JPS63212751A - Control device for motor for controlling vehicle - Google Patents

Abstract

PURPOSE:To prevent the temperature rise and burning of a motor by stopping the motor for a preset time if the current of the DC control motor to follow the target value is kept at the preset duty ratio or higher for a prescribed time or longer. CONSTITUTION:An exhaust control valve 38 is driven to be opened or closed by a DC servo-motor 42 via a wire 40. A CPU 48 reads out from a ROM 50 the data corresponding to the engine rotating speed detected from an ignition circuit 46 and calculates the target opening of the control valve 38. The motor control signal is outputted to a driver 52 based on the difference between the target opening and the present opening of the control valve 38 detected by a potentiometer 42 and the size of the engine load, and the size of the duty ratio of the motor current is controlled. The CPU 48 monitors the duty ratio of the motor current and stops the motor 42 for a preset time if the preset duty ratio or more is continued for a prescribed time or longer. Accordingly, a large motor current is prevented from flowing continuously exceeding the rated current.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention determines a target value corresponding to the operating state of a vehicle engine, and controls a control motor to this target value using a pulse width modulation method (
The present invention relates to a control device for a vehicle control motor that performs follow-up control using a PWM method.

(Background of the invention) Vehicle engines have large rotational speed and load fluctuations, so
BACKGROUND ART There are known systems that detect the operating state of an engine and control the opening and closing of various control valves to achieve optimal control according to the operating state of the engine. For example, an exhaust control valve is installed near the downstream open end of the exhaust pipe, and in the high speed range of the engine, this control valve is fully opened to maximize the dynamic effect of the exhaust system to increase output. There is a system that prevents this dynamic effect from acting in the opposite direction in the speed range and causing a torque valley by closing the control valve to an opening of about 1/2 (Japanese patent application No. 6).
0-263752). Furthermore, various proposals have been made in which a control valve is provided in a connecting pipe that connects a plurality of intake pipes, and the control valve is opened and closed depending on the engine speed to substantially change the length of the intake pipe.

When this type of control valve is opened and closed by a DC motor controlled by the pulse width modulation method (hereinafter referred to as PWM method), the duty ratio of the motor current (the ratio of the current on time to the current off time) is the same as the target value and the current value. Control is performed to change the size depending on the difference and the size of the load. However, if the motor load increases due to, for example, a car indicator or dust sticking to the control valve, the operation continues at a high duty ratio, the remoter current becomes excessive, the motor temperature rises, and the motor stops working. There was a risk of burnout.

(Object of the Invention) The present invention has been made in view of the above circumstances, and provides a PWM method to control a control motor that performs follow-up control so as to follow a target value that changes in accordance with the operating state of the engine. An object of the present invention is to provide a control device for a motor for controlling a heavy wheel, which can reliably prevent motor temperature rise and motor burnout due to an excessive load and a continued high duty ratio of motor current. shall be.

(Structure of the Invention) According to the present invention, this object is provided with a DC control motor that follows a target value that changes depending on the operating state of the engine,
In a device that performs pulse width modulation control of a motor current, a first stage for detecting the operating state of the engine, a seventh stage for calculating a target value for determining a target value corresponding to the operating state, and a current value detecting means for determining the current value of the motor. , a determining means for outputting a motor control signal that changes the duty ratio of the motor current in response to the difference between the target value and the current value, a driver for driving the motor based on the motor control signal, and a determination unit for determining the duty ratio of the motor current. This is achieved by a control device for a motor for controlling a vehicle, characterized in that it includes an energization time management means that monitors the duty ratio and stops the motor for a predetermined time when the state of the duty ratio exceeds a predetermined duty ratio for a predetermined time.

Here, the target value may be a target zone with a width.

(Embodiment) FIG. 1 is an overall diagram of an embodiment of the present invention, FIG. 2 is a block diagram showing functions, and FIG. 3 is an operation flowchart. In FIG. 1, the symbol lO is a four-stroke engine, and the intake valve 1
2 and the exhaust valve 14 are opened and closed at predetermined timing by a valve mechanism (not shown). 16 is a cylinder, 18 is a piston, and 20 is a spark plug. Air intake system is air cleaner 22
, an air flow meter 24, a throttle valve 26, and a fuel injection valve 28. An intake air flow rate determined by the rotational speed of a crankshaft (not shown) of the engine IO and the opening degree of the throttle valve 26 is drawn into the intake system from the air cleaner 22, and the intake air flow rate is measured by an air flow meter 24. A computer (not shown) calculates the optimum fuel supply amount corresponding to this intake air flow rate and engine lO operating conditions (for example, engine temperature, etc.), and this calculated fuel is injected into the intake air from the fuel injection valve 28. Injected into tube 30.

The exhaust system includes a first exhaust pipe 32 connected to the exhaust valve 14,
It includes an expansion chamber 34 connected to the downstream end of this exhaust pipe 32, and a second exhaust pipe 36 connected to the further downstream side of this expansion chamber 34. A butterfly-shaped exhaust control valve 38 is disposed near the downstream end of the first exhaust pipe 32. This exhaust control valve 38 is driven to open and close by a DC servo motor 42 via a wire 40. A potentiometer 44 as a current value detection means A is attached to the motor 42, and this potentiometer 44 detects the rotation angle of the motor 42, that is, the current opening degree of the control valve 38, which is 0 (current value).

Reference numeral 46 denotes an ignition circuit as the operating state detection means B, and the engine rotation speed n is detected from this ignition circuit 46.

48 is a CPU, target value calculating means C1 discriminating means D,
It is provided with various functions such as an energization time management means E. The target value calculation means C is a ROM 50 that stores a control map.
The data corresponding to the rotational speed n is read out from the control valve 38.
■ Calculate the target opening degree Oo (target value). This ROM
50 corresponds to control map reference means F in the functional block diagram of FIG. The determining means outputs a motor control signal α to the driver 52 based on the difference between the target opening degree Oo and the current opening degree 0 and the magnitude of the load. That is, this signal α controls the duty ratio (ratio of on time to off time) of the motor current to be large or small depending on the magnitude of this difference, and also controls the duty ratio to be large or small depending on the magnitude of the load. Note that the direction of the current is reversed depending on whether the difference is positive or negative.

The energization time management means E monitors the duty ratio of the motor current, and outputs a stop signal S to stop the motor 42 for a predetermined time when the duty ratio exceeds a predetermined duty ratio for a predetermined time or longer. The determining means stops the motor 38 based on this stop signal S.

Next, the operation of this embodiment will be explained based on FIG. In this embodiment, a series of operations including the motor control subroutine shown in this figure are repeated at regular intervals (for example, every 2 m5ec). Motor current is 2ms e cX4=8m
Let s e c be one period, 2 ms e C (7) 1.2
．． Four types of duty ratios of 3.4 times are selectable (rr).The CPU 48 enters the subroutine shown in FIG. 3 every 2 msec, and first determines whether the motor current is zero (step 100).The count number N is set to 5000 in advance in the addition/subtraction counter built in the CPU 48, and if I=O, l is added.Step 102)
If I≠0, subtract 2 (step 104). As a result, if the count number N underflows to r after zero (step 108), the determining means E operates the motor 42 for a predetermined period of time, e.g.
It stops for a second (step 11O).

If the count number N does not underflow, N is 500.
It is determined whether it is greater than or equal to 0 (step 112), and if it is greater than or equal to 5000, it is reset to N=5000 (step 114).

For example, if the duty ratio is 1/3, the count number N will not change. However, as the duty ratio becomes larger, N decreases faster and the time required for underflow becomes shorter. For example, if the duty ratio is 100%, the time required for underflow is 2 x 5000 = 10000 m5ec = 1
It becomes 0 sec. Generally, the allowable operating time of the motor 42 changes depending on the magnitude of the duty ratio, but according to this embodiment, the allowable time suitable for the motor 42 can be changed depending on the duty ratio. Adapted control becomes possible.

However, the present invention is not limited to this embodiment, and includes a system in which the duty ratio is monitored and the operation is stopped for a predetermined period of time after determining that the operation has been continued for more than a certain period of time at a constant duty ratio.

In this embodiment, the present invention is applied to drive the exhaust control valve 38 at the downstream end of the exhaust pipe 32, and the valve is opened in the high speed range of the engine and closed in the middle speed range to prevent the occurrence of torque valley in the middle speed range. It is something to do. However, the present invention may be used to control other control valves, such as a control valve that controls the intake pipe length.

(Effects of the Invention) As described above, the present invention monitors the duty ratio of the motor current when controlling the control motor to the target value determined from the engine operating state using the PWM method, and
Since the motor is stopped for a predetermined time if the duty ratio state continues for a predetermined time or more, it is possible to prevent a large motor current from continuing to flow beyond the rated time. Therefore, problems such as the motor heating up and shortening its life do not occur.

[Brief explanation of the drawing]

FIG. 1 is an overall diagram of an embodiment of the present invention, FIG. 2 is a block diagram showing functions, and FIG. 3 is an operation flowchart. DESCRIPTION OF SYMBOLS 10...Engine, 42...Motor, 52...Driver, 0...Current value, θ0...Target value, A...Current value detection stage, B...Operating state detection means , C...Target value calculation means, D...Discrimination means, E...Electrification time management means.

Claims (2)

[Claims] (1) A DC control motor that follows a target value that changes depending on the operating state of the engine, and which controls the motor current by pulse width modulation, comprising means for detecting the operating state of the engine and a target that corresponds to the operating state. target value calculating means for calculating the current value; current value detecting means for calculating the current value of the motor; and determining means for outputting a motor control signal that changes the duty ratio of the motor current in response to the difference between the target value and the current value. a driver that drives the motor based on the motor control signal; and an energization time management means that monitors the duty ratio of the motor current and stops the motor for a predetermined time when the duty ratio exceeds a predetermined duty ratio for a predetermined time or more. A control device for a motor for controlling a vehicle. (2) A patent characterized in that the energization time management means includes an addition/subtraction counter that subtracts a predetermined value when the motor current is on and adds a predetermined value when the motor current is off, and stops the motor when the addition/subtraction counter underflows. Claim 1
A control device for a motor for controlling a vehicle as described in 1.