JPH0370102B2 - - Google Patents

Description

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

The present invention relates to an automatic idle speed governor that stabilizes the idle speed of a vehicle internal combustion engine in response to electrical load and changes over time during idling, and in particular, in a fuel injection system, the amount of intake air is controlled in a bypass passage for a throttle valve. This invention relates to the responsiveness of a feedback control system that adjusts the idle speed by controlling the amount of fuel supplied.

[Conventional technology]

In an internal combustion engine equipped with an electronic fuel injection device, the amount of fuel supplied is controlled based on the amount of intake air measured by an air flow meter in the intake system. Therefore, in order to control the idle speed during idling operation when the throttle valve is fully closed, a control valve in a bypass passage that bypasses the throttle valve is used to control the intake air amount and fuel supply amount when the throttle valve is fully closed. The engine speed changes to increase or decrease the idle speed. To explain this feedback control system in detail, we focused on the fact that the output voltage from the rotation sensor decreases when an electrical load such as a light is applied during idling operation, and the difference between the voltage corresponding to this output voltage and the reference voltage. Based on the difference, the base voltage of the transistor is sequentially increased through the integral element, and the control valve of the bypass passage is opened by controlling the current of the solenoid.

[Problem to be solved by the invention]

However, the rotational speed of the engine crankshaft is 1
Even during rotation, changes occur due to strokes such as compression and explosion, and especially during idling, this rotational fluctuation (hereinafter referred to as cycle fluctuation) is significant. Therefore, if the rotational speed of the engine, which fluctuates along with cycle fluctuations, is randomly captured by the rotation sensor and used for idle correction, unnecessary corrections may be made or hunting may occur. In order to solve this problem, a method of averaging the rotational speed has been proposed, but there are problems such as the circuit becomes complicated and the response speed becomes slow. In connection with the present invention, conventionally, for example, JP-A-55-
There is a prior art in Publication No. 160138, which is based on water temperature,
This method changes the idle standard target rotation speed depending on the transmission position, etc., and is completely different from the method of the present invention, which deals with load fluctuations during idling operation. Furthermore, in Japanese Patent Application Laid-Open No. 57-119135, a crank angle signal outputted from a crank angle sensor every time the crank angle rotates by a predetermined angle is input to a rotation speed signal generation circuit, and the intervals of the crank angle signals are measured by a counter or the like. Although it is shown that the engine speed signal is obtained by using the engine rotation speed signal and the idle speed is controlled using this signal, there is no disclosure of its specific configuration and no general technology is disclosed. It's just that. In view of the above circumstances, it is an object of the present invention to provide an automatic idle speed governor with less malfunction and less delay in response time by incorporating data with less fluctuation in engine rotational speed. .

[Means to solve the problem]

In order to achieve the above object, an automatic idle speed governor according to the present invention includes a rotation sensor that outputs a voltage proportional to the engine speed, a sample hold circuit into which the voltage from the rotation sensor is input via a switch, and a predetermined a crank angle sensor that outputs a crank angle detection signal for each rotation angle and turns on the switch; an integral circuit that adjusts the opening degree of a control valve provided in a bypass passage that bypasses the throttle valve;
a changeover switch that is provided between the sample hold circuit and the integration circuit and connects the sample hold circuit to the integration circuit in conjunction with an idle switch; The switch is turned on and off based on the crank angle detection signal so as to sample the output voltage of the rotation sensor at every predetermined rotation angle between the crank angle and the recess.

[Effect]

According to such means, since the idle rotation speed is corrected by taking in the rotation speed for each predetermined rotation angle with respect to the fluctuating engine rotation speed, the influence of cycle fluctuations is extremely small. In addition, since no averaging processing is performed by calculating cycle fluctuations, there is no delay in response time.

【Example】

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. Referring to FIG. 1, the overall outline of an internal combustion engine with an electronic fuel injection device to which the present invention is applied will be described. Reference numeral 1 indicates an engine body;
An air flow meter 3 provided downstream of an air cleaner 2, an intake pipe 4, a throttle body 5, and an intake manifold 6 are sequentially connected to the intake system of the engine body 1, and an injector 7 is installed for each cylinder of the engine body 1. An injection signal is input from the control unit 8 to the injector 7 based on the amount of intake air measured by the air flow meter 3, and the fuel injection amount is controlled. Further, in order to automatically control the idle speed, a bypass passage 10 is provided for the throttle valve 9 of the throttle body 5, and this passage 10
During this period, the control valve 11 changes the amount of intake air in an idling operating state with the throttle valve fully closed, and accordingly, the amount of fuel injected by the injector 7 also changes to control the idling speed. Next, referring to FIG. 2, the feedback control system of the control valve 11 will be explained. Reference numeral 12 is a rotation sensor that outputs a voltage proportional to the engine speed, and reference numeral 13 is a rotation sensor that is linked to an accelerator pedal or the like and detects when the throttle valve 9 is fully closed. It's an idle switch. Therefore, the output voltage of the rotation sensor 12 is
Capacitor 15 and operational amplifier 1 for charging via
In order to turn on and off the switch 14, a rotor 18 and an electromagnetic pick-up 19 are attached to the crankshaft and have protrusions at every predetermined angle of rotation.
A crank angle sensor 20 is connected to the switch 14 via a waveform shaping circuit 21. In addition, the output side of the sample hold circuit 17 is connected to the integration circuit 23 via a changeover switch 22 that is linked to the idle switch 13, and only when the changeover switch 22 is switched to the idle contact 22a during idling operation, the sample and hold circuit 17 is connected to the integration circuit 23. circuit 17
The sampled voltage is input to the integrating circuit 23 and integrated based on the voltage difference with the reference voltage measured by the potentiometer 24. And the integrating circuit 23
The output side of is the transistor 2 of the actuator 25.
6 to control the current of the solenoid 27 of the control valve 11, and when the solenoid current is opened, the bypass passage 10 is connected to the base side of the control valve 11.
The relationship is such that the air flow rate changes approximately relatively. The operation of the device configured in this way will be explained using FIG. 3. During idling operation, the output voltage of the rotation sensor 12 fluctuates as shown in FIG. If samples are periodically sampled at approximately intermediate predetermined rotation angles, the unevenness of cycle fluctuations becomes almost irrelevant. Therefore, the signal from the crank angle sensor 20 is converted into a pulse signal by the waveform shaping circuit 21 at every predetermined rotation angle S, and by turning on the switch 14, the output voltage of the rotation sensor 12 is changed to the sample and hold circuit. 17 and is sampled, and the output waveform is as shown in FIG. During idling, the sample hold circuit 17 is controlled by the changeover switch 22.
The output voltage is input to the integrating circuit 23, where an electrical load is applied and when the engine speed falls below a predetermined value, a voltage difference is generated between the output of the sample hold circuit 17 and the reference voltage, and the voltage is adjusted according to the voltage difference. The integrated value increases the opening degree of the control valve 11 via the actuator 25. Therefore, the intake air amount and the fuel injection amount of the injector 7 are increased by the bypass passage 10, and the idle speed becomes higher. On the other hand, when the idle speed becomes higher than a predetermined target value, the output voltage of the integrating circuit 23 decreases and the opening degree of the control valve 11 is reduced. The idle rotation speed is corrected based on the output voltage from the rotation sensor 12.

【Effect of the invention】

As is clear from the above description, according to the present invention,
Since the idle rotation speed is corrected by taking in the rotation speed at each predetermined rotation angle with respect to the fluctuating engine rotation speed, the influence of cycle fluctuations is extremely small. In addition, since no averaging processing is performed by calculating cycle fluctuations, there is no delay in response time.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing an example of an internal combustion engine to which the present invention is applied, Fig. 2 is a circuit diagram showing an embodiment of the device according to the present invention, and Fig. 3 is a diagram showing signal waveforms of various parts. . 1...Engine body, 2...Air cleaner, 3
...Air flow meter, 4...Intake pipe, 5...Throttle body, 6...Intake manifold, 7...
...Injector, 8...Control unit,
9...Throttle valve, 10...Bypass passage, 1
1... Control valve, 12... Rotation sensor, 13... Idle switch, 14... Switch, 15... Capacitor, 16... Operational amplifier, 17... Sample hold circuit, 18... Rotor, 19... Electromagnetic pick-up , 20... crank angle sensor, 21
... Waveform shaping circuit, 22 ... Selector switch, 23
... Integral circuit, 24 ... Potentiometer, 25
... Actuator, 26 ... Transistor, 2
7...Solenoid.

Claims (1)

[Claims] 1. A rotation sensor that outputs a voltage proportional to the engine rotation speed, a sample hold circuit into which the voltage from the rotation sensor is input via a switch, and a crank angle detection signal that outputs a crank angle detection signal at every predetermined rotation angle and controls the switch. a crank angle sensor that is turned on; an integral circuit that adjusts the opening degree of a control valve provided in a bypass passage that bypasses a throttle valve; and a crank angle sensor that is provided between the sample hold circuit and the integral circuit;
a changeover switch that connects the sample hold circuit to the integration circuit in conjunction with an idle switch; An automatic idle speed governor characterized in that the switch is turned on and off based on the crank angle detection signal so as to sample the output voltage of the sensor.