JPS635562B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a supercharger device for an engine that supercharges a combustion chamber of the engine with an air-fuel mixture from a carburetor via a supercharging pump.

Conventional devices of this type include, for example, a serial type in which a supercharging pump d such as a screw pump or a Roots pump is interposed in an intake passage c between a carburetor a and a combustion chamber b, as shown in FIG. As shown in FIG. 2, a bypass type is known in which a bypass passage f bypassing a reed valve e interposed in the intake passage c is connected to the intake passage c, and a supercharging pump d is interposed in the bypass passage f.

Although the series type has the advantage of simplifying the circuit configuration, it requires the use of a large-capacity supercharging pump d, which increases the pump driving force and has the disadvantage of worsening fuel efficiency. .

In addition, the bypass type has the advantage that the capacity of the supercharging pump d can be smaller than that of the series type, since the amount of intake air required for high speed rotation is ensured by intake through the reed valve e. The passage on the outflow side of the pump d is a curved longitudinal passage extending from the bypass passage f to the combustion chamber b via the intake passage c, increasing the flow resistance and reducing the flow velocity of the air-fuel mixture injected into the combustion chamber b. In addition, the air pumped from pump d accumulates between combustion chamber b and reed valve e, causing valve e to close, which should provide an intake inertia effect. Inspiratory flow through decreases,
In order to ensure a large flow rate at high speed rotation, the capacity of the pump d cannot be made very small.

The object of the present invention is to provide a device that eliminates such inconveniences, and is a supercharging device for an engine in which a mixture from a carburetor is supercharged into a combustion chamber of the engine via a supercharging pump. In the machine, a main intake passage connected to the carburetor is provided with a sub-intake passage that branches off upstream of a reed valve provided in the main intake passage, and the sub-intake passage is connected to the main intake passage provided in the main intake passage. The combustion chamber is connected to the combustion chamber through an intake valve and a separate sub-intake valve, and the supercharging pump is interposed in the sub-intake passage.

Next, the present invention will be explained with reference to embodiments shown in FIG. 3 and below.

3 and 4, 1 is a cylinder of the engine, 2 is a combustion chamber therein, and 3 is a carburetor connected to an air cleaner 4, which is connected to the downstream side of the carburetor 3. A main intake passage 5 and a sub-intake passage 6 branched from the main intake passage 5 on the upstream side of the reed valve 33 provided in the passage 5 are provided, and the main and sub-intake passages 5 and 6 are connected to the camshaft 7. The combustion chamber 2 is connected to the combustion chamber 2 through separate main and auxiliary intake valves 8 and 9 driven by the auxiliary intake passage 6, and a supercharging pump 10 is interposed in the auxiliary intake passage 6. The pump 10 has its drive shaft 11 disposed as close as possible to the cylinder 1 and parallel to the camshaft 7, and the drive shaft 11 is connected to the camshaft 7 via a chain or other transmission member 12. In this way, the pump 10 is driven by the camshaft 7.

According to the above configuration, the air-fuel mixture discharged from the supercharging pump 10 is directly injected into the combustion chamber 2 from the sub-intake passage 6, and the flow path resistance on the outflow side of the pump 10 is reduced, so that a large amount of the air-fuel mixture is In addition, the intake air is supplied into the combustion chamber 2 at a high speed, and the combustion efficiency is improved during low-speed rotation, which is the main time when the intake air flows through the pump 10, and the low-speed output is improved. The supercharging effect of the pump 10 is maintained even during high-speed rotation when air is being taken in, and the high-speed output is also improved. In this case, by adjusting the opening/closing timing of the auxiliary intake valve 9 to match the low-speed rotation, it is possible to prevent backflow from the combustion chamber 2 in the low-speed range, which would occur when the sub-intake valve 9 is set for high-speed rotation. can.

Furthermore, by interposing a clutch that disengages at high speed rotation between the camshaft 7 and the drive shaft 11 of the pump 10, the low speed output can be improved while the high speed output can be maintained as before.

Furthermore, in the illustrated embodiment, the auxiliary intake passage 6 is separated from the main intake passage 5 as clearly shown in FIG. The sub-intake passage 6 is provided with a control valve 14 interlocked with the throttle valve 13 of the carburetor 3.
The amount of supercharging of the air-fuel mixture is controlled according to the engine load, and the control valve 14 is provided on the inflow side of the pump 10, compared to one provided on the outflow side of the pump 10. The load was reduced and engine power loss was reduced.

Furthermore, when the flow path resistance on the outflow side of the pump 10 is reduced as described above, it becomes possible to use a vane pump suitable for relatively small capacity supercharging as the pump 10. It becomes possible to further improve fuel efficiency by taking advantage of the vane pump's advantage of low drive loss, which is a characteristic of the vane pump.

The configuration of the vane pump is shown in FIGS. 5 to 7, for example.
As clearly shown in the figure, a cylindrical eccentric rotor 17 connected to the drive shaft 11 and a pair of slits 18, 18 on the circumferential surface of the rotor 17 are provided in the pump chamber 16 in the pump body 15. A pair of vanes 20, 20 are provided, each of which is slidably inserted in the direction of the pump chamber 16 and supported on a vane shaft 19 at the center of the pump chamber 16. Ports 22 and 23 on the inflow and outflow sides in front and rear in the rotational direction of the rotor 17 across the contact surface 21 at the bottom of the pump chamber 16, which are in contact with each other, and ports 22 and 23 on the front cover 24 of the pump body 16, respectively. 23 are formed, and the openings 25 and 26 are connected to the auxiliary intake passage 6, and the rotor 17 is rotationally driven by the camshaft 7 described above. , due to a change in the volume of the space between the contact surface 21 and each vane 20, the pump chamber 1 flows from the inflow opening 25 through the inflow port 22 connected thereto.
The air-fuel mixture is sucked into the outlet port 23.
The liquid was discharged into the outflow opening 26 through the outlet.

In this case, supercharging pump 1 consisting of a vane pump
0 is a constant-volume rotating type, which discharges a mixture substantially proportional to the rotational speed, so when the auxiliary intake valve 9 is closed, the pressure on the outflow side increases and an overload is applied to the pump. Therefore, in the illustrated example, an accumulator 27 on the outflow side of the pump 10 is connected to the sub-intake passage 6, so that the increase in pressure is absorbed by the accumulator 27.
The load is reduced and the supercharging effect is increased by pressurizing the air-fuel mixture from the accumulator 27 when the sub-intake valve 9 is opened.

The accumulator 27 may be connected between the pump 10 and the auxiliary intake valve 9, but in the illustrated example, it is integrally assembled with the pump body 15 for compactness, and the pump chamber is It was connected to the bottom rear end of the room on the outflow side (right side in Figure 6) of No. 16. Here, the accumulator 27 is assembled downward to the upper part of the pump body 15 so as to prevent gasoline from pooling, and the bottom surfaces of the openings 25 and 26 are connected to the ports 22 and 23.
The pump chamber 16 is provided horizontally with the bottom surface of the pump chamber 16 or slopes downwardly toward the outside to prevent liquid droplets from remaining in the pump chamber 16 when the engine is stopped.

In addition, the bearing portion 28 of the eccentric rotor 17 and the bearing portion 29 of the vane 20 may be damaged by the gasoline contained in the mixture.
The side seal portion of the pump chamber 16 is connected to the vane 20 to prevent the lubricant from dissolving and impairing the lubricity.
The inner steel receiving plate 3 receives the side thrust of
The bearing part 28 of the eccentric rotor 17 is designed to improve the durability and sealing performance of the seal plate 31 by having a double structure of the carbon seal plate 31 and the outer carbon seal plate 31.
In addition, the bearing part 29 of the vane 20 has a sealing structure, and seal needles 3 on both the front and back sides press the vane 20 into the slit 18.
2 and 32 are provided to improve sealing performance and further reduce power loss due to sliding resistance of the vane 20.

Incidentally, in FIG. 3, numeral 34 indicates an exhaust valve 35, and an ignition plug.

According to the present invention, the main intake passage 5
A sub-intake passage 6 is provided which branches off upstream of the reed valve 33 provided therein, and the sub-intake passage 6 is connected to the main intake valve 8 provided in the main intake passage 5 through a separate sub-intake valve 9. Since the supercharging pump 10 is connected to the combustion chamber 2 and the supercharging pump 10 is interposed in the auxiliary intake passage 6, the flow path resistance on the outflow side of the supercharging pump 10 can be reduced as much as possible, and Main intake passage 5
Since the suction of the mixture is suppressed by the reed valve 33, the pump 10 can effectively suck in the air-fuel mixture and send it into the cylinder. It becomes possible to obtain a supercharging effect, which has the effect of improving low-speed output and fuel efficiency.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of an example of a conventional example, Fig. 2 is a system diagram of another conventional example, Fig. 3 is a system diagram of an example of the device of the present invention, and Fig. 4 is a cutaway front view thereof. , Figure 5 is a cut-away side view of the supercharging pump, and Figure 6 is a cross-sectional view of the supercharging pump.
FIG. 7 is a front view taken along the - line in FIG. 5. 2... Combustion chamber, 3... Carburetor, 5... Main intake passage, 6
... Sub-intake passage, 8... Main intake valve, 9... Sub-intake valve, 1
0...supercharging pump, 27...accumulator.

Claims (1)

[Scope of Claims] 1. In an engine supercharger device in which a combustion chamber of an engine is supercharged with an air-fuel mixture from a carburetor via a supercharging pump, a main intake passage connected to the carburetor is provided with a A sub-intake passage is provided that branches off upstream of a reed valve provided in the main intake passage, and the sub-intake passage is connected to the combustion chamber via a sub-intake valve that is separate from the main intake valve provided in the main intake passage. A supercharger device for an engine, characterized in that the supercharging pump is interposed in the auxiliary intake passage. 2. The engine supercharger device according to claim 1, wherein the supercharging pump is a vane pump. 3. The engine supercharger device according to claim 2, wherein the auxiliary intake passage includes an accumulator on the outflow side of the supercharging pump. 4. The engine supercharger device according to any one of claims 1 to 3, wherein the opening/closing timing of the sub-intake valve is set to a timing suitable for low speed rotation.