JPH0612755U - Mixture supply device for internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide an air-fuel mixture supply device in which fuel is atomized and the distribution of fuel to each cylinder is improved. [Structure] An injector 8 disposed upstream of the throttle valve 1 in an intake passage of the engine when the throttle valve 3 is fully closed.
Fuel injected from the air is atomized by air and flows out of the small hole 4 formed near the outer periphery of the throttle valve 3 to the downstream side of the valve 3, while the air bypasses the throttle valve 3 and is formed in a bypass passage. 5 flows out from the downstream side opening 7 which is close to the small hole 4. Therefore, the air-fuel mixture flowing out from the small holes 4 and the air flowing out from the downstream side opening 7 collide with each other without fail, so that the fuel can be sufficiently atomized. Therefore, the air-fuel ratio of each cylinder becomes uniform,
The fuel distribution of the cylinder is improved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an air-fuel mixture supply device for an internal combustion engine, and more particularly to a fuel injection type air-fuel mixture supply device that intermittently injects upstream of a throttle valve.

[0002]

[Prior art]

 2. Description of the Related Art Conventionally, there is a fuel injection method for injecting fuel into an internal combustion engine, in which one fuel injection valve (injector) is provided on the upstream side of the throttle valve and intermittent injection is performed by this injector.

[0003] For example, in the "mixture supply device" disclosed in Japanese Patent Laid-Open No. 58-35263, a guide groove for collecting fuel is formed on the upstream surface of the throttle valve, and a throttle valve is formed in the collecting portion. A notch that communicates with the downstream side is formed. Then, the injector is injected by a fraction of the number of suction strokes (for example, the number of suction strokes is three and the fuel injection is one). At this time, the movement of the fuel on the valve surface is controlled by the guide groove and the outflow location is limited by the notch so that the amount of fuel drawn into each cylinder does not vary. As a result, the fuel is retained and the amount of fuel drawn into each cylinder is divided into equal parts.

[0004]

[Problems to be solved by the device]

 However, the above-mentioned publication has a problem that the fuel distribution effect by retaining the fuel cannot be obtained when the fuel injection is performed for one intake stroke.

In view of the above problems, an object of the present invention is to provide an air-fuel mixture supply device in which fuel is atomized and the distribution of fuel to each cylinder is improved.

[0006]

In order to achieve the above object, the present invention provides a fuel injection valve upstream of a throttle valve in an intake passage of an engine and sucks fuel injected from the fuel injection valve. In an air-fuel mixture supply device that mixes with air to supply an air-fuel mixture to an engine, a bypass passage that bypasses the throttle valve and opens into the intake passage, and a bypass passage that is formed in the vicinity of the outer periphery of the throttle valve An air-fuel mixture supply device characterized by having an air-fuel mixture passage close to the opening is adopted.

The air-fuel mixture passage may be a small hole formed in the vicinity of the outer periphery of the throttle valve and close to the opening on the downstream side of the bypass passage. Further, the air-fuel mixture passage may be a notch formed on the outer periphery of the throttle valve and close to the opening on the downstream side of the bypass passage.

[0008]

[Action]

 According to the configuration of the air-fuel mixture supply device of the present invention described above, when the throttle valve is fully closed, the fuel injected from the fuel injection valve arranged upstream of the throttle valve in the intake passage of the engine is atomized by air. , The air flows out to the downstream side of the throttle valve from the mixture passage formed near the outer periphery of the throttle valve, while the air flows from the downstream side opening of the bypass passage formed by bypassing the throttle valve and close to the mixture passage. leak. Therefore, the air-fuel mixture flowing out from the air-fuel mixture passage and the air flowing out from the downstream side opening surely collide with each other, so that the fuel can be sufficiently atomized.

[0009]

【Example】

 An embodiment of an air-fuel mixture supply device for an internal combustion engine to which the present invention is applied will be described. FIG. 1 is a sectional view of an embodiment of the present invention. A throttle valve 3 rotatably supported by a shaft 2 is arranged in a throttle body 1 which internally forms an intake passage through which air drawn into an internal combustion engine (not shown) passes. The throttle valve 3 is connected to the accelerator pedal by a link mechanism (not shown). Further, the throttle valve 3 is provided so as to have an inclination with respect to the throttle body 1 when fully closed. Here, the opening when the throttle valve 3 is fully closed is made smaller than in the conventional case, and the gap formed with the body 1 is made as small as possible so that the body 1 is not bitten. Further, as shown in FIG. 2, a small hole 4 is formed in the vicinity of the outer periphery of the throttle valve 3, which is on the downstream side of the shaft 2. Further, in the case of the four-cylinder engine shown in FIG. 3, this small hole 4 is provided with 9a, 9b for four intake manifolds 9a, 9b, 9c, 9d for supplying the air-fuel mixture to each cylinder. 9c and 9d are provided on the line of symmetry that is symmetrical to each other.

Further, the throttle body 1 is provided with a bypass passage 5 that bypasses the throttle valve 3 and allows intake air to flow, and a bypass air valve 6 that adjusts the amount of air passing through the bypass passage 5. The bypass air valve 6 controls the idle speed. The downstream opening 7 of the bypass passage 5 is formed on the side surface of the valve 3 portion which is on the downstream side of the shaft 2 when the throttle valve 3 is fully closed, and is further opened in the direction perpendicular to the shaft 2. Has been formed.

An injector 8 for injecting fuel into the engine is provided upstream of the throttle valve 3. The fuel injection of this injector 8 is performed for one intake stroke.

Next, the operation will be described. When the throttle valve 3 is fully closed, the fuel injected from the injector 8 becomes a spray and is sprayed onto the throttle valve 3 as shown by the broken line in FIG. At this time, since the gap between the throttle valve 3 and the throttle body 1 is sufficiently small, most of the fuel passes through the small hole 4 and flows to the downstream side of the intake passage. On the other hand, the intake air passing through the bypass passage 5 collides vertically with the fuel (fuel mixture) flowing out from the small holes 4 through the downstream opening 7. For this reason, atomization of the fuel is promoted, and the fuel easily rides on the air flow.

Therefore, the fuel injected from the injector 8 surely flows into the cylinder to be sucked when the fuel injection is performed. Therefore, it is possible to prevent the fuel injected from the injector 8 from being atomized without being atomized, so that the fuel distributability to each cylinder is improved. Therefore, the air-fuel ratio (hereinafter referred to as A / F) of each cylinder can be made uniform.

Next, referring to FIGS. 4A, 4B, and 4C, when the above-described configuration is adopted for a 4-cylinder engine and the diameter of the valve 3 is about 40 mm, the dimensions of each part and the A of each cylinder are shown. / F deviation (difference between the largest A / F and the smallest A / F in four cylinders) is shown. In FIG. 4A, x indicates the distance of the small hole 4 from the outer circumference of the throttle valve to the center, in FIG. 4B, φ indicates the diameter of the small hole 4, and in FIG. 4C, y indicates It shows the distance from the throttle valve 3 to the downstream opening 7 when fully closed. According to FIG. 4 (a), the smaller the distance x, the smaller the deviation of A / F, but if the small hole 4 is too close to the outer periphery of the valve 3, the small hole 4 may be distorted due to the processing of the small hole 4. Therefore, it is confirmed that the optimum distance x is about 10 mm. Further, according to FIG. 4B, the deviation of the A / F becomes smaller as the diameter φ becomes larger, but the idle intake air amount increases more than necessary as the diameter φ becomes larger. Therefore, it is set to about 1 to 2 mm. Further, according to FIG. 4C, as the distance y becomes smaller, the air from the downstream opening 7 can collide with the air-fuel mixture from the small hole 4. Therefore, the distance is set to about 50 mm or less.

FIG. 5 shows the A / F of each cylinder when the above-described four-cylinder engine is idle. As shown in this figure, the deviation of the A / F of each cylinder in the above embodiment (shown by the solid line) is about 0. 5, it is confirmed that the cylinder distributability is improved compared to the conventional case (shown by the broken line).

FIG. 6 (a) is a sectional view showing another embodiment, and FIG. 6 (b) is a sectional view of the throttle valve 3 of this embodiment. As shown in this figure, a cutout 11 may be formed on the outer circumference of the throttle valve 3 so as to be close to the downstream opening 7, and this may be used as a mixture passage.

Further, a recess may be formed in the throttle body 1, and the mixture passage may be formed between the throttle valve 3 formed by the recess and the throttle body 1. In the above-mentioned embodiment, the small holes 4 are provided at symmetrical positions with respect to the intake manifold as shown in FIG. 3, but they are formed slightly offset from the symmetrical positions with respect to the intake manifold. However, the downstream side opening of the bypass passage may be formed so as to collide with the mixture flowing out from the small hole. This makes it possible to atomize the fuel.

[0018]

[Effect of device]

 According to the configuration and operation of the air-fuel mixture supply device of the present invention described above, the air-fuel mixture passage is formed in the vicinity of the outer periphery of the throttle valve, and the air-fuel mixture passage is formed by bringing the downstream opening of the bypass passage close to this passage. Since the air-fuel mixture flowing out from the air and the air flowing out from the downstream side opening surely collide with each other, the fuel can be sufficiently atomized. Therefore, since the air-fuel mixture having the same air-fuel ratio can be supplied to each cylinder, the drivability can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a block diagram showing an embodiment of the present invention.

FIG. 4 is a characteristic diagram showing the relationship between the size of each part and the deviation of A / F.

FIG. 5 is a characteristic diagram showing an A / F in each cylinder.

FIG. 6 is a cross-sectional view showing another embodiment.

[Explanation of symbols]

 1 Throttle body 2 Shaft 3 Throttle valve 4 Small hole 5 Bypass passage 7 Downstream opening 8 Injector

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Claims (3)

[Scope of utility model registration request] 1. An air-fuel mixture supply for supplying an air-fuel mixture to an engine by arranging a fuel injection valve upstream of a throttle valve in an intake passage of the engine and mixing fuel injected from the fuel injection valve with intake air. In the apparatus, a bypass passage that bypasses the throttle valve and opens to the intake passage, and a mixture passage that is formed in the vicinity of the outer periphery of the throttle valve and that is close to the bypass passage downstream side opening portion are provided. Air-fuel mixture supply device. 2. The air-fuel mixture supply device according to claim 1, wherein the air-fuel mixture passage is a small hole formed in the vicinity of the outer periphery of the throttle valve and close to the downstream side opening of the bypass passage. 3. The air-fuel mixture supply device according to claim 1, wherein the air-fuel mixture passage is a notch formed on the outer periphery of the throttle valve and close to the opening on the downstream side of the bypass passage.