JP2692422B2 - Idle speed control device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle speed control device for an internal combustion engine.

[0002]

2. Description of the Related Art The following is a conventional example of an idle speed control device for an internal combustion engine. That is, a solenoid driven idle control valve is provided in a bypass passage that bypasses the intake throttle valve.

Then, the idle control valve is driven and controlled by the duty ratio signal set based on the engine operating state, the amount of intake air flowing through the bypass passage is controlled, and the idling is performed based on the detected engine speed. Feedback control is performed so that the rotation speed becomes the target rotation speed. Here, as a method of detecting the idle rotation speed, a reference signal from a crank angle sensor (for example, in a 4-cylinder engine, a crank angle of 180 ° is used).
Output every time) and the number of inputs of the position signal from the crank angle sensor (output at every 1 ° of crank angle, for example) per predetermined time (for example, 10 msec). There is a method of obtaining the engine rotation speed.

[0004]

However, in the former case where the engine rotation speed is obtained from the input cycle of the reference signal, the timer for counting the reference signal cycle has a high disassembly capability, so that the engine rotation speed can be accurately detected. Since the output cycle of the reference signal is long, it is difficult to accurately determine the engine rotation speed when the engine rotation fluctuates, and the engine rotation speed cannot be controlled with good responsiveness. In the latter case where the engine speed is calculated from the number of input position signals, the position signal input cycle is short, but the engine speed cannot be accurately detected because the timer for counting the position signal has a low resolution. There is.

Therefore, these devices have a problem that the idle rotation speed cannot be controlled with high precision and responsiveness. The present invention has been made in view of such circumstances, and an object thereof is to provide an idle rotation speed control device capable of controlling the idle rotation speed with high accuracy and high responsiveness.

[0006]

For this reason, the present invention is based on FIG.
As shown in, an idle control valve C that controls the intake amount of a bypass passage B that bypasses the intake throttle valve A, a reference signal that is synchronized with the engine rotation and that is output at substantially constant crank angles, and that outputs a reference signal that is greater than the reference signal. Based on the crank angle sensor D that outputs a position signal for each short, substantially constant crank angle, and an integral amount that gradually changes the control amount based on the input cycle of the reference signal of the crank angle sensor D, the engine rotation speed is set to the target rotation speed. Based on the number of inputs of the position signal per predetermined time, a proportional amount for rapidly changing the control amount is set so as to bring the engine rotation speed closer to the target rotation speed. Proportional amount setting means F, control amount setting means G for setting a control amount based on the set integral amount and proportional amount,
Drive control means H for controlling the drive of the idle control valve C based on the set control amount.

[0007]

In this way, the control amount is gradually changed by setting the integral amount by the reference signal having a long input cycle to control the engine rotation speed to the target rotation speed with high accuracy, and the position signal having a short input cycle is set. By setting the proportional portion, the control amount is changed rapidly so that the engine speed can be controlled to the target speed with good responsiveness.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In FIG. 2, an intake throttle valve 2 is provided in the intake passage 1, and a bypass passage 3 for backing up the intake throttle valve 2 is formed. A solenoid driven idle control valve 4 is interposed in the bypass passage 3, and the idle control valve 4 is driven by a duty ratio signal from the control device 5 to control the amount of intake air flowing through the bypass passage 3.

The control unit 5 includes a crank angle sensor 6
From the air flow meter 7 and the reference signal (outputted every 180 ° in crank angle in a 4-cylinder engine) and position signal (outputted every 1 ° in crank angle) Sensor 8
The intake throttle valve opening detection signal from the water temperature sensor 9 and the cooling water temperature detection signal from the water temperature sensor 9 are input.

The control device 5 operates according to the flowchart of FIG. 3 to drive and control the idle control valve 4. Here, the control device 5 constitutes a control amount setting means, a proportional amount setting means, an integral amount setting means, and a drive control means. In addition, 10
Is a fuel injection valve, and 11 is an oxygen sensor for detecting the air-fuel ratio from the oxygen concentration in exhaust gas.

Next, the operation will be described with reference to the flowchart of FIG. At S1, various detection signals from the first crank angle sensor 6 and the like are read. In S2, the engine rotation speed NREF (r.pm) is calculated by the following equation based on the input cycle A (see FIG. 4) (msec) of the reference signal. NREF = (60 / A × 10 ⁻³ ) × (1/2) In S3, for Bmsec of the position signal (for example, 10
The engine rotation speed NPOS is calculated by the following equation based on the input number C in msec).

NPOS = (60 / B × 10 ⁻³ ) × (C / 360) In S4, it is determined whether or not the feedback control condition at the time of idling is satisfied. If YES, the process proceeds to S5, and if NO, S9. Proceed to. In S5, it is determined whether the engine rotation speed NREF calculated in S2 is less than or equal to the target rotation speed NSET. If YES, the process proceeds to S6, and if NO, the process proceeds to S7.

At S6, the integral I is decreased and set so that the engine speed is reduced to approach the target speed. This integral I is a feedback control that gradually changes the control amount ISCDY, and is a control that makes the engine rotation speed closer to the target rotation speed with high accuracy. In S7, the integral component I is increased and set so as to increase the engine rotation speed to approach the target rotation speed.

At S8, the engine speed NPOS and the target speed N determined on the basis of the position signal at S3.
Based on SET, the proportional P is calculated by the following equation. P = K × (NSET-NPOS) K is a constant This proportional component P is a feedback control component that rapidly changes the control amount ISCDY and is a control component that brings the engine rotation speed closer to the target rotation speed with good responsiveness.

In S9, the control amount ISCDY is calculated by the following equation based on the integral I obtained in S6 or S7 and the proportional P obtained in S8. In ISCDY = I + P S10, the duty ratio signal corresponding to the calculated control amount ISCDY is output to the idle control valve 4. Thus, the amount of intake air flowing through the bypass passage 3 is controlled, and the idle rotation speed is feedback-controlled so that the actual engine rotation speed is maintained at the target rotation speed.

At this time, the actual engine speed NREF, which is set based on the reference signal output every 180 ° in crank angle, and the target engine speed NSET are compared, and the actual engine speed is determined to be the target engine speed NSET. Since the integral component I for setting the engine rotation speed to approach the target rotation speed with high accuracy is set so that the engine rotation speed approaches, the following effects can be obtained.

That is, the period of the reference signal is shown in FIG.
Although it becomes longer than the cycle of the position signal as shown in, it can correspond to the resolution of the timer that counts the cycle of the reference signal, so the engine speed can be accurately detected during steady operation, so the idle speed The target rotation speed can be controlled with high accuracy. Further, the engine speed NPOS is detected based on the number of inputs of the position signal output every 1 ° at the crank angle per predetermined time,
Since the proportional portion P for making the engine rotation speed close to the target rotation speed with good response is set so that the engine rotation speed NPOS becomes the target rotation speed NSET, when the engine rotation speed fluctuates as follows: effective.

That is, for example, when the load of the power steering device increases and the engine speed decreases as shown in FIG. 5, the input cycle B1 of the position signal becomes much faster than the input cycle A1 of the reference signal. The engine rotation speed can be detected from the position signal by following the actual engine rotation speed with good responsiveness. Therefore, when the engine rotation speed fluctuates, the fluctuation can be followed with good response to bring the engine rotation speed close to the target rotation speed, and the convergence to the target rotation speed can be improved.

[0019]

As described above, according to the present invention, the integral portion is set based on the input cycle of the reference signal and the proportional portion is set based on the number of input position signals to drive and control the idle control valve. Therefore, even if the engine rotation speed fluctuates, the engine rotation speed can be controlled to the target rotation speed with good responsiveness and convergence, and at the same time, the engine rotation speed can be controlled to the target rotation speed with high accuracy.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims of the present invention.

FIG. 2 is a configuration diagram showing one embodiment of the present invention.

FIG. 3 is a flowchart of the above.

FIG. 4 is a diagram for explaining the operation of the above.

FIG. 5 is a view for explaining the operation of the above.

[Explanation of symbols]

 2 ... intake throttle valve 3 ... bypass passage 4 ... idle control valve 5 ... control device 6 ... crank angle sensor

Claims (1)

(57) [Claims] 1. An idle control valve for controlling the amount of intake air in a bypass passage that bypasses an intake throttle valve, and a reference signal that is output at substantially constant crank angle intervals in synchronization with engine rotation and that is substantially constant and shorter than the reference signal. A crank angle sensor that outputs a position signal for each crank angle,
Based on the input cycle of the reference signal of the crank angle sensor, an integral part setting means for setting an integral part for gradually changing the control amount so as to bring the engine rotation speed closer to the target rotation speed, and a predetermined time of the position signal. Based on the number of inputs of the control amount, a proportional amount setting means for setting a proportional amount for rapidly changing the control amount so that the engine rotation speed approaches the target rotation speed, and a controlled amount based on the set integral component and proportional amount. An internal combustion engine idle rotation speed control device comprising: a control amount setting unit that sets the control amount; and a drive control unit that drives and controls the idle control valve based on the set control amount.