JP2501556Y2 - Internal combustion engine intake system - Google Patents

Description

The present invention relates to an intake device for an internal combustion engine, and more particularly to an intake device for an internal combustion engine having a main intake passage and an auxiliary intake passage in an intake manifold.

[Conventional technology]

2. Description of the Related Art Generally, an internal combustion engine for an automobile is provided with an intake device that supplies intake air together with fuel injected by an injector into a combustion chamber. This intake device is composed of an intake passage formed in an intake manifold and an injector provided in the intake passage for injecting fuel toward an intake port.

Further, in recent years, in order to increase the speed of fire propagation in the combustion chamber during low-load movement of an internal combustion engine, the intake passage is composed of a main intake passage having an intake control valve and a sub-intake passage generating swirl in the combustion chamber. Has been proposed (Japanese Utility Model Publication No. 59-156122).

In the intake device having this structure, the intake control valve is configured to close the main intake passage when the internal combustion engine is in a low load state, and the intake air passes through the auxiliary intake passage having a small passage area and enters the combustion chamber. Inflow. At this time, since the auxiliary intake passage is narrow, the intake air flows into the combustion chamber while being accelerated, and a vertical swirl (swirl flow) is generated in the combustion chamber. Due to this swirl, the fuel injected from the injector and the intake air are mixed well and the combustion state is improved.

FIG. 6 shows a conventional intake system for an internal combustion engine shown in the above-mentioned publication. In the figure, 1 is the engine body, 2
Is a combustion chamber, 3 is an intake manifold, 4 is a main intake passage, 5
Is an auxiliary intake passage, 6 is an injector, 7 is an intake valve, 8
Indicate the intake control valves, respectively. As shown in the figure, in the conventional intake device, the main intake passage 4 is provided on the upper side, the sub intake passage 5 is provided on the lower side, and the injector 6 is provided on the upper portion of the main intake passage 4. It was configured.

[Problems to be solved by the device]

As described above, in the conventional intake device, the main intake passage 4 is arranged above the auxiliary intake passage 5, and the injector 6 is configured to inject fuel from the upper portion of the main intake passage 4 toward the intake port 9. Was there. Therefore, the fuel (indicated by a satin arrow in the figure) and the intake air (indicated by a white arrow in the figure) flowing into the combustion chamber 2 have the intake air inside and the outside as shown in the figure. It becomes a vertical swirl with a structure in which fuel flows.

In the structure in which the fuel flows outward and the intake air flows inward when flowing into the combustion chamber 2, the intake air flowing into the combustion chamber 2 acts so as to press the fuel located outside thereof against the bore wall surface 10. To do. As a result, fuel adheres to the bore wall surface 10 and the piston upper surface 12, and a flame-extinguishing layer is generated at this portion, which increases the amount of hydrocarbon (HC) generated.

Further, since the fuel and the intake air flow in the fuel chamber 2 as described above, a lean air-fuel mixture A exists near the ignition plug 11 as shown in FIG. Thus, the air-fuel mixture rich in air-fuel ratio B (performed in satin) is present. Therefore, there is a problem that the ignitability is poor, the fire is not propagated smoothly, and the fuel efficiency is deteriorated.

The present invention has been made in view of the above-mentioned points, and a hydrocarbon layer is configured such that a rich air-fuel ratio layer exists inside and a lean air-fuel ratio layer exists outside in a combustion chamber. It is an object of the present invention to provide an intake system for an internal combustion engine, which is designed to prevent the occurrence of fuel and to make the air-fuel ratio lean, that is, to improve fuel efficiency.

[Means for solving the problem]

In order to solve the above problems, in the present invention, the intake passage is divided into a main intake passage and an auxiliary intake passage that generates a vertical swirl, and an intake control valve and a fuel injection valve that close the main intake passage when the engine load is low. And an injector, and sends the first intake air flowing through the main intake passage and the second intake air flowing through the auxiliary intake passage into the combustion chamber together with the fuel injected from the injector with the opening / closing operation of the intake valve. In an intake device for an internal combustion engine, the shapes of the main intake passage and the auxiliary intake passage are substantially straight and substantially parallel in a predetermined range upstream from a confluence position where the first intake air and the second intake air merge. And a sub-outlet outside the main intake passage with respect to the cylinder so that the first intake air flow passes inside the fuel chamber inflow cross section with respect to the second intake air flow. The air passage is arranged, and is characterized in that is oriented such along the fuel injection direction of the injector in a first flow direction of the intake air.

[Action]

By configuring the intake device of the internal combustion engine as described above, the second intake air flowing in from the auxiliary intake passage flows into the first intake air flowing in from the main intake passage and the fuel injected from the injector to the outside of the vertical swirl. Generate. Further, since the shapes of the main intake passage and the auxiliary intake passage are configured to be substantially straight and substantially parallel to each other in the predetermined range on the side of the confluence position, the first intake air and the injector flowing in the main intake passage are formed. Fuel injected from
The second intake air flowing through the auxiliary intake passage flows into the combustion chamber in a separated state (hereinafter, this state is referred to as a stratified state) with almost no mixing.

Further, the auxiliary intake passage is arranged outside the main intake passage,
Since the flow of the intake air of the second intake air is configured to pass inside the flow of the second intake air, the second intake air flowing from the auxiliary intake passage must flow to the outside of the fuel injected from the injector. become.

Therefore, when the second intake air is stratified as described above and flows into the outside of the fuel injected from the injector, the fuel enters the combustion chamber in a state of being surrounded by the intake air, so that the fuel is bored. It can be prevented from adhering to the wall surface. Further, in the combustion chamber, there is a rich air-fuel ratio layer in the inner portion close to the spark plug, and there is a lean air-fuel ratio layer outside thereof.
The ignitability of the spark plug and the spread of fire after ignition are also good.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an internal combustion engine 21 provided with an intake device 20 which is an embodiment of the present invention.

The internal combustion engine 21 is provided with an engine body 22, a combustion chamber 23, a piston 24, an intake valve 25, an exhaust valve 26, etc., and the intake device 20 is arranged on the intake side of the engine body 22.

The intake device 20 includes an intake manifold 27, a main intake passage 28,
The auxiliary intake passage 29 is formed, and an injector 30 and an intake control valve 31 are provided. In the present invention, the flow of the intake air (first intake air) flowing through the main intake passage 28 is the same as the intake air (second intake air) flowing through the auxiliary intake passage 29.
The auxiliary air intake passage 29 is arranged outside the main air intake passage 28 so as to pass through the inner side with respect to the flow. That is, the main intake passage 28 is arranged below the intake manifold 27, and the auxiliary intake passage 29 is arranged above the main intake passage 28.

Further, the shapes of the main intake passage 28 and the auxiliary intake passage 29 have a predetermined range upstream from the confluence position (the position indicated by arrow a in FIG. 1) where the first intake air and the second intake air merge. The structure (indicated by arrow H in FIG. 1) is configured to be substantially straight and substantially parallel.

Further, the injector 30 is arranged below the main intake passage 28, and the fuel injection direction of the injector 30 is the above-mentioned first direction.
Is configured so as to be along the flow direction of the intake air. Further, the intake manifold 27 reduces the resistance due to the bending of the intake passage to increase the intake speed, and also reduces the resistance caused by the contact of the intake air with the intake valve 25, so the inclination angle with respect to the vertical direction (hereinafter, this angle is Port angle) is set to 40 ° ± 10 °. This improves intake efficiency.

An intake control valve 31 is provided in the main intake passage 28, and the intake control valve 31 is configured to open when the internal combustion engine 21 has a high load and close when the internal load is low. Therefore, when the load is low, the intake air flows into the combustion chamber 23 through the auxiliary intake passage 29 having a small passage area. At this time, since the auxiliary intake passage 29 has a narrow passage area, the intake speed is accelerated, and the intake air vigorously flows into the combustion chamber 23 even in a low load state, so that a strong swirl is generated in the combustion chamber 23. As a result, the speed of fire propagation is increased, and the combustion state at low load can be improved.

When the intake valve 25 opens, the intake valve 25
The intake air in the intake manifold before branching into the main intake passage 28 and the auxiliary intake passage 29 is larger than the intake layer flowing into the combustion chamber 23 from the left side with respect to The flow velocity distribution of is the distribution shown in the same figure. That is, in the figure, the upper side flow velocity is high, and the lower side flow velocity is slow. On the other hand, as described above, in the intake device 20 according to the present invention, the main intake passage 28 is at the lower side,
The auxiliary air intake passage 29 has a structure arranged on the upper side. Therefore, the main intake passage 28 faces the portion where the velocity distribution of the intake air is low, and the auxiliary intake passage 29 faces the portion where the velocity distribution is high. Accordingly, when the intake air having the above velocity distribution flows in, the flow velocity of the intake air in the auxiliary intake passage 29 is further increased, and a stronger swirl can be obtained, so that the combustion improvement is further promoted.

Further, as described above, since the port angle is 40 ° ± 10 °, which is an acute angle, the flow velocity of the intake air flowing into the combustion chamber 23 from the auxiliary intake passage 29 is increased, and a strong vertical swirl can be generated. It is also possible to improve combustion.

Next, in the intake device 20 configured as described above, pay attention to the flow of intake air (indicated by a white arrow in the figure) and the flow of fuel injected from the injector 30 (indicated by a satin arrow in the figure). Will be described below.

In the intake device 20 according to the present invention, the flow of the first intake air flowing through the main intake passage 18 passes inside the flow of the second intake air flowing through the sub intake passage 29, that is, the sub intake passage. 29 is disposed above the main intake passage 28. Further, the injector 30 is disposed below the main intake passage 28, and the fuel injection direction of the injector 30 is oriented so as to be along the flow direction of the first intake air. Therefore, the second intake air flows to the outside of the fuel flow, as indicated by the white and satin arrows in FIG.

On the other hand, in the intake device 20 according to the present invention, the shapes of the main intake passage 28 and the auxiliary intake passage 29 are within a predetermined range H upstream of the confluence position a where the first intake air and the second intake air merge. It is configured to be substantially straight and substantially parallel.
Therefore, the first intake air flowing through the main intake passage 28 and the fuel injected from the injector 30 and the second intake air flowing through the auxiliary intake passage 29 maintain a stratified state with almost no mixing. While flowing into the combustion chamber 23.

Therefore, when the fuel and the first and second intake air flow into the combustion chamber 23, the fuel is in a state of being enclosed in the second intake air as shown in FIG. Thus, the second
Since the intake air flows outside the fuel, the flow of the fuel does not hit the bore wall surface 34 of the combustion chamber 23 and the piston upper surface 24a strongly, and it is possible to prevent the fuel from adhering to each surface 24a, 34. it can. This allows each side 24a, 34
Generation of a quenching layer in the vicinity is prevented, and the generation layer of hydrocarbons (hereinafter referred to as HC) can be reduced.

Focusing on the state of the air-fuel mixture in the vicinity of the ignition plug 35, as shown in FIG.
In the internal combustion engine 21 using, the fuel is in a state of being surrounded by the intake air in the combustion chamber 23, so that a layer having a rich air-fuel ratio (shown in satin) is formed in the vicinity of the ignition plug 35, and A layer having a greener air-fuel ratio than the vicinity of the spark plug is formed on the outside. Therefore, the ignitability of the spark plug 35 is improved, and since the fire is smoothly propagated, stable combustion is achieved and fuel consumption can be reduced.

FIGS. 3 to 5 show the results of experiments conducted by the present inventor in order to demonstrate the effect of the present invention. In each figure, the broken line is an internal combustion engine to which the intake device 20 according to the present invention is applied.
21 (hereinafter, referred to as the engine of the present application), the solid line shows the internal combustion engine to which the conventional intake device is applied (hereinafter,
The experimental results for the conventional engine) are shown respectively. The conditions of the experiment shown in each figure were as follows: engine speed 2000 rpm, load 63.Nm, water temperature 80.

FIG. 3 shows the relationship between the air-fuel ratio and the HC emission amount. As shown in the same figure, it can be seen that the amount of HC generated in the present institution is smaller than that in the conventional institution. In particular, the leaner the air-fuel ratio, the greater the difference. Therefore, as compared with the conventional mechanism, it is possible to achieve the HC reduction effect only in the portion shown by hatching in the figure.

FIG. 4 shows the relationship between the air-fuel ratio and the fuel consumption rate.
As shown in the figure, the fuel consumption rate of the engine of the present application is also lower than that of the conventional engine, and the fuel consumption can be improved by the amount indicated by the arrow in the figure.

Further, FIG. 5 shows the relationship between the air-fuel ratio and the torque fluctuation. As shown in the figure, the engine of the present application has stable torque fluctuations over a wider range of the air-fuel ratio than the conventional engine. Therefore, according to the institution of the present application, good drivability can be provided.

It should be noted that the above-mentioned embodiment is one which is considered to be the best embodiment of the present invention, and the present invention is not limited to this embodiment, and the auxiliary intake passage is provided outside the fuel injected by the injector. It will be apparent from the above description that an intake device having a configuration in which the positions of the injector and the auxiliary intake passage are set so that the intake air flows into the intake device falls within the scope of the present invention.

[Effect of device]

As described above, according to the present invention, it is possible to prevent generation of HC and to improve fuel efficiency.

[Brief description of drawings]

FIG. 1 is a diagram showing an internal combustion engine using an intake system according to an embodiment of the present invention, and FIG. 2 is a view for explaining a mixture state near an ignition plug when the intake system according to the present invention is used. FIGS. 3 to 5 show various characteristics of an internal combustion engine using the intake device according to the present invention in comparison with a conventional example, and FIGS. 6 and 7 explain an example of the conventional intake device. FIG. 20 ... Intake device, 21 ... Internal combustion engine, 22 ... Engine body, 23
...... Combustion chamber, 24 ...... Piston, 24a ...... Piston top, 2
5 …… intake valve, 27 …… intake manifold, 28 …… main intake passage, 29 …… auxiliary intake passage, 30 …… injector, 24
…… Boa wall, 35 …… Spark plug.

Claims (1)

(57) [Scope of utility model registration request] 1. An intake passage is divided into a main intake passage and a sub-intake passage for generating a vertical swirl, and an intake control valve for closing the main intake passage when the engine is under a low load and an injector for injecting fuel are provided. , The first flowing through the main intake passage as the intake valve opens and closes
Of the intake air and the second intake air flowing through the auxiliary intake passage into the combustion chamber together with the fuel injected from the injector, the main intake passage and the auxiliary intake passage have the same shape. The intake air and the second intake air are configured to be substantially straight and substantially parallel in a predetermined range upstream of a confluence position where the first intake air and the second intake air flow. The auxiliary intake passage is arranged outside the main intake passage with respect to the cylinder so as to pass through the inside of the inflow cross section of the fuel chamber, and the fuel injection direction of the injector is changed to that of the first intake air. An intake device for an internal combustion engine, which is oriented along the flow direction.