JPH0913977A - Intake system for internal combustion engine - Google Patents

Abstract

PURPOSE: To attain a high-suction flow at the time of a low-load operation and a high flow coefficient at the time of a high-load operation in an intake system for an internal combustion engine having a drift forming auxiliary suction port made of a recessed groove and provided in parallel with a main suction port. CONSTITUTION: A flap-shaped variable mechanism 13 changing an auxiliary suction port 10 into an opened shape or a closed shape is provided on the drift forming auxiliary suction port 10 made of a recessed groove. The variable mechanism 13 is formed into the shape along a groove bottom section like B in the figure for setting the auxiliary suction port 10 to the opened shape. The variable mechanism 13 is formed into the shape along the bottom face of the main suction port 3 above the groove to block the groove like A in the figure for setting the auxiliary suction port to the closed shape. This intake system has no groove-shaped auxiliary suction port 10. Proper suction control in response to the engine operating state can be made by the variable mechanism 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for an internal combustion engine, and more particularly to a structure of a secondary intake port for forming a drift in a main intake port of a cylinder head in order to generate a vortex in a combustion chamber. .

[0002]

2. Description of the Related Art As a conventional intake system for an internal combustion engine having an auxiliary intake port for forming a non-uniform flow, which is provided in parallel with a main intake port of a cylinder head in order to generate a vortex in a combustion chamber, as shown in FIG. Is known (Shokaisho 59
(See Japanese Patent Publication No. 194533). In this intake device, intake valves 2a, 5a, 5a
Two main intake ports 3a, 3b, which communicate with each other through 5b, are provided, and an intake flow dividing valve for opening and closing the main intake ports 3a, 3b is provided in the intake passage 2 on the upstream side of the main intake ports 3a, 3b. 14 are provided. Further, in the bottom portions of the main intake ports 3a, 3b, from the upstream side of the intake flow dividing valve 14, the intermediate portions of the intake valves 5a, 5b and the intake port partitioning portion 4 are pointed, and a drift formed by a concave groove is formed. Sub-intake ports 10a, 10b for the vehicle are provided. The auxiliary intake ports 10a and 10b generate a tumble swirl flow (longitudinal swirl flow) 6 that is as strong as possible. It is oriented in the direction to do.

When the intake branch valve 14 is closed, the intake flow enters the auxiliary intake ports 10a, 10b from the inflow portions 11a, 11b of the auxiliary intake ports 10a, 10b and is concentrated in the groove to suppress diffusion. While flowing out 12a,
It is guided to 12b and flows into the combustion chamber 1 to generate a strong tumble swirl flow 6. Note that the effect of providing the auxiliary intake ports 10a and 10b formed of the above-described groove is as shown in FIG.
As shown in FIG. 5, compared with the case without the auxiliary intake port shown in FIG. 5B, the degree of concentration of drift is improved and the flow velocity is enhanced. That is, the tumble swirl flow 6 in the combustion chamber 1 is further strengthened by strengthening the flow velocity.

[0004]

However, in the intake system for the internal combustion engine described above, as shown in FIG.
The intake flow concentrated in the auxiliary intake ports 10 (10a, 10b) causes separation at the lower part 7 of the intake port throat when flowing out from the outflow part 12 (12a, 12b).
It has been confirmed experimentally that the flow coefficient decreases (see Tables 1 and 2). Therefore, there is a problem that the flow rate required for high-load operation of the engine cannot be obtained.

[0005]

[Table 1]

[0006]

[Table 2]

In view of the above-mentioned conventional problems, the present invention is directed to an intake system for an internal combustion engine having a sub-intake port for forming a non-uniform flow formed of a concave groove, in which high intake flow and high load operation are performed during low load operation. Sometimes it aims to achieve a high flow coefficient.

[0008]

For this reason, the invention according to claim 1 is directed to an intake system for an internal combustion engine having a sub-intake port for drift formation which is a concave groove extending from the vicinity of the inlet of the main intake port of the cylinder head to the downstream thereof. In the above, a variable mechanism that changes the auxiliary intake port into an open shape or a closed shape according to the engine operating state is provided.

According to a second aspect of the present invention, an intake diversion valve that opens and closes the main intake port according to an engine operating state is provided near the inlet of the main intake port, and when the intake diversion valve is closed,
Most of the intake air is taken into the combustion chamber through the auxiliary intake port. The invention according to claim 3 is a combination of the control of the variable mechanism and the control of the intake flow dividing valve,
An intake control means for performing intake control according to the engine operating state is provided.

According to a fourth aspect of the present invention, there is provided intake control means for controlling the intake according to the engine operating condition by making the control signal of the variable mechanism and the control signal of the intake branch valve common.

[0011]

According to the first aspect of the invention, the auxiliary intake port of the cylinder head is provided with a variable mechanism so that the auxiliary intake port is opened or closed depending on the engine operating condition. In that case, a high intake flow and a high flow coefficient are realized in the closed shape.

According to the second aspect of the invention, when the intake flow dividing valve is closed by the intake flow dividing valve provided near the main intake port inlet of the cylinder head, most of the intake air passes through the auxiliary intake port. To do. According to the third aspect of the present invention, by combining the control of the variable mechanism and the control of the intake shunt valve, intake control according to a wide range of engine operating conditions becomes possible.

According to the fourth aspect of the invention, the control signal for the variable mechanism and the control signal for the intake shunt valve are made common to simplify the intake control.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows an intake system for an internal combustion engine according to an embodiment of the present invention. The intake device branches from a single intake passage 2 provided corresponding to each combustion chamber (cylinder) 1 and communicates with the same combustion chamber 1 via intake valves 5a and 5b, respectively.
Three main intake ports 3a, 3b are provided. Also,
At the bottoms of the main intake ports 3a, 3b, from the vicinity of the inlets of the main intake ports 3a, 3b, toward the intermediate portion between the intake valves 5a, 5b and the intake port partitioning portion 4, for forming a drift formed of a concave groove. Sub-intake ports 10a and 10b are provided. The auxiliary intake ports 10a and 10b generate a strong tumble swirl flow (longitudinal swirl flow) 6 as much as possible. It is oriented in the direction.

The auxiliary intake ports 10a, 10b are provided with flap-shaped variable mechanisms 13a, 13b for changing the auxiliary intake ports 10a, 10b into an open shape or a closed shape. In the variable mechanisms 13a and 13b, the variable mechanism attachment shaft 13c attached to the base end portion of the variable mechanisms 13a and 13b is attached to the intake passage 2
By being rotatably supported on the wall portion of the sub-intake port 10a, 10b, the fulcrum of rotation is supported by the inflow portions 11a, 11b of the auxiliary intake ports 10a, 10b.
It is set near b. In addition, the variable mechanism mounting shaft 13c
A rotary drive shaft of an actuator (not shown) is connected to the actuator, and this actuator is drive-controlled by a control unit (not shown) provided in the vehicle based on the engine operating state. When the actuator is driven and controlled, the variable mechanism mounting shaft 13c rotates about its fulcrum, and the variable mechanisms 13a and 13b are controlled to open and close.

When the auxiliary intake ports 10a and 10b are in the open shape, the variable mechanisms 13a and 13b are set at B in the drawing.
As described above, the intake device has a shape along the groove bottom, and the intake device is configured to have the groove-shaped auxiliary intake ports 10a and 10b. On the other hand, when the auxiliary intake ports 10a and 10b are closed, as shown by A in the figure, the main intake port 3 above the groove is closed.
The intake device has a shape that follows the bottom surfaces of a and 3b and closes the groove, and the intake device does not have the groove-shaped auxiliary intake ports 10a and 10b.

In the above embodiment, the fulcrums of the flap-shaped variable mechanisms 13a and 13b are set at desired positions, and the inflow portions 11a and 11 of the auxiliary intake ports 10a and 10b are located at desired positions.
Although it is provided in the vicinity of b, as shown in FIG. 2, it may be provided in the intermediate portion of the auxiliary intake ports 10a and 10b on the downstream side thereof. Next, the effect (action) of introducing the variable mechanisms 13a and 13b will be described in detail below.

When the variable mechanisms 13a and 13b have an open shape, the inflow of the intake air flowing through the auxiliary intake ports 10a and 10b is suppressed from diffusing in the grooves, and the outflow portions 12a and 12b are suppressed.
The tumble swirl flow 6 into the combustion chamber 1 directly into the combustion chamber 1.
Generate. However, at this time, although the flow velocity enhancement by the auxiliary intake ports 10a and 10b has a flow velocity distribution as shown in FIG. 5A, the auxiliary intake ports 10 (10a, 1
0b), the intake flow concentrated in the outflow portion 12 (12a, 12
When flowing out from b), separation occurs at the lower part 7 of the intake port throat, and as a result, the flow coefficient is as shown in Tables 1 and 2 above.
As shown.

Therefore, when the engine is operating under high load and it is desired to increase the intake flow rate to the combustion chamber 1 as much as possible, the variable mechanisms 13a and 13b are closed so that the auxiliary intake ports 10a and 10b are closed and the intake device is closed. Is not provided with the groove-shaped auxiliary intake ports 10a, 10b, the flow rate coefficient can be improved as shown in Tables 1 and 2 described above.

In the embodiment described above, the main intake port 3a,
3b is provided with auxiliary intake ports 10a and 10b, and variable mechanisms 13a and 13b for changing the auxiliary intake ports 10a and 10b into an open shape or a closed shape are provided. As described above, the intake flow dividing valve 14 for opening and closing the main intake ports 3a, 3b is provided in the intake passage 2 on the upstream side of the main intake ports 3a, 3b, and the auxiliary intake ports 10a,
10b of the inflow parts 11a and 11b are connected to the intake diversion valve 14
It may be configured to be provided on the upstream side of.

With this configuration, when the intake flow dividing valve 14 is closed, most of the intake air flowing through the intake passage 2 will pass through the auxiliary intake ports 10a and 10b by the intake flow dividing valve 14. The tumble swirl flow 6 in the combustion chamber 1 becomes stronger than the structure without the intake flow dividing valve 14 because the flow velocity is strengthened more strongly. On the other hand, the auxiliary intake port 10
Since the flow velocity of the intake air flow passing through a and 10b is increased, when the intake air flow flows out from the outflow portions 12a and 12b, the separation that occurs in the lower portion 7 of the intake port throat is further increased,
As shown in Tables 1 and 2, the decrease in the flow coefficient is further increased. Here, when the engine is operated at a high load, the flow coefficient must be increased in order to obtain the required intake air amount, but the above-mentioned configuration cannot obtain the necessary flow coefficient.

Therefore, as shown in Table 3, the control of the variable mechanisms 13a and 13b and the control of the intake shunt valve 14 are combined according to the load state of the engine, and state 1 (high load) to state 4 (low load) are combined. ) By responding to each operating state,
Intake flow and flow coefficient suitable for a wide range of engine operating conditions can be obtained.

[0023]

[Table 3]

Further, the control signals of the variable mechanisms 13a and 13b and the control signal of the intake flow dividing valve 14 are made common, and the combination thereof is, for example, state 1 (high load) and state 4 shown in Table 3.
By limiting only to (low load), a simple control system can be realized. In the above-mentioned embodiment,
Although the present invention has been used for a four-valve internal combustion engine, it may be used for other internal combustion engines, such as a two-valve, three-valve, five-valve internal combustion engine.

[0025]

As described above, according to the first aspect of the invention, the auxiliary intake port of the cylinder head is provided with the variable mechanism so that the auxiliary intake port is opened or closed depending on the engine operating state. Since it has a shape, a high intake flow can be realized in the open shape, and a high flow rate coefficient can be realized in the closed shape, and both the combustion improvement request at low load operation of the engine and the high flow coefficient request at high load operation can be satisfied. Can be satisfied.

According to the second aspect of the present invention, by the intake diversion valve provided near the inlet of the main intake port of the cylinder head, when the intake diversion valve is closed, most of the intake air passes through the auxiliary intake port. Therefore, the flow velocity of the intake air passing through the auxiliary intake port is strengthened, and a strong tumble swirl flow can be generated. According to the third aspect of the present invention, by combining the control of the variable mechanism and the control of the intake shunt valve, it becomes possible to perform intake control according to a wide range of engine operating conditions. Therefore, when the load is low, a vortex flow such as a tumble swirl flow is generated. It is possible to improve the flow coefficient at high load.

According to the fourth aspect of the present invention, by making the control signal of the variable mechanism and the control signal of the intake shunt valve common, it is possible to prevent the intake control from becoming complicated.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the invention described in claim 1,
(A) is a plan sectional view, (b) is a front sectional view

2A and 2B are views showing another embodiment of the invention according to claim 1, wherein FIG. 2A is a plan sectional view and FIG. 2B is a front sectional view.

FIG. 3 is a diagram showing an embodiment of the invention described in claim 2,
(A) is a plan sectional view, (b) is a front sectional view

4A and 4B are views showing a conventional intake device, in which FIG. 4A is a plan sectional view and FIG. 4B is a front sectional view.

FIG. 5 is a front cross-sectional view of an intake device showing a problem of the prior art, (a) shows a case where a sub groove-shaped auxiliary intake port is provided,
(B) In the case of not having a convex groove-shaped auxiliary intake port

[Explanation of symbols]

 3a, 3b Main intake port 10a, 10b Sub intake port 13a, 13b Variable mechanism 14 Intake diversion valve

Claims (4)

[Claims] 1. An intake system for an internal combustion engine having a sub-intake port for forming a drift in a concave groove extending from the vicinity of an inlet of the main intake port of a cylinder head to a downstream portion thereof, the sub-intake port being opened depending on an engine operating state. Alternatively, an intake device for an internal combustion engine, which is provided with a variable mechanism that is variable in a closed shape. 2. An intake diversion valve for opening and closing the main intake port according to engine operating conditions is provided near the inlet of the main intake port,
2. The intake system for an internal combustion engine according to claim 1, wherein most of the intake air is taken into the combustion chamber through the auxiliary intake port when the intake branch valve is closed. 3. An intake control means for performing intake control according to an engine operating condition by combining control of the variable mechanism and control of the intake flow dividing valve.
An intake system for an internal combustion engine as described. 4. A control signal for the variable mechanism and a control signal for the intake flow dividing valve are made common, and intake control means for controlling intake according to an engine operating state is provided. Intake device for internal combustion engine.