JPH01301942A - Idle number of revolution controller - Google Patents

Abstract

PURPOSE:To prevent stop of an engine, in the case of dash pot control carried out through duty ratio control enabled by a throttle bypass by limiting the duty ratio to a preset value with acceleration off until a car speed is reduced to zero. CONSTITUTION:Dash pot control is carried out by reducing the control duty ratio of an ISC valve 4 at a preset reduction rate with a throttle valve 1 fully closed. Then, the reduction of the duty ratio is restricted to a preset value and this restriction is released when a vehicle speed reaches zero. Consequently, since required air supply is continued until the vehicle speed reaches zero, no engine stop is liable to take place.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an idle rotation speed control device.

[Conventional technology]

In this type of idle speed control device, an idle speed control valve (hereinafter referred to as ISC valve) is provided in a bypass path parallel to the throttle valve, and when the throttle is fully closed, the control duty ratio of the ISO valve is reduced at a predetermined speed. There are some that perform dashpot control by reducing the amount.

[Problem to be solved by the invention]

As a result, the dashpot action ends when the control duty ratio of the ISO valve becomes 0.
If the coasting time is long, the dashpot effect will be completed before the vehicle speed reaches zero, that is, while the vehicle is running, as shown in FIG. Therefore, if the previous idling situation differs from the current idling situation, until the feedback correction is made by idle speed control (that is, ΔT in Fig. 5), the engine speed will change over time. There are problems such as a decrease in the number of engines and engine stalling. Note that in the idle speed control device disclosed in Japanese Patent Application Laid-Open No. 58-174144, the ISC valve opening degree is corrected using a correction value using the cooling water temperature as a parameter, but this does not solve the above problem. . Therefore, in the present invention, when the driving mode changes to the idle mode, in order to prevent the engine speed from temporarily decreasing, the ISO valve is operated at least until the vehicle speed reaches 0.
An object of the present invention is to provide an idle rotation speed control device that maintains its control duty so as to maintain a constant opening amount.

[Means to solve the problem]

To solve this problem, in the present invention, an idle speed control valve is provided in a bypass path parallel to the throttle valve,
When the throttle is fully opened, the control duty ratio of the idle speed control valve is reduced at a predetermined reduction speed to perform dashpot control,
The vehicle is equipped with a valve closing operation limiting means for limiting the changing control duty ratio to a predetermined value when the accelerator is off, and a restriction canceling means for canceling the restriction of the valve closing operation limiting means when the vehicle speed becomes zero. ing.

[For production]

Therefore, the increment of control duty of the ISO valve when the accelerator is depressed is the same as before, but when the accelerator is off, only a predetermined amount of the above increment is reduced by the dashpot action, and the remaining amount is reduced by the vehicle speed. Since it is reduced when the vehicle speed reaches 0, the coasting time is long, and the required air supply is completed until the vehicle speed reaches 0, so that the engine speed is not reduced and there is no risk of engine stalling.

【Example】

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. In FIG. 1, reference numeral 1 indicates a throttle valve provided in an intake passage 2 of the engine, and a bypass passage 2.3 in parallel with the throttle valve 1 includes a throttle valve 1.
ISC valve 4 controls the air flow rate when supplying a small flow of air to the engine during idling operation when the valve is fully closed.
is provided. The ISC valve 4 is controlled to open and close by exciting the solenoid 4a with a duty ratio signal, and supplies air to the engine at a flow rate according to the duty ratio. Further, reference numeral 5 is an engine rotation speed sensor, 6 is a vehicle speed sensor, and 7 is a water temperature sensor that detects the temperature of engine cooling water.
8 is an accelerator switch, 9 is a throttle opening sensor, 1
0 is a neutral switch, and 11 is a starter switch. The output signals from the engine speed sensor 5 and the vehicle speed sensor 6 are subjected to noise removal and waveform shaping at a waveform shaping port F#113.14 in the control unit 12. In addition, the output signal of the water temperature sensor 7 is transmitted to the A/D converter 1.
5, it is converted into a digital signal. The control unit 12 receives signals from the sensors and switches at an input interface 12a, and supplies an output for idle rotation speed control to the solenoid 4a from an output interface 12b according to a required program. The means for controlling the idle rotation speed by the control unit 12 has a configuration as shown in FIG. Here, when the accelerator switch 8 is on, the output signal of the throttle opening sensor 9 is output from the duty ratio increase calculation means 16.
For example, calculations are made using an increasing function of the duty ratio corresponding to the throttle opening between 20% and 80% of the duty ratio, and the calculated value is provided to the calculation circuit 17. Further, when the accelerator switch 8 is off, the output signal of the throttle opening sensor 9 is given to the duty ratio reduction amount calculation means 18, and the control of the SC valve 4 is performed, for example, from 20% to 80% of the duty ratio. The dashpot control amount corresponding to the throttle opening is calculated using a decreasing function of the duty ratio, and is provided to the calculation circuit 17. On the other hand, the output signal of the duty ratio reduction amount calculating means 18 is given to the valve closing operation limiting means 19, and here, when the duty ratio becomes, for example, 50% for controlling the ISC valve 4, the duty ratio reduction amount calculation means 19 calculates the duty ratio reduction amount. A signal to stop calculation is given to the means 18. As a result, the dashpot control completes the throttle correction. Further, the output signal of the vehicle speed sensor 6 is given to the vehicle speed calculation means 20. The vehicle speed calculation means 20 calculates the vehicle speed, and the restriction release means 2
Give the result to 1. The restriction release means 21 gives a release signal to the valve closing operation restriction means 19 when the vehicle speed reaches O, and at that stage, the duty ratio reduction calculation means 18 again performs subtraction, and the result is given to the arithmetic circuit 17. . This completes dashpot control for the remainder. The calculation circuit 17 performs calculations by adding other engine operating conditions as shown in FIG. 1 to the calculation results of the duty ratio increase amount calculation means 16 or the duty ratio reduction amount calculation means 18, give an output signal of the calculated duty ratio to 22;
The solenoid driving means 22 controls the opening and closing of the IsC valve 4 by giving a control signal based on this output signal to the solenoid 4a. Such duty control is realized according to the program of the control unit 12 using the flowchart shown in FIG. Here, in step 3101, the accelerator switch 8
Determine the on/off status of. If accelerator switch 8
If the accelerator switch 8 is on, the duty ratio of the ISO valve 4 according to the throttle opening is calculated using an increasing function in step 5102, and the process moves to step 8106. However, if the accelerator switch 8 is off, the dash of the throttle opening is calculated in step 5103. The duty ratio of the ISC valve 4 corresponding to the pot control is calculated using a decreasing function. in this case,
The lower limit of the duty ratio value is limited to, for example, 50%. Next, in step 5104, it is determined whether the vehicle speed is 0 or not. If it is not 0, the process proceeds to step 3106, but if it is 0, the process proceeds to step 5105. The duty ratio (from 50% to 20%) of the SC valve 4 is calculated using a decreasing function. As a result, in step 8106, the solenoid 4a of the ISO valve 4 is energized using the calculated duty ratio. In such a configuration, as shown in FIG. 4, when the accelerator switch 8 is turned off, the dashpot control amount by the ISO valve 4 when the throttle valve is fully closed is reduced to, for example, 50% duty ratio. When the vehicle speed reaches O, the duty ratio is reduced to 20%, and even during deceleration with long coasting, the engine speed is maintained at the desired value, and even if there are load fluctuations, the engine stalls. It does not decrease enough to cause

【Effect of the invention】

The present invention has been described in detail above, and when the driving mode changes to the idle mode, the control duty is maintained to keep the ISO valve at a constant opening amount at least until the vehicle speed reaches 0, so that the engine speed increases. A temporary decrease in the number of engines can provide benefits such as preventing engine stalls.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram showing an embodiment of the present invention, Figure 2 is an IS
FIG. 3 is a flowchart of the control; FIG. 4 is a time chart showing a duty ratio control mode; and FIG. 5 is a flowchart showing a conventional duty ratio control mode. . 1... Throttle valve, 4... ISC valve, 4
a... Solenoid, 6... Vehicle speed sensor, 8... Accelerator switch, 9... Throttle opening sensor, 12
... Control unit, 16... Duty ratio increase amount calculating means, 17... Arithmetic circuit, 18... Duty ratio decreasing amount calculating means, 19... Valve closing operation limiting means. Patent Applicant: Fuji Heavy Industries Co., Ltd. Agent: Patent Attorney: Nobu Kobashi, Susumu Murai, Patent Attorney: Figure 3, Figure 4, Figure 5

Claims (1)

[Claims] An idle speed control valve is provided in a bypass path parallel to the throttle valve, and when the throttle is fully closed, the control duty ratio of the idle speed control valve is reduced at a predetermined reduction speed to perform dashpot control. Valve closing operation limiting means for limiting the changing control duty ratio to a predetermined value when the vehicle is off, and restriction canceling means for canceling the restriction of the valve closing operation limiting means when the vehicle speed reaches zero. An idle speed control device characterized by: