JPS5949347A - Idling speed control method for internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent engine stall likely to occur when, for ex., the final stage is to be cut off in power steering, by setting the section area of by-pass suction line larger than the study value calculated and stored during feedback control, while the operation is performed at a low temp. and outside the feedback control range. CONSTITUTION:A solenoid-operated air control valve 7 is furnished to adjust the section area of by-pass suction line 6 as detour for the throttle valve 4. Feedback control of EACV of idle speed control of control circuit 10 is made when the specified feedback conditions are met by parameters to represent engine's operating condition, i.e. signals from a water temp. sensor 8, throttle sensor 5, air-conditioner switch 13, car speed sensor 14, etc. While operation is made out of feedback control at a water temp. of 70 deg.C for ex., the EACV 7 is driven greatly toward the open side from the study value obtained during the feedback control, and therefore the section area of by-pass suction line 6 is enlarged.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the idle speed of an internal combustion engine having an idle speed control device.

Conventionally, 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 that bypasses the throttle valve is provided in the intake passage of the engine. ,
Feedback control is performed to feed back this information to adjust the amount of intake air in the bypass intake passage, that is, the flow passage cross-sectional area. In this case, when the operating state parameter does not satisfy the feedback condition (outside the feedback control area), the flow passage cross-sectional area of the bypass intake passage is set to the learning value calculated and stored during feedback control, and This reduces unpleasant shocks even when the engine suddenly changes from running to idling.

However, according to the above-mentioned conventional method, even if the area is outside the feedback control area at low temperatures, the cross-sectional area of the bypass intake passage is set by the learning area calculated and memorized during feedback control. There is a problem in that the amount of air is small, and as a result, when the power steering is performed in the Dk state, the engine N rotation speed decreases and engine stall is more likely to occur.

For the purpose of the present invention, in view of the problems with the conventional method described above, outside the feedback control area at low temperatures, the current is set to be larger than the learning area calculated and stored during feedback control due to the flow passage cross-sectional area of the bypass intake passage. Based on this concept, the intake thrust when the feedback ff1ll# is open at low temperatures also increases t, thereby preventing engine stalling when the power steering stalls, etc.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing an apparatus for carrying out the idle rotation speed control method for an internal combustion engine according to the present invention. In FIG. 1, an air flow meter 3 is provided in an intake passage 2 of an engine body 1. As shown in FIG. The air flow meter 3 directly measures the amount of intake air (1) and has a built-in potentiometer to generate an analog voltage electrical signal proportional to the amount of intake air (3). Further, a throttle sensor (in this case, an idle switch) 5 is provided on the shaft of the throttle valve 4 provided in the intake passage 2 of the engine body 1 to detect whether or not the throttle 9P4 is fully closed. .

Further, a bypass intake passage 6 is provided which completely connects the upstream and downstream sides of the throttle valve 4 and bypasses the throttle valve 4.
An electromagnetic air pollution control valve (hereinafter referred to as EACV) 7 is provided in the middle thereof for fully adjusting the cross-sectional area of the bypass intake passage 6.

Further, the cylinder block of the engine body 1 is provided with a water temperature sensor 8 for detecting the temperature of cooling water. The water temperature sensor 8 generates all analog voltage electrical signals depending on the temperature of the cooling water.

The IJ computer 9 is provided with two rotation angle sensors 11 and 12 that generate an angular position signal every time its shaft rotates, for example, by 360' or 30 degrees in terms of a crankshaft. The angular position signals of the rotation angle sensors 11 and 12 act as a reference timing signal for fuel injection timing, a reference timing signal for ignition timing, an interrupt request signal for fuel injection calculation, an interrupt request signal for ignition timing calculation, etc. 0 13 is an air conditioner switch for turning on and off the air conditioner digital switch.

Reference numeral 14 denotes a vehicle speed sensor, which is composed of, for example, a reed switch and a permanent magnet.

That is, when the permanent magnet is rotated by the speedometer cable, the reed switch performs on and off operations, resulting in the generation of a pulse signal with a frequency proportional to the vehicle speed.

Further, the intake passage 2 is provided with a fuel injection valve 15 for supplying pressurized fuel from a fuel supply system to the full intake boat for each cylinder.

The control circuit 10 includes an air flow meter 3, a water temperature sensor 8,
Rotation angle sensor 11, 12, slot)/l/sensor 5,
It digitally processes each signal from the air conditioner switch 13 and the vehicle speed sensor 14 to calculate the EACV opening of the idle speed control, the fuel injection time, etc., and is configured as, for example, a microcomputer (Fig. 2). 2 is a detailed block circuit diagram of the control circuit 10 of FIG. 1. FIG. In FIG. 1, each analog signal of the air flow meter 3 and water temperature sensor 8 is connected to a multiplexer 101'.
i is supplied to the A/D converter 102. That is, the A/D converter 102 converts the analog output signals of the air flow meter 3 and water leak sensor 8 sent via the multiplexer 101 selectively controlled by the CPU 108 into A/D converters using the clock signal CLKe of the clock generation circuit 109. converts the interrupt signal to CP0 after completing the A/D conversion.
108. As a result, in the interrupt routine, the latest data of the air flow meter 3 and water temperature sensor 8 are
It will be stored in the required area of AM110.

Each digital output signal of the rotation angle sensors 11, 12 is supplied to a timing generation circuit 103 for generating an interrupt signal and a reference timing signal. Further, the digital output signal of the rotational angle sensor 12 is supplied to the rotational speed forming circuit 104 via the rotational speed forming circuit 104'i to the crank angle 30'i.
It consists of a gate that is controlled to open and close every ', and a counter that counts the number of pulses of the clock signal CLK from the clock generation circuit 109 that passes through this gate. will be formed.

The digital output signals of the throttle sensor 5 and the air conditioner switch 13 are directly supplied to a predetermined position of the input boat 105. The digital output signal of the vehicle speed sensor 14 is supplied to the waveform shaping circuit 1.
06 and the input boat 1 through the vehicle speed forming circuit 107'i.
050 is supplied to a predetermined position. The waveform shaping circuit 106 converts the output signal of the vehicle speed sensor 14 into a rectangular wave signal and supplies it to the vehicle speed forming circuit 107 . The vehicle speed forming circuit 107 includes, for example, a flip 70, a gate, and a counter. That is, the flip-flops are alternately set and reset by the rectangular wave signal of the waveform shaping circuit 106, and as a result, the 0 counter whose gate is open only while the flip-flop is set or reset is processed through the open gate. Count the number of pulses of the clock signal CLK of the clock generation circuit 109. 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 of the human-powered boat 105. Data N1 Vehicle speed data V is stored in the RAM 100 area as necessary in the main routine, subroutine, interrupt routine, etc. OROM III includes the main routine, idle speed control EACV opening control routine, fuel injection time calculation routine, Programs such as ignition timing calculation routines and various fixed data and constants necessary for these processes are stored in advance.

CPU 10 s u Controls the opening of EACV7 by the drive circuit 113 in the idle speed control E A CV opening control routine described later 0CP010
8 is a fuel injection control routine, in which all fuel injection time data is read out from RAMll0 and sent to a predetermined position of the output port 112, so that the drive circuit 114 is within a predetermined operating cycle of the engine (8) The above-mentioned fuel injection The fuel injection valve 15 is energized for the time. As a result, an amount of fuel corresponding to the fuel injection time is delivered to the combustion chamber of the engine body 1.

FIG. 3 is a flowchart V) for explaining the operation of the control circuit shown in FIG.
It starts with the output signal of 03. Note that the feedback control of the EACV for idle speed control is based on engine operating state parameters such as the water temperature sensor 8,
This is performed when the signals from the throttle sensor 5, air conditioner switch 13, vehicle speed sensor 14, etc. satisfy the feedback condition of the Pfr leg.

In step 302, the CPU 108 controls idle speed control (ISO) according to the operating state parameters described above.
) Feedback CF/B) Determine whether or not it is under control. If feedback control is in progress, the process proceeds to step 303, where a target rotational speed is calculated as a learning value based on predetermined operating state parameters of the engine and stored in RAMll0, and the EACV7' is opened by that value. As a result, the engine rotational speed during idling operation becomes appropriate. On the other hand, if it is determined in step 302 that feedback control is not being performed, the process proceeds to step 304.

In step 304, the CPU 108 compares the water temperature data THW in RAMll0 with a predetermined value, for example, 700C. If THW≦70°C, step 305
On the other hand, if THW>70°C, proceed to step 30
Proceed to step 6.

In step 305, the CPU 108 reads the feedback learning value obtained during the feedback control stored in the RAM 110, and multiplies the value by a constant or a fixed amount 71I] and sends the value ratio value to the drive circuit 113 as opening degree data. As a result, the EACV 7 is driven to the open side to a greater extent than the learned force under the feedback control, and therefore the flow passage cross-sectional area of the bypass intake passage 6 becomes larger.

In step 306, the CPU 108 outputs all the feedback learning values obtained during the feedback control stored in the RAMIIO, and sends the values to the drive circuit 113 as opening data. It will only open.

When each step 303, 305, 306 is completed, the routine proceeds to step 307, and this routine ends.O As explained above, according to the present invention, in the feedback control region at low temperatures, Since the feedback learning value is set larger than the gold feedback learning value, the amount of intake air increases, and therefore, engine stalling when the power steering stalls, etc. can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a device for carrying out the idle speed control method for an internal combustion engine according to the present invention, FIG. 2 is a detailed circuit diagram of the control circuit of FIG. 1, and FIG. 3 is a detailed circuit diagram of the control circuit of FIG. 70-chi-r-) for explaining the operation of the control circuit. 1: Engine body, 4: Throttle valve, 5: Throttle sensor, 6: Bypass intake passage, 7: Electromagnetic air control valve (EACV), 8: Water temperature sensor, 10: Control circuit. Patent applicant Toyota Motor Corporation Patent agent Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney Akira Yamaguchi

Claims (1)

[Claims] 1. A bypass intake passage is provided that connects an intake passage upstream and an intake passage downstream of a throttle valve of the internal combustion engine and bypasses the throttle valve, and when a predetermined operating state parameter satisfies a feedback condition, the bypass intake passage In the idle rotation speed control method for an internal combustion engine, which performs feedback control so that the engine rotation speed becomes a target rotation speed by adjusting the flow passage cross-sectional area of the passage, when the predetermined operating state does not satisfy the feedback condition, and when the cooling water temperature of the engine is below a predetermined value, the flow passage cross-sectional area of the bypass intake passage is controlled to be larger than the flow passage cross-sectional area learning value obtained by the feedback control. Idle rotation speed control method for an internal combustion engine with