JPS6113108B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mixture supply device for a multi-cylinder engine,
In particular, the present invention relates to a single-point fuel injection type air-fuel mixture supply device.

For example, as disclosed in Japanese Unexamined Patent Publication No. 51-7335, a single-point air-fuel mixture supply system in which one fuel injection valve is placed downstream of the intake cylinder throttle valve is a mixture supply system that has a fuel injection valve for each cylinder. Although it has the advantage of being able to reduce the number of injectors compared to conventional systems, the fuel injected into the mixing chamber from the injectors is guided to each cylinder by the intake manifold, so the fuel distribution performance between each cylinder is poor. It had the disadvantage of becoming.

When fuel distribution among multiple cylinders becomes uneven in this manner, the engine rotation becomes uneven, and the composition of the exhaust gas from the engine deteriorates, resulting in an increase in fuel consumption and a decrease in engine output.

In order to reduce these drawbacks, it is effective to make the distribution of fuel within the mixing chamber more uniform, but heretofore, structural measures against this have been insufficient.

An object of the present invention is to provide a single-point fuel injection type mixture supply device suitable for obtaining uniform mixture distribution. A mixture rectifying guide is provided in the mixing chamber so that the mixture is distributed evenly between the cylinders by hitting the wall surface of the mixing chamber.

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 connected to the mixing chamber 2. The mixing chamber 2 communicates with a manifold 3 which in turn communicates with the cylinders of the engine.

A hot wire type air flow meter 8 is installed in the bypass passage 9 communicating with the narrowest part of the bench lily part 10, and measures the flow rate of air flowing through the bench lily part 10. The signal from the air flow meter 8 is processed and output to the fuel injection valve 5, and the opening time of the fuel injection valve 5 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 11 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. During normal operation, intake air is supplied from this primary side air supply cylinder 6, but during high speed or high load operation, the intake air is supplied from the secondary side air supply cylinder 7 in conjunction with the primary side throttle valve 11. The next throttle valve 12 also opens to increase the amount of intake air.

This intake air mixes with the fuel injected from the fuel injection valve 5 in the mixing chamber 2 and is taken into the cylinder during the intake stroke, but inside the mixing chamber 2 there is a relatively large vortex of intake air as shown by the solid line arrow. The injected fuel adheres to the wall surface 13 of the mixing chamber due to the vortex, and flows into each cylinder as a liquid stream. As a result, the difference in the inflowing liquid flow results in a difference in distribution performance between the cylinders, causing deterioration in the air-fuel mixture distribution. In the present invention, a guide 4 is provided to uniformly distribute and rectify the liquid flow of fuel adhering to the mixing chamber wall surface 13 to each cylinder, thereby achieving uniform air-fuel mixture distribution.

FIG. 2 is a vertical sectional view taken from a direction rotated by 90 degrees from FIG. The same parts as in FIG. 1 are given the same reference numerals.

As described in FIG. 1, the fuel injected from the fuel injection valve 5 adheres to the wall surface 13 of the mixing chamber and flows into each cylinder as a liquid stream. Without the guide 4 according to the present invention, a liquid flow of fuel would flow into the cylinders at both ends, impairing the air-fuel mixture distribution, as shown by the broken lines.

In this embodiment, guides 4 are provided between the first intake pipe 31 and the second intake pipe 32 and between the third intake pipe 33 and the fourth intake pipe 34 of the manifolds communicating with each air cylinder, so that the fuel The liquid flow is distributed and rectified as shown by the solid line,
The aim is to equalize the air-fuel mixture distribution between cylinders.

FIG. 3 is a horizontal sectional view of FIG. 1. The same parts as in FIG. 1 are given the same reference numerals.

FIG. 4 shows an example of a conventional air-fuel mixture supply device including a conventional mixing chamber 2 without a guide.

Figure 5 shows an output comparison between the guided mixture supply system according to the present invention and the conventional non-guide mixture supply system using the same engine under the same conditions with the primary and secondary throttle valves fully open. . It can be seen that the torque of the present invention with the guide is improved over the entire area.

FIG. 6 shows the mixture distribution performance of each cylinder during the full throttle test shown in FIG. The maximum cylinder difference in mixture distribution at 1000 engine revolutions without a guide was 5.7% (CO concentration), but using the guided mixing chamber according to the present invention, the cylinder difference was improved to a maximum difference of 0.9% (CO concentration). has been done.

FIG. 7 is a vertical sectional view showing another embodiment,
The difference from the above-described embodiment is that the water channel 40 through which engine cooling water circulates is connected to the mixing chamber wall surface 13 of the mixing chamber 2.
It is a point that is set up so that it can be heated.

As a result, the mixing chamber 2 is heated by the temperature of the cooling water, and the droplets adhering to the wall surface are evaporated and atomized, and the mixture is also heated, so that the atomization and vaporization of the mixture is further promoted and quality is improved. A mixture of mixtures can be formed. Further, although not shown, a water flow control valve made of a temperature-sensitive member may be inserted between the water channel 40 and the cooling water channel of the engine body to control the temperature of the mixing chamber 2. In addition to the engine cooling water mentioned above, heating means for the mixing chamber include introducing exhaust gas and lubricating oil into the wall surface of the mixing chamber, or installing an electric heater to heat the mixing chamber to achieve the same mixing atomization effect as described above. can be obtained. Further, by using a heat pipe as a heat transfer means, the same effect can be obtained with a more compact configuration.

On the other hand, in order for the engine to produce high output, it is desirable to stop heating the mixing chamber, lower the intake air temperature, and increase the filling efficiency of the intake air. For this purpose, conditions such as engine load, cooling water temperature, oil temperature, outside temperature and intake temperature, rotational speed, and vehicle speed are converted into electrical signals, and the heat transfer path is intermittent with an electrically actuated actuator.
It is also possible to adopt a system in which the presence or absence of heating can be selected by comparing it with a preset program.

As explained above, since fuel atomization can be promoted, distribution performance between each cylinder can be improved.

FIG. 8 is a vertical sectional view showing another embodiment,
The difference from the above embodiment is that a water channel 41 through which engine cooling water circulates is provided on one wall of the manifold 3, which heats the manifold to evaporate and atomize the fuel droplets adhering to the inner wall of the manifold, and to evaporate and atomize the air-fuel mixture. Since the mixture is also heated, atomization and vaporization of the air-fuel mixture are further promoted and a high-quality air-fuel mixture can be formed.

9 and 10 show other embodiments.

Figure 9 shows the mixing chamber 2 located ahead of the center of the guide 4.
By arranging the walls close to each other, this configuration allows the fuel flowing on the wall surfaces to be guided to the second and third suction pipes as much as possible.

In FIG. 10, the guide 4 is removed, and a curved surface portion 42 that gradually widens from the upstream side to the downstream side of the mixing chamber 2 is provided. If a guide 4 is attached to this, the distribution will be further improved.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a main part of a mixture supply device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of FIG. 1, FIG. 3 is a cross-sectional view of FIG. 1, and FIG. Cross-sectional views of main parts of a conventional air-fuel mixture supply device, FIGS. 5 and 6
The figure shows a comparison of rotation speed, shaft torque, and CO%.
FIG. 7, FIG. 8, FIG. 9, and FIG. 10 are cross-sectional views of air-fuel mixture supply devices according to other embodiments of the present invention. 1...Air supply cylinder, 2...Mixing chamber, 3...Manifold,
4... Guide, 5... Fuel injection valve, 6... Primary side air supply cylinder, 7... Secondary side air supply cylinder, 8... Air flow meter, 9... Bypass passage, 10... Bench lily section , 11... Primary side throttle valve, 12... Secondary side throttle valve, 13... Mixing chamber wall surface, 31... First suction pipe,
32...Second suction pipe, 33...Third suction pipe, 34
...4th suction pipe, 40... waterway, 41... waterway.

Claims (1)

[Scope of Claims] 1. An electromagnetic fuel supply valve for injecting fuel upstream of a collection point of intake manifolds of a multi-cylinder engine,
In the intake passage having a mixing chamber between the position where the fuel supply valve opens and the gathering part, 1
A rectifying guide that divides the air-fuel mixture discharged from the downstream air supply cylinder into a plurality of flows is formed protrudingly on the wall surface of the mixing chamber facing the primary side air supply cylinder, and the guide is connected to the secondary side air supply cylinder. The protrusion is formed to widen toward the position where they face each other, and its end extends toward the branching point between the adjacent cylinders, and the height of the protrusion is changed from the primary air supply cylinder side to the secondary side air supply cylinder side. An air-fuel mixture supply device characterized in that the air-fuel mixture is gradually lowered toward the lower end. 2. The air-fuel mixture supply device according to claim 1, characterized in that means for heating the air-fuel mixture is provided on the wall surface of the mixing chamber. 3. The air-fuel mixture supply device according to claim 1, wherein means for heating the air-fuel mixture is provided on the wall surface of the manifold pipe. 4. In the mixture supply device according to claim 1, the mixing chamber volume is set to 0.17 of the total engine displacement.
A mixture supply device characterized by a ratio of ~0.25. 5. The air-fuel mixture supply device according to claim 1, characterized in that the intake cylinder has a primary side and a secondary side, with the primary side disposed on the upper side in the vertical direction.