JPH06257448A - Intake device of internal combustion engine - Google Patents

Abstract

PURPOSE:To improve exhaust emission purifying performance and driving performance by atomizing the fuel wall flow stuck on a intake port wall surface after being separated therefrom. CONSTITUTION:In the state where a swirl control valve 13 is closed, the supply of intake air into a second intake port 12b is limited, and a differential pressure is generated between pressures on the upstream and downstream sides of the swirl control valve 13 faced to the second intake port 12b, thereby air flows into an air introducing passage 18 from an air intake 18a and injected and supplied to a valve seat part. And the wall flow is separated from the port by a step provided in the second intake port 12b, and also atomized by air injected and supplied from the injection hole 18b of the air introducing passage 18, so as to be introduced into a combustion chamber 11.

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 technique for separating a wall flow generated by adhering fuel injected from a fuel injection valve to an intake port into fine particles.

[0002]

2. Description of the Related Art As a conventional intake system for an internal combustion engine, for example, there is one shown in FIG.
829). That is, this is the fuel injection valve 1
Is attached to the upper wall of the intake pipe 2, and a swirl control valve 3 is provided upstream of the intake port 4 for the purpose of strengthening the intake swirl.

The swirl control valve 3 is closed in the low speed and low load region of the engine so that the intake flow velocity increases and the combustion chamber 5 increases.
A powerful swirl is generated in the interior to promote atomization of the fuel and improve the mixing efficiency with the air to improve the combustion efficiency.
While reducing O etc., it is configured to increase the intake passage area by increasing the intake passage area by opening in the high speed and high load region to improve the output.

[0004]

By the way, in such a conventional intake system for an internal combustion engine, as shown in FIG.
When the swirl control valve 3 is open, the optimum air amount for the fuel injection amount from the fuel injection valve 1 is the intake ports 4a, 4b.
Since the intake flow velocity A and the fuel injection amount B are equal in the left and right intake ports 4a and 4b, the fuel wall flow adhering to the wall surface of the intake port 4 is also equal in both ports 4a and 4b.

However, as shown in FIG. 9, when the swirl control valve 3 is closed, the intake port 4 on the side facing the notch 3a.
In contrast to a, although the intake flow velocity a of the intake port 4b not facing the notch 3a on the opposite side is extremely reduced, the amount of injected fuel injected from the fuel injection valve 1 toward each intake port 4 is reduced. Since the amount B is the same, as shown in (b), on the intake port 4b side, the injected fuel adheres to the wall surface of the intake port 4b and the fuel wall flow C increases, and the discharge amount of HC increases rather. However, there was a problem that the drivability was deteriorated.

As a means for atomizing the wall flow adhering to the intake port, there has been proposed one as shown in FIG. 10 (see Japanese Utility Model Laid-Open No. 64-47972). That is, this is the one upstream of the throttle valve 7 and the intake port 4
Assist air is introduced from the vicinity of the valve seat 4c of the intake port 4 by utilizing the pressure difference with the downstream, but the generation of wall flow increases as in the case where the swirl control valve as described above is provided. In the case of an intake port that operates, it is not always possible to expect sufficient atomization of fuel.

The present invention has been made in view of such conventional problems, and improves the exhaust purification performance and the operation performance by separating the fuel wall flow adhering to the wall surface of the intake port into fine particles. An object is to provide an intake system for an internal combustion engine.

[0008]

In order to achieve the above object, the present invention has a plurality of intake ports for each cylinder, and one of the intake ports is provided in an intake passage upstream from a branch point of these intake ports. A swirl control valve having a notch at a position facing the, and closing the swirl control valve under a predetermined operating condition to circulate intake air through an intake port facing the notch while generating swirl. In an intake device for an internal combustion engine, which supplies fuel to at least an intake port that does not face the notch, a step is provided near the valve seat portion below the inner wall of the downstream end of the intake port that does not face the notch of the swirl control valve. At the same time, an air introduction passage is provided, which is introduced from the upstream side of the swirl control valve and injects and supplies air from the injection hole opened immediately below the step.

Further, the injection hole may be formed so that the air injection direction is toward the substantially central portion of the combustion chamber.
Further, a guide part for collecting the wall flow adhering to the intake port may be provided immediately upstream of the injection hole of the intake port provided with the air introduction passage. Further, the air intake port of the air introduction passage may be provided immediately upstream of the swirl control valve at a position not facing the notch.

[0010]

According to this structure, in the closed state of the swirl control valve, the fuel injection amount from the fuel injection valve is the same in each port, but the notch on the opposite side to the intake port facing the notch is provided. Since the amount of air decreases in the intake port that does not face the above, the injected fuel adheres to the wall surface of the intake port in the intake port, and wall flow easily occurs.

Further, in this state, a differential pressure is generated by the swirl control valve closed upstream and downstream of the swirl control valve on the side not facing the notch, and this differential pressure causes air to flow from the upstream of the swirl control valve. It is introduced through the air introduction passage.
Then, the wall flow adhering to the wall surface of the intake port is separated from the port by a step provided near the valve seat portion on the inner wall of the downstream end of the intake port, and then introduced from the upstream of the swirl control valve through the air introduction passage. It is atomized by the air injected and supplied from the injection hole that opens directly below the step, and is introduced into the combustion chamber. This reduces HC and
The combustion efficiency can be improved.

Moreover, since the air is introduced into the downstream portion of the intake port by utilizing the differential pressure between the upstream and downstream of the swirl control valve, parts such as a solenoid valve are not required, and the HC can be reduced at a low cost. And combustibility can be improved. Further, when the injection hole is formed so that the air injection direction is directed to the substantially central portion of the combustion chamber, the air injection direction is directed to the central portion of the swirl generated in the combustion chamber, which hinders the swirl effect. The HC can be reduced by separating the wall flow from the intake port and atomizing the wall flow.

Further, when a guide portion for collecting the wall flow adhering to the intake port is provided immediately upstream of the injection hole of the intake port provided with the air introduction passage, more wall flow is collected and intake is performed. By peeling from the port and atomizing,
It is possible to further reduce HC. Further, when the air intake port of the air introduction passage is provided immediately upstream of the swirl control valve at a position not facing the notch, the differential pressure generated between the upstream and downstream of the swirl control valve becomes large, so A large amount of air can be introduced into the air introduction passage, whereby atomization of the separated wall flow can be promoted and combustion efficiency can be further improved.

When the swirl control valve is open, an air amount suitable for the fuel injection amount from the fuel injection valve is introduced into each intake port. Further, since no pressure difference is generated between the upstream side and the downstream side of the swirl control valve, air does not flow into the air introduction passage.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. First, referring to FIG. 1 and FIG. 2, the overall structure of an intake system according to an embodiment of the present invention will be described. An internal combustion engine is equipped with a first intake port 12a and a second intake port 12b for each combustion chamber 11 of each cylinder. The intake ports 12a, 12
A swirl control valve 13 is mounted on the upstream side of b.

The swirl control valve 13 is constructed so that it can be opened and closed by a solenoid valve 14 and a diaphragm 15. A notch 13a is provided on the side of the swirl control valve 13 facing the first intake port 12a, and it is closed. When the valve is open, sufficient intake air is supplied to the first intake port 12a side through the notch 13a, but intake air supply to the second intake port 12b side is restricted.

A fuel injection valve 17 is mounted on the upper wall portion 16a of the intake pipe 16 leading to the intake port 12, and the fuel injection valve 17 is a control unit (not shown).
An electromagnetic fuel injection valve is energized by a drive pulse signal output from the electromagnetic coil to open the valve, and deenergized to close the electromagnetic coil from the injection hole 17a at the tip to the intake port 12a.
Fuel is injected and supplied toward 12b.

Also, from the upstream of the swirl control valve 13 to the second
An air introduction passage 18 communicating with the vicinity of the valve seat portion of the intake port 12b is provided, and the air intake 18a of the air introduction passage 18 ensures a sufficient pressure difference between the upstream side and the downstream side as shown in FIG. The swirl control valve 1 facing the second intake port 12b side so that sufficient air can be injected and supplied to the valve seat portion of the second intake port 12b.
3 is open on the upstream side.

Then, a step 2 is formed in the vicinity of the valve seat portion on the inner wall of the downstream end of the second intake port 12b and faces downward toward the downstream side.
0 is provided, and an injection hole 18b for injecting and supplying the air in the air introduction passage 18 is opened immediately below the step 20.
As shown in FIG. 5, after the air that has flowed in from the air introduction passage 18 once enters the pressure chamber 18c to reduce pulsation, the injection hole portion is increased in pressure from the injection hole 18b whose passage width is narrowed. It is designed to eject at a sufficient flow rate.

Next, the operation of the present invention will be described with reference to FIGS. During low speed / low load operation of the engine, the swirl control valve 13 is controlled to be closed. As a result, as described above, the supply of intake air to the second intake port 12b is limited, while the intake air is supplied to the first intake port 12a via the notch 13a of the swirl control valve 13 with an increased flow velocity. Therefore, a strong swirl is generated in the combustion chamber 11.

Then, as shown in FIG. 2, the fuel injection valve 1
The fuel injection amount B from 7 is the same in both ports, but the air amount a of the second intake port 12b on the opposite side is smaller than the air amount A of the first intake port 12a facing the notch 13a. In addition, the fuel easily becomes the wall flow C in the intake port. However, since a pressure difference is generated between the upstream side and the downstream side of the swirl control valve 13 facing the second intake port 12b, the air intake passage 18 is introduced from the air intake port 18a.
The air flows into the valve seat, and the air is jetted and supplied to the valve seat portion. Then, the step 2 provided in the second intake port 12b
When 0, the wall flow C is separated from the port and atomized by the air injected and supplied from the injection holes 18b of the air introduction passage 18 and introduced into the combustion chamber 11.

As a result, HC is reduced, exhaust gas purification performance can be improved, and combustion is stabilized to improve fuel efficiency. Also, when the engine is operating at high speed and high load,
The swirl control valve 13 is controlled to open. In this case, both the first intake port 12a and the second intake port 12b are fully opened, and the intake air flow rate is large, so the flow of intake air is sufficiently strong in both ports, and the fuel does not become a wall flow and mixes with air. Exhaust gas purification performance can be maintained satisfactorily while being sufficiently secured and satisfying high output performance.

The injection direction D of the air supplied from the injection hole 18b of the air introduction passage 18 is set to the direction toward the center of the swirl E generated in the combustion chamber as shown in FIG. , H is obtained by separating the wall flow C from the port and atomizing it without disturbing the effect of the swirl E.
It is possible to reduce C. Next, another embodiment will be described with reference to FIG.

This has the same basic structure as that of the embodiment shown in FIG. 1, and the wall flow adhering to the intake port is formed on the inner wall of the second intake port 12b located immediately upstream of the injection hole 18b. A collecting guide portion 12d is provided. This makes it possible to reduce HC by collecting a larger amount of the wall flow and separating the collected wall flow from the intake port to atomize the wall flow.

[0025]

As described above, according to the present invention,
A step is provided in the vicinity of the valve seat below the inner wall of the downstream end of the intake port that does not face the notch of the swirl control valve, and air is injected and supplied from a nozzle hole that is introduced upstream of the swirl control valve and opens immediately below the step. Since the air introduction passage is provided so that the wall flow is separated from the port by the step provided in the intake port, the atomization is promoted by receiving the air injected and supplied from the opening of the air introduction passage. Therefore, it is possible to reduce HC and improve combustibility.

Moreover, since the air is introduced to the downstream portion of the intake port by utilizing the differential pressure between the upstream and downstream of the swirl control valve, parts such as a solenoid valve are unnecessary, and HC can be reduced at low cost. And combustibility can be improved. Further, when the injection hole is formed so that the air injection direction is toward the substantially central portion of the combustion chamber, the injected air is directed toward the central portion of the swirl generated in the combustion chamber, so the effect of the swirl It is possible to separate the wall flow from the intake port and atomize it without interfering with the above, and to reduce HC.

Further, when a guide portion for collecting the wall flow adhering to the intake port is provided immediately upstream of the injection hole of the intake port provided with the air introduction passage, more wall flow is collected and intake is performed. By peeling from the port and atomizing,
It is possible to further reduce HC. Further, when the air intake port of the air introduction passage is provided immediately upstream of the swirl control valve at a position not facing the notch, the differential pressure generated between the upstream and downstream of the swirl control valve becomes large, so A large amount of air can be introduced into the air introduction passage, which makes it possible to promote atomization of the separated wall flow.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram for explaining the operation of the intake device according to the present invention.

FIG. 3 is an explanatory diagram for explaining the operation of the intake device according to the present invention.

FIG. 4 is an explanatory diagram for explaining the operation of the intake device according to the present invention.

FIG. 5 is a partially enlarged view showing a nozzle hole portion of the intake device according to the present invention.

6A is a cross-sectional view showing the structure of an intake device according to another embodiment of the present invention, FIG. 6B is a cross-sectional view taken along the line AA of FIG. 6A, and FIG. ) BB sectional drawing.

FIG. 7 is a plan view showing the configuration of a conventional intake device.

FIG. 8 is an explanatory diagram for explaining an operation of a conventional example in a state where a swirl control valve is opened.

FIG. 9 is an explanatory diagram for explaining the operation of the conventional example in the state where the swirl control valve is closed.

FIG. 10 is a cross-sectional view showing the configuration of a conventional intake device.

[Explanation of symbols]

 11 Combustion chamber 12a 1st intake port 12b 2nd intake port 12d Guide part 13 Swirl control valve 13a Notch 16 Intake pipe 17 Fuel injection valve 17a Injection hole 18 Air introduction passage 18a Air intake 18b Injection hole 20 Step

Claims (4)

[Claims] 1. A swirl control valve having a plurality of intake ports for each cylinder, the intake passage upstream of a branch point of the intake ports having a notch at a position facing any of the intake ports, By closing the swirl control valve under a predetermined operating condition, the intake air is circulated through the intake port facing the notch to generate swirl, and at least the fuel is supplied to the intake port not facing the notch. In the intake device for an internal combustion engine, a step is provided near the valve seat portion on the lower side of the inner wall of the intake port downstream end that does not face the notch of the swirl control valve, and is introduced from upstream of the swirl control valve to directly below the step. An intake device for an internal combustion engine, comprising an air introduction passage for injecting and supplying air from an injection hole opened at a position. 2. The intake system for an internal combustion engine according to claim 1, wherein the injection hole is formed so that an air injection direction is directed toward a substantially central portion in the combustion chamber. 3. A guide part for collecting a wall flow adhering to the intake port is provided immediately upstream of the injection hole of the intake port provided with the air introduction passage. Intake device for internal combustion engine. 4. The air intake port of the air introduction passage is provided immediately upstream of the swirl control valve at a position not facing the notch, according to any one of claims 1 to 3. Intake device for internal combustion engine.