JP3811959B2 - Intake control device for internal combustion engine - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an intake control device including a swirl control valve for an internal combustion engine, and more particularly to a technique for suppressing wall flow due to fuel adhesion from a fuel injection valve to an intake port wall.
[0002]
[Prior art]
An example of a conventional intake control device for an internal combustion engine is shown in FIG. 14 (see Japanese Utility Model Laid-Open No. 60-45829).
That is, in this device, the fuel injection valve 6 is mounted on the upper wall portion of the intake pipe, and fuel is injected and supplied from the injection hole at the tip of the fuel injection valve 6 to the two intake ports 2 and 3, and the intake swirl is strengthened. For the purpose, a swirl control valve 9 is provided upstream of the intake ports 2 and 3.
[0003]
The swirl control valve 9 is closed in the low speed and low load region of the engine, so that the intake air flow rate is increased and a strong swirl is generated in the combustion chamber of the cylinder 1 to promote atomization of the fuel and improve the miscibility with air. It is configured to improve combustion efficiency and reduce HC, CO, etc., while increasing the intake passage area by opening it in the high speed and high load region to increase the intake charge efficiency into the combustion chamber and improve the output Is.
[0004]
[Problems to be solved by the invention]
By the way, in such a conventional internal combustion engine intake control device, when the swirl control valve 9 is opened, an air amount optimum for the fuel injection amount from the fuel injection valve 9 is introduced into each intake port 2, 3. Since the intake flow rate / velocity and the fuel injection amount are the same at the left and right intake ports 2, 3, the fuel wall flow attached to the wall surfaces of the intake ports 2, 3 is also the same at both ports 2, 3.
[0005]
However, as shown in FIG. 15, when the swirl control valve 9 is closed, the intake air flow rate and flow velocity of the intake port 3 not facing the notch 9a on the opposite side to the intake port 2 facing the notch 9a are Although the amount of fuel injected from the fuel injection valve 9 toward the intake ports 2 and 3 is the same even though the fuel injection valve 9 is extremely low, as shown in FIG. On the third side, there is a problem that the injected fuel adheres to the wall surface of the intake port 3 and the fuel wall flow increases, and the HC discharge amount is increased to deteriorate the drivability.
[0006]
In order to reduce the fuel wall flow adhering to the wall surface of the intake port 3 not facing the notch 9a, it is also conceivable that the fuel is injected and supplied only to the intake port 2 side facing the notch 9a. However, in this case, a difference occurs in the air-fuel ratio of the intake air introduced from the intake ports 2 and 3, so that a uniform air-fuel mixture is not formed, combustion is not stable, and exhaust emission deteriorates. It cannot be adopted.
[0007]
The present invention has been made in view of such conventional problems, and promotes the atomization of fuel on the intake port side that does not face the notch of the swirl control valve to reduce the wall flow rate, thereby purifying the exhaust gas. An object of the present invention is to provide an intake control device for an internal combustion engine with improved performance and operational performance.
[0008]
[Means for Solving the Problems]
In order to achieve such an object, the present invention has a plurality of intake ports for each cylinder, and has a notch at a position facing one of the intake ports in an intake passage upstream from a branch point of these intake ports. The swirl control valve is provided, and the swirl control valve is closed under a predetermined operating condition to cause the intake air to flow through the intake port facing the notch to generate a swirl, while supplying fuel to each intake port In the intake control apparatus for an internal combustion engine, the intake introduction by the intake valve provided in the intake port facing the notch of the swirl control valve is introduced from the intake introduction by the intake valve provided in the intake port not facing the notch. an intake introducing delay setting means for setting also slow, the intake air introduction delay setting means, the intake stroke early intake valve provided in the intake ports facing the notch of the swirl control valve The kicking lift, characterized in that it is a intake valve lift amount setting means for setting lower than the lift amount of the intake valve provided in an intake port, not facing the cutout.
[0011]
[Action]
According to such a configuration, in the closed state of the scan whirlpool control valve, the fuel injection amount from the fuel injection valve is the same in each of the intake ports, the surface to notch of each intake valve swirl control valve when open simultaneously Compared to the intake port, the intake port that does not face the notch on the opposite side of the intake port has a lower air flow rate and flow velocity, so the injected fuel adheres to the wall surface of the intake port and generates a wall flow. It becomes easy.
[0012]
Therefore, set slower than intake air by the intake valve provided in an intake port, not facing the intake air by the intake valve provided in an intake port facing the notch of the swirl control valve in the notch by the intake introducing delay setting means .
[0016]
In particular, the intake introduction delay setting means is used to set the lift amount at the initial stage of the intake stroke of the intake valve provided in the intake port facing the notch of the swirl control valve to the intake valve provided in the intake port not facing the notch. The intake port lift amount setting means is set lower than the lift amount, and by reducing the effective opening area of the intake valve provided in the intake port facing the notch of the swirl control valve at the initial stage of the intake stroke, the intake port This prevents the intake air from being introduced to the side and allows more intake air to be introduced to the intake port that does not face the notch, reducing wall flow HC adhering to the wall of the intake port not facing the notch and improving combustion efficiency Can be achieved.
[0018]
According to this, when the swirl control valve is closed, the same effect as the above-described invention is achieved, and in the high speed / high load region where the swirl control valve opens, the valve overlap becomes larger than when the valve is closed. , Combustion gas exchange is promoted. Further, since the intake air flow rate of each intake port becomes equal, the uniformization of the air-fuel mixture is promoted.
[0019]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
In FIG. 1 showing one embodiment, the internal combustion engine is provided with two intake ports 2 and 3 and two exhaust ports 4 and 5 for each cylinder 1 of each cylinder. The intake ports 2 and 3 are passages for introducing the air-fuel mixture supplied from the upstream side into the combustion chamber of the cylinder 1. The intake ports 2 and 3 have intake air that opens and closes the intake ports 2 a and 3 a. Valves 11 and 12 are provided, and are opened and closed by cams 17 and 18 via an intake cam mechanism 15. Here, the intake valves 11 and 12, the intake cam mechanism 15, and the cams 17 and 18 have a function as intake introduction delay setting means.
[0020]
As shown in FIG. 4, the cams 17 and 18 are arranged so that the opening timing (indicated by dotted lines) of the intake valve 11 provided in the intake port 2 facing the notch 9a of the swirl control valve 9 faces the notch 9a. The intake ports 3 are set so as to have different cam profiles so as to be later than the opening timing of the intake valve 12 provided in the intake port 3.
The exhaust ports 4 and 5 are passages for discharging the burnt gas burned in the combustion chamber to the outside. The exhaust ports 4 and 5 have an exhaust valve 13 for opening and closing the exhaust ports 4a and 5a. , 14 are provided and are opened and closed by cams 19, 19 via an exhaust cam mechanism 16.
[0021]
Further, upstream of the intake ports 2 and 3, a fuel injection valve 6 is mounted on the upper wall portion of the intake pipe 20, and the fuel injection valve 6 receives an electromagnetic coil by a drive pulse signal output from the control unit 7. Is an electromagnetic fuel injection valve that opens when energized, and closes when energized, and is configured to inject and supply fuel from the nozzle hole at the tip thereof toward the two intake ports 2 and 3.
[0022]
A swirl control valve 9 (SCV) is mounted upstream of the intake ports 2 and 3. The swirl control valve 9 is configured to be able to be opened and closed by controlling the solenoid valve 10 according to the operating state of the diaphragm actuator 8, and a notch 9a is provided on the side of the swirl control valve 9 facing the intake port 2. When the valve is closed, sufficient intake air is supplied to the intake port 2 side through the notch 9a, but supply of intake air to the intake port 3 side is limited.
[0023]
The control unit 7 includes a microcomputer including a CPU, a ROM, a RAM, an A / D converter, an input / output interface, and the like, receives input signals from various sensors, performs arithmetic processing, and performs fuel injection. 6 and the actuator 8 are controlled.
As the various sensors, an air flow meter 23 is provided in an intake duct (not shown) and outputs a signal corresponding to the intake air flow rate Qa of the engine.
[0024]
Further, a distributor (not shown in FIG. 1) has a built-in crank angle sensor 21, and counts a crank unit angle signal output from the crank angle sensor 21 in synchronization with the engine rotation for a certain period of time or The period of the reference angle signal is measured to detect the engine rotational speed Ne.
Further, a water temperature sensor 24 for detecting a cooling water temperature Tw of a water jacket (not shown) of the engine is provided.
[0025]
Further, a boost sensor 22 for detecting the intake negative pressure Boost of the engine is provided.
Next, the operation of the embodiment will be described based on the flowchart of FIG.
First, in step 1 (hereinafter referred to as S 1), the engine rotation speed Ne detected by the crank angle sensor 21 and the suction negative pressure Boost detected by the boost sensor 22 are read and input to the control unit 7.
[0026]
In S2, an open / close region (ON / OFF) of the swirl control valve 9 (SCV) assigned by the engine rotational speed Ne and the suction negative pressure Boost is searched from a previously stored map table. That is, as shown in FIG. 3, this map table is set so that the SCV is closed (ON) in the low speed / low to medium load region of the engine and the SCV is opened (OFF) in other high speed / high load regions. Yes.
[0027]
If the engine operating region is in the low speed / low to medium load region, the SCV is closed (ON) in S3, the intake air flow rate is increased and a strong swirl is generated in the combustion chamber to atomize the fuel. While promoting, improve the mixing with air to improve combustion efficiency and reduce HC, CO, etc.
If it is in the other high speed and high load region, the SCV is opened (OFF) in S4, thereby increasing the intake passage area to increase the efficiency of intake charge into the combustion chamber and improve the output.
[0028]
Here, when the swirl control valve 9 is closed, the fuel injection amount from the fuel injection valve 6 is the same in each intake port 2, 3, but when the intake valves 11, 12 are simultaneously opened, the swirl control valve 9 Compared with the intake port 2 facing the notch 9a, the intake port 3 not facing the notch 9a on the opposite side has a lower air flow rate and flow velocity. 3 It becomes easy to generate wall flow by adhering to the wall surface.
[0029]
However, as shown in FIG. 4, the cam profiles of the cams 17 and 18 that drive the intake valves 11 and 12 open the intake valve 11 provided in the intake port 2 facing the notch 9a of the swirl control valve 9. Since the timing (indicated by the dotted line) is set to be later than the opening timing (indicated by the solid line) of the intake valve 12 provided in the intake port 3 that does not face the notch 9a, the intake air that does not face the notch 9a As shown in FIG. 5A, the fuel wall flow attached to the wall surface of the port 3 is first atomized by the air introduced only into the intake port 3 at the beginning of the intake stroke and introduced into the combustion chamber. Thereafter, as shown in FIG. 5B, intake air is introduced by the intake valve 11 provided in the intake port 2 facing the notch 9a, and intake air is introduced from both ports 2 and 3. The wall flow adhering to the wall surface of the intake port 3 not facing the notch 9a can be atomized to reduce HC and improve the combustion efficiency.
[0030]
Further, the swirl control valve 9 is controlled to be opened during high speed / high load operation of the engine. In this case, both intake ports 2 and 3 are fully open and the intake air flow rate is large, so the intake air flow rate and flow velocity are sufficiently strong at both ports, and the fuel does not flow into the wall and ensures sufficient mixing with air. Thus, the exhaust gas purification performance can be maintained well while satisfying the high output performance.
[0031]
Next, another embodiment will be described with reference to FIG.
This is basically the same as the embodiment shown in FIG. 1, and the cam profile of the cams 17 and 18 for driving the intake valves 11 and 12 is different from that shown in FIG. As described above, the lift amount (portion A) of the intake valve 11 provided in the intake port 2 facing the notch 9a of the swirl control valve 9 at the initial stage of the intake stroke is provided in the intake port 3 not facing the notch 9a. The difference is that it is set to be lower than the lift amount of the intake valve 12.
[0032]
According to this, the effective opening area in the initial stage of the intake stroke of the intake valve 11 provided in the intake port 2 facing the notch 9a of the swirl control valve 9 is reduced, and intake air introduction to the intake port 2 side is reduced. Since a large amount of intake air can be introduced to the intake port 3 side that does not face the notch 9a, the same operation and effect as in the above embodiment can be achieved without changing the opening timing of the intake valves 11 and 12. Can play.
[0033]
Next, another embodiment will be described with reference to FIG.
This is basically the same as the embodiment shown in FIG. 1 and includes a variable valve timing lift mechanism 20 as a valve opening / closing timing varying means on the intake side, and when the swirl control valve 9 is closed and opened. The variable valve timing lift mechanism 20 is different in that the valve timing is varied.
[0034]
Next, an example of the variable valve timing lift mechanism 20 will be described with reference to FIGS.
That is, the variable valve timing lift mechanism 20 is hydraulic, has a hydraulic oil passage 25a therein, and drives the intake valve 11 on the SCV notch side to the rocker shaft 25 fixedly held by the cylinder head. A first rocker arm 26, a second rocker arm 27 for driving the intake valve 12 on the opposite side of the SCV notch, and a free rocker arm 28 disposed between the first and second rocker arms 26, 27 are attached, and the three rocker arms are connected. And it has the structure which has the hydraulic connection switching means 29 which opens. The hydraulic pressure in the hydraulic oil passage 25 a is switched between high pressure and low pressure by the variable valve timing lift mechanism 20.
[0035]
The cams 17, 18a, 18b for driving the rocker arms 26 to 28 have a shape as shown in FIG. 9, for example, and the cam 17 has an intake valve opening timing as compared with the other two cams 18a, 18b. The profile is slow.
The hydraulic connection switching means 29 includes a first switching pin 30 that can connect the first rocker arm 26 and the free rocker arm 28, a second switching pin 31 that can connect the second rocker arm 27 and the free rocker arm 28, and the first and first switching pins 29. 2 A regulation pin 32 that regulates the movement of the switching pins 30 and 31 and a return spring 33 that urges each of the pins 30 to 32 to the connection release side are operated by hydraulic pressure introduced from the hydraulic oil passage 25a.
[0036]
That is, when the hydraulic pressure in the hydraulic oil passage 25a is on the low pressure side, the pins 30 to 32 are urged to the connection release side by the urging force of the return spring 33, and the rocker arms 26 to 28 become independent from each other. The intake valve 11 on the side is opened and closed by a first rocker arm 26 driven by a cam 17, and the intake valve 12 on the side opposite to the SCV notch is opened and closed by a second rocker arm 27 driven by a cam 18b. At this time, the motion of the free rocker arm 28 driven by the cam 18 a is not transmitted to the first and second rocker arms 26 and 27.
[0037]
Further, when the hydraulic pressure in the hydraulic oil passage 25a is on the high pressure side, the pins 30 to 32 move to the connection side against the urging force of the return spring 33 by the hydraulic pressure, and the rocker arms 26 to 28 are connected to each other. . At this time, since the movement of the free rocker arm 28 driven by the cam 18a is transmitted to the first and second rocker arms 26, 27, the intake valves 11, 12 open and close according to the profile of the cam 18a.
[0038]
As shown in FIG. 10, when the SCV is open, the hydraulic pressure in the hydraulic oil passage 25a is set to a high pressure, and the valves 11 and 12 are opened and closed by the cam 18a via the rocker arms 26 to 28. By lowering the hydraulic pressure in the passage 25a, the intake valve 11 on the SCV notch side is opened and closed by the cam 17 via the rocker arm 26, and the intake valve 12 on the opposite side to the SCV notch is cammed via the rocker arm 27. It is opened and closed by 18b. As shown in FIGS. 9 and 10, the profiles of the cams 18a and 18b are the same, and only the lift curve of the intake valve 11 on the SCV notch side is cut by valve timing control switching performed in conjunction with the opening and closing of the SCV. Change.
[0039]
As shown in the flowchart below, the control unit 7 is provided with some functions as a valve opening / closing timing varying means and an intake introduction delay setting means in software.
Next, the operation of the above embodiment will be described based on the flowchart of FIG.
First, in S11, the open / close state of the swirl control valve 9 is determined. If the swirl control valve 9 is in the closed state, the valve timing at the time of closing is selected in S12, and a control signal is output from the control unit 7 to the variable valve timing lift mechanism 20 in S13. That is, as shown in FIG. 10, the opening timing (indicated by the dotted line) of the intake valve 11 provided in the intake port 2 facing the notch 9a of the swirl control valve 9 is set to the intake port 3 not facing the notch 9a. A cam profile set so as to be later than the valve opening timing (shown by a solid line) of the provided intake valve 12 is selected.
[0040]
If the swirl control valve 9 is in the open state, the valve timing at the time of opening is selected in S12, and a control signal is output from the control unit 7 to the variable valve timing lift mechanism 20 in S13. That is, the cam profile set so that the opening timings of both the intake valves 11 and 12 indicated by the solid line in FIG. 10 are the same is selected.
As a result, when the swirl control valve is closed, the same operation and effect as in the embodiment of FIG. 1 are obtained, and in the high speed / high load region where the swirl control valve opens, the valve overruns compared to when the valve is closed. Since the wrap becomes larger, the exchange of the combustion gas is promoted. Further, since the intake air flow rate of each intake port becomes equal, the uniformization of the air-fuel mixture is promoted.
[0041]
Next, another embodiment will be described with reference to FIGS.
This is basically the same as the embodiment shown in FIG. 7, and the valve timing of the intake valves 11 and 12 is set to be the valve timing shown in FIG. 12, unlike the one shown in FIG. It is different in point.
That is, as shown in the figure, when the SCV is closed, the intake valves 11 and 12 are different from those when the SCV is opened and have different lift curves. This is because the cams 17 and 18a as shown in FIG. , 18b by setting the profile.
[0042]
According to this, in the low-speed / low-load region where the swirl control valve is closed, the valve overlap is small, so that combustion is stable and the closing timing of the intake valve is advanced, so that high torque is obtained and swirl control is performed. In the high-speed and high-load region where the valve opens, the valve overlap is larger than when the valve is closed, so the exchange of combustion gas is promoted, the intake valve is closed late and the valve lift is large, resulting in high output. can get. The same effects as those of the embodiment of FIG.
[0043]
【The invention's effect】
As described above, according to the present invention, the intake introduction by the intake valve provided in the intake port facing the notch of the swirl control valve is more than the intake introduction by the intake valve provided in the intake port not facing the notch. An intake introduction delay setting means for setting the intake valve later, and the intake introduction delay setting means is arranged so that the lift amount at the beginning of the intake stroke of the intake valve provided in the intake port facing the notch of the swirl control valve Since the intake valve lift amount setting means is set to be lower than the intake valve lift amount provided in the intake port, the wall flow on the intake port side that does not face the notch can be atomized. Can be reduced and combustibility can be improved.
[Brief description of the drawings]
FIG. 1 is a system diagram showing the overall configuration of an intake control device for an internal combustion engine according to an embodiment of the present invention.
FIG. 2 is a flowchart for explaining the operation of the intake control device according to the embodiment of FIG. 1;
FIG. 3 is a map table showing an open / close region of a swirl control valve assigned to an engine speed Ne and a suction negative pressure.
FIG. 4 is a view showing valve timings in the embodiment of FIG. 1;
FIG. 5 is an explanatory diagram for explaining the operation of the embodiment of FIG. 1;
FIG. 6 is a view showing valve timing according to another embodiment of the present invention.
FIG. 7 is a system diagram showing the overall configuration of an intake control device for an internal combustion engine according to another embodiment of the present invention.
8 is a cross-sectional view showing a variable valve timing lift mechanism of the embodiment of FIG.
9 is a view showing a cam shape of the embodiment of FIG.
FIG. 10 is a diagram showing valve timings in the embodiment of FIG.
FIG. 11 is a flowchart for explaining the operation of the intake control device according to the embodiment of FIG. 7;
FIG. 12 is a diagram showing valve timing in another embodiment of the present invention.
13 shows a cam shape having the cam profile of FIG. 12. FIG.
FIG. 14 is a cross-sectional view showing a configuration of a conventional intake control device.
FIG. 15 is an explanatory diagram for explaining a defect of a conventional intake control device.
[Explanation of symbols]
1 Cylinder 2, 3 Intake port 4, 5 Exhaust port 6 Fuel injection valve 7 Control unit 8 Actuator 9 Swirl control valve 9a Notch 10 Solenoid 11, 12 Intake valve 13, 14 Exhaust valve 15 Intake cam mechanism 16 Exhaust cam mechanism 17 Intake Cam (open valve delay side)
18 Intake cam 19 Exhaust cam 20 Intake variable valve timing mechanism 21 Crank angle sensor 22 Boost sensor 23 Air flow meter

Claims (1)

Each cylinder has a plurality of intake ports, and a swirl control valve having a notch at a position facing any one of the intake ports is provided in the intake passage upstream of the intake port branch point. In the intake control device for an internal combustion engine, the swirl is generated by swirling the intake valve through the intake port facing the notch by closing the swirl control valve, while supplying the fuel to each intake port.
Intake introduction delay setting means for setting the intake introduction by the intake valve provided in the intake port facing the notch of the swirl control valve to be set later than the intake introduction by the intake valve provided in the intake port not facing the notch is provided. e,
The intake introduction delay setting means determines the lift amount at the initial stage of the intake stroke of the intake valve provided at the intake port facing the notch of the swirl control valve, and the lift amount of the intake valve provided at the intake port not facing the notch. An intake control device for an internal combustion engine, characterized in that the intake valve lift amount setting means is set lower .

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