JPH06129304A - Fuel supply system of engine - Google Patents

Abstract

PURPOSE:To prevent useless fuel supply during no-firing rotation, and to eliminate lack of initial power by providing a by-pass communicating an upper stream part of a carbureter with a lower stream part in an inlet air passage connected to an inlet air port of an engine, and by providing an opening and closing valve which opens during a running period, and closes during a stationary period. CONSTITUTION:A by-pass 18 is provided in an inlet air passage 7 of an engine 3 on both sides of a carbureter 9 so as to communicate an upper stream passage 7a to a lower stream passage 7b. An electromagnetic valve 19 is provided at the middle of the by-pass 18, and in addition, a chamber 20 is provided in the lower stream part of the electromagnetic valve 19, and further, an exit port 18a for the lower stream passage 7b is connected to the position just before an inlet port 10. This electromagnetic valve 19 is closed during a stationary period. So, the pressure in the lower stream passage 7b coincides with that in the upper stream passage 7a. Thus, even if the engine 3 rotates in a state of no-firing, fuel supply to a fuel chamber 11 is prevented. Lack of power at the start is prevented by the fuel remained in the lower stream passage 7b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply system for an engine, and more particularly to a fuel supply system suitable for an engine mounted on a golf car.

[0002]

2. Description of the Related Art In an engine mounted on a golf car, start and stop are interlocked with accelerator operation in order to reduce the influence of exhaust gas on lawns and the like, and the throttle valve of the carburetor opens when the accelerator is depressed. At the same time, the start switch is turned on to start, and when the accelerator is released, the throttle valve closes and the ignition circuit turns off to automatically stop.
With this configuration, if the accelerator is released when the golf car is going downhill, the engine goes into the non-ignition rotation state due to the ignition circuit being off, and fuel is sucked from the slow port provided near the throttle valve. It is discharged and waste fuel is supplied to the combustion chamber.

[0003] Conventionally, as a measure for preventing such wasteful fuel supply, there has been proposed one provided with an opening / closing valve that closes the slow port at the same time when the accelerator is released (Japanese Patent Laid-Open No. 57-57).
-116145 gazette). Although the intended purpose of eliminating wasteful fuel supply was achieved by such measures, in addition to the fact that fuel is not sucked out from the slow port when the engine runs without ignition as described above, the carburetor is also removed. Due to the high negative pressure on the downstream side, most of the fuel remaining on the downstream side is sucked into the combustion chamber. Therefore, when the engine was started next time, there was no explosion until the fuel that was first sucked from the main jet of the carburetor reached the combustion chamber, which made the vehicle's departure difficult. In particular, this output shortage has become a problem when the user finishes going downhill and then tries to climb uphill.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to prevent unnecessary fuel supply during non-ignition rotation when the engine is stopped, and to prevent fuel shortage at the initial stage when the engine is started next time. It is to provide a supply device.

[0005]

In the fuel supply system of the present invention which achieves the above object, a bypass is provided in an intake passage connected to an intake port of an engine, the bypass communicating between the upstream side and the downstream side of a carburetor. The bypass is provided with an on-off valve which is closed when the engine is operating and is opened when the engine is stopped or when the engine is not ignited.

Since the on-off valve provided in the bypass connecting the upstream and downstream of the carburetor in this way is opened when the engine is stopped or when no ignition is performed, the pressure on the downstream side of the carburetor is almost the same as that on the upstream side. Fuel is not sucked out from the slow port when the engine is in non-igniting rotation, and unnecessary fuel is not supplied. Further, during this non-ignition rotation, not all of the fuel remaining on the downstream side of the carburetor is sucked into the combustion chamber.Therefore, the above-mentioned residual fuel is supplied at the beginning of the next engine startup, resulting in insufficient output. There is no invitation.

[0007]

1 and 2 show a golf car equipped with an engine having a fuel supply system according to the present invention. In these figures, 1 is a front wheel provided on the front left and right of the vehicle body, 2 is a rear wheel provided on the left and right rear portions, and 3 is an engine provided in the center of the vehicle body. The front wheels 1 are operated as steering wheels by the steering wheel 4, and the rear wheels 2 are used as driving wheels to transmit the power of the engine 3. In addition, a step 5 for standing up is provided at the rear of the vehicle body, and a golf bag mount 6 is provided at the front.
Is provided.

An intake passage 7 connected to the intake side of the engine 3.
Is equipped with an air cleaner 8 at its tip, and a carburetor 9 is interposed in the middle thereof, and the intake port 1 of the combustion chamber 11 shown in FIG.
It has reached 0. Further, an exhaust pipe 13 is connected to the exhaust port 12 on the exhaust side, and a silencer 14 is provided in the exhaust pipe 13. The carburetor 9 has the same structure as that known per se, and has a throttle valve (not shown) provided therein and a main jet for fuel injection and a slow port provided therein. As shown in FIG. 3, a throttle valve operating wire 15 is connected to the throttle valve of the carburetor 9, and the wire 15 is operated by interposing a governor mechanism 16 for controlling the engine rotation speed. It is connected to the child 17. Throttle valve operator 1
Reference numeral 7 is an accelerator lever attached to the handle 4 as shown in FIG. 1, or an accelerator pedal (not shown). The governor mechanism 16 is known per se (see, for example, Japanese Unexamined Patent Publication No. 62-228634), and the engine rotation speed becomes a certain speed or more in accordance with the operation amount of the throttle valve operator 17 in a predetermined relationship. It is automatically controlled so that it does not happen.

In the above structure, the intake passage 7 of the engine 3 is provided with a bypass 18 for connecting the upstream passage 7a and the downstream passage 7b with the carburetor 9 interposed therebetween, as shown in FIGS. Has been. This bypass 18 is provided with a solenoid valve 19 at an intermediate portion, a chamber 20 having a relatively large volume is provided on the downstream side thereof, and the downstream passage 7 is provided.
The outlet 18a for b is connected immediately before the intake port 10. The outlet 18a of the bypass 18 is connected to the intake passage 7
The inner wall of the combustion chamber 12 is opened obliquely and is directed obliquely to the combustion chamber 12.

The solenoid valve 19 has a rubber mount 21 on the outer circumference.
The rubber mount 21 is supported by the engine body by being supported by the stay 22. The electromagnetic valve 19 is closed when the engine is operating, but is opened when the engine is stopped. Therefore, when the engine is stopped, the pressure in the downstream passage 7b of the carburetor 9 is passed through the bypass 18 to the upstream passage 7b.
By communicating with a, the pressure becomes almost the same, so that even if the engine rotates without ignition with the throttle valve closed, fuel will not be sucked out from the slow port of the carburetor 9. There is. Therefore, the fuel remaining in the downstream passage 7b is not sucked into the combustion chamber 11 at the time of non-ignition rotation, and the retained fuel is supplied to the combustion chamber at the next engine startup. It is designed not to invite.

Further, the chamber 20 of the bypass 18
The portion on the further downstream side has a function of drawing in a part of the exhaust gas that flows backward when the opening timing of the intake valve and the exhaust valve overlaps during engine operation and temporarily storing it. Then, the exhaust gas temporarily stored in this way is discharged together with the air-fuel mixture from the outlet 18a into the combustion chamber 1 during the intake stroke.
1 is obliquely injected to generate a swirl in the combustion chamber 11, so that the combustion efficiency is improved. Also, due to such a swirl effect, the air-fuel ratio can be set to a thin setting, and NOx, CO, HC in exhaust gas can be reduced.
Etc. can be reduced.

FIG. 5 shows an example of an electric circuit for operating the above-mentioned engine. Reference numeral 31 is a battery that serves as a power source for the golf car.
1, the solenoid valve 19, the starting circuit 32, and the ignition circuit 33 are connected together. The accelerator switch 42 is normally opened, and is made to interlock with the accelerator lever (throttle valve operator) 17. The accelerator switch 42 is closed when the accelerator lever 17 is closed and opened when the accelerator lever 17 is opened.

The starting circuit 32 is provided with a relay 34 and a starting motor 35, an armature 36 of which is connected to the relay 34 via a series winding field coil 37, and a shunt winding field coil 38 is connected to a regulator 39. . The contact 34 a of the relay 34 is connected between the battery 31 and the series winding field coil 37, and the coil 34 b is connected to the battery 31 via the ignition circuit 33, the contact 40 a of the relay 40, and the power switch 41. . Relay 4
The zero contact 40a is closed when the accelerator switch 42 is closed and the coil 40b is excited.

The ignition circuit 33 is connected to a power switch 41 via a contact 40a of a relay 40, and an ignition coil 43,
The igniter 44 and the ignition timing signal generating coil 45 are connected. The ignition timing signal generating coil 45 generates an ignition timing signal in the recess 46a of the rotor 46 that rotates in synchronization with the crankshaft. The igniter 44 connects and disconnects the output transistor 47 based on this ignition timing signal to cut off the current flowing through the primary coil 43a of the ignition coil 43, and the secondary coil 4
A high voltage is generated at 3b. The secondary coil 43b is connected to the spark plug 48.

In the above-mentioned electric circuit, when the power switch 41 is closed and the accelerator lever 17 is closed (that is, the throttle valve of the carburetor 9 is opened), the ignition circuit 33 and the solenoid valve 19 are connected. When both are closed, the starting circuit 32 is closed, so that the armature 36 is rotated and the engine is started. Further, since the solenoid valve 19 is closed, the bypass 18 is closed. Conversely, when you release your hand from the accelerator lever 17, the accelerator switch 4
2 is opened and the ignition circuit 33 is opened, so the engine 3
Is stopped and the circuit of the solenoid valve 17 is also opened at the same time, so that the solenoid valve 19 of the bypass 18 is opened to establish a communication state between the upstream passage 7a and the downstream passage 7b.

FIG. 6 shows another embodiment of the present invention. As an on-off valve provided in the bypass 18, instead of the solenoid valve 19 described above, it is normally closed by a spring 25,
And the rear side is connected to the downstream side passage 7 of the carburetor 9 by the pipe line 24.
A diaphragm valve 19 'communicated with b is provided. With such a configuration of the diaphragm valve 19 ′, when the throttle valve is closed and the engine rotates without ignition, the negative pressure generated in the downstream passage 7 b opens the diaphragm valve 19 ′ and the bypass 18 is in the communicating state. To Therefore, also in the case of this embodiment, the same effect as that of the above embodiment can be obtained.

In the above-mentioned embodiments, the case of the engine mounted on the golf car has been described, but the fuel supply system of the present invention can be applied to other general-purpose engines such as an engine installed in an engine generator. .

[0018]

As described above, in the fuel supply system of the present invention, the intake passage is provided with a bypass connecting the upstream and downstream of the carburetor, and the opening / closing valve provided in this bypass is opened when the engine is stopped or when no ignition is performed. In this way, the pressure on the downstream side of the carburetor is made to be almost the same as that on the upstream side, so that even if the engine rotates without ignition, fuel is not sucked out from the slow port and unnecessary fuel is not supplied. . Also, during this non-ignition rotation, not all of the fuel remaining on the downstream side of the carburetor is sucked into the combustion chamber.Therefore, the above-mentioned residual fuel is supplied at the beginning of the next engine startup, resulting in insufficient output. There is no invitation.

[Brief description of drawings]

FIG. 1 is a perspective view of a golf car equipped with an engine having a fuel supply device according to the present invention.

FIG. 2 is a plan view showing the golf car with the upper side removed.

FIG. 3 is an enlarged plan view showing an engine portion of the golf car.

FIG. 4 is a rear view showing a portion taken along the line IV of FIG.

FIG. 5 is an electric circuit diagram of the golf car.

FIG. 6 is an enlarged view corresponding to FIG. 3 showing another embodiment of the present invention.

[Explanation of symbols]

3 engine 7 intake passage 7a (for carburetor) upstream passage 7b (for carburetor) downstream passage 9 carburetor 10 intake port 17 accelerator lever (throttle valve operator) 18 bypass 19 solenoid valve (open / close valve) 19 'diaphragm Valve (open / close valve)

Claims (2)

[Claims] 1. A bypass that connects an upstream side and a downstream side of a carburetor is provided in an intake passage connected to an intake port of an engine, and the bypass is closed when the engine is operating and is opened when the engine is stopped. A fuel supply device for an engine provided with an on-off valve that operates. 2. An intake passage connected to an intake port of an engine is provided with a bypass communicating between a carburetor upstream side and a carburetor side, and the bypass is closed when the engine is in operation, and the engine does not rotate without ignition. An engine fuel supply system with an on-off valve that opens at times.