JPH0223824Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a mixture supply system for an internal combustion engine using a fuel injection valve.

As an air-fuel mixture supply device for an internal combustion engine having multiple cylinders, a smaller number than the number of cylinders, for example, one fuel injection valve, is provided upstream of the branch point of the intake passage to each cylinder, and the fuel injection valve is formed here. There is a structure in which the air-fuel mixture is distributed to each cylinder (for example, Japanese Patent Application Laid-open No. 134223/1983). According to this, the electronic fuel injection amount control circuit, fuel piping, electrical wiring, etc. are simpler and lower cost than a fuel injection device that has one fuel injection valve in each cylinder intake port. On the other hand, it is much more advantageous in terms of air-fuel ratio control accuracy than when using a carburetor.

However, in such a configuration in which the fuel injection valve is provided upstream of the branch part of the intake passage, when the engine is operated at a relatively high load, the airflow is turbulent due to the high airflow velocity, causing the injected fuel to become turbulent. The fuel mixes well with air and can distribute a uniform mixture to each cylinder. However, at low loads, the air flow rate is slow and it is difficult to achieve a uniform mixture of fuel and air, so the mixture distributed to each cylinder is The disadvantage is that the concentration varies depending on the cylinder.

This idea was created in view of the above points, and aims to improve the distribution characteristics to each cylinder by ensuring a sufficient intake air flow rate even when the engine speed is low and the load is relatively small. An object of the present invention is to provide a mixture supply device for an internal combustion engine.

That is, the air-fuel mixture supply device for an internal combustion engine according to this invention can be used in an internal combustion engine having multiple cylinders.
A fuel injection valve is provided in a direction substantially perpendicular to the intake flow upstream of the branching portion of the intake passage to each cylinder, while a primary throttle valve and a secondary throttle valve are arranged in parallel downstream of the fuel injection valve. A reflector plate facing the fuel injection valve is provided to guide the fuel mainly to the primary throttle valve, and an intake passage downstream of the throttle valve is connected to the primary and secondary throttle valves. The intake passage is divided into two systems, the primary intake passage and the secondary intake passage, which communicate with each other up to the vicinity of the intake valve, and the upper end of the partition wall between the two is located downstream from the fully closed position of the secondary throttle valve, thereby increasing the intake air amount. When the engine is running at low speed and with a relatively low load, the entire amount of fuel injected from the fuel injection valve and intake air is supplied to the engine via the primary intake passage, and when the engine is running at high speed and with a high load, both the primary and secondary sides are supplied. It is characterized by being supplied to the engine via a passage.

Hereinafter, one embodiment of this invention will be described in detail based on the drawings.

FIG. 1 shows a mixture supply system according to this invention, in which 1 is an internal combustion engine having a plurality of cylinders, 2 is an intake pipe, 3 is a throttle chamber, and 4 is an air cleaner. 3 is divided downstream of the bench lily portion 5 into a primary passage 6 and a secondary passage 7, and a primary throttle valve 8 and a secondary throttle valve 9 are provided respectively. The secondary throttle valve 9 is opened when the opening degree of the primary throttle valve 8 has increased to a certain extent, and in this embodiment, it is driven by an actuator 10 operated by the negative pressure of the bench lily portion 5. Although it is configured, it may be mechanically interlocked.

The fuel injection valve 11 is located upstream of the primary throttle valve 8 and the secondary throttle valve 9, specifically, the primary side, the secondary side passage 6,
The control circuit 12 controls the timing of opening and closing, that is, the fuel injection amount, as appropriate. In addition, 13 is a fuel tank,
14 is a fuel pump, 15 is a fuel filter, and 16 is a pressure regulating valve. Reference numeral 17 denotes an air flow rate sensor for detecting the air flow rate which basically determines the fuel injection amount, and is provided in the bypass passage 18.

Furthermore, a partition wall 19 is formed in the intake pipe 2 and is connected to the partition wall 32.
A primary side intake passage 20 communicating with the primary side passage 6 of the throttle chamber 3 and a secondary side intake passage 21 communicating with the secondary side passage 7 of the throttle chamber 3 are formed separately. Furthermore, the intake port 22
In addition, a partition wall 23 is formed near the intake valve 24 so as to be connected to the partition wall 19, and divides the inside of the port 22 into a primary port 25 and a secondary port 26. Reference numeral 27 denotes a cooling water passage for heating intake water, which is integrally formed with the intake pipe 2, and is provided so as to be in contact with the primary side intake passage 20.

Further, the fuel injection valve 11 is installed in a manner substantially orthogonal to the intake air flow from the primary side passage 6 toward the secondary side passage 7 side, and the fuel injection valve 11 is installed upstream of the secondary throttle valve 9. A reflecting plate 31 is fixedly provided opposite to the injection direction. That is, the configuration is such that the fuel injected from the fuel injection valve 11 collides with the reflecting plate 31 and is reflected, thereby guiding the fuel mainly to the primary throttle valve 8 side. And Throttle Chamber 3
The upper end of the inner partition wall 32 is located downstream from the fully closed position of the secondary throttle valve 9, and is configured such that the fuel dripping onto the throttle valve 9 flows into the primary side passage 6.

In the air-fuel mixture supply system configured as described above, only the primary throttle valve 8 is open and the secondary throttle valve 9 is fully closed during low-load operation when the intake air amount of the engine is small. Therefore, the entire amount of intake air flows from the primary throttle valve 8 through the primary side intake passage 20 at a relatively high flow rate. Here, the fuel is injected toward the reflector plate 31 upstream of the primary throttle valve 8, and upon collision, becomes fine droplets and mainly flows into the primary passage 6. Further, a part of the fuel dropped onto the secondary throttle valve 9 also flows into the primary passage 6 along the slope of the secondary throttle valve 9, that is, the entire amount flows into the primary passage 6. The mixture is uniformly mixed by the turbulence of high-speed airflow in the primary passage 6 and the primary intake passage 20, both of which have relatively small passage diameters, and distributed to each cylinder. Then, this air-fuel mixture flows into the combustion chamber 28 from the primary side port 25 via the intake valve 24 at high speed, and generates a vortex flow within the combustion chamber 28.

That is, even during low-load operation when the amount of intake air of the engine is small, a homogeneously mixed air-fuel mixture is evenly distributed to each cylinder. At the same time, as described above, a strong vortex is generated within the combustion chamber 28, which increases the combustion speed and ensures stable combustion even when a large amount of exhaust gas is recirculated or under a lean air-fuel ratio.

On the other hand, when the load is high, the secondary throttle valve 9 further opens due to an increase in the amount of intake air, and part of the air-fuel mixture flows from the primary intake passage 20 through the secondary passage 7 and the secondary intake passage 21. Combustion chamber 2 with the mixture of
8 will be introduced. Therefore, even under high load, there is no reduction in output due to suction resistance. here,
Fuel is supplied to both the primary passage 6 and the secondary passage 7, and is uniformly mixed with air in both the primary and secondary intake passages 20, 21, so that the entire amount of fuel is supplied to the primary passage 6. The properties of the air-fuel mixture flowing into the combustion chamber 28 can be made better than when the fuel is only supplied to the combustion chamber 28, and the distribution of the fuel is also improved.

In addition, since the cooling water passage 27 for heating intake water is provided on the primary intake passage 20 side, fuel vaporization can be effectively promoted by hot water heating during low speed and low load operation, while during high load operation The air flowing through the secondary intake passage 21 is hardly heated, and a decrease in output due to a decrease in filling efficiency can be avoided.

As is clear from the above explanation, the mixture supply device for an internal combustion engine according to this invention can obtain a high-speed intake air flow in the intake passage even during low-load operation, and the turbulence of this high-speed air flow This makes it possible to improve the mixing of fuel and air and evenly distribute a homogeneous air-fuel mixture to each cylinder, thereby improving the stability of the engine. In particular, the fuel is injected from the fuel injection valve toward the reflector, where it collides and becomes atomized in advance, so that it mixes better with air. Also, during high-load operation, fuel flows into both the primary intake passage and the secondary intake passage, and a flammable mixture is formed in both. Mixability and uniformity can be improved, and distribution properties can also be improved.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram showing an embodiment of the air-fuel mixture supply device according to this invention. DESCRIPTION OF SYMBOLS 1... Internal combustion engine, 2... Intake pipe, 3... Throttle chamber, 8... Primary throttle valve, 9... Secondary throttle valve, 11... Fuel injection valve, 17... Air flow rate sensor, 19 ...Bulkhead, 20...Primary side intake passage, 2
1... Secondary intake passage, 23... Bulkhead, 25...
Primary side port, 26...Secondary side port, 27...
Cooling water passage.

Claims (1)

[Scope of utility model registration request] In an internal combustion engine having multiple cylinders, a fuel injection valve is provided upstream of the branching portion of the intake passage to each cylinder, facing in a direction substantially perpendicular to the intake flow;
A primary throttle valve and a secondary throttle valve are arranged in parallel downstream of the fuel injection valve, and a reflecting plate is provided facing the fuel injection valve to guide the fuel mainly to the primary throttle valve side. Further, the intake passage downstream of the throttle valve is divided into two systems, a primary intake passage and a secondary intake passage, which communicate with the primary and secondary throttle valves, respectively, up to the vicinity of the intake valve, and the upper end of the partition between the two The secondary throttle valve is located downstream of the fully closed position of the secondary throttle valve, and the entire amount of fuel and intake air injected from the fuel injection valve is routed through the primary intake passage when the engine is operating at low speed and low load with a relatively small amount of intake air. A mixture supply device for an internal combustion engine, characterized in that the mixture is supplied to the engine through both primary and secondary passages during engine high-speed, high-load operation.