JPS5835263A - Fuel-air mixture supply system - Google Patents

Abstract

PURPOSE:To level the pulsation of fuel caused by its intermittent injection in a mixture feeder of fuel injection type, by providing the upstream side of a throttle valve with guide grooves for collecting clinging fuel drops so that the fuel stays in the grooves. CONSTITUTION:The upstream side of a throttle valve 3, which faces an injection valve, is provided with numerous grooves 7 extending from prescribed gathering sections 7a and with notches 6 for connecting the gathering sections to the downtream or peripheral side of the throttle valve. Drops of fuel ejected on the valve 3 are guided by the grooves 7 so that the fuel is collected to the gathering sections 7a and flows out through the notches 6. At that time, the fuel does not flow out along all the circumference of the throttle valve 3 but is restricted to flow out only along prescribed sections so that overflows 12 are caused. Since the fuel temporarily stays near the prescribed sections which function as regulating dams, the pulsation of the fuel caused by its intermittent injection is leveled.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mixture supply device for an internal combustion engine, and more particularly to a mixture supply device l/c of a fuel injection type that intermittently injects fuel upstream of a throttle valve.

Fuel injection systems have been increasingly used in recent years because they meet exhaust gas regulations while ensuring fuel efficiency and good drivability.

Since injection valves are expensive, it is preferable to have as few number as possible from the viewpoint of cost. When the number of injection valves is set to one, the koji is injected at the jet position of a normal carburetor, that is, upstream of the throttle valve.

It is preferable for engine operation that the number of injection cycles is the same as the number of repetitions of the suction stroke of the engine or an integral multiple thereof, but due to the characteristics of the injection valve, there are cases where it is not possible to reduce the number of repetitions below the limit for the valve opening time. In the case of jin, it is injected in number or % of the number of intake strokes of the engine. In other words, the opening time of the injection valve is determined in order to secure eight or three suction strokes in one injection operation. At this time, rotational ram may occur, mainly during idling operation. This is because fuel is injected and supplied intermittently, so even if a normal air-fuel ratio is maintained on average, the air-fuel ratio becomes unstable during the intake stroke immediately after each intake fuel is injected and the next. On the other hand, because the same amount of air is inhaled each time, the air-fuel ratio differs with each intake stroke, and the repeated over-enrichment and over-lean changes cause the explosion pressure to change and become weak. This phenomenon is explained in detail with a diagram. Figure 1 shows a conventional device, and the intake pipe 1 of the engine.
Fuel is injected from the injection valve l installed at 0G! ! lJI and collides with the upstream face of the throttle valve 3. When this situation is viewed from the injection valve side, as shown in FIG. 8, the spray forms irregular lumps 1G on the throttle valve surface and moves radially in the direction of arrow 11, that is, toward the outer periphery of the throttle valve.

It is re-atomized together with air from the surrounding area and is sucked into the engine downstream of the throttle valve. 4 is the shaft of the throttle valve. 7 The fuel on the surface of the throttle valve 8 flows out from the entire circumference, so there is nothing to impede its flow on the surface of the valve body, and the fuel always moves at a uniform speed, so there is no stagnation of the liquid, and therefore the intermittent injection Fuel employment will not be leveled.

The present invention has been developed with this point in mind, and its gist is to control the movement of liquid on the surface of the valve body, collect it in one or several places, and limit the outflow location, thereby causing the fuel to stagnate. It's about leveling out the pulsation.

Figure 8 is a sectional view of one embodiment of the present invention, and shows the injection valve l.
From there, the fuel becomes a spray and is sprayed onto the throttle valve 8. The throttle valve 8 has a notch 6 that communicates the 7 and the collecting portion 7a to the downstream side or the outer peripheral side of the throttle valve I8.
is provided.

Next, the operation will be explained. The fuel droplets sprayed onto the valve body 8 are guided by the groove 7, collect in the collecting portion 7a, and flow out from the notch 6. In this case, the flow does not flow from all of the throttle valves, but only from a limited number of locations, causing an overflow and causing fuel to accumulate in this area, which acts as a regulating dam, so that the pulsation of intermittent injection is averaged out. . FIG. 5 shows a throttle valve 8 according to another embodiment, and an annular inner groove 7.
A small hole 6a is provided in the collecting portion 7a, and FIG. 6 is a cross-sectional view thereof, showing a soft melt penetrating the bottom surface of the small hole 6aFi collecting portion 7a. Off view tli is a sectional view of a further embodiment, in which a bulkhead 8 is thrown instead of the guide i@7vc. In either embodiment, the operation is the same: the movement of droplets on the surface of the valve body toward the outer periphery is restricted and the outflow hole is restricted to cause fuel to stagnate, thereby leveling out the pulsation.

In this way, when the fuel is leveled and the same amount is inhaled each time, the aerodynamic ratio becomes the same each time, and the engine can operate stably even when the engine speed is intermittently injected and the number of injections is smaller than the number of intake strokes. can. Furthermore, since the surface of the valve body has a leveling effect, the flow of air and fuel spray is not obstructed during high-load operation of the engine, and a good atomized mixture inherent to fuel injection can be obtained.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a conventional device, Fig. 2 is an explanatory diagram showing the movement of droplets in the conventional device, Fig. 8 is a cross-sectional view showing an embodiment of the present invention, and Fig. 4 is a diagram of a conventional device. FIG. 5 is a top view of another embodiment of the present invention, and FIG. 6 is a cross-sectional view of still another embodiment of the present invention. In the figure, l is the injection valve, 2 sprayers, 8 is the valve body of the slotted valve L-7, number is the shaft of the throttle valve, b is downstream of the throttle valve, 5
．． 6a is a notch or a small hole, 7 is a guide groove, and 8 is a bulkhead. Agent Shin Kuzuno −

Claims (1)

[Claims] ■ A fuel injection valve is disposed upstream of a throttle valve in the intake passage of the engine, and the fuel injected from the fuel injection valve is mixed with intake air to supply an air-fuel mixture to the engine. In the air-fuel mixture supply device, a guide groove or a guide partition is formed on the upstream surface of the throttle valve to collect adhesion-resistant fuel at one or more locations. 2) The fuel collected at one or more locations on the throttle valve is configured to flow out through a small hole or a notch communicating with the outer circumferential side or downstream side of the throttle valve. mixture supply device.