JPS639092B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a throttle valve opening degree control device for starting correction in an automobile engine equipped with an electronic control system.

Conventionally, in gasoline engines for automobiles, various engine-related controls have been performed, such as A/F (air-fuel ratio) depending on accelerator opening and load torque.
Most of the control, starting correction, warm-up correction, and idle speed control were performed independently by the carburetor.

However, in recent years, electronic control systems have been developed that use microcomputers (hereinafter referred to as microcomputers) to capture various data representing engine operating conditions and comprehensively control engine operating conditions via various actuators. Engine control systems have become widely adopted.

An example of such an electronically controlled engine control system will be explained with reference to FIGS. 1 to 5.

Figure 1 shows the entire system. In the figure, 1 is the engine, 2 is the carburetor, 3 is the slow solenoid, 4 is the main solenoid, 5 is the fuel solenoid, 6 is the limit switch, and 7 is the throttle actuator. 8 is an intake negative pressure sensor, 9 is a cooling water temperature sensor, 10 is a pulse type engine speed sensor, 11 is an idle detection switch, and 12 is a control unit.

FIG. 2 shows the configuration of the throttle actuator 7.

In the figure, 14 is a throttle valve (hereinafter referred to as
13 is a shaft (referred to as a throttle valve), 15 is an opening/closing lever attached to the shaft 14, 16 is a return lever, 1
7 is a return spring, 18 is a stroke shaft, 19 is a reduction gear, 20 is a DC motor, 21
is a spring. Note that 2 is a carburetor, 11 is an idle detection switch, 12 is a control unit, and 13 is a throttle valve.

When the accelerator pedal is not operated, the throttle valve 13 returns to the return position due to the tension of the return spring 17. At this time, the return position is such that the opening/closing lever 15 is in the position of the stroke shaft 18.
It is determined by the position where it touches. Since the stroke shaft 18 is held on the gear 19 by a screw, it sends a signal to the motor 20 to move the gear 1.
By rotating the throttle valve 9, the return position of the throttle valve 13 can be arbitrarily controlled.

The stroke shaft 18 and the gear 19 as a whole are configured to be able to move slightly in the longitudinal direction of the shaft 18, and when the throttle valve 13 is opened from the return position by operating the accelerator pedal, the stroke shaft 18 and the gear 19 are moved as shown in the figure by the spring 21. As shown by the broken line, the switch 11 is opened by being displaced to the left, and when the throttle valve 13 returns to its return position under the tension of the return spring 17, the opening/closing lever 15 is pressed against the stroke shaft 18, and the spring 21 is pushed in. The switch 11 is configured to close. Therefore,
By turning the switch 11 on and off, it is possible to detect whether the throttle valve 13 is being operated via the accelerator pedal or whether it has returned to the return position.

Furthermore, when the throttle valve 13 returns to the standard opening near the fully closed position, the limit switch 6 operates, so the data of this limit switch 6
It is possible to detect that the throttle valve 13 has returned to the reference opening degree θ ₀ by L _isw .

FIG. 3 shows an example of the control unit 12, which includes a control logic 22, a microprocessor 23, a ROM 24, and a multiplexer 2.
5. Consists of an analog-to-digital converter 26, etc., and detects the intake negative pressure Vc from the negative pressure sensor 8 (Fig. 1)
Analog data such as the engine temperature T _W from the coolant temperature sensor 9 is sent to the limit switch 6 via the multiplexer 25 and the analog-to-digital converter 26.
Data L _isw from the idle detection switch 11, data T _HSW from the idle detection switch 11, and digital data such as the engine rotation speed N from the rotation speed sensor 10 are respectively input as they are into the control logic 22, and then sent to the microprocessor 23, ROM 24, etc. and controls various actuators such as the slow solenoid 3, main solenoid 4, fuel solenoid 5, and throttle actuator 7 to perform optimal control according to the operating state of the engine.

Therefore, in a system configured in this way,
Depending on various data representing the operating state of the engine, the A/F is controlled to the optimum level through the control of the slow and main solenoids 3 and 4 during steady operating conditions, and the fuel solenoid 5 is controlled during warm-up operating conditions. Therefore, by controlling the A/F to the optimum state and further controlling the throttle actuator 7, it is possible to control the engine speed to the optimum state in the idle state and the left warm-up state.
The opening degree of the throttle valve 13 at the time of starting can be maintained at a predetermined value.

The control mode for the throttle actuator 7 at this time is to drive the DC motor 20 with pulses in order to enable digital control by the control unit 12, thereby moving the stroke shaft 18 in and out to adjust the throttle. Valve 1
3, and the pulse supplied at this time has a waveform as shown in FIG. 4, and has a predetermined pulse width P _W during a predetermined repetition period T. Therefore, when this pulse is supplied to the DC motor 20, the number of revolutions obtained each time one pulse is supplied becomes a constant value, and the amount of movement of the stroke shaft 18 is determined by the number of supplied pulses. will be done.

Then, the return position of the throttle valve 13, that is, the opening degree of the throttle valve 13 in the idle state is determined depending on the position to which the stroke shaft 18 has moved, and the engine rotation speed is thereby determined. As shown in FIG. 5, the opening degree of the throttle valve can be controlled from θ ₀ to θ _n by the number of pulses supplied to the DC motor 20 of FIG.
In FIG. 5, straight line A shows the characteristic when a pulse of positive polarity is applied, and line B shows the characteristic when a pulse of negative polarity is applied.

Therefore, in such an electronic control system, when it is detected that the throttle valve 13 enters the idle state by turning on the idle detection switch 11, the control unit 12 activates the throttle actuator according to one of the programs executed by the microcomputer. Eta 7
By adding a control program, it is possible to always control the throttle valve opening to an appropriate state during idle conditions, including during startup and warm-up.

However, in the throttle valve opening control method for starting correction that has been conventionally adopted in such systems, the ignition switch
When the engine is turned on to start, the engine temperature data T _W from the cooling water temperature sensor 9 is taken in to control the throttle actuator 7 so that the opening degree of the throttle valve 13 becomes an opening degree suitable for starting. was.

However, when the system is used in low temperature conditions, the battery voltage may drop or the throttle actuator 7 may freeze, so the conventional throttle valve opening control device described above is However, there was a drawback that it was difficult to set a sufficient opening.

Also, when starting, the ignition switch is turned on.
It may take some time for the throttle valve opening to be set to the predetermined value, and in such cases, the engine may start before the throttle valve opening is set. Another drawback was that the engine stalled immediately after starting.

Additionally, related devices of this type include:
For example, the disclosure of Japanese Patent Application Laid-open No. 57639/1983 can be mentioned.

SUMMARY OF THE INVENTION An object of the present invention is to provide a throttle valve opening control device that eliminates the above-mentioned drawbacks of the prior art and always provides the correct throttle valve opening when starting an engine.

To achieve this objective, the present invention stores data such as the engine temperature at that time when the engine is started, and then stores the data when the ignition switch is turned off and the engine is stopped. The present invention is characterized in that the throttle actuator is operated based on the above data, and the throttle valve opening degree is set to a predetermined opening degree given by the above data.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a throttle valve opening control device according to the present invention will be described.

FIG. 6 is a flowchart showing the operation of one embodiment of the present invention, which will be explained below.

The hardware configuration of the system to which this embodiment is applied is the same as the system described with reference to FIGS. 1 to 5, so detailed explanation thereof will be omitted.

When the system starts executing the program according to the flowchart shown in FIG. 6, the first step (hereinafter referred to as SI) is to check whether the ignition switch has been turned on. When the result in SI is YES, the process advances to S2, where data N from the rotational speed sensor 10 (FIG. 1) is checked to determine whether it is 0 or not. The result in S2 is NO,
In other words, when the engine is running, the next S3
, it is checked whether flag 1 is set, and only when NO, the data T _W from the cooling water temperature sensor 9 at that time is stored in the memory as data T _WO , and in the following S5, flag 1 is set. , then proceed to S6.

On the other hand, if the result in S3 is YES, the process immediately proceeds from this step to S6.

In S6, the throttle valve opening degree when the accelerator pedal is not operated is controlled by engine speed data N and water temperature data T _W , etc. The engine speed control (ISC) and the like are executed as explained in the system of FIGS. 1 to 5, and the program according to this flow ends.

The process from this SI to S3 via S2 is only after the ignition switch is turned ON and the engine has started, and this is determined by S3, so in the end, it is the first time immediately after the engine starts. S4 and S5 are passed only when this flow is entered, and water temperature data _TWO immediately after the engine is started, which indicates a value close to the air temperature, is stored in the memory.

Next, when the judgment result of the SI is NO, that is, the SI judges that the ignition switch has just been turned off, it turns to S7 and first turns off the power to the entire system including the control unit 12 after a predetermined period of time. Starts the power OFF delay timer to turn OFF. This allows the entire system to power up at the same time the ignition switch is turned on.
Even if the ignition switch is turned off, it does not turn off immediately, but only after a predetermined period of time has elapsed.

In this way, even if the ignition switch is turned off in S7, the power of the entire system remains on for a while, then the process proceeds to S8 to reset flag 1, and the process proceeds to S9 to read data from memory. The data T _WO is read, and the number n ₀ of pulses corresponding to the data T _WO is read out using a table or the like as shown in FIG.

Next, in S10, limit switch 6 (first
Check the data L _isw in the figure) to determine whether switch 6 is ON or not. When the result in S10 is YES, go to S11 and set the limit switch 6.
Positive voltage is supplied to the motor 20 of the throttle actuator 7 until it is turned OFF.

Further, if the result in S10 is NO, that is, the limit switch 6 is OFF, proceed to S12,
A negative voltage is supplied to the motor 20 of the throttle actuator 7 until the limit switch 6 is turned on.

After exiting S11 or S12, proceed to S13,
The n ₀ pulses A obtained in S9 are supplied to the motor 20 of the throttle actuator 7 to open the throttle valve 13 to a predetermined opening degree, and this flow ends.

As a result, when the ignition switch is turned off, the throttle actuator 7 is operated and the opening degree of the throttle valve 13 is controlled as shown in FIG.

First, control from time t ₀ to t ₁ in FIG. 8 is performed by S10 to S11 or S12, and the throttle valve opening is made to be close to the reference opening θ ₀ . That is, when the throttle valve opening is larger than the reference opening θ ₀ at time t ₀ (this is approximately the time when the judgment result in S1 changes from YES to NO), the result in S10 becomes NO, and the result in S12 By motor 20
is supplied with a negative voltage, and at time t ₁ the throttle valve opening becomes θ ₀
be made into Furthermore, when the throttle valve opening is smaller than the reference opening θ ₀ at time t ₀ , the result in S10 is
Since the answer is YES, a positive voltage is applied to the motor 20 in S11, and the motor 20 is opened to the reference opening degree θ ₀ at time t ₁ .

Next, in S13, as shown from time _t1 to _t2 in FIG. 8, _n0 pulses A obtained in S9 are supplied to the motor 20 of the throttle actuator 7, so that the throttle valve is The opening degree will be set to the opening degree corresponding to the temperature data T _WO when the engine was started before then.

At this time, the number of pulses n ₀ in FIG. 7 corresponds to the opening degree of the throttle valve necessary to provide appropriate starting characteristics for the engine temperature, so in the end, according to this embodiment, When the ignition switch is turned off and the engine stops, the opening of the throttle valve is subsequently changed to the opening corresponding to the cooling water temperature data stored in advance when the engine was started, and the next Control is performed to maintain the same throttle valve opening until the engine is started.

As a result, when starting the engine, the throttle valve opening is always maintained at the appropriate opening for starting, which prevents the engine from starting with an inappropriate throttle valve opening as in conventional technology. can do.

In the example shown in Fig. 6, when the result in S2 is NO, it indicates that the engine has stalled, so in this case, the throttle valve opening should be adjusted again from S9 to a position suitable for starting. It is starting to move forward.

Furthermore, the use of the limit switch 6 in the above embodiment, which once returns the throttle valve 13 to the reference opening and then moves the throttle valve 13 to a predetermined opening, results in a relatively complicated configuration. This is to eliminate the need for a throttle valve opening sensor, which tends to increase costs, and as a result, according to the above embodiment, a low-cost system with fewer failures can be achieved.

As is clear from this, if the opening degree of the throttle valve 13 is directly detected using the opening degree sensor, steps S10 to S13 in FIG. 6 can be omitted and the characteristics in FIG. 7 can be replaced. S using a table etc. that gives the throttle valve opening directly from the water temperature data T _W.
It is only necessary to provide a step after S9 in which the opening degree of the throttle valve 13 is directly applied to the throttle actuator 7 to control the opening degree of the throttle valve 13 read in step S9.

Furthermore, in the above embodiment, the throttle valve opening required at startup is determined based on the engine cooling water temperature data _TW , but the throttle valve opening is given as a function of data representing the engine intake air temperature. It's okay.

As explained above, according to the present invention, the throttle valve opening degree for starting the engine is set immediately after engine operation is stopped by the ignition switch, and when the battery voltage and engine temperature are sufficiently high. Therefore, it is possible to provide a throttle valve opening control device that eliminates the drawbacks of the prior art and does not cause problems in setting the throttle valve opening due to insufficient operation of the throttle actuator. can.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of an electronic control system for an engine to which the present invention is applied, FIG. 2 is a schematic diagram of a throttle actuator, FIG. 3 is a block diagram of a control unit, and FIGS. FIG. 5 is a characteristic diagram for explaining the operation, FIG. 6 is a flowchart for explaining the operation of one embodiment of the throttle valve opening control device according to the present invention, and FIGS. 7 and 8 are for explaining the operation. FIG. 1... Engine, 6... Limit switch, 7... Throttle actuator, 9... Cooling water temperature sensor,
DESCRIPTION OF SYMBOLS 10... Rotation speed sensor, 11... Idle detection switch, 12... Control unit, 13... Throttle valve, 20... DC motor.

Claims (1)

[Scope of Claims] 1. A throttle valve opening control device that is equipped with an actuator means for controlling the throttle valve return opening and a temperature sensor, and that automatically sets the throttle valve opening when the engine is started. Switch ON
A memory means for storing data of the temperature sensor immediately after operation, and an ignition switch for the engine.
A timer means that is activated by an OFF operation, and a return opening degree control means that is activated by the output of the timer means and operates the actuator means according to data read from the memory means to set the opening degree of the throttle valve. . A throttle valve opening degree control device, characterized in that, after the engine is stopped, the opening degree of the throttle valve is set to a predetermined value in preparation for the next start. 2. In claim 1, there is provided a limit switch means for detecting that the throttle valve has returned to the reference opening, and after the switch means detects that the throttle valve opening has reached the reference opening, the above-mentioned memory is A throttle valve opening degree control device, characterized in that said return opening degree control means is configured to supply a number of pulse signals corresponding to the data read from said means to said actuator means. 3. The throttle valve opening control device according to claim 1, wherein the temperature sensor is an engine cooling water temperature sensor or an intake air temperature sensor.