JPH0742583A - Idle rotation control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To ensure a sufficient air amount and to increase the engine speed by a method wherein when fuel of which an amount is corrected to increase is injected after the high temperature starting of an internal combustion engine, a bypass control valve is controlled so that a bypass passage is fully opened. CONSTITUTION:An internal combustion engine 2 has a fuel injection valve 18 disposed in an intake passage 4. Further, a bypass control valve 32 is disposed in a bypass 30 and communicated with the intake passage 4 after it bypasses an intake throttle valve 10. A fuel injection valve 18 is controlled by a control part 48 based on the operation state of the internal combustion engine detected by various sensors 36-44 so that an air-fuel ratio is adjusted to a target air-fuel ratio. During idle running of the internal combustion engine 2, the bypass control valve 32 is controlled by opening and closing the bypass passage 30 so that the number of revolutions of an engine is adjusted to a target value. In this case, when fuel of which an amount is corrected to increase is injected through the fuel injection valve 18 after the high temperature starting of the internal combustion engine 2, the bypass control valve 32 is controlled so that the bypass passage 30 is fully opened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine idle speed control device, and more particularly to an internal combustion engine idle speed control device capable of reducing rotational fluctuations of an internal combustion engine after a high temperature start and preventing engine stall. Regarding the device.

[0002]

2. Description of the Related Art Some internal combustion engines mounted on vehicles or the like are equipped with an idle speed control device for controlling the engine speed to a target speed during idle operation. The idle rotation control device is provided with a bypass passage that bypasses the intake throttle valve of the internal combustion engine and communicates with the intake passage, a bypass control valve that opens and closes the bypass passage, and opens and closes the bypass passage during idle operation of the internal combustion engine. The operation of the bypass control valve is feedback-controlled by the duty ratio so that the engine speed becomes the target speed.

An example of such an idle speed control device for an internal combustion engine is disclosed in Japanese Patent Laid-Open No. 62-10433. The idle rotation control device disclosed in this publication increases the intake air amount when the temperature is equal to or higher than a predetermined temperature at the time of starting the internal combustion engine, and when a predetermined time has elapsed after the start or when the engine speed is the predetermined speed. When the number of intake air exceeds the number, the amount of increase of the intake air amount is controlled to be decreased.

Some internal combustion engines have a fuel injection valve in the intake passage. The fuel injection valve injects fuel in which the basic injection amount is corrected by various correction coefficients according to the operating state of the internal combustion engine, and is controlled so that the air-fuel ratio becomes the target air-fuel ratio.

[0005]

Some internal combustion engines are equipped with a supercharger. Since the internal combustion engine equipped with a supercharger has severe thermal conditions, fuel vapor may be generated in the fuel injection valve due to engine residual heat when the drive is stopped after high temperature and high load operation. .

For this reason, when the internal combustion engine is driven at high temperature and under high load, the driving is stopped, and the internal combustion engine is restarted in a high temperature state before it is sufficiently cooled, it is generated in the fuel injection valve. The injection of the fuel vapor makes the air-fuel ratio lean and causes fluctuations in rotation, which easily causes engine stall.

Therefore, conventionally, it is determined whether or not the fuel vapor is generated based on the conditions such as the cooling water temperature and the intake air temperature at the time of starting, and as shown in FIG. When the engine is started in this state, the fuel that has been increased and corrected by the high-temperature post-startup increase correction coefficient FHS is injected from the fuel injection valve, and the air-fuel ratio is tilted to the rich side to prevent engine stall.

However, in the conventional idle rotation control device, as shown in FIG. 4A, the idle injection of the fuel by the evaporated fuel after the high temperature start in the state where the fuel vapor is generated in the fuel injection valve, That is, there is a disadvantage that the idle rotation control has a poor followability with respect to a rapid decrease in rotation when the air-fuel ratio becomes lean due to the injection of fuel vapor from the fuel injection valve, and engine stall is likely to occur.

That is, as shown in FIG. 4 (c), the internal combustion engine in the high temperature state immediately after the driving is stopped, immediately after the start of the cranking and the complete explosion, immediately after the start of the fuel injection valve, the increase correction coefficient after the high temperature start is corrected. The injection of the fuel whose amount has been corrected by FHS is started, and the air-fuel ratio is tilted to the rich side. The increase correction coefficient FHS after high temperature start is a value determined by the cooling water temperature, and is decreased by a fixed amount for each injection.

At this time, the idle rotation control device is shown in FIG.
As shown in (c), the operation of the bypass control valve is controlled so as to temporarily fully open the bypass passage immediately after the internal combustion engine is completely exploded. The fully open time for temporarily fully opening the bypass passage is determined by the cooling water temperature. The idle rotation control device feedback-controls the operation of the bypass control valve based on the duty ratio so that the engine rotation speed becomes the target rotation speed after the full opening time has elapsed, and opens and closes the bypass passage.

However, the conventional idle rotation control device is
Since the operation of the bypass control valve is controlled so that the engine speed becomes the target speed after the temporary full open time has elapsed, as shown in FIG. When the air-fuel ratio becomes lean due to the air injection to cause a sudden decrease in rotation, the followability of the idle rotation control is poor as shown in FIG. There is an inconvenience that tends to occur.

[0012]

In order to solve such inconvenience, the present invention provides a fuel injection valve in the intake passage of an internal combustion engine and bypasses the intake throttle valve of the internal combustion engine to introduce the intake passage. A bypass control valve for opening and closing the bypass passage is provided for injecting fuel corrected by various correction coefficients according to the operating state of the internal combustion engine so that the air-fuel ratio becomes the target air-fuel ratio. An idle rotation control device for an internal combustion engine, which controls the operation of the fuel injection valve and controls the operation of the bypass control valve so that the engine speed becomes a target speed by opening and closing the bypass passage during idle operation of the internal combustion engine. In the case where the fuel whose injection amount is corrected by the increase correction coefficient after high temperature injection is injected from the fuel injection valve after the internal combustion engine is started at high temperature, the bypass passage is Characterized in that a control means for controlling the operation of the bypass control valve Beku Hirakisu.

[0013]

According to the structure of the present invention, when the idle rotation control device injects the fuel whose amount is increased and corrected by the increase correction coefficient after the high temperature start from the fuel injection valve by the control means after the high temperature start of the internal combustion engine. By controlling the operation of the bypass control valve to fully open the bypass passage, it is possible to secure a sufficient amount of air by the bypass passage that is fully opened after the internal combustion engine is started at a high temperature, and increase the engine speed during idle operation. You can

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings.

1 to 3 show an embodiment of the present invention. In FIG. 3, 2 is an internal combustion engine, 4 is an intake passage, and 6 is an exhaust passage. The intake passage 4 of the internal combustion engine 2 mounted on a vehicle (not shown) has an air cleaner 8 at the upstream end and communicates the downstream end with a combustion chamber (not shown). An intake throttle valve 10 is provided in the intake passage 4.
A compressor 14 of the supercharger 12 is provided in the intake passage 4 upstream of the intake throttle valve 10. Supercharger 12
Means that the compressor 14 provided in the intake passage 4 is connected to the exhaust passage 6
The intake air is pressure-fed by being driven by the turbine 16 provided in the.

The internal combustion engine 2 is provided with a fuel injection valve 18 in the intake passage 4 facing a combustion chamber (not shown). The fuel injection valve 18 communicates with a fuel tank 22 via a fuel passage 20. In the fuel tank 22, a fuel pump 24 that supplies fuel to the fuel passage 20 is provided. A fuel pressure adjusting valve 26 for adjusting the fuel pressure by the intake pressure of the intake passage 4 is provided in the middle of the fuel passage 20. The fuel pressure adjusting valve 26 adjusts the fuel pressure in the fuel passage 20 to a predetermined pressure, and returns excess fuel to the fuel tank 22 through the return passage 28.

The intake passage 4 is provided with a bypass passage 30 that bypasses the intake throttle valve 10. Bypass passage 3
0 communicates one end side with the intake passage 4 on the upstream side of the intake throttle valve 10 and on the downstream side of the compressor 14 of the supercharger 12, and the other end side with the combustion on the downstream side of the intake throttle valve 10. It communicates with an intake passage 4 leading to a chamber (not shown). The bypass passage 30 is provided with a bypass control valve 32 which is controlled by the duty ratio according to the operating state of the engine 2.

Further, the internal combustion engine 2 is provided with an air valve 34. The air valve 34 is operated by the temperature of the cooling water, and when the cold engine is started, the intake passage 4 on the downstream side of the intake throttle valve 10 is operated.
The amount of air supplied to the engine is increased to raise the engine speed higher than the idle speed to bring the engine into the first idle operation state.

The intake passage 4 is provided with a throttle sensor 36 for detecting the opening of the intake throttle valve 10, an intake temperature sensor 38 for detecting the intake temperature, and an intake pressure sensor 40 for detecting the intake pressure. There is. In the internal combustion engine 2,
A rotation angle sensor 42 and a cooling water temperature sensor 44 that detects the cooling water temperature are provided. The rotation angle sensor 42 is provided in the distributor 46. These various sensors 36 to 44 are connected to the input side of a control unit 48 which is a control means constituting the idle rotation control device.

On the input side of the control section 48, a diagnosis signal section 50 for inputting a diagnosis signal is also provided.
And the air conditioner (air conditioner: not shown) turned on
・ Air conditioner switch 52 to input the OFF signal,
A speedometer 54 for inputting a vehicle speed signal, an initial set portion 56 for inputting an initial set signal,
An O ₂ sensor 58 provided in the exhaust passage 6, a CO adjustment resistor section 60 for inputting a CO adjustment signal, and a battery 62.
And are connected.

On the output side of the control unit 48, the fuel injection valve 18, the fuel pump 24, the bypass control valve 32,
Are connected. The fuel pump 24 is a pump relay 6
4 are connected. On the output side of the control unit 48, a negative pressure switching valve 66 for an air bypass valve (not shown) and a negative pressure switching valve 68 for an EGR control valve (not shown).
, Ignition coil 70, monitor 72, and turbo lamp 7
4 and the duty meter 76 are connected.

The controller 48 includes an A / D converter 78 and a C
It includes a PU 80, an output unit 82, a shaping unit 84, and a buffer unit 86. The control unit 48 outputs an injection valve drive signal to the fuel injection valve 18, a pump drive signal to the fuel pump 24, an ignition command signal to the ignition coil 70, and a fuel injection according to signals input from various sensors. The fuel is appropriately injected from the valve 18 and the spark plug (not shown) is appropriately fired.

The control unit 48 includes various sensors 36 to 44.
The fuel input valve 18 controls the operation of the fuel injection valve 18 so that the air-fuel ratio becomes the target air-fuel ratio by injecting fuel whose basic injection amount is corrected by various correction coefficients according to the operating state of the internal combustion engine 2 by a signal input from Adjust the injection amount. In addition, the control unit 4
8 indicates a bypass passage 30 when the internal combustion engine 2 is idle.
Is opened and closed to feedback control the operation of the bypass control valve 32 by the duty ratio so that the engine speed becomes the target speed, and the amount of bypass air in the bypass passage 30 is adjusted.

This idle rotation control device has a control unit 48.
After the high temperature start of the internal combustion engine 2, the fuel injection valve 18
When the fuel whose amount has been increased and corrected by the high temperature after-start-up amount increase correction coefficient FHS is being injected, the operation of the bypass control valve 32 is controlled so as to fully open the bypass passage 30.

In the control section 48, a cooling water temperature judgment value A of the cooling water temperature THW and an intake air temperature judgment value B of the intake air temperature THA are set. When the internal combustion engine 2 is started, the control unit 48 compares the cooling water temperature THW and the cooling water temperature determination value A with the intake air temperature THA and the intake temperature determination value B to determine whether or not the engine is a high temperature startup, After the startup, when the increase correction is performed by the high temperature after-start increase correction coefficient FHS, the operation of the bypass control valve 32 is controlled to fully open the bypass passage 30, and the bypass air amount is increased.

Next, the operation will be described.

In the internal combustion engine 2, intake air supercharged by a supercharger 12 is metered and supplied by an intake throttle valve 10, fuel is supplied by a fuel injection valve 18, and an ignition plug (not shown) is used. Ignition and combustion. The fuel supply amount and the ignition timing are appropriately controlled by the control unit 48.

The idle speed control device controls the operation of the fuel injection valve 18 by the control unit 48 so that the air-fuel ratio becomes the target air-fuel ratio when the internal combustion engine 2 is in operation. The operation of the bypass control valve 32 is controlled so that the target rotation speed is achieved.

This idle rotation control device is used in the internal combustion engine 2
When the engine is started, the bypass control valve 32 is controlled as follows.

As shown in FIG. 1, when the ignition switch (not shown) is turned on to start the stopped internal combustion engine 2 (step 100), the control unit 48 detects the cooling water detected by the cooling water temperature sensor 44. It is determined whether or not the temperature THW is equal to or higher than the cooling water temperature determination value A (step 102).

When the cooling water temperature THW is equal to or higher than the cooling water temperature determination value A, it is determined whether the intake air temperature THA detected by the intake air temperature sensor 38 is equal to or higher than the intake temperature determination value B (step 104).

When the cooling water temperature THW is equal to or higher than the cooling water temperature determination value A and the intake air temperature THA is equal to or higher than the intake temperature determination value B, the internal combustion engine 2 produces evaporated fuel in the fuel injection valve 18. There is a risk of high temperature.

When the internal combustion engine 2 in such a high temperature state is started, the internal combustion engine 2 is started (step 106).
After the start is completed, the fuel injection valve 18 injects the fuel whose amount has been increased and corrected by the high-temperature post-startup amount increase correction coefficient FHS (step 108), and controls the operation of the bypass control valve 32 to fully open the bypass passage 30 (step 108). 110)
Then, it is determined whether the increase correction coefficient FHS after high temperature start is larger than 0 (zero) (step 112).

The high-temperature post-startup increase correction coefficient FHS is a value determined by the cooling water temperature THW, and is decreased by a fixed amount to 0 (zero) for each injection. If it is determined in step 112 whether or not the high temperature after-start-up increase correction coefficient FHS is larger than 0 (zero), if the high-temperature-start-up increase correction coefficient FHS is larger than 0 (zero),
The process returns to the full opening of the bypass passage 30 by the bypass control valve 32 (step 110).

After the high temperature start, the increase correction coefficient FHS is 0.
Judgment whether it is greater than (zero) (step 112)
At high temperature, the increase correction coefficient FHS after high temperature start is 0 (zero)
In this case, the control for fully opening the bypass passage 30 is ended, the bypass passage 30 is opened / closed, and the operation of the bypass control valve 32 is feedback-controlled by the duty ratio so that the engine speed becomes the target speed (step 120). ),
The amount of bypass air in the bypass passage 30 is adjusted.

On the other hand, in determining whether the cooling water temperature THW is equal to or higher than the cooling water temperature determination value A (step 102), the cooling water temperature THW is determined to be the cooling water temperature determination value A.
If the cooling water temperature THW is equal to or higher than the cooling water temperature determination value A, it is determined whether the intake air temperature THA is equal to or higher than the intake temperature determination value B (step 104).
When the intake air temperature THA is lower than the intake air temperature determination value B, the internal combustion engine 2 is not in a high temperature state and is sufficiently cooled.

When the internal combustion engine 2 in such a cooled state is started, the internal combustion engine 2 is started (step 114).
Then, after the start is completed, after the high temperature start, the increase correction coefficient FH
Without performing the increase correction by S (step 116), the fuel is injected from the fuel injection valve 18 after being corrected by the normal correction coefficient, and the operation of the bypass control valve 32 is controlled to temporarily fully open the bypass passage 30 ( Step 118).

The fully open time for temporarily opening the bypass passage 30 is determined by the cooling water temperature THW. When this fully open time has elapsed, the bypass passage 30 is opened and closed, and the operation of the bypass control valve 32 is feedback-controlled by the duty ratio so that the engine speed becomes the target rotation speed (step 120). Adjust the air volume.

As described above, in the idle speed control device, after the internal combustion engine 2 is started at high temperature by the control unit 48, the fuel injection valve 18 increases the amount by the increase correction coefficient FHS after high temperature start, as shown in FIG. When the corrected fuel is being injected, the operation of the bypass control valve 32 is controlled so as to fully open the bypass passage 30, as shown in FIG. 2 (c).

As a result, a sufficient amount of air can be secured by the bypass passage 30 that is fully opened after the internal combustion engine 2 is started at high temperature, and the engine speed during idle operation can be increased.

Therefore, after the internal combustion engine 2 is started at a high temperature, as shown in FIG. 2 (a), it is possible to reduce the decrease in rotation when the air-fuel ratio becomes lean due to the idle injection of the fuel by the evaporated fuel. Fluctuations can be reduced, and engine stalls can be prevented from occurring. In addition,
The full-open control of the bypass passage 30 ends when the post-high temperature increase correction coefficient FHS becomes 0 (zero) and is opened / closed by normal feedback control.

[0042]

As described above, according to the present invention, a sufficient amount of air can be secured by the bypass passage that is fully opened after the internal combustion engine is started at a high temperature, and the engine speed during idle operation can be increased. Therefore, after the internal combustion engine is started at a high temperature, the reduction in rotation when the air-fuel ratio becomes lean due to the idle injection of fuel with evaporated fuel can be reduced, which can reduce the rotation fluctuation and prevent engine stalls. can do.

[Brief description of drawings]

FIG. 1 is a flow chart of control by an idle rotation control device showing an embodiment of the present invention.

FIG. 2A is a diagram showing a change in engine speed after a high temperature start. (B) is a figure which shows the change of the increase correction coefficient after high temperature start after high temperature start. (C) is a figure which shows the change of the duty ratio after a high temperature start.

FIG. 3 is a schematic configuration diagram of an idle rotation control device for an internal combustion engine.

FIG. 4A is a diagram showing a change in engine speed after a conventional high temperature start. (B) is a figure which shows the change of the increase correction coefficient after high temperature start after the conventional high temperature start.
(C) is a figure which shows the change of the duty ratio after the conventional high temperature start.

[Explanation of symbols]

 2 internal combustion engine 4 intake passage 6 exhaust passage 10 intake throttle valve 12 supercharger 18 fuel injection valve 30 bypass passage 32 bypass control valve 38 intake air temperature sensor 44 cooling water temperature sensor 48 control unit

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[Procedure amendment]

[Submission date] September 20, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Fig. 2]

[Figure 3]

[Figure 1]

[Figure 4]

Claims (1)

[Claims] 1. A fuel injection valve is provided in an intake passage of an internal combustion engine, a bypass passage is provided that bypasses the intake throttle valve of the internal combustion engine and communicates with the intake passage, and a bypass control valve that opens and closes the bypass passage is provided. The operation of the fuel injection valve is controlled so that the air-fuel ratio becomes the target air-fuel ratio by injecting the fuel corrected by various correction coefficients according to the operating state of the internal combustion engine, and the bypass passage is opened during the idle operation of the internal combustion engine. In an idle rotation control device for an internal combustion engine, which controls the operation of the bypass control valve so that the engine speed is opened and closed to reach a target speed, an increase correction coefficient after high temperature start from the fuel injection valve after high temperature start of the internal combustion engine When the fuel whose amount has been increased and corrected is being injected by the control means, the control means for controlling the operation of the bypass control valve is provided so as to fully open the bypass passage. Idle rotation control device for internal combustion engine.