JPH0726968A - Intake device of internal combustion engine - Google Patents

Abstract

PURPOSE:To stabilize combustion by improving a flow state of gas to flow into a combustion chamber in an internal combustion engine provided with two intake ports formed by being branched from an intake passage simply provided in correspondence with respective cylinders, and communicated with the inside of the same cylinder. CONSTITUTION:A valve body 19 is so constituted as to selectively blow out bypassed air or exhaust reflux toward an intake port 15A in which main flow is made to flow after crossing an intake port 15B on the side where the intake flow is small controlled by the valve body 19, thereby gas flow to flow into a combustion chamber is stabilized, so as to generate sufficient swirls, so that the stabilization of combustion can be attempted.

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 an internal combustion engine equipped with an intake control valve device for controlling the intake flow to an intake port, for controlling the flow state of gas flowing into a combustion chamber. Regarding technology to improve.

[0002]

2. Description of the Related Art As a conventional intake system for an internal combustion engine, there are, for example, those shown in FIGS.
1-84138, etc.). That is, the intake port 3 having two intake valves 1 and 2 is disposed inside the intake port 3 and
4a for closing one of the intake valves 1 corresponding to
And a valve body 4 that is opened and closed with a notch-formed opening 4b that opens a portion corresponding to the other intake valve 2 and controls the flow state of the gas flowing into the combustion chamber 5. ,
A swirl control valve (SCV) device is provided to enhance the intake swirl.

For example, by closing the valve body 4,
The combustion speed is increased to improve the fuel consumption rate at low load and to stabilize the engine operating condition at lean air-fuel ratio.

[0004]

By the way, the optimum value of the formation range (opening ratio) of the opening 4a of the valve body 4 is different between the high load range and the low load range of the engine, and the open range is high in the high load range. A large value is preferable, and a small opening ratio is preferable in the low load region. However, in the structure of the valve element 4 as described above, the opening ratio is set in advance so as to be optimal for either the high load range or the low load range. The aperture ratio cannot be set to an optimum value in both load regions.

For example, when the opening ratio of the valve body 4 is preset to a small value that is optimum for the low load range, an optimum swirl flow is generated in the low load range, and lean combustion becomes possible. However, the swirl flow becomes too strong in the high load range,
At the same time as knocking is likely to occur, the valve element becomes an intake resistance, and the engine cannot operate at a sufficiently high load. On the contrary, when the opening ratio of the valve body 4 is preset to a large value that is optimum for the high load range, lean combustion is possible even in the high load range, but the open ratio is large in the low load range. Therefore, the flow ratio of the gas flowing from the two intake ports into the combustion chamber is not always constant, and the strength of the swirl ratio fluctuates in each engine cycle, resulting in unstable gas flow. , Combustion becomes unstable.

Therefore, in the past, it was difficult to perform lean combustion in the entire operating range of the engine. In view of the above conventional problems, the present invention is an internal combustion engine including two intake ports that branch from a single intake passage corresponding to each cylinder and communicate with the same cylinder. It is an object of the present invention to improve the flow state of gas flowing into a combustion chamber in an engine to stabilize combustion.

[0007]

For this reason, the present invention provides an internal combustion engine having two intake ports which branch from a single intake passage corresponding to each cylinder and communicate with each other in the same cylinder. In the engine, an intake control valve device having a structure for closing the valve body provided in the intake passage to control the intake flow to one intake port to be small is provided, and the intake port forming wall on the downstream side of the valve body is provided. A gas outlet that blows gas toward the other intake port across the intake port on the side where the intake flow is controlled to be small is provided, and part of the intake air is bypassed from the valve body upstream of the intake passage. A bypass intake passage leading to the gas outlet, an exhaust recirculation passage guiding a part of exhaust gas recirculated from an exhaust passage to the gas outlet, and the bypass intake passage and the exhaust recirculation passage selectively switched. A road switching means, and as provided.

[0008]

In such a construction, for example, when the opening ratio of the valve body is preset to a large value that is optimum for the high load range, lean combustion is possible in the high load range when the valve body is closed. Further, in the conventional configuration, when the valve body is closed, the opening ratio is too large in the low load region, so the ratio of the gas flow flowing into the combustion chamber from both intake ports is not always constant, and the swirl ratio is strong. Results in a change in each engine cycle,
The gas flow becomes unstable and combustion becomes unstable.

Therefore, in the structure of the present invention, when the valve body is closed, in the low load range, the switching means is provided at a position where the bypass intake passage and the gas outlet are communicated with each other or the exhaust gas recirculation passage and the gas outlet. The bypass intake air or exhaust gas recirculation is blown out from the gas outlet port toward the other main-flowing intake port across the intake port on the side where the intake flow is controlled to be small.

As described above, when the bypass intake air or exhaust gas recirculation is blown out, the gas always flows toward the intake port side, so that the main flow flowing through the intake port is strengthened, and the engine having the swirl ratio of each cycle is strengthened. The fluctuation can be suppressed to a small level, the gas flow flowing into the combustion chamber is stabilized, a sufficient swirl flow is generated, and combustion is stabilized.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. 1 to 3, the cylinder 1 of each cylinder 10
1, two intake valves 12A and 12B are provided, and a single intake passage 14 led from a collector 13 is provided corresponding to each cylinder 11. Further, two intake ports 15A and 15B that branch from the intake passage 14 and communicate with the same cylinder 11 are provided. An ignition plug 16 is arranged at the center of the cylinder 11.

Intake pipe 14A constituting the intake passage 14
A fuel injection valve 17 for injecting fuel into the intake ports 15A and 15B is attached to the. The fuel injection valve 17 is controlled based on a control signal output from the control unit 18. In such an internal combustion engine, there is provided an intake control valve device configured to control the intake flow by closing the valve element 19 provided in the intake passage 14 in a predetermined engine operating state.

In this embodiment, a swirl control valve device is provided as the intake control valve device, and the valve body 1 of the swirl control valve device is provided.
9 is arranged in the intake passage 14 in the vicinity of the branch portions of the intake ports 15A and 15B. On one side portion corresponding to one intake port 15B of the lower half of the valve body 19, a closing portion 19a for closing a portion of the intake port 15B corresponding to the intake valve 12B is provided, and the other intake port is provided. A notched opening 19b for opening a portion corresponding to the other intake valve 12A is formed in one side portion corresponding to 15A, respectively.

The rotary shaft 20 of the valve body 19 is the cylinder 11
It is set in a direction substantially orthogonal to the extending direction of the central axis of the, i.e., in the lateral direction, and the opening 19b is formed avoiding the rotating shaft 20. The above swirl control valve device is controlled on the basis of the control signal output from the control unit 18, the valve body 19 is closed in a predetermined engine operating state, and the intake portion 15a is closed by the closing portion 19a.
The intake flow to B is controlled to be small. In this case, the main intake air flows through the other intake port.

Here, in the intake port forming wall 21 on the downstream side of the valve body 19, the gas flows toward the intake port 15A where the other main flow flows across the intake port 15B on the side where the intake flow is controlled to be small. A gas outlet 22 for blowing out is provided. Then, the valve body 19 of the intake passage 14
A bypass intake pipe 23 as a bypass intake passage that guides a part of intake air (hereinafter referred to as bypass air) from the upstream side to the gas outlet 22 by bypassing the valve body 19, and the exhaust passage 2
Part of exhaust gas recirculated from 4 (hereinafter referred to as recirculation gas)
An exhaust gas recirculation pipe 25 that guides the gas to the gas outlet 22 and a switching valve 26 as a passage switching unit that selectively switches the bypass intake pipe 23 and the exhaust gas recirculation pipe 25 are provided.

The gas outlet 22 is formed at a substantially intermediate portion in the circumferential direction of the peripheral portion of the intake port forming wall 21 on the downstream side of the valve body 19 on the intake port 15B side. The bypass intake pipe 23
Is connected to the intake pipe 14A on the upstream side of the valve body 14 and the other end is connected to the port a of the switching valve 26. One end of the exhaust gas recirculation pipe 25 is connected to the exhaust pipe 24A that constitutes the exhaust passage 24, and the other end thereof is connected to the port b of the switching valve 26. One end of a gas outlet pipe 27 is connected to the port c of the switching valve 26, and the other end of the gas outlet pipe 27 is branched into a plurality of gas outlets 22 provided for each cylinder 10. Connected to.

The switching valve 26 connects the port a and the port c and connects the bypass intake pipe 23 and the gas outlet pipe 27 with each other, and the port b and the port c.
The exhaust recirculation pipe 25 and the gas outlet pipe 27 are connected to each other, and the port c is closed. The switching valve 26 is controlled to be switched to any one of the three switching operation positions according to the engine operating state based on the control signal output from the control unit 18.

In such a structure, for example, when the opening ratio of the valve body 19 is preset to a large value that is optimum for the high load range, lean combustion is possible in the high load range when the valve body 19 is closed. . Further, in the conventional configuration, the valve body 1
Since the opening ratio is too large in the low load region when the valve 9 is closed, the ratio of the gas flows flowing into the combustion chamber 21 from both the intake ports 15A and 15B is not always constant, and the strength of the swirl ratio varies from engine cycle to engine cycle. As a result, the gas flow becomes unstable, and the combustion becomes unstable (see FIG. 4A).

Therefore, in the structure of this embodiment, the switching valve 26 is operated in the low load region when the valve body 19 is closed.
Is switched to a position in which the bypass intake pipe 23 and the gas outlet pipe 27 are communicated with each other or a position in which the exhaust gas recirculation pipe 25 and the gas outlet pipe 27 are communicated with each other, and bypass air or recirculation gas is passed through the gas outlet pipe 27. The gas is blown out from the gas outlet 22 across the intake port 15B on the side where the intake flow is controlled to be small toward the intake port 15A in which the other main flow flows.

As described above, when the bypass air or the recirculation gas is blown out, the gas always flows to the intake port 15A side, so that the main flow flowing through the intake port 15A is strengthened and each cycle of the engine having the swirl ratio is strong. Each fluctuation can be suppressed to a small level, the gas flow flowing into the combustion chamber 21 is stabilized, a sufficient swirl flow is generated, and combustion is stabilized (see FIG. 4 (B)).

In this case, the bypass air or the recirculation gas does not always have to be blown out, and may be a trigger for generating a stable swirl flow at the initial stage of opening the intake valves 12A, 12B (at the time of low lift). For example, the intake valve 12A,
At the initial stage of valve opening of 12B (at the time of low lift), the intake pulsation effect causes intake negative pressure for a certain period of time (see FIG. 5). Due to the negative pressure of the intake air, the bypass air or the recirculation gas flows through the intake port 15B on the side where the intake flow is controlled to be small and the other main flow flows through the intake port 15.
Even if the bypass air or the recirculation gas is not guided into the intake port 15A after being blown out toward A and generating a stable swirl flow, the gas will flow toward the intake port 15A. .

On the other hand, when the valve body 19 is opened, neither in the lean region nor in the exhaust gas recirculation, so that no swirl flow is generated, so that the blowing of the bypass air or the recirculation gas into the intake port 15A is stopped. FIG. 6A is a characteristic diagram showing a control relationship between opening and closing of the valve body 19 and blowing of bypass air and stopping thereof when blowing the bypass air into the intake port 15A when only the bypass air is used. Yes, control is performed to close the valve body 19 to blow out the bypass air, and control to open the valve body 19 to stop blowing out the bypass air.

Further, FIG. 6 (B) shows that when using bypass air or recirculation gas, these are taken in through the intake port 15
FIG. 6 is a characteristic diagram showing a control relationship between opening / closing of the valve element 19 and blowing out of bypass air and recirculation gas and stopping thereof when blowing into A, and control for closing the valve element 19 and blowing out bypass air. The control for closing the valve body 19 to blow out the recirculation gas and the control for opening the valve body 19 to stop the blowout of the bypass air or the recirculation gas are performed.

Next, another embodiment of the present invention is shown in FIG.
Incidentally, FIG. 7A is a cross-sectional view of the intake port forming portion,
(B), (C) and (D) are CC sectional views taken in the direction of (A). In the embodiment of FIGS. 7 (B) and 7 (C), a plurality of gas outlets 22 are provided in the intake port forming wall 21, respectively. In particular, the blowing direction of the gas outlets 22 is
The main flow is set appropriately according to the flow of the main flow in the intake port 15A to stabilize the main flow. For example, in the embodiment of FIG. 7B, the gas outlet 22 is set downward when the main flow in the intake port 15A is downward, and in the embodiment of FIG. 7C, the main flow in the intake port 15A is set. Is set to face upward, the gas outlet 22 is set to face upward.

Further, in the embodiment shown in FIG. 7D, a large number of gas outlets 22 provided in the intake port forming wall 21 are set so that bypass air or recirculation gas is blown out throughout the intake port 15A. Thereby, the gas flow can be further enhanced. Although the present invention has been described with reference to the specific embodiments as described above, the present invention is not limited to this, and the patents attached to the present invention by a person skilled in the art or the like. It should be noted that various changes and modifications can be made without departing from the scope of the claims.

[0026]

As described above, according to the intake system for an internal combustion engine of the present invention, two intakes branching from a single intake passage corresponding to each cylinder and communicating with the same cylinder. In an internal combustion engine having a port, an intake control valve device is configured to close the valve body provided in the intake passage to control the intake flow to one of the intake ports to a small value, and bypass the valve body. By-pass intake air or exhaust gas recirculation is selectively blown across the intake port on the side where the intake flow is controlled to be small toward the other main intake air flow port. In conditions where swirl flow does not occur,
Since the gas always flows to the intake port side where the main flow flows, the main flow is strengthened, the fluctuation of the swirl ratio strength for each cycle of the engine can be suppressed to a small level, and the gas flow flowing into the combustion chamber is stabilized. However, there is an advantage that a sufficient swirl flow is generated and combustion is stabilized, which is of great utility.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an entire embodiment of an intake device for an internal combustion engine according to the present invention.

2A and 2B are views showing a configuration of an intake port portion of the embodiment, in which FIG. 2A is a horizontal sectional view, FIG. 2B is a vertical sectional view, and FIG. 2C is a sectional view taken along line AA in FIG.

3A and 3B are views showing a configuration of an intake port portion in all cylinders in the embodiment, in which FIG. 3A is a cross-sectional view and FIG. 3B is a cross-sectional view taken along the line BB in FIG. 3A.

FIG. 4 is a transverse cross-sectional view illustrating the operation of the above-described embodiment

FIG. 5 is a diagram showing a relationship among a valve lift, an intake flow velocity, and an intake pressure.

FIG. 6 is a characteristic diagram for explaining the control contents of the above embodiment.

FIG. 7 is a view showing another embodiment of the present invention, in which (A) is a cross-sectional view and (B), (C) and (D) are cross-sectional views taken along the line CC in (A).

FIG. 8 is a vertical sectional view showing an example of a conventional intake device for an internal combustion engine.

FIG. 9 is a perspective view of the above conventional device.

[Explanation of symbols]

 11 Cylinder 12A Intake valve 12B Intake valve 15A Intake port 15B Intake port 19 Valve body 22 Gas outlet 23 Bypass intake pipe 24 Exhaust passage 25 Exhaust gas recirculation pipe 26 Switching valve

Claims (1)

[Claims] 1. An internal combustion engine comprising two intake ports branching from a single intake passage corresponding to each cylinder and communicating with the same cylinder. A valve provided in the intake passage. An intake control valve device having a structure for closing the body to control the intake flow to one of the intake ports to be small is provided, and the gas is controlled to be small to the intake port forming wall on the downstream side of the valve body. Side air intake port is provided to blow out toward the other air intake port toward the other air intake port, and a bypass air intake passage for guiding a part of the air intake from the upstream side of the air valve in the air intake passage to the gas air outlet by bypassing the air valve An exhaust gas recirculation passage for guiding a part of the exhaust gas recirculated from the exhaust passage to the gas outlet, and a passage switching means for selectively switching the bypass intake passage and the exhaust gas recirculation passage. An intake system for an internal combustion engine that.