceleration performance of the engine. When the engine shifts to the high speed range, the intake control valve is positively opened to allow the intake air of the engine to pass through both the one passage and the other passage, effectively reducing the intake resistance. However, the volumetric efficiency of the engine can be increased and high output can be achieved. In particular, a plurality of passages that connect a plurality of throttle bodies connected to the back of the forwardly tilted cylinder head of a parallel multi-cylinder engine and an air intake port of an air cleaner are arranged in parallel with each other in the front-rear direction of the vehicle. This makes it possible to equalize the intake resistance between the air intake port of the air cleaner and each cylinder regardless of the presence of a plurality of passages. Therefore, the air taken into the air cleaner can be easily and accurately supplied to a plurality of cylinders through the plurality of passages. Can be evenly distributed to the engine, which can greatly contribute to improving the output performance of the engine.

In addition to the first feature of the present invention, the upstream end of the plurality of throttle bodies is connected to the rear bottom wall of the air cleaner, and the portion of the air cleaner that extends forward from the throttle body is described above. The second feature is that it is arranged above the cylinder head.

According to this second feature, the air cleaner,
The layout of multiple throttle bodies and the engine is rational, and these can be compactly and centrally arranged, and the air cleaner above the engine can be easily arranged.

Further, in addition to the second characteristic, the present invention has a third characteristic that a fuel injection valve is mounted on the rear wall of the throttle body.

According to the third feature, the maintenance of the fuel injection valve can be easily performed without being disturbed by the engine and the air cleaner.

Further, in addition to the third feature, the present invention has a fourth feature in that a fuel tank attached to the main frame is arranged so as to cover the throttle body and the air cleaner from above.

According to the fourth feature, the air cleaner,
The layout of multiple throttle bodies, engines and fuel tanks is rational, and these can be compactly and centrally arranged, and as a result, a relatively large capacity fuel tank can be arranged above the air cleaner.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below based on an embodiment of the present invention shown in the accompanying drawings.

FIG. 1 is a side view of a motorcycle equipped with an engine intake and exhaust control device according to the present invention, FIG. 2 is a longitudinal sectional side view of an essential part of the intake control device, and FIG. 3 is an operation explanatory view corresponding to FIG. 4 is a sectional view taken along line 4-4 of FIG. 2, and FIG.
6 is a sectional view taken along line 6-6 of FIG. 4, FIG. 7 is a perspective view of an exhaust system, FIG. 8 is a side view of an exhaust control device, and FIG. 9 is a sectional view taken along line 9-9 of FIG. 10 is an explanatory view of the action corresponding to FIG. 9,
11 is a plan view of the drive device for the intake control valve and the exhaust control valve, FIG. 12 is a sectional view taken along line 12-12 of FIG. 11, and FIG. 13 is a sectional view taken along line 13-13 of FIG.

In FIG. 1, a vehicle body frame 2 of a motorcycle 1 has a pair of left and right main frames 4 and 4 each having a head pipe 3 at a front end thereof, extending downward to the rear, and connecting rear end portions thereof to each other. The seat rails 5 are connected to the rear ends of 4, 4 and extend rearward.
The parallel four-cylinder engine E is attached to the pair of main frames 4 and 4. At that time, the engine E is arranged such that the cylinder block 8 and the cylinder head 9 are tilted slightly forward and the cylinder head 9 is inserted between the main frames 4 and 4.

A front fork 6f, which pivotally supports a front wheel 7f, is operably connected to the head pipe 3, and a rear wheel 7r is provided.
The rear fork 6r that supports the rear fork 6r is swingably connected to the rear of the crankcase 10 of the engine E via a pivot 11, and the rear cushion unit 12 is interposed between the rear fork 6r and the main frames 4 and 4. To be done.
The output shaft 13 of the engine E arranged in front of the pivot 11 drives the rear wheel 7r via the chain transmission 14.

A fuel tank 15 is mounted on the main frames 4 and 4, and a tandem main seat 16 is mounted on the seat rail 5.

Air cleaner 17 and throttle body 1
The intake system In of the engine E including the cylinder head 9
Is located above the fuel tank and is covered by the fuel tank 15.
The exhaust system Ex of the engine E including the exhaust pipes 51a to 51d and the exhaust muffler 54 is arranged so as to extend obliquely upward from the front surfaces of the cylinder head 9 and the cylinder block 8 through the lower part of the crankcase 10.

First, referring to FIG. 1 to FIG.
The intake system In will be described.

As shown in FIGS. 1 to 4, the engine E
The four cylinder bodies 9 are connected to four throttle bodies 18, 18 ... Corresponding to four cylinders, and the air funnels 21, 21, ... Are connected to the inlets 18a of the throttle bodies 18, 18 ,. Further, the rear bottom wall of the cleaner case 22 of the air cleaner 17 that accommodates all the air funnels 21, 21 ... Is connected to the upstream ends of the four throttle bodies 18, 18. And
Throttle body 18, 18 of cleaner case 22 ...
The portion projecting forward from is arranged above the cylinder head 9. By doing this, the air cleaner 1
The layout of the seven or four throttle bodies 18, 18 ... And the engine E is rationalized, and these can be compactly and centrally arranged, and the air cleaner 17 above the engine E can be easily arranged.

Further above the air cleaner 17,
Since the fuel tank 15 that covers this is arranged, the layout of the air cleaner 17, the four throttle bodies 18, 18, ..., The engine E and the fuel tank 15 is rational, and these can be compactly and centrally arranged. As a result, the fuel tank 15 having a relatively large capacity can be arranged above the air cleaner 17.

The cleaner case 22 comprises a lower case half body 22b fixed to the throttle bodies 18, 18 ... And an upper case half body 22a separably joined to the lower case half body 22b by a screw 27. An element mounting plate 25 for partitioning the inside of the cleaner case 22 into a lower unpurified chamber 23 and an upper purified chamber 24 is arranged so as to be sandwiched between the case halves 22a and 22b. A cleaner element 26 is mounted in a mounting hole 25a provided in the element mounting plate 25.

On one side of the lower case half body 22b is provided an air intake port 28 for opening the unpurified chamber 23 to the atmosphere, while the air funnels 21, 21 ... Include the bottom wall of the lower case half body 22b. It is arranged so as to penetrate therethrough and open an inlet to the purification chamber 24. Therefore, during the operation of the engine E, the air flowing into the unpurified chamber 23 from the air intake port 28 is filtered by the cleaner element 26 and then moved to the purified chamber 24, where the air funnel 21 and the throttle body 1 are moved.
8 and is sucked into the engine E while the flow rate is adjusted by the throttle valve 29 in each throttle body 18. At that time, fuel is injected from the fuel injection valve 32 mounted on the rear wall of each throttle body 18 toward the intake port of the engine E. As described above, the fuel injection valve 32 is attached to each rear wall of the throttle body 18 attached to the rear surface of the cylinder head 9, so that the fuel injection valve 32 can be attached and detached without being disturbed by the engine E and the air cleaner 17. Easy to do,
Its maintainability becomes good.

Throttle valve 2 of all throttle bodies 18
Reference numeral 9 links and connects the valve shafts 29a to each other, and is attached to a steering handle of the motorcycle 1 via a pulley 30 fixed to the outer valve shaft 29a and an operation wire 31 connected to the pulley 30. The throttle grip is opened and closed.

An unpurified chamber 23 is provided in the lower case half body 22b.
The partition wall 34 that divides the middle part of the above into a small cross-sectional area passage 33a at the lower part and a large cross-sectional area passage 33b at the upper part is integrally molded. It is arranged so as to extend to. An intake control valve 35 that opens and closes the large cross-sectional area passage 33b is pivotally supported by the partition wall 34.

The intake control valve 35 comprises a valve plate 36 and a valve shaft 37 integrally formed at one end of the valve plate 36. The partition wall 34 has one end of the valve shaft 37. One bearing 38 that is rotatably supported and a pair of left and right bearings 39 and 39 that rotatably supports the other end of the valve shaft 37 are provided.

As shown in FIG. 3, the intake control valve 35 has a valve plate 36 whose first end is brought into contact with the ceiling surface of the large cross-sectional area passage 33b to fully close the large cross-sectional area passage 33b. It rotates between the control position A (see FIG. 2) and the second intake control position B in which the valve plate 36 is parallel to the partition wall 34 and the passage 33b is fully opened. Is about 45 ° in the illustrated example. Second of the intake control valve 35
At the intake control position B, the valve plate 36 has a large cross-section area 3
The intake negative pressure of the engine E acts so as to urge the valve plate 36 in the closing direction by taking an inclined posture toward the upstream side of 3b.

A return spring 41 for urging the valve plate 36 in the closing direction, that is, the first intake control position A side, is connected to the arm 40 formed integrally with one end of the valve shaft 37. . The other end of the valve shaft 37 has a pair of bearings 39, 3
A driven pulley 46 connected to a drive pulley 73 of an actuator 71, which will be described later, via a first transmission wire 75a is rotatably attached between the 9 and 9.
A lost motion mechanism 42 is provided between the valve 6 and the valve shaft 37 to interconnect them. The lost motion mechanism 42 includes a transmission pin 43 protruding from one side surface of the valve shaft 37.
A circular arc groove 44 formed in the inner peripheral surface of the driven pulley 46 and extending in the circumferential direction to engage the transmission pin 43, and the driven pulley 46 is urged toward the first intake control position A side of the intake control valve 35. It consists of a lost motion spring 45. The center angle of the circular arc groove 44 is set to be larger than the opening / closing angle of the intake control valve 35, and when the driven pulley 46 rotates from the retracted position to the opening direction of the intake control valve 35, that is, to the second intake control position B side, a predetermined value is obtained. Arc groove 44 after the play angle α of
One end surface of the above-mentioned abuts on the transmission pin 43 and starts to move the intake control valve 35 to the second intake control position B side.

By the way, the layout of the small cross-sectional area passage 33a, the large cross-sectional area passage 33b, the intake control valve 35, and the air funnels 21, 21 ... Inside the cleaner case 22 is rational, which makes the air cleaner compact. ， It can be easily placed on the upper part of the engine.

Next, the exhaust system Ex of the engine E will be described in detail with reference to FIGS. 1 and 7 to 20.

In FIGS. 1 and 7, the four parallel cylinders of the engine E are arranged from the left side of the vehicle to the first to fourth cylinders 50a to 50c.
I will call it d, and the ignition in each cylinder is the first cylinder 50
a, second cylinder 50b, fourth cylinder 50d, third cylinder 50c
In order. First to fourth exhaust pipes 51a to 51d respectively corresponding to the first to fourth cylinders 50a to 50d are connected to the front surface of the cylinder head 9, and these exhaust pipes 51a to 51d are connected.
d descends from the front of the engine E and bends rearward below. The first and fourth exhaust pipes 51a and 51d are arranged on the left and right, and the second and third exhaust pipes 51b and 51c are
The first and fourth exhaust pipes 51a and 51d are arranged right and left immediately below. When these exhaust pipes 51a to 51d pass below the engine E, the first and fourth exhaust pipes 51a, 5d
1d is an upper first collecting exhaust pipe 52a for collecting these
And the second and third exhaust pipes 51b and 51c are connected to a lower first collective exhaust pipe 52b for assembling them. After that, the two collecting exhaust pipes 52a and 52b are connected to a second collecting exhaust pipe 53 that collects them, and an exhaust muffler 54 is connected to the rear end thereof.

Below the engine E, a common exhaust control valve 55 is provided in the middle of the first to fourth exhaust pipes 51a to 51d. The exhaust control valve 55 completely intervenes in the upper first and fourth exhaust pipes 51a, 51d, and in the upper part of the lower second and third exhaust pipes 51b, 51c. Arranged cylindrical valve housing 5
6 and a valve body 57 rotatably disposed therein, and communication holes 58, 58 opening to the valve housing 56 are provided above the second and third exhaust pipes 51b, 51c. It is provided. The valve housing 56 has first to
The fourth exhaust pipes 51a to 51d are welded in an airtight manner.

Bearings 5 are provided on both end walls of the valve housing 56.
9, 60 are provided, and the valve element 5 is attached to the bearings 59, 60.
A pair of valve shafts 61 and 62 projecting from both ends of 7 are rotatably supported. The outer end of one bearing 59 is closed by the plug 63, and the seal member 64 is attached to the outer end of the other bearing 60.

The valve element 57 has a space of approximately 18 between the first exhaust control position C (see FIG. 9) and the second exhaust control position D (see FIG. 10).
The first exhaust control position C is rotated by 0 °, and the communication holes 58 of the second and fourth exhaust pipes 51b and 51c are
Partition walls 65 and 65 for closing 58, respectively, and communication holes 58 between the first exhaust pipe 51a and the second exhaust pipe 51b, and between the fourth exhaust pipe 51d and the third exhaust pipe 51c at the second exhaust control position D, respectively. And guide walls 66, 66 that communicate with each other via 58.

The valve shaft 62 supported by the bearing 60 is
The seal member 64 penetrates the seal member 64 and projects outward, and a driven pulley 67 that is driven by a drive pulley 73 of an actuator 71, which will be described later, via second and third transmission wires 75c is fixed to the end portion of the seal member 64.

Next, a drive device for the intake control valve 35 and the exhaust control valve 55 will be described with reference to FIGS. 1 and 11 to 13.

As shown in FIGS. 1 and 11, the engine E
Above the crankcase 10, an actuator 71 common to a pair of brackets 70, 70 fixed to the inner surface of the main frame 4 is attached by a bolt 78 via an elastic member 77. At that time, the actuator 7
1 is the intake control valve 35 and the exhaust control valve 55
Are arranged so that the respective distances up to are approximately equal. In the illustrated example, the actuator 71 is composed of an electric motor capable of rotating in the forward and reverse directions, and a drive pulley 73 fixed to an output shaft 72 of the actuator 71 has a first wire groove 73a having a small diameter and second and third transmission wires having a large diameter. It has grooves 73b and 73c. The first transmission wire 75a is engaged with the first wire groove 54a and the wire groove 46a of the driven pulley 46 (see FIG. 5) on the intake control valve 35 side, and both terminals of the first transmission wire 75a are driven and driven pulleys 73, Connected to 46. Further, the second and third wire grooves 73b and 73c and the pair of wire grooves 67b and 67c of the driven pulley 67 (see FIG. 9) on the exhaust control valve 55 side are wound around the second and third transmission wires 75b and 75c. And the terminals are connected to the drive pulley 73 and the driven pulley 67, respectively.

The actuator 71 is driven and controlled by an electronic control unit 76 which receives a signal based on the number of revolutions of the engine E and boost negative pressure from a sensor (not shown).

Next, the operation of this embodiment will be described.

In the low speed rotation range of the engine E, the electronic control unit 76 operates the actuator 71 correspondingly, whereby the intake control valve 35 is moved to the first intake control position A.
Further, the exhaust control valve 55 is held at the first exhaust control position C, respectively.

When the intake control valve 35 is held at the first intake control position A, the valve plate 36 completely closes the large cross-sectional area passage 33b as shown in FIG. When the air taken in passes through the air cleaner 17,
It is obliged to pass through the small cross section passage 33a. Therefore, when the opening degree of the throttle valve 29 is suddenly increased in order to rapidly accelerate the rotation of the engine E, even if the increase in the amount of fuel injected from the fuel injection valve 32 may be delayed, the intake air of the engine E Since the excessive increase is suppressed by the throttling resistance of the small cross section passage 33a, the engine E can be supplied with a proper rich air-fuel mixture, and good acceleration performance can be exhibited.

On the other hand, when the exhaust control valve 55 is held at the first exhaust control position C, as shown in FIG. 9, the partition wall 65,
Since the communication holes 58, 58 of the second and third exhaust pipes 51b, 51c are closed by 65, the first to fourth exhaust pipes 51
The effective pipe lengths of a and 51d are maximum lengths from the engine E to the upper and lower first collective exhaust pipes 52a and 52b. These maximum effective pipe lengths depend on the resulting exhaust inertia effect and / or
Alternatively, the exhaust pulsation effect is set so as to enhance the volumetric efficiency of the engine E in the low speed rotation range, and therefore, the low speed output performance of the engine E can be enhanced.

As described above, since the low speed corresponding function is provided to both the intake system In and the exhaust system Ex, the low speed output performance of the engine E can be effectively enhanced.

When the engine E shifts to the high speed rotation range, the actuator 71 receives a signal corresponding thereto from the electronic control unit 76 and causes the drive pulley 73 to rotate in the normal direction. By the normal rotation of the drive pulley 73, the first and second transmission wires 75a and 75b are simultaneously pulled, and the third transmission wire 75c is loosened. Then, the driven pulley 46 on the intake control valve 35 side is rotationally driven to the second intake control position B side, and the driven pulley 67 on the exhaust control valve 55 side is rotationally driven to the second exhaust control position D side, respectively. The pulley 67 is
Since it is integrally connected to the valve shaft 62 of the exhaust control valve 55,
Although the valve 55 is immediately rotated to the second exhaust control position D, the former driven pulley 46 has a play angle α until the transmission pin 43 of the valve shaft 37 comes into contact with one end of the circular arc groove 44 of the lost motion spring. When it rotates independently against the urging force of 45 and exceeds its play angle α, the driven pulley 46 causes the intake control valve 35 via the transmission pin 43 to return the intake control valve 35 to the urging force of the spring 41 so that the second intake air flows. Start rotating to the control position B side.
Then, the intake control valve 35 and the intake control valve 35 simultaneously reach the second intake control position B and the second exhaust control position D, respectively.

When the intake control valve 35 is positively rotated by the actuator 71 to the second intake control position B, the valve plate 36 is moved to the large cross-section area 33b as shown in FIG.
Since the air is sucked into the engine E, the air taken into the engine E can pass not only the large cross-sectional area passage 33b which is not obstructed by the valve plate 36 but also the small cross-sectional area passage 33a when passing through the air cleaner 17, Therefore, the intake resistance is effectively reduced, the volumetric efficiency of the engine E is increased,
High-speed output performance can be improved.

In particular, the four throttle bodies 18, 18 ... Connected to the rear surface of the forwardly tilted cylinder head 9 of the parallel four-cylinder engine E and the air intake port 28 of the air cleaner 17 are connected to each other through a small cross sectional area passage 33a. Since the large cross-sectional area passages 33b are arranged in the front-rear direction of the vehicle and in parallel with each other, the intake resistance between the air intake port 28 of the air cleaner 17 and each cylinder is equalized despite the presence of the passages 33, 33b. Therefore, the air taken into the air cleaner 17 can be easily and accurately distributed evenly to a plurality of cylinders through the passages 33 and 33b.
This can greatly contribute to the improvement of the output performance of the engine E.

On the other hand, when the exhaust control valve 55 is operated to the second exhaust control position D, as shown in FIG.
Since the first and the fourth exhaust pipes 51a and 51d and the second and the third exhaust pipes 51b and 51c are communicated with each other by the guide walls 66 and 66, respectively, since
The effective pipe length of the fourth exhaust pipes 51a to 51d is the minimum length from the engine E to the exhaust control valve 55. These minimum effective pipe lengths are set so that the exhaust inertia effect and / or the exhaust pulsation effect thereby increase the volumetric efficiency of the engine E in the high speed rotation range, and therefore, the high speed output performance of the engine E can be improved. .

As described above, since the high speed corresponding function is provided to both the intake system In and the exhaust system Ex, the high speed output performance of the engine E can be effectively enhanced.

By the way, when the drive pulley 73 is normally rotated by the actuator 71, as described above, the rotation start timing of the intake control valve 35 having a small rotation angle to the second intake control position B is set to the exhaust control valve having a large rotation angle. By appropriately delaying the rotation start timing of 55 to the second exhaust control position D,
With the common actuator 71, the intake control valve 35 and the exhaust control valve 55 having different rotation angles can be simultaneously moved to the second intake control position B and the second exhaust control position D, respectively.

When the engine E returns to the low speed rotation range again, the actuator 71 causes the drive pulley 73 to rotate in the reverse direction and the first
And the 2nd transmission wires 75a and 75b are loosened, and the 3rd transmission wire 75c is pulled. When the first transmission wire 75a is loosened, the driven pulley 46 is reversed by the urging force of the lost motion spring 45, and the intake control valve 35 is returned to the first intake control position A by the urging force of the return spring 41.

When the third transmission wire 75c is pulled, the driven pulley 67 is reversed and the exhaust control valve 55 is returned to the first exhaust control position C.

In this case, since the intake control valve 35 and the exhaust control valve 55 simultaneously start reverse rotation, the intake control valve 35 having a small rotation angle has the exhaust control valve 55 at the first exhaust control position C.
The first intake control position A is reached before being returned to. After that, in the driven pulley 46, one end wall of the arc groove 44 is separated from the transmission pin 43 of the intake control valve 35 until the exhaust control valve 55 reaches the first exhaust control position C as the drive pulley 73 is rotated in the reverse direction. By doing so, the reverse rotation can be continued.

As described above, even if there is a difference in the rotation angles of the intake control valve 35 and the exhaust control valve 55, the lost motion mechanism 42 absorbs the difference, so that both control valves 35 and 55 are operated by the common actuator 71. It can operate accurately, and therefore simplifies the structure of its drive system.
It is possible to improve engine performance and reduce cost, and at the same time contribute to weight reduction.

The present invention is not limited to the above embodiments, and various design changes can be made without departing from the scope of the invention. For example, the intake control valve 35 may be configured to change the effective pipe length of the intake system In according to the operating state of the engine E. Further, the present invention can of course be applied to the intake system and the exhaust system of other multi-cylinder engines.

[0058]

As described above, according to the present invention, a parallel multi-cylinder engine in which a cylinder block and a cylinder head are tilted forward is mounted on a vehicle body frame, and a plurality of cylinders corresponding to each cylinder are mounted on the rear surface of the cylinder head. An engine intake control device for a motorcycle in which the throttle bodies of the above are connected with their upstream ends facing upward, and an air cleaner for purifying the air flowing into these throttle bodies is arranged above the engine. The air cleaner has a plurality of passages extending in the front-rear direction of the vehicle and arranged in parallel with each other to communicate between the air intake of the air cleaner and the plurality of throttle bodies, and at least one passage of the plurality of passages is formed. Since the intake air control valve that opens and closes is provided in the air cleaner, the intake air control valve can be installed in a plurality of passages in the low engine speed range. By keeping at least one passage closed, when the throttle valve is suddenly opened, the intake air amount is limited by the other passages, the lean mixture of the intake air mixture of the engine is suppressed, and the acceleration performance of the engine is improved. You can
When the engine shifts to the high speed range, the intake control valve is positively opened to allow the intake air of the engine to pass through both the one passage and the other passage, effectively reducing the intake resistance. It is possible to reduce the volume, improve the volumetric efficiency of the engine, and achieve high output. In particular, a plurality of passages that connect a plurality of throttle bodies connected to the back of the forwardly tilted cylinder head of a parallel multi-cylinder engine and an air intake port of an air cleaner are arranged in parallel with each other in the front-rear direction of the vehicle. This makes it possible to equalize the intake resistance between the air intake port of the air cleaner and each cylinder regardless of the presence of a plurality of passages. Therefore, the air taken into the air cleaner can be easily and accurately supplied to a plurality of cylinders through the plurality of passages. Can be evenly distributed to the engine, which can greatly contribute to improving the output performance of the engine.

According to the second feature of the present invention, in addition to the first feature, the upstream bottom ends of the plurality of throttle bodies are connected to the rear bottom wall of the air cleaner, and the upstream ends of the throttle body of the air cleaner are connected. Since the portion projecting forward is arranged above the cylinder head, the layout of the air cleaner, the plurality of throttle bodies and the engine is rational, and these can be compactly and centrally arranged, and the air cleaner can be arranged above the engine. Can be done easily.

Further, according to the third feature of the present invention, the second
In addition to the above feature, since the fuel injection valve is mounted on the rear wall of the throttle body, the fuel injection valve can be easily maintained without being disturbed by the engine and the air cleaner.

Furthermore, according to the fourth aspect of the present invention,
In addition to the third feature, since the fuel tank attached to the main frame is arranged so as to cover the throttle body and the air cleaner from above, the layout of the air cleaner, the plurality of throttle bodies, the engine and the fuel tank is rational. Thus, these can be compactly and centrally arranged, and as a result, a relatively large capacity fuel tank can be arranged above the air cleaner.

[Brief description of drawings]

FIG. 1 is a side view of a motorcycle including an engine intake and exhaust control device of the present invention.

FIG. 2 is a vertical cross-sectional side view of a main part of the intake control device.

FIG. 3 is an operation explanatory view corresponding to FIG.

4 is a sectional view taken along line 4-4 of FIG.

5 is a sectional view taken along line 5-5 of FIG.

6 is a sectional view taken along line 6-6 of FIG.

FIG. 7 is a perspective view of an exhaust system.

FIG. 8 is a side view of the exhaust control device.

9 is a sectional view taken along line 9-9 of FIG.

FIG. 10 is an operation explanatory view corresponding to FIG. 9.

FIG. 11 is a plan view of a drive device for the intake control valve and the exhaust control valve.

12 is a sectional view taken along line 12-12 of FIG.

13 is a sectional view taken along line 13-13 of FIG.

[Explanation of symbols]

E ... Engine 1 ... Motorcycles 2 ... Body frame 3 ... Headpipe 4 ... Mainframe 8 ... Cylinder block 9 ... Cylinder head 15 ... Fuel tank 17 ... Air cleaner 18 ... Throttle body 28 ... Air intake 32 ... Fuel injection valve 33a, 33b ... multiple passages 33b ... Passages opened and closed by the intake control valve 35 ... Intake control valve

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02M 35/10 F02M 35/10 301F (72) Inventor Tetsuya Nakayasu 1-4-1, Chuo, Wako, Saitama Incorporated in Honda R & D Co., Ltd. (72) Inventor Akihiro Hamada 1-4-1 Chuo, Wako, Saitama Incorporated in Honda R & D Co., Ltd. F-term (reference) 3G065 AA04 AA10 BA01 CA00 DA02 HA02 HA03 HA21

Claims (4)

[Claims] 1. A parallel multi-cylinder engine (E) in which a cylinder block (8) and a cylinder head (9) are tilted forward is mounted on a vehicle body frame (2), and a rear surface of the cylinder head (9) is provided with each of them. A plurality of throttle bodies (18) corresponding to cylinders are connected with their upstream ends facing upward, and an air cleaner (17) for purifying the air flowing into these throttle bodies (18) is connected to the engine (E). An engine intake control device for a motorcycle arranged above, comprising: an air cleaner (17) extending in the front-rear direction of the vehicle and juxtaposed to each other in the air cleaner (17).
A plurality of passages (33a, 33a) communicating between the air intake port (28) of the vehicle and the plurality of throttle bodies (18).
b) and an intake control valve (35) for opening and closing at least one passage (33b) of the plurality of passages (33a, 33b) is provided in the air cleaner (17). Engine intake control device. 2. The engine intake control system for the motorcycle according to claim 1, wherein the upstream bottom ends of the plurality of throttle bodies (18) are connected to the rear bottom wall of the air cleaner (17), and the air cleaner (17) is connected to the upstream end of the air cleaner (17). An engine intake control device for a motorcycle, wherein a portion protruding forward from the throttle body (18) is arranged above the cylinder head (9). 3. The engine intake control system for a motorcycle according to claim 2, wherein a fuel injection valve (32) is mounted on a rear wall of the throttle body (18). apparatus. 4. The engine intake control system for a motorcycle according to claim 3, wherein a fuel tank (15) attached to the main frame (4) is provided from above the throttle body (18) and the air cleaner (17). An engine intake control device for a motorcycle, which is arranged so as to cover the motorcycle.