JPH0510187A - Step motor controller in internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the extent of startability at the time of power cutoff by judging this power cutoff from a step position of a step motor driving a throttle valve, and omitting the content check of a random access memory at this cutoff time. CONSTITUTION:The current step position of a step motor at the operation start of a microprocessing unit is detected by a current step position detecting means 11 for detecting the current position of a throttle valve, and whether the current step position is more than the specified value or not is judged. In the case where it is less than the specified value or the last random access memory(RAM) check is abnormal, this RAM check is carried out, thereby preventing any malfunction from occurring, and in the case where it is more than the specified value and the last RAM check is normal, this RAM check is omitted, that is, control over the quantity of fuel and air is started, thus startability at the power 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, an electronic control unit used in an automobile or the like includes a microprocessor (hereinafter referred to as MPU) for detecting an engine state and controlling a fuel injection time, and a random access memory (for storing various control calculation results). Below R
(Hereinafter referred to as AM), etc., the MPU confirms whether or not the RAM is normal, and then starts controlling the amount of fuel or air.

Conventionally, the method of confirming the contents of the RAM of this type is shown in FIG.
Check all contents, and if normal, proceed to step 32 to start control of the amount of fuel and air. On the other hand, if the contents of the RAM are not normal, the process branches to step 33 to perform an alarm operation.

Another method is to use MP as shown in FIG.
Immediately after U start, control of the amount of fuel and air is started (step 41), and the contents of RAM are divided and confirmed so as not to hinder the control (steps 41 → 42 → 43 → 4).
1) There is known a method of performing an alarm operation (step 44) when it is not normal.

[0005]

However, the method of confirming the contents of the RAM before starting the process of controlling the amount of fuel and air as shown in FIG. There is a problem that the control of the amount of air is delayed and normal control cannot be performed.

On the other hand, as shown in FIG. 4, the method of dividing and confirming the contents of the RAM during the process of controlling the amount of fuel or air can solve the above-mentioned problems, and can also detect abnormalities during operation. It can be found, but because of the limited amount of time that can be confirmed in one loop (step 42), the confirmation range needs to be split, so
There is a problem in that there is a risk of malfunction due to the delay in the abnormality detection time.

Here, the starting point of the MPU for controlling the amount of fuel and air will be described. Since the power supply voltage of the on-vehicle battery as a power supply is low, a large current flows through the starter motor at the time of starting. , Periodically decreases to near 0 volts, so the MPU is reset and restarted. Further, as shown in FIG. 5, 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, after the MPU is reset and restarted due to a voltage drop due to cranking or the like, a time interval Tint until the TDC signal (51 in FIG. 5).
If the fuel cannot be injected during the period, the fuel cannot be injected, and if the time interval Tint is set to be long, the startability deteriorates.

Therefore, as shown in FIG. 3, the method of confirming whether the RAM is normal or not before starting the process of controlling the amount of fuel or air is said to deteriorate the startability when the power supply voltage decreases. There is a problem.

The present invention solves such conventional problems, and is excellent in preventing malfunctions when the power is turned on and improving startability in the event of a momentary interruption. Another object of the present invention is to provide a step motor controller.

[0010]

In order to achieve the above object, the present invention detects the current step position of a step motor which drives a throttle valve for adjusting the amount of fuel or air,
Means for detecting whether or not the current step position is equal to or greater than a predetermined value, a microprocessor for controlling the required step position corresponding to the operating state of the internal combustion engine, and random access for storing calculation results for performing fuel control and the like. A memory is provided to prevent malfunction of the step motor when the power is turned on, and to improve startability at the time of momentary interruption.

[0011]

Therefore, according to the present invention, when the ignition key of the vehicle is turned on and the MPU is started,
Since the step motor is returned to the fully closed position by the spring or the like, the current step position is less than the predetermined value, and the RAM
Since the confirmation of the contents of step 1 is performed, malfunction of the step motor can be prevented.

On the other hand, when the MPU is reset and restarted due to a power interruption during running or cranking, the step motor is not returned to the fully closed position,
The current step position is greater than or equal to the predetermined value, and in this case R
Since the processing for controlling the amount of fuel or air is immediately started without executing the confirmation of the contents of AM, it is possible to improve the startability at the time of a momentary interruption.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic block diagram showing an embodiment of the present invention, in which 11 is a current step position of a step motor for driving a throttle valve, and the current step position is a predetermined value THL0 or more or a predetermined value. Current step position detecting means for detecting whether the current step position is less than THL0, 12 is operated by the power supply voltage, and when the current step position is less than the predetermined value THL0, or the current step position is more than the predetermined value THL0, the contents of the RAM are checked last time If the result is abnormal, RA
When the contents of M14 are confirmed and the current step position is equal to or more than the predetermined value THL0 and the previous RAM contents confirmation result is normal, the contents of RAM14 are not confirmed and a control device for immediately controlling the amount of fuel or air is used. is there.

The control device 12 is composed of an MPU 13 for controlling the required step position of the step motor based on the output of the current step position detecting means 11 and a RAM 14 for storing various calculation results. The optimum fuel injection timing is calculated from various inputs indicating the state of the engine in synchronism with the TDC signal indicating, and the motor drive circuit 15 and the solenoid drive circuit 16 of the step motor that drives the throttle valve are driven.

When the ignition key of the car is turned on, M
When the PU 13 is started, the step motor is returned to the fully closed position by the spring or the like, so the current step position is less than the predetermined value, while the MPU 13 is reset and restarted due to cranking while running. At times, the step motor does not return to the fully closed position, and the current step position becomes a predetermined value or more.

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 21
Detects a momentary interruption in the power supply voltage, and in the case of a momentary interruption, step 2
If you branch to 2 and the power is turned on instead of instantaneous interruption,
The process branches to step 23. In step 22, it is determined whether or not the flag indicating that the RAM has been confirmed last time (hereinafter referred to as the RAM checked flag) is "1", and the flag is "1".
When the flag is “0”, the process branches to step 28. When the flag is “0”, the process proceeds to step 23. In step 23, the contents of the RAM are confirmed, and it is determined in step 24 whether the result is normal or not.
If the determination result is normal, the process branches to step 27. If the determination result is not normal, the RAM checked flag is reset to "0" in step 25, and an alarm operation is performed in step 26 to notify the driver of the abnormality. Also, step 2
In step 7, the RAM checked flag is set to "1", and thereafter, the process of controlling the amount of fuel and air (step 28) is started.

As described above, according to the above-described embodiment, the current step position detecting means 11 detects the current step position of the step motor when the operation of the MPU 13 is started, and whether or not the current step position is equal to or more than a predetermined value. When the current step position is detected and the current step position is less than the predetermined value, that is, when the ignition key of the vehicle is turned on and the MPU 13 is started, the current step position is less than the predetermined value, and in this case, the content of the RAM 14 is confirmed. Therefore, malfunction of the step motor can be prevented.

When the MPU 13 is reset and restarted due to a momentary power failure during traveling or cranking, the current step position is above a predetermined value. In this case, the contents of the RAM 14 are not checked. Since the process of controlling the amount of fuel or air is immediately started, the startability can be improved.

[0019]

As is apparent from the above embodiment, the present invention has the effect that there is no risk of malfunction of the step motor because the contents of the RAM are always confirmed when the power is turned on. In addition, when the power supply is momentarily turned off during driving or the power supply voltage drops and the power supply voltage returns within a predetermined time, the contents of the RAM are not checked and the amount of fuel or air is immediately controlled. Since the processing 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. 2 is a flowchart showing the operation of the device.

FIG. 3 is a flowchart showing the operation of a conventional step motor control device.

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

FIG. 5 is a timing chart for explaining the operation of the MPU when the power supply voltage changes.

[Explanation of symbols]

 11 Current Step Position Detection Means 12 Control Device 13 Microprocessor (MPU) 14 Random Access Memory 15 Step Motor and Its Drive Circuit 16 Fuel Injection Injector and Its Drive Circuit 17 Alarm Device

Claims (1)

Claim: What is claimed is: 1. A current step position of a step motor that drives a throttle valve for adjusting the amount of fuel or air of an internal combustion engine is detected, and it is detected whether or not the current step position is a predetermined value or more. Means, a microprocessor for controlling the required step position corresponding to the operating state of the internal combustion engine, and a random access memory for storing calculation results for performing fuel control, etc. A step motor control device, wherein when the current step position is less than a predetermined value, all the contents of the random access memory are confirmed, and when the current step position is more than a predetermined value, the above confirmation is not performed.