JPH0534495B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling deceleration of an internal combustion engine having an idle speed control device.

[Conventional technology]

Generally, in order to bring the engine rotation speed during idling operation of an internal combustion engine to the target rotation speed, a bypass intake passage is provided that bypasses the throttle valve provided in the intake passage of the engine, and the actual engine rotation speed during idling operation is adjusted. Feedback control is performed in which the flow rate of intake air in the bypass intake passage is adjusted by feeding back the detected information. In addition, outside the feedback control area, the cross-sectional area of the bypass intake passage is set to the learned value calculated and stored during feedback control, so that even if the engine suddenly changes from running to idling, This reduces the occurrence of unpleasant shots.

[Problem to be solved by the invention]

Even in an engine that performs the above-mentioned idle speed feedback control, if the engine is decelerated by fully closing the throttle valve other than during feedback control, in order to prevent the engine from stalling due to the decrease in rotational speed immediately after the throttle is fully closed, It is conceivable to set the air-fuel ratio as an output by making the flow passage cross-sectional area of the bypass intake passage larger than the learned value obtained by feedback control.

However, when the throttle valve is fully closed to enter a deceleration state, always making the flow passage cross-sectional area of the bypass intake passage larger than the above learned value reduces the deceleration effect and is disadvantageous in terms of fuel efficiency. There is.

Therefore, an object of the present invention is to prevent engine stall while maintaining the deceleration effect and prevention of deterioration of fuel efficiency when the engine is decelerated due to fully closing the throttle valve in an internal combustion engine having an idle speed control device. It is in.

[Means to solve the problem]

A means for solving the above-mentioned problems is to provide a bypass intake passage that connects an intake passage upstream and an intake passage downstream of a throttle valve of an internal combustion engine and bypasses the throttle valve, and reduces the amount of intake air in the bypass intake passage. is adjusted so that the engine rotation speed during idling becomes the target rotation speed, and during non-feedback control, the flow passage cross-sectional area of the bypass intake passage is adjusted to the flow passage cross-sectional area obtained by the feedback control. In an internal combustion engine with a specified value, during non-feedback control, when the throttle valve is fully closed and the speed of the vehicle equipped with the engine is below a predetermined value corresponding to the value immediately before stopping, the bypass intake passage is The objective is to make the flow passage cross-sectional area larger than the flow passage cross-sectional area learning value obtained by the feedback control.

[Effect]

According to the above-mentioned means, even when the throttle valve is fully closed, when the vehicle speed is high, the flow passage cross-sectional area of the bypass intake passage is not increased, so that the deceleration effect and prevention of deterioration of fuel efficiency are maintained. On the other hand, during deceleration, just before the vehicle stops, for example when the vehicle speed is below 10 km/h, the brake booster operates, and air that does not go through the air flow meter enters the combustion chamber of the engine in order to operate the brake vacuum booster. Even if it is fed, in this case, the cross-sectional area of the bypass intake passage increases, so the engine torque increases, and engine stall can be prevented. Especially recently,
In order to improve fuel efficiency, the idle speed of the engine tends to be set low, and this is effective in preventing engine stall in this case.

The present invention will be explained below with reference to the drawings.

FIG. 1 is a schematic diagram of an apparatus for executing a deceleration control method for an internal combustion engine as an embodiment of the present invention. In FIG. 1, an air flow meter 2 is provided in an intake passage of an engine body 1. As shown in FIG. The air flow meter 2 directly measures the amount of intake air, has a built-in potentiometer, and generates an analog voltage electrical signal proportional to the amount of intake air. In addition, the throttle valve 3 installed in the intake passage of the engine
A throttle sensor 4 is provided on the shaft for detecting that the throttle valve 3 is in a fully closed state.

Further, a bypass intake passage 5 is provided which connects the upstream intake passage and the downstream intake passage of the throttle valve 3 and bypasses the throttle valve 3. Solenoid air control valve (hereinafter referred to as EACV) 6
is provided.

The cylinder block of the engine body 1 is provided with a water temperature sensor 7 for detecting the temperature of cooling water.

The distributor 8 of the engine is provided with two rotation angle sensors 9, 11 which generate angular position signals each time the shaft rotates, for example, by 360 degrees or 30 degrees in terms of a crankshaft. Rotation angle sensor 9, 1
The angular position signal No. 1 acts as a reference timing for fuel injection timing and ignition timing, and as an interrupt request signal for fuel injection calculation and ignition timing calculation.

Reference numeral 12 denotes a vehicle speed sensor, which is composed of, for example, a reed switch and a permanent magnet.
Here, when the permanent magnet is rotated by the speedometer cable, the reed switch is turned on.
The off-operation is performed, and as a result, a pulse signal with a frequency proportional to the vehicle speed is generated.

Further, in the intake passage of the engine, a fuel injection valve 13 is provided for each cylinder for supplying pressurized fuel from a fuel supply system to an intake port portion.

In the internal combustion engine described above, the amount of intake air supplied to the engine is detected by the air flow meter 2, and an amount of fuel corresponding to this amount of intake air is injected from the fuel injection valve 13. Therefore, the throttle valve 3
When the engine is in the idle position, the amount of intake air in the bypass intake passage 5 is controlled by the EACV 6, and as a result, the engine rotational speed during idle operation becomes the target value.

The control circuit 10 digitally processes signals from the air flow meter 2, water temperature sensor 7, rotation angle sensors 9, 11, throttle sensor 4, and vehicle speed sensor 12 to control the EACV 6 and the fuel injection valve 1.
3 controls the pulse width of the pulse signal supplied to the pulse signal. This control circuit 10 is configured as a microcomputer, for example.

FIG. 2 is a detailed block circuit diagram of control circuit 10 of FIG. 1. In FIG. 2, analog output signals from the air flow meter 2 and the water temperature sensor 7 are sent to the A/D converter 1 via a multiplexer 101.
02. That is, the A/D converter 102 uses the clock signal CLK of the clock generation circuit 107 to A/D convert the output signal of the air flow meter 2 or water temperature sensor 7 sent through the multiplexer 101 selectively controlled by the CPU 108. After the A/D conversion is completed, an interrupt signal is sent to the CPU 108. As a result, the latest data of the air flow meter 2 and water temperature sensor 7 will be stored in a predetermined area of the RAM 110 in the interrupt routine.

Each digital output signal of the rotation angle sensors 9, 11 is supplied to a timing generation circuit 103 for generating an interrupt signal and a reference timing signal. Furthermore, the output digital signal of the rotation angle sensor 11 is supplied to a predetermined position of the input port 105 via the rotation speed forming circuit 104. The rotational speed forming circuit 104 consists of a gate that is controlled to open and close every 30 degrees of crank angle, and a counter that counts the number of pulses of the clock signal CKL of the clock generation circuit 108 that passes through the gate.
A binary signal will be formed that is inversely proportional to the rotational speed of the engine.

The digital output signal of the throttle sensor 4 is supplied to a predetermined position of the input port 105.

A digital signal from the vehicle speed sensor 12 is supplied to a predetermined position of the input port 105 via a waveform shaping circuit 106 and a vehicle speed forming circuit 107. The waveform shaping circuit 106 converts the output signal of the vehicle speed sensor 12 into a rectangular wave signal and supplies the rectangular wave signal to the vehicle speed forming circuit 107. On the other hand, the vehicle speed forming circuit 107 is composed of, for example, a flip-flop, a gate, and a counter. That is, the flip-flops are alternately set by the rectangular wave signal of the waveform shaping circuit 106,
The gate is opened only while this flip-flop is set or reset, and the counter counts the number of pulses of the clock signal CKL of the clock generation circuit 109 via this gate. Therefore, the value of the counter is inversely proportional to the frequency of the rectangular wave signal, that is, inversely proportional to the vehicle speed. The latest rotational speed data and vehicle speed data are stored in a predetermined area of RAM 110 via input port 105 during main routine or subroutine processing.

The ROM 111 stores programs such as a main routine, a fuel injection time calculation routine, and an ignition timing calculation routine, as well as various data necessary for these processes.
Constants etc. are stored in advance.

The CPU 108 reads the opening degree data of the EACV 6 from the RAM 110 and sends it to a predetermined position of the output port 112, thereby causing the drive circuit 113 to supply a current to the EACV 6 according to the opening degree data. Further, the CPU 108 reads fuel injection time data from the RAM 110 and sends it to a predetermined position of the output port 112, thereby causing the drive circuit 114 to operate the fuel injection valve 13 for the above-mentioned fuel injection time within the predetermined operating cycle of the engine. energize. As a result, an amount of fuel corresponding to the fuel injection time is sent into the combustion chamber of the engine body 1.

The operation of the control circuit 10 shown in FIG. 2 will be explained with reference to the flowchart shown in FIG.

The operation of the control circuit 10 starts in step 301, and in step 302, the throttle sensor 4,
It is determined whether feedback control of idle speed control using data from the water temperature sensor 7, vehicle speed sensor 14, etc. is in progress. If feedback control is in progress, the process proceeds to step 303, where a target rotational speed is calculated based on predetermined operating state parameters of the engine, and the EACV 6 is opened by that value. As a result, the engine rotational speed during idling becomes appropriate. On the other hand, if feedback control is not in progress at step 302, the process advances to step 304.

In step 304, it is determined whether the throttle valve 3 is fully closed. That is, the CPU 108 inputs the output signal of the throttle sensor 4 to the input port 10.
5, and it is determined whether the signal level is "1" or "0". If the throttle valve 3 is not fully closed, it is not decelerating, so proceed to step 307.
On the other hand, if the throttle valve 3 is fully closed, the process proceeds to step 305 because deceleration is in progress.

In step 305, it is determined whether the vehicle speed is 10 km/h or less. In other words, the CPU 108
Read the latest vehicle speed data from RAM11010
Compare with Km/h. If the vehicle speed is >10 km/h, there is no risk of engine stall due to the engine rotational speed, so proceed to step 307 and open EACV 6 by the learning value obtained by feedback control. On the other hand,
If the vehicle speed is 10 km/h, there is a risk of engine stall, so proceed to step 306.

In step 306, the CPU 108
Data obtained by multiplying the feedback learning value of the EACV 6 stored in the EACV 110 by a constant number or adding a certain amount to the drive circuit 113 are sent to the drive circuit 113 as opening degree data.
As a result, the EACV 6 is driven to the open side with a value larger than the learned value during feedback, and therefore the flow passage cross-sectional area of the bypass intake passage 5 becomes large.

After completing each step 303, 306, and 307, the process advances to step 308.

〔Effect of the invention〕

As explained above, according to the present invention, when the throttle valve is fully closed and a deceleration state occurs, the deceleration effect and the prevention of deterioration of fuel efficiency are maintained, and the bypass intake air is activated immediately before the throttle valve is fully closed and the throttle valve is fully closed. Since the cross-sectional area of the passage is set larger than the learned value, which is a normal set value, the engine output can be increased, and therefore, engine stall can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a device for implementing a deceleration control method for an internal combustion engine as an embodiment of the present invention, FIG. 2 is a detailed block circuit diagram of the control circuit 10 shown in FIG. 1, and FIG. 3 is a flowchart for explaining the operation of the control circuit 10 of FIG. 2. FIG. 1: Engine body, 2: Air flow meter, 3: Throttle valve, 4: Throttle sensor, 5: Bypass intake passage, 6: Electromagnetic air control valve (EACV),
7: Water temperature sensor, 8: Distributor, 9,
11: Rotation angle sensor, 10: Control circuit, 12: Vehicle speed sensor.

Claims (1)

[Scope of Claims] 1. A bypass intake passage that connects an intake passage upstream and an intake passage downstream of a throttle valve of an internal combustion engine and bypasses the throttle valve, and adjusts the amount of intake air in the bypass intake passage. Feedback control is performed so that the engine rotation speed during idling becomes the target rotation speed, and during non-feedback control, the flow passage cross-sectional area of the bypass intake passage is set to the flow passage cross-sectional area learning value obtained by the feedback control. In the engine, during non-feedback control, when the throttle valve is in a fully closed state and the speed of a vehicle equipped with the engine is below a predetermined value corresponding to a value immediately before stopping, the flow passage cross-sectional area of the bypass intake passage of,
A deceleration control method for an internal combustion engine, characterized in that the learning value of the flow passage cross-sectional area is made larger than the learned value obtained by the feedback control.