JPH07103117A - Idle speed control device for engine - Google Patents

Abstract

PURPOSE:To reduce variation in idle speed by setting a reference igniting time to a specified time at on of an idle switch after an engine has been started and compensating the present engine speed controllably based on the water temperature and time ellapsed after the starting of the engine. CONSTITUTION:In an engine 2, a fuel injection valve 42 is arranged in the intake manifold 32 of an intake passage 22. Also an air valve is arranged in the throttle body 28 of the intake passage 22. In this case, the detection signals from a sensor 70 to detect the speed of the engine 2, a sensor 58 to detect the pressure in the intake passage, a sensor 74 to detect the temperature of coolant, and a switch to be turned on at idle operation are inputted into a control means 78. Then, in the control means 78, a first idle compensation angle initial value is set to set a reference igniting time at on of an idle switch to a specified time, and the present engine speed is compensated controllably based on the coolant temperature and time ellapsed after the starting of the engine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine idle speed control device, and more particularly to an engine in which an injector for injecting fuel into an intake system is provided and an air valve including a thermowax and a valve body is provided in a throttle body. The present invention relates to an idle rotation control device.

[0002]

2. Description of the Related Art In some vehicles, in order to purify exhaust gas discharged from an internal combustion engine, a catalyst body is provided in the middle of an exhaust pipe of an exhaust system and an O ₂ sensor is provided. Some of such internal combustion engines have an air-fuel ratio control device such as an ignition timing control device, an idle rotation control device, a fuel injection control device, or the like.

As disclosed in Japanese Patent Laid-Open No. 62-17369, a method for controlling the ignition timing when the internal combustion engine is idle is based on an ignition advance value optimally determined according to the operation of the internal combustion engine. In the ignition timing control method of controlling the ignition timing of the air-fuel mixture, it is determined whether the engine is in a predetermined idle region, it is detected whether the engine temperature is a predetermined value or more, and the engine is placed in the predetermined idle region. Yes, and when the engine temperature is equal to or higher than a predetermined value, the actual engine speed is detected and the determined ignition advance value is retarded by a predetermined value. There is a method in which the difference between the number and the detected actual rotational speed is corrected by a value multiplied by a predetermined coefficient, and the ignition timing is controlled based on the corrected ignition advance value.

Further, the engine idle speed control device detects the engine speed during idle operation,
When the engine speed is lower than a predetermined target speed, the ignition timing of the engine is advanced by a predetermined amount according to the difference between the detected speed and the target speed to control the engine speed to reach the target speed. In an engine idle speed control device equipped with a mechanism for setting the engine speed to a higher value, the larger the difference between the engine speed and the target speed is, the larger the advance angle is set and the engine speed is set. In some cases, below the rotation speed, the advance amount is set smaller as the difference between the engine rotation speed and the target rotation speed increases.

[0005]

By the way, in the conventional engine, the engine speed is controlled by the air valve from the time when the engine is started to the time when the warm-up is completed. That is, the air valve is opened during cooling and closed after warming up, and the engine speed is controlled by adjusting the amount of passing air.

However, in the above-mentioned engine, if there is an error in the performance of the air valve, the engine speed varies, and the air valve alone can precisely control the engine speed. I could not do it.

For example, if the engine speed is low during warm-up, the warm-up performance of the engine deteriorates, which is disadvantageous in practical use, and the engine speed is higher than necessary during warm-up. In that case, there is a disadvantage that the fuel efficiency is deteriorated and it is economically disadvantageous.

[0008]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention provides an injector for injecting fuel into the intake system and an air valve comprising a thermowax and a valve body on the throttle body. In this engine, a rotation speed sensor for detecting the engine rotation speed is provided, a pressure sensor for detecting the intake pipe pressure is provided, a water temperature sensor for detecting the cooling water temperature is provided, and an idle switch that is turned on during idle operation is provided. By inputting various kinds of information in advance, the initial value of the fast idle correction angle is set in advance, and when the idle switch is turned on after the engine is started, the basic ignition timing is set as the preset basic idle ignition timing, and the water temperature at the start and the start Current engine speed based on the target engine speed map calculated from the elapsed time Characterized in that a control means for correcting control.

[0009]

According to the invention as described above, various information is input to the control means from the rotation speed sensor, the pressure sensor, and the water temperature sensor, and the initial value of the first idle correction angle is set in advance. When it is ON, the basic ignition timing is set to the preset basic ignition timing at idle, and the current engine speed is corrected and controlled by the target engine speed map calculated from the water temperature at the start and the elapsed time after the start. There is.

[0010]

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

1 and 2 show an embodiment of the present invention. In FIG. 2, 2 is an internal combustion engine, 4 is a cylinder block, 6 is a cylinder head, 8 is a cylinder head cover, 10 is a piston, 12 is a combustion chamber, 14 is an intake valve, 1
6 is an exhaust valve, 18 is an intake port, and 20 is an exhaust port.

An intake passage 22 is connected to the intake port 18 of the internal combustion engine 2. The intake passage 22 includes an air cleaner 24 and an intake throttle valve 26, which are arranged from the upstream side.
Throttle body 28 and surge tank 3
0, the intake manifold 32.

Further, the exhaust port 20 of the internal combustion engine 2 has
The exhaust passage 34 is connected. This exhaust passage 34 is
It is formed by the exhaust manifold 36 and the exhaust pipe 38. A catalytic converter 40 is arranged at the upstream portion of the exhaust pipe 38.

At a downstream portion of the intake manifold 32,
A fuel injection valve 42 is attached so as to be directed toward the combustion chamber 12.

A bypass air passage 44 is provided to bypass the intake throttle valve 26 in the throttle body 28. In the middle of this bypass air passage 44,
An ISC valve (VSV) 46, which is an electromagnetic valve that opens and closes the bypass air passage 44 to adjust the intake air amount, is interposed.

Further, in the throttle body 28,
As shown in FIG. 3, an air valve 48 is provided. The air valve 48 includes an air valve passage 50 that bypasses the intake throttle valve 26, and the air valve 4 depending on the cooling water temperature.
It has a thermo wax 52 for opening and closing 8, a valve body 54, and a spring 56.

The air valve 48 is a thermo wax 5.
It is opened and closed by 2 according to the cooling water temperature. That is,
When the temperature is low, the air valve 48 is opened to supply the air bypassing the intake throttle valve 26 to the engine 2 side, and when the temperature is high, the air valve 48 is closed to shut off the supply of the air bypassing the intake throttle valve 26 to the engine 2 side. To do.

The surge tank 40 has a pressure sensor 5
A pressure introducing passage 60 for detection that guides the pressure in the surge tank 30 is connected to 8.

Further, an intake air temperature sensor 62 for detecting the intake air temperature is attached upstream of the intake manifold 32.

Further, there is provided a throttle sensor 64 for detecting the opening state of the intake throttle valve 26 to judge the idle rotation state of the internal combustion engine 2.

Further, a distributor 68 is connected to the spark plug 66 arranged at a substantially central portion of the internal combustion engine 2. A rotational speed sensor 70 is attached to the distributor 68, and an ignition coil 72 is connected to the distributor 68.

Further, a water temperature sensor 74 for detecting the cooling water temperature is attached to the cylinder block 4 of the internal combustion engine 2.

Furthermore, an O ₂ sensor 76, which is an exhaust sensor, is provided at a location upstream of the catalytic converter 40 in the exhaust system.

Further, the fuel injection valve 42, the ISC valve (idle speed control valve, VSV) 46, the pressure sensor 58, the intake air temperature sensor 62, the throttle sensor 64,
The rotation speed sensor 70, the ignition coil 72, the water temperature sensor 74, and the O ₂ sensor 76 are connected to the control means 78. A vehicle speed sensor 80 is connected to the control means 78.

The control means 78 has a rotation speed sensor 70 for detecting the engine rotation speed, a pressure sensor 58 for detecting the intake pipe pressure, and a water temperature sensor 74 for detecting the cooling water temperature.
Also, various information from an idle switch (not shown) that is turned on during idle operation is input to set the initial value of the fast idle correction angle in advance, and basic ignition is performed when the idle switch (not shown) is turned on after the engine is started. The timing is set to a preset basic ignition timing at idle, and the current engine speed is corrected and controlled by a target engine speed map calculated from the water temperature at start and the elapsed time after start.

More specifically, the control means 78 sets the fast idle correction angle (so that the engine speed after the start becomes the target engine speed calculated from the coolant temperature at the start and the elapsed time after the start. θ _FID ) is used to correct the ignition timing and control the engine speed.

That is, the target engine rotational speed calculated from the target engine rotational speed map (see FIG. 5) consisting of the cooling water temperature at the time of starting and the elapsed time after startup is higher than the idle determination rotational speed (x) (rpm). When the idle switch (not shown) is ON, the control by the fast idle correction angle (θ _FID ) is performed, and at other times, the fast idle correction angle (θ _FID ) is set to 0.

First idle correction angle (θ _FID )
The control by means that when the target engine speed and the actual engine speed are equal, the first idle correction angle (θ
_FID ) does not change and the actual engine speed is higher than the target engine speed, the fast idle correction angle (θ _FID ) is retarded and the target engine speed is higher than the actual engine speed. _Indicates that the first idle correction angle (θ _FID ) has been advanced.

The basic ignition timing (θ _B ) is the basic ignition timing at idle (A, fixed value) when the idle switch (not shown) is ON, and the basic ignition timing map (A) at other times. The target ignition timing (θ _ADV ) is finally determined by the following equation, θ _ADV = θ _B + θ _FID , and the ignition timing control is performed.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG.

When the program starts (100),
First, various information such as engine speed, intake pipe pressure, and cooling water temperature are read (102), and then various data are initialized. At this time, the first idle correction angle (θ _FID ) is also set to the correction angle initial value (INT) (° C A) according to the cooling water temperature as shown in FIG. 6 (10
4).

When the engine 2 is started (10
6) The target engine speed (Ne) is calculated from the target engine speed map (see FIG. 5) consisting of the cooling water temperature at the start and the elapsed time after the start (108).

After that, it is judged (110) whether or not the idle switch is ON, and this judgment (110) is Y.
In the case of ES, the basic ignition timing (θ _B ) is set to the basic ignition timing at idle (A, a fixed value) (112), and whether the target engine speed exceeds the idle determination rotation speed (x) (rpm) When the determination (114) is YES, a determination (116) is made as to whether or not the target engine speed and the current engine speed are different.

If the judgment (116) is YES, it is judged (118) whether or not the target engine speed is less than the current engine speed, and this judgment (118) is Y.
In case of ES, first idle correction angle (θ _FID )
As shown in FIG. 7, is decreased by the fast idle correction angle change amount (α) (° C. A) according to ΔNe (12
0). The ΔNe is a set value of the difference between the target engine speed and the current engine speed.

Thereafter, the target ignition timing (θ _ADV ) is set to the following equation, θ _ADV = θ _B + θ _FID (122), and the ignition timing control is performed based on the target ignition timing (θ _ADV ). ), The next control information is read (126), and the process returns to (108).

If the determination (110) as to whether the idle switch is ON is NO, the basic ignition timing (θ _B ) is the basic ignition timing map (engine speed and intake pipe pressure). (See FIG. 8) (MAP) is read and set (128), the first idle correction angle (θ _FID ) is set to 0 (130), and the process proceeds to the process (122).

Further, if the determination (114) as to whether the target engine speed exceeds the idle determination speed (x) (rpm) is NO, the first idle correction angle (θ _FID ) is set to 0 ( 130) and the process (122) is performed.

Furthermore, it is judged whether the target engine speed and the current engine speed are different (116).
If is NO, the fast idle correction angle (θ _FID )
Is held (132), and the process moves to (122).

If the determination (118) as to whether the target engine speed is less than the current engine speed is NO, the first idle correction angle (θ _FID )
Is increased by the fast idle correction angle change amount (α) (° C A) according to ΔNe, as shown in FIG.
Moved to 2).

As a result, even if there is a performance error in the air valve, variations in idle speed can be reduced, precise engine speed control can be performed, which is advantageous in practice, and for example, in the same vehicle model. The manual transmission (MT) and the automatic transmission (AT) with different settings can be shared.

Further, it is possible to deal with the problem only by changing the program of the control means 78 without adding the parts of the control means 78 or replacing the parts, which is economically advantageous because the manufacturing cost can be kept low.

[0042]

As described in detail above, according to the present invention, in an engine in which an injector for injecting fuel into the intake system is provided and an air valve including a thermowax and a valve body is provided in a throttle body, A rotation speed sensor for detecting the number, a pressure sensor for detecting the intake pipe pressure, a water temperature sensor for detecting the cooling water temperature, and an idle switch that is turned on during idle operation are provided, and various kinds of information are input. The initial value of the fast idle correction angle is set in advance, and when the idle switch is turned on after the engine is started, the basic ignition timing is set to the preset basic ignition timing during idling, and is calculated from the water temperature at the start and the elapsed time after the start. Control means is provided to correct and control the current engine speed based on the target engine speed map. Since, it is possible to reduce the variation in the idle speed when there is error in the performance air valve to obtain and controls the precise engine speed, it is practically advantageous. Further, it is possible to deal with the problem only by changing the program of the control means without adding the parts of the control means or replacing the parts, and it is possible to keep the manufacturing cost low, which is economically advantageous.

[Brief description of drawings]

FIG. 1 is a flowchart of an engine idle rotation control device according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an engine idle rotation control device.

FIG. 3 is an enlarged sectional view of a throttle body.

FIG. 4 is a diagram showing a relationship between a cooling water temperature and an air flow rate passing through an air valve.

FIG. 5 is a map of target engine speed.

FIG. 6 is a diagram showing a first idle correction angle initial value.

FIG. 7 is a diagram showing a first idle correction angle change amount.

FIG. 8 is a map showing a basic ignition timing.

[Explanation of symbols]

2 Internal combustion engine 22 Intake passage 26 Intake throttle valve 34 Exhaust passage 40 Catalytic converter 42 Fuel injection valve 46 ISC valve 48 Air valve 50 Air valve passage 52 Thermowax 54 Valve body 56 Spring 58 Pressure sensor 60 Detection pressure introduction passage 62 Intake temperature sensor 64 Throttle sensor 66 Spark plug 68 Distributor 70 Rotation speed sensor 72 Ignition coil 74 Water temperature sensor 76 O ₂ sensor 78 Control means

[Procedure amendment]

[Submission date] November 17, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

[Figure 1]

[Fig. 2]

[Figure 3]

[Figure 4]

[Figure 5]

[Figure 6]

[Figure 7]

[Figure 8]

Claims (1)

[Claims] 1. An engine in which an injector for injecting fuel to an intake system is provided and an air valve including a thermowax and a valve body is provided in a throttle body is provided with a rotation speed sensor for detecting an engine rotation speed, and an intake pipe is provided. A pressure sensor for detecting the pressure is provided, a water temperature sensor for detecting the cooling water temperature is provided, an idle switch that is turned on during idle operation is provided, and various kinds of information are input to set a first idle correction angle initial value in advance. When the idle switch is turned on after the engine is started, the basic ignition timing is set to the preset basic idle ignition timing, and the current engine speed is calculated by the target engine speed map calculated from the water temperature at the start and the elapsed time after the start. Of an engine characterized by having a control means for correcting and controlling the engine Rotation control device.