JPH06249117A - Idle speed control device for engine - Google Patents

Abstract

PURPOSE:To stabilize an engine speed at idling operation and improve fuel consumption performance by detecting an electric load condition through fluctuation of a battery voltage, controlling an air supply amount to an engine while adjusting an ignition timing, and thereby controlling an engine speed. CONSTITUTION:A rotational speed of an engine 2 and voltage of a battery 6 are read by a control device 54. The read battery voltage is compared to the previously read voltage. When the present voltage is not smaller than difference between the previous voltage and a fixed value, advance of an ignition timing corresponding to the voltage is determined based on an ignition timing table. Relation is obtained in respect to the engine speed and a lower limit value of a target engine speed in an idling operation, hereinafter referred simply to the target engine speed. When the engine speed is smaller than the lower limit value, a duty ratio of an idle adjusting valve 30 is increased. In the opposite case, and the engine speed is smaller the upper limit value of the target engine speed, the duty ratio is decreased. Accordingly, the ignition timing is advanced according to the battery voltage for detecting the electric load condition. A supply amount of air to the engine is kept constant without increasing. The engine speed is thus stabilized, and fuel consumption performance is improved.

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, which does not require an electric load signal, has a simple structure, stabilizes the engine speed during idle operation, and reduces fuel consumption. The present invention relates to an engine idle rotation control device that can be improved.

[0002]

2. Description of the Related Art Some vehicle engines are equipped with an electronically controlled fuel injection system as a countermeasure to the problems of harmful exhaust gas components and fuel consumption rate.

This fuel injection system is provided with a bypass passage bypassing an intake throttle valve provided in the middle of the intake passage, and an ISC valve (idle speed control valve) (VSV) which is an idle adjusting valve for opening and closing the bypass passage. During the idle operation of the engine, the fuel injection amount is determined by the map of the intake pipe pressure and the engine speed, and the ISC valve is operated by the duty ratio based on the fuel injection amount to control the air amount to the engine. Alternatively, there is one provided with a control means for adjusting the ignition timing in order to stabilize the engine speed during idle operation.

In this fuel injection system, when the air conditioner is operated, the ISC valve is operated to correct the air amount by the amount corresponding to the electric load due to the operation of the air conditioner. That is, when there is an electric load, the ISC valve is operated as it is according to the electric load to control the air amount, or the electric load signal from the electric circuit is taken out, and the ISC valve or the like is extracted by the electric load signal. Is controlled to stabilize the engine speed during idle operation.

In this way, when controlling the air amount by controlling the operation of the ISC valve, as shown in FIG. 7, when the program of the control means is started (step 202), first, the engine speed (NE) is read. (Step 20
4) Then, the relationship between the engine speed (NE) and the lower limit value B of the target engine speed during idle operation is NE>
It is judged whether or not it is B (step 206).

If NO in step 206, as shown in FIG. 8, the duty ratio to the ISC valve is increased (u
p) (step 208), and the step 204
Return to.

On the other hand, if YES in step 206, it is determined whether or not the relationship between the engine speed (NE) and the upper limit value A of the target engine speed during idle operation is NE <A (step S20). 210).

If NO in step 210, the duty ratio to the ISC valve is lowered as shown in FIG.
own) (step 212), and step 2
Return to 04.

On the other hand, if YES at step 210, the program is returned (step 21).
4).

As a result, as shown in FIG. 8, when the radiator fan operates as an electric load during idle operation, the duty ratio to the ISC valve is changed to control the operation of the ISC valve to control the engine speed. is doing.

Further, such a fuel injection system is disclosed in, for example, JP-A-59-201972 and JP-A-57-68544. JP 59
In the one disclosed in Japanese Patent Publication No. 201972, the torque generated in the expansion stroke of each cylinder is detected, and the detected engine speed and average engine speed for each cylinder are set so as to be constant between the cylinders. In comparison, if the former is higher than the latter, the ignition timing is retarded, or if the former is lower than the latter, the ignition timing is advanced, and the engine speed fluctuates even if there is some variation in the operating conditions between the cylinders. To stabilize the idle operation and to control the vibration and noise of the engine. Further, the one disclosed in Japanese Patent Laid-Open No. 57-68544 discloses a change amount or a change rate of operating parameters such as an engine speed and an intake pipe pressure of an engine with an electronic fuel injection device, a predetermined engine crank angle or a predetermined engine crank angle. By correcting the controlled objects such as the ignition timing and the fuel injection amount according to the change amount of each operating parameter or the change rate of the change rate, the engine speed during idle and low speed running is stabilized, and When the rotation speed fluctuates, the fluctuation is promptly converged according to the state of the engine at that time to prevent unpleasant vibration from being given to the driver.

[0012]

However, conventionally, in a fuel injection system that does not take in an electric load signal when an electric load is applied during idle operation, the air amount is corrected by controlling the operation of the ISC valve. As shown in 8,
A delay occurs in the duty ratio to the ISC valve (D ₁ in FIG. 8,
Indicated by D _2), Thus, there is a disadvantage that the rotation drop in the engine rotational speed (indicated by S _1, S ₂ in FIG. 8) is generated. Further, in the fuel injection system that takes in the electric load signal, another circuit is added to the electric circuit, which has a disadvantage that the configuration is complicated and the cost is high.

If there is an electric load signal, the IS
Since the air amount is controlled only by controlling the operation of the C valve, when the air amount increases, the air-fuel ratio feedback control is performed. Therefore, as the air amount increases, the fuel injection amount also unnecessarily increases. There was an inconvenience that the fuel efficiency deteriorated.

[0014]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention firstly provides a bypass passage bypassing an intake throttle valve provided in the middle of the intake passage, and opens and closes the bypass passage. In the idle rotation control device of the engine which controls the air amount to the engine by opening and closing the idle adjustment valve during idle operation of the engine to detect an electric load state by a change in battery voltage, It is characterized in that control means for controlling the engine speed by adjusting the ignition timing while suppressing an increase in the amount of air to the engine is provided. Also, the second
A bypass passage that bypasses the intake throttle valve provided in the middle of the intake passage, and an idle adjustment valve that opens and closes the bypass passage.When the engine is idle, the idle adjustment valve is opened and closed to move air to the engine. In an engine idle speed control device for controlling the amount, an electric load state is detected by a change in battery voltage, an ignition timing is advanced and an idle adjustment valve is operated while suppressing an increase in the amount of air to the engine. It is characterized in that a control means for controlling the engine speed is provided.

[0015]

According to the structure of the present invention, the control means detects the electric load state by the change of the battery voltage, adjusts the ignition timing while suppressing the increase of the air amount to the engine, and controls the engine speed. . This makes it possible to maintain an appropriate amount of air to the engine, maintain an appropriate engine speed during idle operation, stabilize the engine speed during idle operation, and improve fuel efficiency. . Further, it is possible to simplify the configuration of the electric circuit by eliminating the electric load signal as in the conventional case.

Further, the idle speed can be controlled more finely by adjusting the amount of air to the engine constant by advancing the ignition timing and controlling the operation of the idle adjusting valve, and the idle operating condition can be improved. Can be secured.

[0017]

Embodiments of the present invention will be described in detail and specifically with reference to the drawings. 1 to 6 show an embodiment of the present invention. In FIG. 6, 2 is an engine, 4 is an air cleaner, and 6 is an air cleaner 4 from the engine 2
First intake passage 6-1 and second intake passage 6-2 that guide intake air to the
Is an intake passage, 8 is a throttle body, 10 is an intake throttle valve, 12 is a surge tank, and 14 is an exhaust passage.

A fuel injection valve 16 for injecting fuel into the engine 2 is provided in the second intake passage 6-2 on the engine 2 side. The fuel injection valve 16 is connected to the other end of a fuel supply passage 22 whose one end is connected to the fuel pump 20 in the fuel tank 18.

The fuel pressure of the fuel injection valve 16 is adjusted by the fuel pressure adjusting valve 24. This fuel pressure control valve 24
Is connected to one end side of the fuel return passage 26. The other end of the fuel return passage 26 is open to the inside of the fuel tank 18.

One end side of the first bypass passage 28 communicates with the inside of the surge tank 12. The other end of the first bypass passage 28 communicates with the first intake passage 6-1 on the upstream side of the intake throttle valve 10. An ISC valve (idle speed control valve) (VSV) 30, which is an idle adjusting valve, is provided in the middle of the first bypass passage 28.

Further, one end side of the second bypass passage 32 is communicated with the surge tank 12. The other end side of the second bypass passage 32 communicates with the first intake passage 6-1 on the upstream side of the intake throttle valve 10. An air conditioner idle up valve (VS
V) 34 is interposed.

A distributor 38 of an ignition device 36 is attached to the engine 2. An ignition coil 40 is connected to the distributor 38.

An intake air temperature sensor 42 for detecting the intake air temperature of the first intake passage 6-1 is provided in the first intake passage 6-1.

The throttle body 8 is provided with an idle switch 44 for detecting the open / closed state of the intake throttle valve 10 to detect the idle state.

In order to detect the intake pipe pressure in the intake passage 6, the pressure introducing passage 4 whose one end communicates with the surge tank 12
A pressure sensor 48 is provided on the other end side of 6.

A rotation angle sensor 50 for detecting a rotation angle is attached to the distributor 38.

The engine 2 is provided with a water temperature sensor 52 for detecting the temperature of cooling water in a cooling water passage (not shown).

The fuel injection valve 16, the fuel pump 20 and I
The SC valve 30, the air conditioner idle up valve 34, the ignition coil 40, the intake air temperature sensor 42, the idle switch 44, the pressure sensor 48, the rotation angle sensor 50, and the water temperature sensor 52 are connected to the control means 54. The fuel pump 2
A pump relay 56 is provided between 0 and the control means 54.

The control means 54 includes a speedometer 5
8 and the battery 60 are in communication with each other.

As a result, the control means 54 inputs various signals and detects the electric load state by the voltage change of the battery 60, that is, when the radiator fan or the like is operated, the electric load state is changed by the voltage change of the battery 60. Is detected to control the engine speed by adjusting the ignition timing by operating the ignition device 36 while suppressing an increase in the amount of air to the engine 2, or alternatively, the electrical load state is detected by the voltage change of the battery 58. Then, the ignition timing is advanced in the ignition device 36 while the increase in the air amount to the engine 2 is suppressed, and the ISC valve 30 is opened / closed to control the engine speed.

For this reason, the control means 54 has an electric load detection circuit 54a as shown in FIG. 1 and, as shown in FIG. 2, a one-dimensional ignition timing table for the voltage (VB) of the battery 60, that is, It has a relationship diagram between the voltage (VB) and the advance angle of the ignition timing. The ignition timing table of FIG. 2 determines the advance angle of the ignition timing (Ig.T) according to the voltage (VB) of the battery 60.

The control means 54, as shown in FIG.
When the ignition timing (Ig.T) is advanced under the same air amount during idle operation, the engine speed (N
E) has a map in which the ignition timing (Ig.
T) is advanced to maintain an appropriate engine speed (NE) during idle operation with the same air amount.

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

When the program of the control means 54 is started (step 102), first, the engine speed (NE)
Is read (step 104), and the voltage (VB) of the battery 60 is read (step 106).

Then, the voltage (VB) of the battery 60 and 1
The relationship with the previous voltage (VB.0) is VB <VB. 0-
It is determined whether or not it is C (step 108). Where C
Is a fixed value.

If YES at step 108,
The relationship between the duty ratio (DISC) of the ISC valve 30 and the duty ratio one time before (DISC.0) is DISC = D.
ISC. 0 + X is calculated (step 110), and the process returns to step 104. Here, X is a fixed value.

On the other hand, if NO in step 108, the advance angle of the ignition timing (Ig.T) corresponding to the voltage (VB) is determined from the ignition timing table of FIG. 2 (step 11
2) Then, the relationship between the engine speed (NE) and the lower limit value (B) of the target engine speed during idle operation is N
It is determined whether E> B (step 114).

If NO at step 114, I
The duty ratio to the SC valve 30 is increased (up) (step 116), and the process returns to step 104.

If YES at step 114,
It is determined whether the relationship between the engine speed (NE) and the upper limit value (A) of the target engine speed during idle operation is NE <A (step 118).

If NO at step 118, I
The duty ratio to the SC valve 30 is lowered (down) (step 120), and the process returns to step 104.

On the other hand, if YES at step 118, the program is returned (step 12).
2).

That is, when the voltage (VB) of the battery 60 is read as an electric load and the amount of change in the voltage (VB) is large, the duty ratio to the ISC valve 30 should be increased by a fixed value (C). At the same time, the advance of the ignition timing (Ig.T) due to the voltage (VB) is interpolated from the ignition timing table of FIG. 2, and the ignition timing is set to the voltage (VB) in the ignition device 36.
Advance according to.

More specifically, as shown in FIG. 4, when a radiator fan is operated as an electric load (indicated by K ₁ in FIG. 4), the voltage (VB) is once greatly reduced and then largely restored (FIG. 4). Indicated by E). Along with this, the ignition timing (Ig.T) advances (indicated by F in FIG. 4). And
Since the amount of change in the voltage (VB) is large, the duty ratio to the ISC valve 30 is temporarily increased by a fixed value (C) (see FIG. 4).
(Indicated by G in FIG. 2), and thereafter, feedback is performed to stabilize the engine speed (NE).

Further, as shown in FIG. 5, when the electric load is considerably large, the movement of each signal is similar to that in FIG. 4 described above, and after the electric load is turned off (shown by K ₂ in FIG. 5). ), The voltage (VB) of the battery 60 returns slowly (indicated by M in FIG. 5), but the ignition timing (Ig.
T) also changes (indicated by N in FIG. 5), which causes ISC
Since the duty ratio to the valve 30 does not change so much, the engine speed (NE) is stabilized.

As a result, the electric load state is detected by the change in the voltage (VB) of the battery 60, and this voltage (VB) is detected.
Since the ignition timing (Ig.T) is advanced in accordance with the above, the amount of air to the engine 2 can be made constant without increasing, the engine speed can be stabilized, fuel consumption can be improved, and the electric power can be improved as in the conventional case. The load signal is unnecessary, and the configuration of the electric circuit can be simplified.

The ignition timing advance adjustment and the ISC valve 30
Since the engine speed is controlled by the operation control of
The engine speed during idling can be controlled more finely to ensure a proper idling state.

[0047]

As is apparent from the above detailed description, according to the present invention, firstly, the electric load state is detected by the change of the battery voltage, and the ignition timing is controlled while suppressing the increase of the air amount to the engine. By providing a control unit that adjusts and controls the engine speed, the engine speed during idle operation is maintained appropriately while the air volume to the engine is kept constant, and the idle operation state is satisfactorily secured and fuel consumption is improved. It is possible to reduce the cost of the electric circuit by simplifying the structure of the electric circuit.

Further, a control means for detecting the electric load state by the change of the battery voltage, advancing the ignition timing while suppressing the increase of the air amount to the engine, and operating the idle adjusting valve to control the engine speed. By providing the above, it is possible to more finely control the engine speed during idle operation, and it is possible to favorably secure the idle operation state.

[Brief description of drawings]

FIG. 1 is a flowchart of idle rotation control based on a battery voltage.

FIG. 2 is a relationship diagram between a battery voltage and an ignition timing advance angle.

FIG. 3 is a diagram showing a relationship between an advance angle of ignition timing and an engine speed.

FIG. 4 is a time chart when the radiator fan operates and stops.

FIG. 5 is a time chart when the electric load is large.

FIG. 6 is a system configuration diagram of an idle rotation control device.

FIG. 7 is a flowchart of a conventional idle rotation control.

FIG. 8 is a time chart of conventional idle rotation control.

[Explanation of symbols]

 2 engine 16 fuel injection valve 30 ISC valve 36 ignition device 44 idle switch 54 control means

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[Procedure amendment]

[Submission date] April 20, 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 (3)

[Claims] 1. A bypass passage bypassing an intake throttle valve provided in the middle of the intake passage, an idle adjusting valve for opening and closing the bypass passage, and an opening / closing operation of the idle adjusting valve during idle operation of the engine. In an engine idle rotation control device for controlling the amount of air to the engine, an electric load state is detected by a change in battery voltage, and an ignition timing is adjusted while suppressing an increase in the amount of air to the engine to control the engine speed. An idle rotation control device for an engine, which is provided with a control means for controlling. 2. The idle rotation of the engine according to claim 1, wherein the control means is a control means having an ignition timing table that determines an advance angle of the ignition timing corresponding to a change in the battery voltage. Control device. 3. A bypass passage bypassing an intake throttle valve provided in the middle of the intake passage, an idle adjusting valve opening / closing the bypass passage, and opening / closing the idle adjusting valve during idle operation of the engine. In an engine idle rotation control device for controlling the amount of air supplied to the engine, an electric load state is detected by a change in battery voltage, the ignition timing is advanced while the increase in the amount of air supplied to the engine is suppressed, and the idle adjustment valve is also provided. An idle speed control device for an engine, characterized in that a control means for operating the engine to control the engine speed is provided.