JPS6128732A - Method of controlling number of idle revolutions of engine - Google Patents

Abstract

PURPOSE:To perform excellent control of the number of idle revolutions through prevention of stop of an engine, by a method wherein a difference between the opening of an actuator during the starting and the opening of a reference actuator after the starting is set as a feedback amount to perform control of an amount of air right after the starting. CONSTITUTION:When a starting mode is shifted to a normal operation mode, a difference between the opening during the starting and the value of reference characteristics is set as a feedback amount (step S14). Thereafter, feedback processing is effected in a normal operation mode according to steps S7-S11, an actuator 10 for controlling the number of idle revolutions is driven and the number of revolutions of an engine is controlled to the given desired number of revolutions. This ensures an enough amount of air right after the starting to reliably prevent stop of an engine even during the starting on a highland, resulting in the possibility to perform excellent control of the number of idle revolutions.

Description

[Detailed description of the invention]

[Industrial Application Field 1] The present invention relates to a method for controlling the idle speed of an automobile engine, and in particular, the invention relates to an idle speed control actuator that controls the intake air amount to control the intake air amount at the time of starting and the idle speed after starting. This invention relates to a control method for performing control. [Prior Art] For idle rotation speed control, for example, Japanese Patent Application Laid-Open No. 55-5416
As shown in Japanese Patent Application Laid-open No. 55-1453, there is a feedback control method that controls the engine intake air flow rate according to the difference between the engine rotation speed and the target value of the idle link rotation. The idle speed control actuator used for this feedback control is also used to control the amount of intake air at the time of starting, and its control mode is based on whether the starter switch is on or the engine rotation, etc., and when starting, conditions such as water temperature etc. Set the actuator to a predetermined opening so that the air flow rate is set in advance. After starting, return the actuator to the preset opening depending on the engine water temperature, etc., and calculate the difference between the target rotation speed and the actual engine rotation speed from this opening. Feedback control is performed based on the difference, and the idle speed is controlled to a predetermined target speed. That is, the feedback amount immediately after starting is set to zero, and idle rotation speed control is started.

[Problems to be solved by the invention]

The amount of air required for an engine to maintain a predetermined idle speed is not necessarily the same even if the same engine is operated at the same water temperature, and the difference in the amount of air required is particularly large at low and high altitudes. Normally, the idle air amount set at low altitudes will barely stall the engine at high altitudes and will not maintain a stable state. Therefore, the insufficient amount of air is added to the feedback, but at high altitudes, a large amount of air m is required immediately after starting, but immediately after starting, the feedback control starts from zero, so feedback control is used to compensate. There was a delay in engine control, and engine stalling could occur when switching from starting mode to normal control mode, which also includes idle control. SUMMARY OF THE INVENTION The present invention aims to provide an idle speed control method that prevents such engine stalling immediately after starting and allows smooth engine starting even when the required amount of air is large, such as at high altitudes.

[Means to solve the problem]

The present invention prepares as control information at least an actuator opening at startup and a basic actuator opening after startup, which are set as parameters, and a feedback amount for closed-loop control of the idle rotation speed after startup to a predetermined value. , at the time of starting, the air amount is controlled by the actuator opening at starting, and after starting, the air amount is controlled using the sum of the basic actuator opening and the feedback amount as the actuator opening, and the actuator opening immediately after starting is the actuator opening at starting. The feedback amount is initially set to be equal to the opening degree (characterized by a control method).

[For production] To prevent engine stalling immediately after starting by setting the actuator opening immediately after starting to a feedback amount that makes the amount of air as large as the actuator opening at starting, and to improve starting performance by ensuring idling. 【Example】

FIG. 2 is a block diagram of a control method showing an embodiment of the present invention. In the figure, reference numeral 1 is a rotation sensor that captures engine rotation;
2 is a throttle opening sensor that detects the throttle opening;
3 is an air conditioner switch that detects whether the air conditioner is on or off, 4 is a neutral switch that determines the idle state of the engine, 5 is a water temperature sensor that measures the engine cooling water temperature, and 6 is a starter switch that detects the start of the engine starter. Signals from these switches and sensors are input to the control unit 7. The output of the control unit 1 is input to an idle speed control actuator 10 installed in a bypass passage 9 that bypasses the throttle valve 8 of the engine, and the opening degree of the idle speed control actuator 10 is controlled by the input. By changing the airflow m@ of the bypass passage 9, the idle speed of the engine is controlled to a predetermined value IIJ. The control unit 7 is put into the disaster state shown in FIG. An A/D transformer 111 that converts the analog signal of the water temperature sensor 5 into a digital quantity, pulse input from the rotation sensor 1, input from other switches 2゜3.4.6, and further input from the CPU 100. Drive circuit 11 by command
2, the idle speed control actuator 10
a control logic 110 that outputs signals to a ROM 101 in which instructions and various predetermined data for performing arithmetic processing using a store program method are written in advance;
c.
RAM 102 for temporarily saving data from the CPU 100;
．． , RQM 101. RAM 102. Control logic 110 is organically coupled by path lines 105 to form a computer system. FIG. 1 is a control flowchart of the control unit 7. Based on the turning on of the starter switch 6 and the count of the engine rotation sensor 1, it is determined whether the engine rotation speed is 300 rpm or less and whether it is the starting mode or the normal operation mode (step S"l and step 82). During the starting mode, the water temperature sensor 5 is measured. A predetermined control lI opening degree is read out from the ROM l01 using the value as a parameter (step S3), and the opening degree of the idle rotation speed control actuator 10 is controlled via the control logic 110 and drive circuit 112 (step S84). The optimum amount of air is supplied to the engine. During normal operation, it is determined whether or not it is the first time after the engine is started (step S5), and from the second time onwards, predetermined basic characteristic values are stored from the ROM 101 using the water temperature as a parameter. Further, it is determined whether the actual engine rotation speed is higher than the first target rotation (step S7), and if the actual engine rotation speed is higher than the first target rotation, the feedback amount is decreased by a predetermined amount (step S8). Step 89) to determine whether the rotation speed is higher or lower than the target rotation speed of step 2, and if it is low, increase the feedback amount by a predetermined amount (step 510), and add this feedback amount to the basic characteristic value to calculate the actuator opening degree. 511)
By using this calculated value as the control output in step $4, the engine rotation is controlled to a predetermined target rotation speed. Next, the first control in the normal operation mode will be explained. At the first time when switching from the starting mode to the normal operation mode (step 85), the opening degree data at the time of starting with the water temperature as a parameter is read out from the ROM 101 (step 512), and the basic characteristic values in the normal operation mode are read out. read from the ROM 101 (step 813),
The difference between the opening degree at the time of starting and the basic characteristic value is set as a feedback amount (step 514). Thereafter, feedback processing is performed in steps 87 to S'11 in the second and subsequent normal operation modes, and the idle speed control actuator 10 is driven to control the engine speed to a predetermined target speed. That is, the opening degree of the control actuator 10 is changed from the opening degree at the time of startup toward the opening degree at the target rotation speed by feedback control. Effect of the Invention 1 According to the present invention, the difference in the opening degree information is used as a feedback amount to control the air amount immediately after starting when shifting from the actuator opening at the time of starting to the basic actuator after starting. This has the effect of ensuring a sufficient amount of air, thereby reliably preventing engine stalling even when starting at high altitudes, and achieving good idle speed control.

[Brief explanation of the drawing]

Fig. 1 is a 7[1-chart showing the control method of the present invention, Fig. 2 is a block diagram of the control method of the present invention, and Fig. 3 is a 2-chart showing the control method of the present invention.
It is a block diagram of the control unit in a figure. DESCRIPTION OF SYMBOLS 1... Engine rotation sensor, 2... Throttle sensor, 3... Air conditioner switch, 4... Neutral switch, 5... Water temperature sensor, 6... Starter switch, 7... Control unit, 8... Throttle valve, 9... Bypass passage, 10... Idle rotation speed control actuator, 100... CPLI, 10
1...ROM, 102...RAM, 110...
Control logic, 111...A/D converter. Patent applicant: Fuji Heavy Industries Co., Ltd. Agent: Patent attorney: Makoto Kobashi Ukiyo Patent attorney: Susumu Murai Figures 2 and 3

Claims (1)

[Claims] In an engine in which the intake air amount at engine start and the idle speed after engine start are controlled by controlling the opening of the idle speed control actuator, the actuator opening at start and after engine start are set using at least the engine cooling water temperature as a parameter. The basic actuator opening and the feedback amount for closed-loop control of the idle rotation speed after startup to a predetermined value are prepared as control information, and at the time of startup, the intake air amount is controlled by the actuator opening at the time of startup, and after startup, The air amount is controlled by using the sum of the basic actuator opening and the feedback amount as the actuator opening, and the feedback amount is initially set so that the actuator opening immediately after starting is equal to the actuator opening at the time of starting. A method for controlling the idle speed of an engine.