JPS6236150B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mixture supply system for a gasoline engine, and more particularly to a single-point fuel injection type mixture supply system.

For example, in a single-point air-fuel mixture supply system in which one fuel injection valve is installed downstream of a throttle valve in an air supply cylinder, as seen in Japanese Patent Application Laid-Open No. 51-7335, the fuel injected from the fuel injection valve is The mixture is once placed in the mixing chamber and mixed with intake air, but in reality, the flow direction is determined even within the mixing chamber, so the mixture enters the manifold convergence connected to the mixing chamber without being completely mixed. The manifold convergence section is branched midway and connected to each cylinder, but the lengths and directions of the manifolds are different. Therefore, each time the cylinder in the intake stroke changes, the branch pipe through which the air-fuel mixture flows changes, and if the air-fuel mixture is not completely mixed, the amount of fuel supplied will be uneven between cylinders. easy.

If the amount of fuel distributed between multiple cylinders becomes uneven in this way, the engine will not rotate smoothly, and
The exhaust composition from the engine deteriorates, resulting in increased fuel consumption. In order to reduce these drawbacks, it is effective to mix the fuel and intake air more uniformly in the mixing chamber, but
Conventionally, structural measures against this problem have been insufficient.

An object of the present invention is to provide a single-point fuel injection type mixture supply device suitable for obtaining a uniform mixture, and its characteristics are as follows: A guide is used to deflect the flow direction of the air-fuel mixture so that it merges with the previous air flow flowing into the collecting chamber from the secondary side supply cylinder and not being deflected to any manifold side. It is located downstream of the injection valve in the side air supply cylinder.

With this configuration, the airflow flowing into the gathering room from the secondary side air supply cylinder and the air mixture flowing into the gathering room from the primary side air supply cylinder can be reliably mixed in the gathering room, and the secondary side Even after the throttle valve in the air supply cylinder opens, a uniform mixture ratio of air-fuel mixture can be supplied to each manifold.

FIG. 1 is a vertical cross-sectional view of a mixture supply device that is an embodiment of the present invention. The air supply cylinder 1 is divided into a primary side air supply cylinder 6 and a secondary side air supply cylinder 7 downstream of the bench lily section 10, and is connected to the mixing chamber 2. The mixing chamber 2 communicates with a manifold collection 3, which in turn communicates with the cylinder 4 of the engine 5. A hot wire type air flow meter 8 is installed in a bypass passage 9 that communicates the upstream side of the bench lily section 10 with the narrowest part of the bench lily section 10, and measures the flow rate of air flowing through the bench lily section 10. The signal from the air flow meter 8 is processed and output to the fuel injection valve 11, and the opening time of the fuel injection valve 11 is controlled in proportion to the intake air amount of the air supply cylinder 1. That is, an amount of fuel proportional to the amount of intake air is injected into the primary air supply cylinder 6.

A primary throttle valve 12 is installed in the primary air supply cylinder 6, and the amount of intake air sent to the mixing chamber 2 is adjusted by changing its opening degree by the driver. In normal operating conditions, intake air is supplied from this primary side air supply cylinder 6, but during high speed or high load operation, the secondary side of the secondary side air supply cylinder 7 is supplied in conjunction with the primary side throttle valve 12. The throttle valve 13 also opens to increase the amount of intake air. These intake airs are mixed with fuel injected from the fuel injection valve 11 in the mixing chamber 2, and are sucked into the cylinder 4 which is in the intake stroke.

A cylindrical pipe 15 is provided at the lower end of the primary air supply cylinder 6.
is installed. Since this pipe 15 opens at the center of the mixing chamber 2, the primary throttle valve 1
The mixed air flow of the intake air and the injected fuel that has passed through the gap around the mixing chamber 2 is guided to the bottom of the mixing chamber 2. Inside the pipe 15, fine particles of fuel injected in an oblique direction are vaporized while being carried by the intake air flow, but relatively large fuel particles wet the wall surface of the pipe 15 and vaporization is promoted by the intake air flow. In this way, the vaporized fuel and the intake air are uniformly mixed and flowed out from the pipe 15, and further hit the bottom of the mixing chamber 2 and are dispersed. Therefore, the uniformity of the mixture in the mixing chamber 2 is increased, and even if the intake cylinders 4 are changed, the uniformity of fuel distribution is improved.

Conventionally, since the pipe 15 was not provided, the water flowed through the mixing chamber 2 along the shortest path as shown by the broken line and was sucked into the manifold pipe collecting section 3. This rich mixture flows intermittently according to the valve opening cycle of the fuel injection valve, so when the manifold through which it flows changes, the transition of the rich mixture is delayed and a uniform amount of fuel can be sent to each cylinder. I couldn't do it. On the other hand, in the case of this embodiment, the mixed air flow that exits the pipe 15 is further dispersed and diffused in the mixing chamber 2, and is mixed uniformly.
A uniform amount of fuel is supplied to each cylinder 4.

In addition, when the shape of the pipe 15 is not made into a cylindrical tube but the tip opening is deformed into a long rectangular shape in the direction perpendicular to the plane of the paper to forcefully disperse the air mixture, the fuel distribution to each cylinder 4 is further improved. can be done. In addition, the pipe 15 is provided with a large number of holes,
The degree of mixing can be improved by allowing the air-fuel mixture to flow out in all directions from this hole, or a diffusion plate may be attached to the tip of the pipe 15 to forcefully disperse the air-fuel mixture. Furthermore, if the pipe 15 is made of an electrically resistive material and electricity is applied from the upper and lower ends of the pipe 15 to generate heat, the fuel adhering to the pipe 15 can be rapidly vaporized and the air-fuel mixture can be heated to further improve diffusivity. It becomes possible to do so.

The air-fuel mixture supply device of this embodiment has a pipe-shaped guide that guides the air-fuel mixture flow at the lower end of the primary side air supply cylinder 6 in which the fuel injection valve is installed, thereby achieving uniformity in fuel distribution to each cylinder. It has the effect of being able to improve

FIG. 2 is a vertical sectional view of a mixture supply device according to another embodiment of the present invention, in which the same parts as in FIG. 1 are given the same reference numerals.

In this device, a protrusion 18 is provided at the outlet of the primary air supply cylinder 6 and below the open end of the fuel injection valve 11. When the primary throttle valve 12 opens, the fuel injection valve 1
The amount of intake air passing near the opening of 1 increases particularly,
This intake air flow detects the injected fuel, hits the protrusion 18, and changes its direction. At this time, the air mixture is dispersed and diffused into the mixing chamber 2 to produce a uniform air mixture, which is evenly distributed to each cylinder 4.

The air-fuel mixture supply device of this embodiment has the effect of producing a uniform air-fuel mixture and improving fuel distribution by providing a protrusion downstream of the fuel injection valve opening.

In all of the above embodiments, the flow direction of the air-fuel mixture is changed so that the flow path between the primary air supply cylinder 6 and the intake pipe 3 does not follow the shortest path.

By doing this, the fuel in the mixture is diffused or dispersed, and the air-fuel ratio of the mixture taken into each cylinder 4 is made more uniform, and the engine 5
The rotation of the engine becomes smoother, and the fuel consumption is reduced and the exhaust composition is improved.

The air-fuel mixture supply device of the present invention has the effect of being able to supply a uniform amount of fuel to a plurality of cylinders even if it is a single-point fuel injection type.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a mixture supplying device according to an embodiment of the present invention, and FIG. 2 is a vertical cross-sectional view of a mixture supplying device according to another embodiment of the present invention. 1...Air supply cylinder, 2...Mixing chamber, 3...Manifold collection section, 4...Cylinder, 5...Engine, 6...Primary side air supply cylinder, 7...Secondary side air supply cylinder , 11...Fuel injection valve, 12...Primary side throttle valve, 15...Pipe,
18... Protrusion.

Claims (1)

[Scope of Claims] 1. A manifold pipe that communicates a plurality of cylinders of a gasoline engine with a mixing chamber, a primary air supply cylinder connected to the mixing chamber, and a secondary air supply cylinder connected to the mixing chamber. In a mixture supply device having an air cylinder and a fuel injection valve installed downstream of a throttle valve of the primary side air supply cylinder,
Before the airflow from the secondary supply cylinder is deflected to either of the manifolds, the mixture from the primary supply cylinder is merged with the airflow from the secondary supply cylinder. An air-fuel mixture supply device characterized in that a guide is provided at an inlet portion of a gathering chamber downstream of the fuel injection valve of the primary side air supply cylinder. 2. The air-fuel mixture supply device according to claim 1, wherein the guide is a pipe installed at the lower end of the primary air supply cylinder and opened into the mixing chamber. 3. The air-fuel mixture supply device according to claim 1, wherein the guide is a heated pipe installed at the lower end of the primary side air supply cylinder and opened into the mixing chamber. 4. The air-fuel mixture supply device according to claim 1, wherein the guide is a protrusion installed at the lower end of the primary side air supply cylinder.