JP2003065161A - Motorcycle and carburetor mounted on motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motorcycle capable of smoothly accelerating without delicately operating a throttle at a low speed stage. SOLUTION: A negative pressure chamber 1 and an aerator 20 communicating with the air side A by the operation of a solenoid valve 21 are installed in a variable venturi carburetor Ca, the solenoid valve 21 is connected to a control unit Cu through a control line, a gear change stage detecting means 30 detecting a gear change stage of a transmission Tm, a speed detecting means 32 detecting speed, and a throttle operation speed detecting means 34 detecting a throttle operation speed are connected to the control unit Cu through a control line, and the control unit Cu controls so that the operation of a suction piston of the carburetor Ca operated by suction pressure is made slow by opening the solenoid valve 21 when the gear change stage becomes a preset stage, the speed becomes a set value, and the operation speed of the throttle becomes a set value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motorcycle having a fuel tank provided adjacent to the front of a riding type seat, and an engine unit disposed below the fuel tank and provided with a variable venturi type carburetor. And a variable venturi type carburetor suitable for the motorcycle and the like.

[0002]

BACKGROUND OF THE INVENTION Like a four-wheeled vehicle, a motorcycle has, of course, not only running performance,
It also improves fuel efficiency and quietness.

In terms of fuel economy, in the case of a motorcycle,
A variable venturi-type carburetor with good fuel economy is used mainly for utility vehicles.

By the way, in the case of a motorcycle, since the engine occupies a large portion of the vehicle body frame, there is a tendency to promote weight reduction and size reduction with the intention of improving fuel efficiency.
On the other hand, higher output is also required. In general, the engine output is determined by the product of the displacement, combustion pressure and engine speed.Therefore, in order to obtain a high output, the engine speed has been increased, and in recent years, a high-speed engine with good response has been developed. Has been increasing. As a result, the usable engine speed range is widened, and the rider has a wider selection range of the engine speed (horsepower selection range). Therefore, a light throttle operation (accelerator work) by the rider causes the engine speed to increase instantaneously and in a wide range. In particular, when the gear is a low speed, the driving force (wheel driving torque) is large and a large acceleration can be obtained. Therefore, when trying to obtain a smooth acceleration state without jerky feeling, the throttle at the low speed is used. The operation requires delicate movements. Specifically, when driving in the suburbs, there are few traffic lights and traffic congestion, so you can drive at high gears without frequent throttle operations, but when driving in urban areas, there are many traffic lights and congestion. Therefore, there are many opportunities to perform the throttle operation at the low speed stage, and therefore it is necessary to frequently perform the delicate throttle operation.

The present invention has been made in view of such a situation, and a motorcycle which does not perform a throttle operation at a low speed very delicately and a variable venturi type carburetor suitable for the motorcycle. The purpose is to provide.

[0006]

The object of the first invention is to:
The problem can be solved by the motorcycle having the following configuration. That is, the motorcycle according to the present invention is a motorcycle equipped with an engine unit provided with a variable venturi type carburetor, wherein the variable venturi type carburetor has a negative pressure chamber and an atmosphere side of a solenoid valve. A ventilation device that allows communication by operation is attached, and this solenoid valve is connected to a control device via a control line, and to this control device,
A shift speed detecting means for detecting a shift speed of the transmission, a vehicle speed detecting means for detecting a vehicle speed, and a throttle operating speed detecting means for detecting a throttle operation speed are connected through a control line, When the gear reaches a preset gear, the vehicle speed reaches a preset value, and the throttle operating speed reaches a predetermined value, the solenoid valve is opened and operated by suction pressure. It is characterized in that it is configured to control the operation of the suction piston of the vaporizer to be slowed.

However, according to the motorcycle thus constructed, the vehicle speed is a preset value at a predetermined gear stage,
And when the throttle operation speed is a predetermined value,
Since the operation of the suction piston of the carburetor becomes slow, the vehicle speed does not increase greatly in proportion to the operating speed of the throttle even when the operating speed of the throttle is high. Therefore, the rider can obtain a smooth acceleration state without jerky feeling without performing a delicate throttle operation.

Further, in the motorcycle, the motorcycle includes a fuel tank provided adjacent to the front of the riding type seat, and an engine unit provided below the fuel tank and provided with a variable venturi type carburetor. In the motorcycle provided with the variable venturi carburetor, at least a part of the ventilation device is housed in a central space of a coil spring that biases the suction piston to a side that closes the suction piston. Since at least a part of the ventilating device is arranged in the central space of the coil spring, which is a dead space in the carburetor in the related art, it is not bulky above the engine. As a result, the structure can be applied to a motorcycle in which a fuel tank is arranged near the carburetor. Here, the fuel tank includes not only an actual fuel tank but also auxiliary devices such as an air cleaner having a fuel tank shape which is provided as a dummy in appearance in addition to the actual fuel tank, or a cover similar thereto. Including.

In the motorcycle, if the opening degree of the solenoid valve can be changed in proportion to the signal from the control line, a smooth engine output characteristic can be obtained.

In the motorcycle, the preset gear stage is a low speed stage, the preset vehicle speed range is 10 to 50 km / h, and the operation speed of the throttle is 300 ° in the rotation angle display. If the operating speed is (degrees) / second or more, smooth acceleration without jerky feeling even if the throttle is operated at a large speed under the same conditions as in city driving, that is, in a low speed and low vehicle speed state. Can be obtained. Therefore, the motorcycle can be easily handled by a rider who is not good at delicate throttle operation or a beginner rider.

The object of the second invention can be solved by a carburetor having the following structure. That is,
In the carburetor according to the second aspect of the present invention, the suction piston is arranged on the air cleaner side of the throttle valve, one end of the suction piston is exposed to the negative pressure chamber, and the negative pressure chamber and the air cleaner side of the suction piston are communicated with each other. Then
Due to the decrease in pressure on the air cleaner side due to the opening operation of the throttle valve, the suction piston is lifted by overcoming the spring force of the coil spring that urges the suction piston downward to supply more fuel. In the variable venturi-type carburetor configured as described above, at least a solenoid valve whose tip communicates with the atmosphere side through a ventilation path is provided in the central space of the coil spring that urges the carburetor to close the suction piston. It is characterized by arranging a ventilation device configured to accommodate a part thereof.

According to the carburetor having the above construction, however, at least a part of the ventilating device is housed in the portion which has conventionally been a dead space, so that the outer shape does not become large. Therefore, it becomes a suitable carburetor to be mounted on a motorcycle in which a fuel tank is arranged adjacent to the front of a riding type seat and an engine is mounted below the fuel tank.

In the carburetor, if the opening of the solenoid valve is variable, a more delicate control can be performed, which is a preferred embodiment.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A motorcycle equipped with a variable venturi type carburetor according to an embodiment of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a partially enlarged view of a variable venturi-type carburetor according to an embodiment of the present invention, in which a portion below a center of a ventilation passage is omitted, and FIG. 2 is an automatic system equipped with the variable venturi-type carburetor of FIG. FIG. 3 is an overall side view of the motorcycle, FIG. 3 is a partially enlarged side view of the carburetor and engine and fuel tank portion of the motorcycle shown in FIG. 2, and FIG. 4 is a control system for operating a solenoid valve of the carburetor shown in FIG. It is a conceptual diagram which represented notionally.

In the motorcycle according to the embodiment of the present invention, the variable Venturi type carburetor Ca shown in FIG.
As shown in FIG. 2 or FIG. 3, the fuel tank Tf is disposed below and in proximity to the fuel tank Tf. As shown in FIG. 2, the motorcycle is configured to rotate a rotatable throttle Sr provided at a grip portion of a handle Hn so as to rotate via a connecting cable (not shown).
The carburetor Ca shown in FIG. 1 is configured so that the throttle valve 10 can be opened and closed. And the throttle valve 1
When "0" is operated to "open", the pressure in the intake passage 8 in which the throttle valve 10 is arranged becomes negative pressure, and this negative pressure becomes
The negative pressure chamber 1 of the variable Venturi vaporizer Ca is configured to have a negative pressure via a communication passage 2 formed at the bottom of the suction piston 4. Further, when the negative pressure chamber 1 becomes a negative pressure, the suction piston is arranged so that its upper end faces the negative pressure chamber 1 and is surrounded by a bellows 5 made of a rubber sheet to surround the lower space. Four
However, the coil spring 3 overcomes the downward pressing force (spring force) and is pulled upward. Further, a jet needle Jn is integrally arranged below the suction piston 4, and a lower portion of the jet needle Jn is accommodated in a needle jet Nj that can be raised and lowered. In this variable Venturi vaporizer Ca, a part of the ventilation device 20 is arranged in a cylindrical space 3C in the center of the coil spring 3. Of course, when the ventilation device 20 is small enough to be accommodated in the space 3C, it is desirable that the ventilation device 20 is arranged so as to be entirely accommodated in the space 3C. The ventilation device 20 includes an electromagnetic valve 21 inside and a ventilation path 22 that is opened and closed by the electromagnetic valve 21 and communicates with the atmosphere side A. By opening and closing the electromagnetic valve 21, the negative pressure chamber 1 is connected to the negative pressure chamber 1. It is possible to communicate with the atmosphere side A. Then, as shown in FIG. 4, the solenoid valve 21 is connected to the control device C of the motorcycle by the electric wire 25.
The solenoid valve 21 is connected to u and is configured to operate “open” by the “open” signal from the control unit Cu. This “open” operation may be simply an “open” and “closed” ON-OFF operation as in this embodiment.
For example, the opening may be changed in proportion to a signal (for example, voltage) applied to the electric wire 25. The voltage and the opening may have a characteristic that is linearly proportional to the characteristic of the carburetor Ca or the characteristic of the engine of the motorcycle, or have a characteristic that is proportional to the curve. May be

As shown in FIG. 4, the control unit Cu includes a gear position detection sensor 30 provided in a transmission unit Tm provided adjacent to the crankcase chamber Cr of the engine E of the motorcycle. It is connected by an electric wire 26, and is a low speed stage of the motorcycle, specifically, the first speed stage to the fourth speed stage in the case of the sixth forward speed stage (the first speed stage in the case of the fourth forward speed stage).
The second speed and the first speed in the case of the third forward speed) are configured to be detected, and are connected by the electric wire 27 to the vehicle speed detection sensor 32 arranged at the rotating portion of the front wheel Wf of the motorcycle. , Is configured to detect the vehicle speed of the motorcycle. As the vehicle speed sensor 32, in addition to the above,
It may be of a type in which the speed is electrically detected from a transmission gear or a sprocket of the engine. Further, in this embodiment, the control device Cu is
It is connected to a throttle operation speed detection sensor 34 provided in the throttle valve 10 via the, and is configured to detect the operation speed of the throttle valve 10. In reality, the throttle operation speed detection sensor 34 can be configured by a potentiometer and a control device.

Further, referring to FIG. 2, the general structure of the motorcycle having the above-mentioned structure will be described. By the engine E provided below the fuel tank Tf, the engine E is integrally provided below the engine E. Gearbox T provided
The rear wheel Wr is driven via m and the drive chain Ch so that the vehicle can travel. Also, the front wheel Wf
The steering wheel Hn is configured to be steerable left and right by a predetermined angle, and the steering wheel Hn is steered to turn in a desired direction. Further, although the engine E is a single cylinder four-cycle engine in this embodiment, the engine E is not limited to this and may be a multi-cylinder engine.

A rider seat St is disposed adjacent to the rear of the fuel tank Tf, and an air cleaner Ac is disposed below the seat St.
The air cleaner Ac and the vaporizer Ca are connected by a flexible pipe (rubber pipe in this embodiment) 27. Further, as described above, the fuel tank Tf may be an auxiliary device such as an air cleaner having a fuel tank shape or a cover similar thereto which is provided as a dummy in appearance in addition to the actual fuel tank, as described above. Good.

However, the motorcycle provided with the variable venturi-type carburetor constructed as described above operates as follows. That is, in the variable Venturi type carburetor Ca according to this embodiment, as shown in FIG. 1, a part of the ventilation device 20 including the solenoid valve 21 has a cylindrical shape at the center of the coil spring 3 of the carburetor Ca. Arranged (accommodated) in space
Therefore, the external appearance is compact, as it slightly protrudes from the upper end of the conventional variable Venturi vaporizer. That is, the solenoid valve slightly protrudes above the carburetor Ca.

In this motorcycle, when the rider rapidly operates the throttle Sr while traveling at the third speed and at a vehicle speed of 30 km / h, the controller C
u indicates that the speed stage of the transmission is the first to fourth speeds, and the vehicle speed is in the range of 10 to 50 km / h,
And that the operation speed of the throttle is in the operation speed state of 300 ° / sec or more.
4 to issue an "open" signal to the solenoid valve 21 of the ventilation device 20 so as to "open" for a predetermined time. As a result, when a predetermined amount of air is introduced into the negative pressure chamber 1, the level of negative pressure is lowered, and the speed at which the suction piston 4 of the carburetor Ca is raised is reduced by the amount of the reduction. That is, the lifting operation of the suction piston 4 becomes slow. As a result, the number of revolutions of the engine E is slowly increased, and as a result, smooth acceleration without jerky feeling is achieved even when the throttle is operated at a large speed in a state where the vehicle is running at a low speed and close to a city running state. Will be obtained. In the case where the opening of the solenoid valve 21 is changed in proportion to the voltage applied to the solenoid valve 21 via the electric wire 25, for example, in a case where the opening degree of the solenoid valve 21 is changed,
A preferred embodiment is configured so that the applied signal value (control amount) is changed according to the degree of vehicle speed or the speed state of throttle operation. Further, the predetermined value of the operation speed of the throttle may be appropriately set in relation to the actual jerky feeling.
The value is not limited to “0 ° / second” and can be set to an appropriate value.

[0022]

As described above, according to the motorcycle of the present invention, it is possible to obtain a smooth acceleration state without jerky feeling without performing a delicate throttle operation at a low speed stage.

Further, according to the variable venturi type carburetor of the present invention, at least a part of the ventilating device for introducing the atmosphere into the negative pressure chamber is a dead space, which is a cylindrical space in the center of the coil spring. The fuel vaporizer is suitable for a motorcycle in which the fuel tank and the like are disposed in the vicinity of the upper portion of the vaporizer.

[Brief description of drawings]

FIG. 1 is a partially enlarged view of a variable venturi-type carburetor according to an embodiment of the present invention, in which a portion below a center of a ventilation passage is omitted.

2 is an overall side view of a motorcycle equipped with the variable venturi type carburetor of FIG. 1. FIG.

FIG. 3 is a partially enlarged side view of the carburetor, engine and fuel tank portion of the motorcycle shown in FIG. 2, showing a state in which the fuel tank and the carburetor are fitted together.

4 is a conceptual diagram conceptually showing a control system for operating a solenoid valve of the vaporizer shown in FIG. 1. FIG.

[Explanation of symbols]

E ... Engine Ca: Variable venturi type vaporizer A: Atmosphere side Cu ... Control device 1 ... Negative pressure chamber 20 ... Ventilation device 21 ... Solenoid valve 30 ... Gear position detection 32 …… Vehicle speed detection 34 ...... Throttle operating speed detection

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02M 9/06 F02M 9/06 V 9/12 9/12 C

Claims (6)

[Claims] 1. A motorcycle comprising an engine unit equipped with a variable venturi type carburetor, wherein a negative pressure chamber of the carburetor and an atmosphere side can be communicated with the variable venturi type carburetor by operating a solenoid valve. A ventilator is attached to the control device, and the solenoid valve is connected to the control device through a control line. The control device includes a shift speed detecting means for detecting the shift speed of the transmission, a vehicle speed detecting means for detecting the vehicle speed, and a throttle. A throttle actuation speed detecting means for detecting an operation speed is connected via a control line, and the control device is such that the shift speed is a preset shift speed,
And when the vehicle speed reaches a preset value and the throttle operating speed reaches a predetermined value, the solenoid valve is opened to slow the operation of the suction piston of the carburetor operated by the suction pressure. A motorcycle characterized by being configured so as to control. 2. The motorcycle according to claim 1, wherein the motorcycle includes a fuel tank provided adjacent to the front of a riding type seat, and an engine unit disposed below the fuel tank and provided with a variable venturi type carburetor. The motorcycle according to claim 1, wherein at least a part of the ventilation device is housed in a central space of a coil spring that biases a suction piston of the variable venturi-type carburetor to a side that closes the suction piston. 3. The opening of the solenoid valve is changeable in proportion to a signal from a control line.
Or, the motorcycle according to 2. 4. The preset gear stage is a low gear stage, the preset vehicle speed range is 10 to 50 km / h, and the operation speed of the throttle is 300 ° / sec or more. The motorcycle according to any one of claims 1 to 3, characterized in that. 5. A suction piston is arranged on the air cleaner side of the throttle valve, one end of this suction piston is exposed to a negative pressure chamber, and the negative pressure chamber and the air cleaner side of the suction piston are communicated with each other to open the throttle valve. Due to the decrease in the pressure on the air cleaner side due to the operation, the suction piston is lifted by overcoming the spring force of the coil spring that urges the suction piston downward, and more fuel is supplied.
A variable venturi-type carburetor, comprising a solenoid valve whose tip communicates with the atmosphere side through a ventilation path in a central space of a coil spring which urges the carburetor to close a suction piston. A variable venturi-type vaporizer characterized in that it is configured to accommodate at least a part thereof. 6. The variable venturi type carburetor according to claim 5, wherein the opening of the solenoid valve is variable.