JPS6328218B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to an idle speed control device for an internal combustion engine used in an automobile or the like. [Prior art] In automobiles, when the engine is idling, the engine speed is compared with the target idle speed, and the opening degree of the throttle valve is changed according to the deviation to control the engine speed to the target speed. Some vehicles are equipped with an idle speed control device designed to reduce fuel consumption. By the way, in conventional idle speed control devices, an inexpensive DC motor is used as an actuator to change the throttle valve opening, and this DC motor is used to adjust the polarity of the rotation speed deviation between the target rotation speed and the actual rotation speed. There are devices that control the rotational direction, and in order to further improve control accuracy, drive intermittently using intermittent feedback control pulses of a constant period, and furthermore, control the pulse width depending on the magnitude of the rotational speed deviation. This pulse period is set large so that the pulse pause time is relatively long, taking into consideration the meandering time of the DC motor and the delay time from when the throttle valve opening is changed until it is reflected as a change in engine speed. has been done. Therefore, if an engine load such as an air conditioner or power steering operates during a predetermined downtime and the engine speed is expected to fluctuate or become abnormally low, the system detects the operation of that load and generates a pulse. Even when performing estimated correction by width correction, it is necessary to wait for the next pulse, which has the disadvantage that the response to engine load fluctuations is delayed and, in some cases, the engine rotation stops. [Summary of the Invention] The present invention has been made to solve the above-mentioned drawbacks, and its purpose is to provide an idle speed control device for an internal combustion engine that is highly responsive to changes in engine load. . To this end, the present invention provides detection means for detecting the operating state of the engine load operated during idling and that the engine speed has become abnormally low, and performs normal feedback control according to the output of the detection means. The control pulse is configured to generate a control pulse for changing the throttle valve opening at a time independent from the pulse, and furthermore, after the first control pulse is generated due to the start of engine load operation, an abnormal decrease in engine speed is required. The generation of the second control pulse is prohibited for a certain period of time to avoid duplication of throttle valve opening control. [Embodiment of the Invention] FIG. 1 is a configuration diagram showing an embodiment of the present invention. In the figure, first, the configuration of the engine side will be explained. 1 is a piston, 2 is a cylinder, 3 is an intake valve,
4 is an exhaust valve, 5 is an exhaust pipe, 6 is a three-way catalytic converter, 7 is an intake pipe, and 8 is a throttle valve. A bench lily 9 and an air cleaner 10 are provided on the upstream side of the throttle valve 8. The fuel enters the main fuel passage 1 when the intake air taken in through the air cleaner 10 passes through the bench lily 9.
The air is drawn into the cylinder 2 through the throttle valve 8 and the intake pipe 7, where it is atomized and becomes a mixture with intake air. In this case, a main air bleed 13 is provided in the middle of the main fuel passage 12, and the float chamber 11
The fuel inside is atomized in advance by intake air from a main air bleed passage 14 provided upstream of the bench lily 9, and then atomized. On the other hand, an idle port 15 is provided on the downstream side of the throttle valve 8, and a slow air bleed passage 16 is provided on the upstream side of the bench lily 9, and the fuel in the main fuel passage 12 is drawn from the slow air bleed passage 16. Air is atomized in slow air bleed 17 and idle port 1
It is discharged from 5. As a result, the throttle valve 8
Fuel is secured during idling when the opening is almost fully closed. In this case, idle port 1
The amount of fuel discharged from the fuel pump 5 is adjusted by a slow adjust screw 18. Here, the throttle valve 8 is connected to an accelerator pedal (not shown), and its opening degree corresponds to the amount of depression of the accelerator pedal while driving, and when the throttle valve 8 is idling after releasing the accelerator pedal, it is necessary to maintain the idling state. Required opening degree (almost fully closed)
becomes. Further, the throttle valve 8 is provided with a lever 19 on its rotating shaft, and by driving this lever 19 with an actuator 20, which will be described later, the opening degree during idling can be varied. Next, to explain the configuration of the idle rotation speed control system, 20 is a DC motor 21 and a gear mechanism 22.
It is an actuator that converts the rotational movement of the DC motor 21 into linear movement of the plunger 23 in the gear mechanism 22, and uses this linear movement to drive the lever 19 to vary the opening degree of the throttle valve 8. 21 is supplied with a forward rotation control pulse U and a reverse rotation control pulse D having a predetermined pulse width from the control circuit 30. In this case, the actuator 20 is provided with an idle state detection switch 24 that is turned on (closed) when the tip of the plunger 23 is in contact with the lever 19, that is, when the accelerator pedal is released and the vehicle is idle. Next, 25 is a rotation speed detector that detects the engine rotation speed, and here, an ignition coil 26 and an interrupter 27
A rotation pulse signal with a period corresponding to the engine rotation speed N is extracted from the connection point with the engine rotation speed N. 28 is an air conditioner operation start switch (hereinafter abbreviated as A/C SW), which is one of the engine loads, and 29 is a switch that indicates that the transmission (not shown) is in the neutral position or

〔Effect of the invention〕

As explained above, the present invention provides detection means for detecting the operating state of the engine load operated during idling and that the engine speed has become abnormally low. It is configured to generate a control pulse for changing the throttle valve opening at a time independent of the feedback control pulse, and furthermore, after the first control pulse is generated due to the start of operation of the engine load, an abnormal decrease in the engine speed is prevented. The second control pulse serving as the condition is configured to prohibit its generation for a certain period of time. Therefore, it is possible to immediately respond to fluctuations in engine load or changes to abnormally low engine speeds and converge the engine speed to the target speed, thereby preventing sudden changes in engine speed or stopping due to load fluctuations during idling. It can be prevented. Further, it is possible to prevent adverse effects such as an excessive increase in engine speed due to the duplication of two types of prospective control, and it is possible to accurately and quickly converge to the target engine speed.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing one embodiment of the present invention, and FIG.
The figure is a block diagram showing the detailed configuration of the control circuit.
4 and 4 are flowcharts showing the operation details of the control circuit, FIG. 5 is a graph showing an example of the actuator drive time with respect to the deviation from the target rotation speed, and FIG. Fig. 7 is a flowchart showing the details of the operation when the engine speed decreases at abnormally low speeds, and Figs. This is a time chart showing the situation. 1... Piston, 2... Cylinder, 3... Intake valve, 6... Three-way catalytic converter, 7... Intake pipe,
8... Throttle valve, 9... Bench lily, 10...
...Air cleaner, 11...Float chamber, 19...
Lever, 20... Actuator, 21... DC motor, 22... Gear mechanism, 23... Plunger, 24... Idle switch, 25... Rotation speed detector, 28... A/C/SW, 29... Gear shift switch, 30... Control circuit, 300... Arithmetic processing unit, 301... Read only memory, 302...
...Random access memory, 303...Interface circuit.

Claims (1)

[Claims] 1. A valve device that variably controls the intake air amount of the engine;
an actuator including an electric motor that variably controls the opening degree of the valve device, a rotation speed detection means for detecting the rotation speed of the engine, and a load state detection means for detecting the operating state of the engine load operated when the engine is idling;
Abnormal rotation detection means for detecting an abnormal decrease in engine rotation speed, and intermittent feedback control pulses and engine load for converging the engine rotation speed to the target idle rotation speed when the engine is idling in response to the detection outputs of the above-mentioned detection means. control means for generating first and second control pulses for respectively increasing the amount of intake air by a predetermined amount at the start of operation and when the engine speed is abnormally reduced, and driving the electric motor with each of these control pulses; An idle rotation speed control device for an internal combustion engine, comprising prohibition means for prohibiting generation of the second control pulse within a predetermined time after generation of the first control pulse.