JPH0571456A - Idling speed control device for engine - Google Patents

Abstract

PURPOSE:To improve controllability in an idling speed control device for an engine by suppressing excessive control and securing a sufficient control rate according to an engine operation condition. CONSTITUTION:A final ignition timing is obtained by adding a spark-advance control rate TN which is set according to a rotation change during idling operation and spark-advance control rates TA/C, TP/S which are set according to application of load such as an air conditioner, a power steering to a reference ignition timing. An upper limit value TMAX of the spark-advance control rate is set according to an operation condition of an engine (S16, S17). The lower an engine water temperature THW is, or the smaller an engine speed Ne and a load Ce are, the higher the upper limit value is set (S15).

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.

[0002]

2. Description of the Related Art Conventionally, as described in, for example, Japanese Unexamined Patent Publication No. 1-121568, during engine idle operation, the engine speed is adjusted according to the operating condition by adjusting the ignition timing according to the operating condition of the load. There is known an idle rotation control device that controls to match a set target rotation speed. Idle rotation control based on such ignition timing normally corrects the ignition timing to the advance side when the engine speed is lower than the target value in the retard side region of the ignition timing where the torque becomes the maximum, and also the target value. When it is higher, it is corrected to the retard side.

[0003]

By the way, in the case of the idle rotation control by adjusting the ignition timing as described above, when the engine rotation, the load, etc. are small, the engine output itself lowers and engine stall easily occurs. It is necessary to secure a large control width of the advance angle control amount. However, if it is attempted to increase the control range of the advance angle control amount at low rotation and low load, etc., the basic ignition timing will be set to the retard side relative to normal, and at high rotation and high load, etc. Excessive control is performed, which causes deterioration of fuel efficiency.

The present invention has been made in view of the above problems, and it is possible to secure a sufficient control amount according to an engine operating state and improve controllability while suppressing excessive control. It is an object of the present invention to obtain an engine idle rotation control device capable of achieving the following.

[0005]

According to the present invention, as shown in FIG. 1, an idle speed control device for an engine detects a basic ignition timing setting means for setting a basic ignition timing of the engine and an operating state of the engine. The operating state detecting means, an idle time ignition timing correcting means for controlling the engine rotation by advancing the basic ignition timing by a predetermined amount during the idle operation by receiving the output of the operating state detecting means, and the output of the operating state detecting means. And an upper limit value setting unit for setting an upper limit value of the advance angle control amount according to the operating state so that the advance angle control amount of the ignition timing correction timing correction unit becomes equal to or less than a predetermined value. Achieved the task.

Here, the ignition timing correction means for idling can be constructed so that the ignition timing is advanced in accordance with the fluctuation of the engine rotation, and the ignition timing is adjusted in accordance with the load applied to the engine. It is also possible to configure the timing to be advanced.

Further, the upper limit value setting means can set the upper limit value of the advance angle control amount to be larger as the engine water temperature is lower, and the advance angle control amount can be set to be smaller as the engine speed and the load are smaller. The upper limit value can be set to be large.

[0008]

In the present invention, the ignition timing control at the time of idling adds to the basic ignition timing the advance control amount set in accordance with the fluctuation of the rotation (deviation from the target rotation speed) and the load application to the engine. It is executed in the form of In this case, the advance angle correction amount is set to an upper limit value according to the operating state of the engine, and thereby it is possible to secure a sufficient control amount according to the engine operating state while suppressing excessive control.

Here, if the upper limit value of the advance control amount is increased as the engine water temperature becomes lower, the basic ignition timing at high water temperature is advanced and fuel consumption is improved while compensating for the small increase in rotation at low water temperature. Is planned.

Further, if the upper limit value of the advance control amount is increased as the engine speed and load are smaller, the basic ignition timing in a relatively high rotational load condition is compensated for while compensating for the small increase in rotational speed at low rotational speed and low load. Fuel economy is improved with the angle of advance being set to.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments will be described below with reference to the drawings.

FIG. 2 is an overall system diagram of an embodiment of the present invention. In this embodiment, the combustion chamber 2 of the engine 1
A spark plug 3 is provided on the top of the
Is connected to an igniter 5 via a distributor 4. A fuel injection valve 7 that injects fuel toward an intake port 6 is provided in an intake system of the engine 1, and a throttle valve 9 is provided upstream of a surge tank 8. A bypass passage 11 that bypasses the throttle valve 9 is provided in the intake passage 10, and a duty control valve 12 that opens and closes the passage 11 is provided in the middle of the bypass passage 11. Further, the throttle valve 9 is provided with an idle switch 13 for detecting the fully closed state of the throttle valve 9, and the intake passage 10 upstream of the throttle valve 9 is provided with an air flow meter 14 for detecting the intake air amount. There is.

In the cylinder block 15 of the engine 1,
A water temperature sensor 16 that detects the temperature of the cooling water is provided, and an O ₂ sensor 17 that detects the oxygen concentration in the exhaust gas is provided in the exhaust system of the engine 1.

The igniter 5 and the fuel injection valve 7 are a control unit 18 composed of a microcomputer.
Controlled by. The control unit 18 includes a rotation sensor 19 built in the distributor 4.
From the engine flow rate signal, the intake air amount signal from the air flow meter 14, the idle switch signal from the idle switch 13, the engine water temperature signal from the water temperature sensor 16, the air-fuel ratio signal from the O ₂ sensor 17, and the like.
The control unit 18 calculates the ignition timing and the fuel injection amount based on these signals, and outputs the ignition signal and the injection signal to the igniter 5 and the fuel injection valve 7, respectively.

The ignition timing is controlled on the basis of the final ignition timing calculated by adding the basic ignition timing with a correction amount due to the application of an external load such as an air conditioner or power steering and a correction amount according to the rotational speed deviation. At that time, an upper limit value is set for the correction amount (advance angle control amount) to be added to the basic ignition timing, and the control is executed within a range not exceeding the upper limit value. Here, the upper limit value is set to a larger value as the engine speed Ne and the load Ce are smaller, and is set to a larger value as the engine coolant temperature _THW is lower.

Next, the control of the ignition timing in this embodiment will be described with reference to the flow charts shown in FIGS. In the figure, S1 to S18 indicate steps.

In this flow, when starting, the engine speed Ne, the load Ce and the engine water temperature _THW are read (S1), and then the basic ignition timing is read (S2).

Next, an idle switch (IDLSW)
Is on (S3), when it is on, then it is checked whether the engine speed Ne is smaller than a predetermined value N (S4), and when both of these conditions are satisfied, the idle operation is performed. Since it is in the state, it is next checked whether the air conditioner (A / C) is in the on state (S
5). On the other hand, if the determinations in S3 and S4 are NO, it means that the engine is not in the idle state, and this flow ends.

If the determination in S5 is YES, that is, if the A / C is on, then it is checked whether the previous A / C was on (S6). Then, the determination in S6 is N
O, that is, when the A / C is turned on for the first time this time, the advance control amount (correction amount) T _{A / C} due to the input of the _{A / C}
Is set (S7), while the determination in S5 is NO, that is, A
If / C is not on, set T _{A / C} to 0 (S
8). Also, the determination in S6 is YES, that is, A /
Even when C is in the ON state, T _{A / C} is also set to 0 because the correction based on the air amount is being executed.

Then, in each of the following steps S9 to S12, the above S is determined depending on whether the power steering (P / S) is on or not.
The same processing as that of each of steps 5 to S8 is performed to set the advance angle control amount T _{P / S} by turning on P / S.

When the advance angle control amount by turning on the external load is set in this way, the target rotation speed N ₀ is then read (S
13) The advance angle control amount (correction amount) T _N corresponding to the deviation Ne−N ₀ between the actual engine speed Ne and the target engine speed N ₀ is calculated from the map (S14). Here, the value of T _N is set to a larger value as the deviation Ne−N ₀ is larger on the negative side, and a smaller value as the deviation Ne−N ₀ is larger on the positive side.

Then, in the next step, the upper limit value T _MAX of the advance angle control amount is read (S15). This T _MAX is calculated as the sum of the engine speed Ne and T _MAX1 set by the map corresponding to the load Ce, and T _MAX2 set according to the engine coolant temperature T _HW. Where T _MAX1 is Ne
And Ce are set to a larger value, and T _MAX2 is set to a larger value as T _HW is lower.

Next, the sum T _{A / C} + T _{P / S} + T of each advance angle control amount
Check whether _N is larger than the upper limit value T _MAX (S16),
If larger, fix T _{A / C} + T _{P / S} + T _N to T _MAX (S1
7) Final correction amount, while T _{A / C} + T _{P / S} + T _N ≦
At the time of T _MAX , the value of the sum T _{A / C} + _{TP / S} + _TN is used as the final correction amount. Then, the final ignition timing is calculated by adding the correction amount to the basic ignition timing (S18).
To return.

[0024]

Since the present invention is configured as described above, it is possible to secure a sufficient control amount according to the engine operating state and improve controllability while suppressing excessive control.

Here, if the upper limit value of the advance angle control amount is increased as the engine water temperature is lower, the basic ignition timing at high water temperature is advanced and fuel consumption is improved while compensating for the small increase in rotation at low water temperature. Can be achieved.

Further, if the upper limit value of the advance angle control amount is increased as the engine speed and load are smaller, the basic ignition timing in a relatively high rotation load condition is compensated for while compensating for the small increase in rotation at low rotation and low load. The fuel consumption can be improved by making the advance angle side.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of the present invention.

FIG. 2 is an overall system diagram of an embodiment of the present invention.

FIG. 3 is a flowchart for executing control of the same embodiment.

FIG. 4 is a flowchart for executing the control of the same embodiment.

[Explanation of symbols]

 1 Engine 3 Spark Plug 5 Igniter 13 Idle Switch 16 Water Temperature Sensor 18 Control Unit 19 Rotation Sensor

Claims (5)

[Claims] 1. A basic ignition timing setting means for setting a basic ignition timing of an engine, an operating state detecting means for detecting an operating state of the engine, and an output of the operating state detecting means for setting the basic ignition timing during idle operation. Idle time ignition timing correction means for controlling the engine rotation by correcting the advance angle by a predetermined amount, and operation for receiving the output of the operating state detection means so that the advance angle control amount of the idle time ignition timing correction means becomes a predetermined value or less. An engine idle rotation control device comprising: an upper limit value setting means for setting an upper limit value of the advance angle control amount according to a state. 2. The engine idle rotation control device according to claim 1, wherein the ignition-timing ignition timing correction means corrects the ignition timing by advancing the ignition timing in accordance with fluctuations in the engine rotation. 3. The engine idle rotation control device according to claim 1, wherein the ignition timing correction means corrects the ignition timing in advance in response to the load applied to the engine. 4. The engine idle speed control device according to claim 1, wherein the upper limit value setting means sets a larger upper limit value of the advance control amount as the engine water temperature becomes lower. 5. The engine idle speed control device according to claim 1, wherein the upper limit value setting means sets the upper limit value of the advance angle control amount to be larger as the engine speed and load are smaller. ..