JPH112134A - Intake device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce HC discharge quantity by reducing fuel close to a cylinder wall surface of a combustion chamber in an internal combustion engine in which swirl combustion can be performed to achieve favorable fuel consumption. SOLUTION: A swirl control valve 6 which is closed in low load operation is provided on a first intake port 3, as in an ordinary internal combustion engine in which swirl combustion is performed, and a protrusion 13 to convert a direction of intake air to be introduced in the tangential direction relative to a cylinder wall surface 5a of a combistion chamber 5 is provided on a second intake port 4. The protrusion 13 has a through hole 16 to be directed to a spark plug 14, so part of fuel mist injected from a fuel injection valve 9 is directly introduced toward the spark plug 14 nearby. Otherwise, a step 17 may be formed to positively introduce intake air or fuel mist to an inlet of the through hole 16. Fuel around the spark plug 14 is thus increased, and ignition performance and combustion conditions are improved, thereby fuel around the cylinder wall surface 5a is reduced to decrease HC discharge quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake device for an internal combustion engine, and more particularly to a shape and structure of an intake port for generating a swirl flow of a mixture of intake air and fuel in a combustion chamber.

[0002]

2. Description of the Related Art As described in, for example, Japanese Patent Application Laid-Open No. 3-237216, two intake ports are formed in one cylinder, and a swirl control valve (SC) is provided in one intake port.
V), and in the internal combustion engine provided with a swirl-producing projection at the other intake port, the swirl control valve is closed to stop the flow of intake air at the one intake port, thereby providing the other port having the projection. The intake air flows into the combustion chamber from an intake port of the fuel cell to generate a swirl flow in the combustion chamber, thereby increasing the combustion speed of the air-fuel mixture and realizing combustion with an air-fuel ratio leaner than the stoichiometric air-fuel ratio.

[0003] The air-fuel mixture of the internal combustion engine is guided tangentially to the cylinder wall surface by a projection in the intake port.
A swirl flow is formed in the combustion chamber. Since the swirl flow generates a flow of the air-fuel mixture along the cylinder wall surface in the combustion chamber, the air-fuel ratio of the air-fuel mixture in the vicinity of the spark plug at the center of the combustion chamber is increased mainly by centrifugal force acting on the fuel spray ( Become thin. As a result, the swirl flow increases the combustion rate of the air-fuel mixture near the spark plug, but increases the amount of fuel spray present near the cylinder wall, increasing the amount of fuel discharged from the combustion chamber without burning.
There is a problem that the emission of HC that pollutes the atmosphere increases.

[0004]

SUMMARY OF THE INVENTION The present invention addresses the above-mentioned problems in the prior art and provides a good fuel economy with low fuel consumption resulting from a high combustion velocity due to swirl flow;
An ideal combustion state that could not be realized at the same time by the conventional technology, that is, a combustion state with good ignitability and low HC emission by reducing the fuel near the cylinder wall and increasing the fuel near the spark plug Are intended to be compatible with each other by simple means, and to solve the problems of the prior art.

[0005]

Means for Solving the Problems In order to solve the above problems, means described in each claim can be adopted. According to these means, it is possible to generate a swirl flow of the intake air by the projection provided in the second intake port, and to allow the fuel spray to flow directly into the vicinity of the ignition plug from the through hole formed in the projection. Therefore, it is possible to achieve both a reduction in fuel consumption obtained in a favorable combustion state by the swirl flow and a reduction in fuel near the cylinder wall surface, and thus a reduction in HC emission due to an increase in fuel near the spark plug.

Further, by forming a step near the through hole provided in the projection to guide a part of the flow of the intake air and the fuel spray to the inlet of the through hole, the second intake port can be formed. Only when the flow velocity of the flowing intake air is high, the flow of the intake air and the fuel spray is turned by the step to flow into the through hole into the inlet, and can be efficiently guided to the vicinity of the ignition plug.

[0007]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a system configuration diagram of an internal combustion engine provided with an intake device of the present invention, showing one cylinder of a multi-cylinder internal combustion engine. In the system of FIG. 1, the intake air flows into the surge tank 2 through the throttle valve 1. Then, the intake air is diverted from the surge tank 2 to the first intake port 3 and the second intake port 4 provided for each cylinder, and the intake air is supplied to the intake valves 8 (8a, 8b) provided for the respective intake ports. It flows into the combustion chamber 5 from the opening.

The amount of air passing through each of the first intake port 3 and the second intake port 4 changes according to the operating state of the engine, and is provided in the first intake port 3 in the operating state from no load to light load. The swirl control valve 6 is an electronic control device (E
Since the actuator 7 operates and closes the valve according to the signal output from the CU), almost all the intake air flows into the combustion chamber 5 from the second intake port 4. At this time, the flow of the intake air is changed by the projection 13 provided in the second intake port 4 and flows tangentially to the cylinder wall surface 5 a forming the combustion chamber 5. A swirl flow is formed therein.

In moderate to high load operating conditions,
Since a signal from the ECU is not input to the actuator 7, the swirl control valve 6 is opened, so that a large amount of intake air according to the magnitude of the load is supplied to both the first intake port 3 and the second intake port 4. From the combustion chamber 5.

The fuel is injected from the fuel injection valve 9 into the first intake port 3 and the second intake port 4, and flows into the combustion chamber 5 through the opening of the intake valve 8 together with the intake air. The amount of the supplied fuel is ignited in the combustion chamber 5 by the discharge of the spark plug 14 and the signal of the pressure sensor 15 provided in the surge tank 2 for detecting the intake air amount, and the fuel is burned.
It is determined by the ECU according to the operating state of the engine from the signal of the air-fuel ratio sensor 12 that measures the air-fuel ratio of the gas discharged to the exhaust port 11 through 0. The determined fuel amount is controlled as the width of a pulse signal (duration of the signal) output from the ECU to open the fuel injection valve 9.

Next, the shape and structure of the projection 13 corresponding to the features of the present invention will be described. FIG. 2 is a detailed view of a portion of the intake ports 3 and 4, FIG. 2 (a) is a plan view of an enlarged cross section of a part of FIG. 1, and FIG. 2 (b) is a second intake port. FIG. 4 is a side view of the cross section of FIG. The protrusion 13 is formed with a through hole 16 penetrating from the second intake port 4 toward the spark plug 14.
Step 17 having a wall surface protruding toward the intake valve 8b at the inlet of
It has.

With such a configuration, in the internal combustion engine of the embodiment, when the swirl control valve 6 is closed and the intake air is flowing substantially only from the second intake port 4, the intake air Is the projection 1 in the second intake port 4
3, while maintaining the swirl flow generated by flowing into the combustion chamber 5 tangentially to the cylinder wall surface 5a while flowing through the through-hole 16 provided in the projection 13. By forming a part of the flow of the intake air and the fuel spray toward the periphery of the spark plug 14, the concentration of the air-fuel mixture in the vicinity of the spark plug 14 can be increased while maintaining the rapid combustion by the swirl flow, The amount of fuel spray near the cylinder wall surface 5a can be reduced. Thereby, an improvement in ignitability and an expansion of the flame propagation range are achieved. Therefore, it is possible to achieve both fuel efficiency and reduction of HC emission.

Further, by changing the shape of the step 17 provided on the projection 13, the amount of fuel directly flowing into the vicinity of the ignition plug 14 through the through hole 16 can be reduced by the amount of intake air of the second intake port 4. Can be controlled in accordance with

The details of this operation will be described more specifically with reference to FIG. 3A shows a case where the flow rate of the intake air flowing through the second intake port 4 is high (fast), and FIG.
Indicates a case where the flow rate of the intake air is low (slow).
As shown in FIG. 3A, when the flow rate of the intake air is high, the swirl flow is strong, and the mixture concentration near the spark plug 14 is low (thin), the fuel spray injected from the fuel injection valve 9 is When the flow is turned by the protrusion 13 together with the flow of the intake air, a considerable portion flows into the through-hole 16. Further, since the flow of the intake air flowing through the second intake port 4 is strong, the amount of the fuel spray passing through the through hole 16 increases due to the effect that the amount of air flowing into the through hole 16 by colliding with the step 17 increases. Therefore, the amount of fuel spray increases in a portion from the vicinity of the outlet of the through hole 16 to the spark plug 14 as compared with other portions.

On the other hand, as shown in FIG. 3B, when the flow rate of the intake air is low, the swirl flow is weakened. As a result, when the mixture concentration near the spark plug 14 does not become low (thin), the intake 3A, the flow direction of the fuel spray injected from the fuel injection valve 9 is less likely to be bent by the projections 13 together with the flow of the intake air. The amount of fuel spray flowing through is reduced. Further, in this case, since the amount of air flowing into the through hole 16 by colliding with the step 17 is also reduced, in such a state that the swirl flow is weak and a relatively large amount of fuel spray exists near the ignition plug 14, The amount of the air-fuel mixture flowing into the combustion chamber 5 from the second intake port 4 side is increased by an amount corresponding to the reduction in the amount of the air-fuel mixture passing through the through hole 16, and an rich air-fuel mixture is formed near the ignition plug 14. Can be avoided.

As described above, according to the intake system for an internal combustion engine of the present invention, in an operation state in which a swirl flow is generated in the combustion chamber 5, an optimum around the ignition plug 14 according to the flow rate of the intake air of the engine is provided. Since it becomes possible to form an air-fuel mixture of a concentration, it is possible to simultaneously improve fuel efficiency and reduce HC emissions.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram schematically showing the entire system with a focus on a plan view of a cross section of an intake device as an embodiment of the present invention.

FIGS. 2A and 2B are detailed views of a portion of an intake port, wherein FIG. 2A is a plan view of a cross section in which a part of FIG. 1 is enlarged, and FIG. 2B is a side view of a cross section of a second intake port.

3A and 3B are plan views illustrating an operation state of the intake device of the embodiment, in which FIG. 3A illustrates a case where the flow rate of intake air is high, and FIG. 3B illustrates a case where the flow rate of intake air is low.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 ... 1st intake port 4 ... 2nd intake port 5 ... Combustion chamber 5a ... Cylinder wall surface 6 ... Swirl control valve 8 (8a, 8b) ... Intake valve 9 ... Fuel injection valve 13 ... Projection 14 ... Spark plug 16 ... Through-hole 17 ... steps

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tokio Obama 14 Iwatani, Shimowasumi-machi, Nishio-shi, Aichi Prefecture Inside the Japan Automobile Parts Research Institute Co., Ltd. Automobile Co., Ltd.

Claims (2)

[Claims] 1. A first intake port and a second intake port provided in one cylinder, and a swirl control provided in the first intake port and capable of substantially blocking the flow of intake air. An internal combustion engine, comprising: a valve; and a projection provided in the second intake port and capable of generating a swirl flow of intake air in a combustion chamber by diverting the flow of intake air. By providing a through-hole opening toward the spark plug, a part of the fuel spray injected to the upstream side of the protrusion can be supplied directly to the periphery of the ignition plug through the through-hole. An intake device for an internal combustion engine, comprising: 2. The method according to claim 1, wherein a step is formed near the entrance of the through hole provided in the projection to guide a part of the flow of the intake air and the fuel spray to the entrance of the through hole. An intake device for an internal combustion engine according to claim 1.