JPH0510184A - Step motor controller in internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the extent of startability at the time of instantaneous power cutoff by monitoring a state of supply voltage, detecting the power instantaneous cutoff, and omitting any operation check of a step motor driving a throttle valve at this instantaneous cutoff, then starting control over the quantity of fuel and air at once. CONSTITUTION:Voltage of a car-mounted battery is monitored in a time lag manner by a supply voltage monitoring means 11, and whether the detected voltage is more than the specified value or not is judged, and when it is less than the specified value or the last check is abnormal, each operation check of a step motor and its drive circuit 15 takes place, thereby preventing any malfunction from occurring. In the case where it is more than the specified value (at time of instantaneous cutoff) and the last check is normal, the operation check of the step motor and the drive circuit 15 is omitted, that is, control over the quantity of fuel and air is started at once, through which startability at the instantaneous cutoff is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a step motor control device in an internal combustion engine used for controlling a step motor which drives a throttle valve.

[0002]

2. Description of the Related Art Generally, in an internal combustion engine in which the amount of fuel or air supplied into an engine cylinder of an automobile or the like is controlled by using a step motor, the step motor and its drive circuit operate normally. After checking, the control of the amount of fuel and air is started.

Conventionally, as shown in FIG. 4, a method of confirming this kind of step motor and its drive circuit is as follows. In step 41, the required step position is set to a value for confirming a specific step motor operation, and in step 42, the step motor is checked. The step motor is driven and controlled so that the current step position of the step motor becomes the required step position, and in step 43, it is confirmed whether or not the current step position of the step motor matches the required step position. The process waits until the position and the required step position match (step 44), and if they match, the process of controlling the amount of fuel or air (step 45) is started.

As another method, as shown in FIG. 5, in step 51, the required step position is set to a value for confirming a specific step motor operation, and in step 52, the current step position of the step motor becomes the required step position. The step motor is drive-controlled at step 53, and if the step motor and its drive circuit are normal at step 53, the step motor is surely waited until the current step position reaches the required step position. It is confirmed whether or not the step position matches the required step position, and if they do not match, an alarm operation is performed in step 55, and if they match, the process of controlling the amount of fuel or air is started (step 56). The method is known.

[0005]

However, as shown in FIGS. 4 and 5, the method of checking the operation of the step motor and its drive circuit before starting the process of controlling the amount of fuel or air is There is a problem that the control of the amount of fuel or air is delayed by the time required for confirmation, and normal control cannot be performed.

Here, the starting point of the microprocessor (hereinafter referred to as MPU) for controlling the amount of fuel and air will be described. The power supply voltage is low in the supply capacity of the on-vehicle battery that is the power supply, and the starter motor is started at the time of start. Due to the large current flowing through it, the voltage is periodically reduced to near 0 volt, so that the MPU is reset and restarted. Further, as shown in FIG. 6, the power supply voltage fluctuates due to the load when the engine rotates, and this fluctuation is synchronized with the top dead center detection signal (hereinafter referred to as TDC signal) indicating the fuel injection timing.
Then, due to voltage drop due to cranking, etc., MPU
After resetting and restarting, if fuel injection is not possible during the time interval Tint (61 in FIG. 6) until the TDC signal, fuel injection cannot be performed, and if the time interval Tint is set long, it will start. Sex decreases.

Therefore, as shown in FIGS. 4 and 5, the method of confirming the operation of the step motor and its drive circuit before starting the process of controlling the amount of fuel and air is a startability when the power supply voltage drops. There is a problem in that

The present invention solves the above-mentioned conventional problems. When the power is turned on, the operation of the step motor and its drive circuit can be confirmed, and the startability at the time of momentary interruption can be obtained. An object of the present invention is to provide an excellent step motor control device that can be improved.

[0009]

In order to achieve the above object, the present invention provides a means for detecting the current step position of a step motor which drives a throttle valve for adjusting the amount of fuel and air, and an operating state of an internal combustion engine. A stepping motor and its corresponding stepping motor when the power is turned on, and a microprocessor for controlling the required stepping position of the stepping motor corresponding to The operation of the drive circuit can be confirmed, and the startability at the time of momentary interruption is improved.

[0010]

Therefore, according to the present invention, when the ignition key of the vehicle is turned on and the MPU is started,
The detected voltage of the power supply voltage is less than a predetermined value. In this case, the operation of the step motor and its drive circuit can be checked, and any trouble in the operation can be immediately detected.

On the other hand, when the MPU is reset and restarted due to a momentary power failure during traveling or cranking, the detected voltage of the power supply voltage is equal to or higher than a predetermined value. In this case, the step motor and its drive are driven. Since the process of controlling the amount of fuel or air is immediately started without checking the operation of the circuit, the startability can be improved.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic block diagram showing an embodiment of the present invention, in which a power source voltage E of an on-vehicle battery or the like is monitored with a time delay, and a detection voltage Ed thereof is a predetermined value Eth or more. Reference numeral 12 is a power supply voltage monitoring unit that detects whether the value is less than the value Eth, and operates by the power supply voltage E. If the detection voltage Ed is less than the predetermined value Eth, or if the detection voltage Ed is more than the predetermined value Eth, the previous check is performed. Is abnormal,
The operation of the step motor and its drive circuit 15 is checked, and when the detected voltage Ed is equal to or higher than the predetermined value Eth and the previous check is normal, the operation of the step motor and its drive circuit 15 is not checked, and the amount of fuel or air is immediately confirmed. Is a control device that performs the control process of.

The controller 12 controls the MPU 13 that controls the required step position of the step motor based on the output of the power supply voltage monitoring means 11, and a non-volatile memory that stores various calculation results as correction values for the step position of the step motor. The motor drive circuit of the step motor for driving the throttle valve by calculating the optimum fuel injection timing from various inputs 19 indicating the state of the engine in synchronization with the TDC signal 18 indicating the fuel injection timing. 15 and the solenoid drive circuit 16 of the injector for injecting fuel are driven.

In FIG. 2, the power source voltage E of the vehicle battery or the like is monitored with a time delay, and the detected voltage Ed thereof has a predetermined value Et.
It is an embodiment of the power supply voltage monitoring means 11 for detecting whether it is equal to or more than h or less than a predetermined value Eth, and is a time constant circuit composed of resistors r1, r2, r3 and a capacitor c, and an output terminal of the resistor r3 is an analog input of the MPU 13. It is connected to the terminal AN1. Due to the time constant, the voltage of the analog input terminal AN1 of the MPU 13 becomes equal to or higher than the voltage judgment value ADVRF after the time interval t1 when the power is turned on, and when the power is turned off, as shown in FIG. As shown in C), the voltage determination value becomes equal to or lower than the voltage determination value ADVRF after the time interval t2.

Therefore, when the ignition key of the vehicle is turned on and the MPU 13 is started, the output voltage of the power supply voltage monitoring means 11 is equal to or lower than the voltage judgment value ADVRF, while the MPU 13 is caused by cranking while traveling.
Is reset and restarted, the output voltage of the power supply voltage monitoring means 11 becomes equal to or higher than the voltage determination value ADVRF.

Next, the operation of the MPU 13 will be described with reference to FIG. As described above, the MPU 13 is reset and restarted when the power is turned on or the power supply voltage drops. After starting MPU13, step 31
In, it is determined whether or not the output voltage of the power supply voltage monitoring means 11 is equal to or higher than the voltage determination value ADVRF. If YES, the process branches to step 32, and if NO, the process proceeds to step 33.

In step 32, it is determined whether or not the flag (hereinafter referred to as a motor confirmed flag) indicating that the step motor and its driving circuit, which have been confirmed in operation, stored in the non-volatile memory 14 is "1". , If yes, go to step 38, if no, go to step 33
Branch to.

In step 33, the operation of the step motor and its drive circuit 15 is confirmed. If not normal, the process branches to step 35 to reset the motor confirmed flag to "0", and in the following step 36, the alarm device 17 To inform the driver of the motor abnormality. Further, in step 37, the motor confirmed flag is set to "1".
And start the process of controlling the amount of fuel and air.
(Step 38) That is, when the power is turned on by the ignition key and the MPU 13 is started, the output voltage of the power supply voltage monitoring means 11 is equal to or lower than the voltage determination value ADVRF as shown in FIG. 2B. Step 3
As shown in FIG. 3, the step motor and its drive circuit 15
Check the operation of.

On the other hand, when the power supply is momentarily turned off during operation or is reset and restarted when the power supply voltage drops, as shown in FIG.
When the power supply voltage is restored within the range, since the output voltage of the power supply voltage monitoring means 11 at the time of restoration is equal to or higher than the voltage determination value ADVRF, the process branches from step 31 to step 32, and the result of the operation check last time is normal. If (motor confirmed flag = 1), the process of controlling the amount of fuel or air is started without performing the operation confirmation in step 33, and if the result of the operation confirmation is not normal last time (motor confirmed flag = 0)
First, after confirming the operation in step 33, the process of controlling the amount of fuel and air is started.

As described above, according to the above-described embodiment, the power supply voltage monitoring means 11 detects the fluctuation of the power supply voltage with a time delay and also detects whether or not the detected voltage is equal to or higher than a predetermined value, and detects the detected voltage. When the voltage is less than the predetermined value, that is, when the ignition key of the vehicle is turned on and the MPU 13 starts, the detected voltage of the power supply voltage is less than the predetermined value. In this case, check the operation of the step motor and its drive circuit. Therefore, malfunction can be prevented.

Further, when the MPU 13 is reset and restarted due to a momentary power interruption during traveling or cranking, the detected voltage of the power source voltage is a predetermined value or more. In this case, the step motor and its drive are driven. Since the process of controlling the amount of fuel or air is immediately started without checking the operation of the circuit, the startability can be improved.

[0022]

As is apparent from the above-described embodiment, the present invention has an effect that there is no risk of malfunction because the operation of the step motor and its drive circuit is always checked when the power is turned on. If the power is momentarily turned off during driving, or if the power supply voltage drops and returns to the power supply voltage within a predetermined time, the operation of the step motor and its drive circuit is not checked and fuel or air Since the process of controlling the amount is started, there is an effect that the startability can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram of a step motor control device in an internal combustion engine according to an embodiment of the present invention.

FIG. 2A is a circuit diagram of a power supply voltage monitoring unit of the same apparatus. FIG. 2B is an operation explanatory view of the power supply voltage monitoring unit of the same apparatus.

FIG. 3 is a flowchart showing the operation of the device.

FIG. 4 is a flowchart showing the operation of a conventional step motor control device.

FIG. 5 is a flowchart showing the operation of a conventional step motor control device.

FIG. 6 is a timing chart for explaining the operation of the MPU when the power supply voltage changes.

[Explanation of symbols]

 11 Power Supply Voltage Monitoring Means 12 Control Device 13 Microprocessor (MPU) 14 Nonvolatile Memory 15 Step Motor and Its Driving Circuit 16 Fuel Injection Injector and Its Driving Circuit 17 Alarm Device 18 Top Dead Center Detection Signal 19 Engine State Detection Signal

Claims (1)

Claim: What is claimed is: 1. A means for detecting the current step position of a step motor that drives a throttle valve that adjusts the amount of fuel or air in the internal combustion engine, and the step motor that corresponds to the operating state of the internal combustion engine. A microprocessor for controlling the required step position and power supply voltage monitoring means for detecting whether or not the power supply voltage is below a predetermined value by a predetermined time, and the detection voltage of the power supply voltage monitoring means is less than a predetermined value. At this time, the required step position is set as a value for step motor operation confirmation, and it is confirmed whether or not the current step position of the step motor moves to the required step position, and the detected voltage of the power supply voltage monitoring means is a predetermined value or more. Sometimes, the step motor control device is characterized in that the above confirmation is not performed.