JPH0578455B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for an electromagnetic clutch for a vehicle.

[Conventional technology]

As a conventional device of this type, for example,
There is No. 1431. FIG. 5 shows a configuration diagram of a conventional device. In the figure, 1 is clutch current control means, 2
1 is a clutch current calculation means such as a microcomputer, 3 is an on-vehicle battery, 4 is an electromagnetic clutch consisting of an excitation coil 41 and a power supply mechanism 42, 11 is a positive side transistor, 12 is a negative side transistor, 13 is a clutch current detection resistor, and 14 is a A deviation amplifier 15 calculates the difference between the current control signal S _I given from the clutch current calculation means 2 and the current feedback signal S _F that feeds back the clutch current, and 15 generates an on/off signal for the positive side transistor 11 based on the output of the deviation amplifier 14. pulse width modulator, 16 and 17 are freewheeling diodes, 1
Reference numerals 8 and 19 refer to reverse excitation resistors for causing a minute reverse excitation current to flow through the clutch current when both transistors 11 and 12 are off. Reference numerals 20 and 21 represent output terminals of the clutch current control means 1, which are connected to the electromagnetic clutch 4. .

The operation of the above structure will be explained using the flowchart of FIG. 6 showing the operation of the clutch current calculation means 2. In step 601, vehicle speed is calculated, and in step 602, engine rotation speed is calculated. Also, in step 603, travel control information S _D is input, and the step
At 604, engine control information S _E is input. In step 605, the clutch torque is calculated from the above information,
In step 606, a clutch current corresponding to this clutch torque is output. When the clutch is released, both transistors 11 and 12 are turned off by the output of the pulse width modulator 15 and the release signal S _O from the clutch current calculation circuit 2, and the clutch 4 is opened.
A minute reverse excitation current flows through resistors 18 and 19. Also, when the clutch is connected, transistor 1
2 remains on, the feedback value S _F of the clutch current detected by the resistor 13 and the command signal S _I from the arithmetic circuit 2 are compared in the deviation amplifier 14, and the deviation is outputted via the pulse width modulator 15. By applying it to transistor 11, it turns transistor 11 on and off and controls the clutch current. Note that when the transistor 11 is off, a return current flows through the diode 16.

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional device, protection for the output transistors 11 and 12 is not considered at all, so there may be problems such as faulty vehicle wiring and clutch power supply mechanism 42.
There were many cases where the output transistors 11 and 12 were destroyed by overcurrent due to a defect in the excitation coil 41 or poor insulation of the excitation coil 41. In particular, even though the control mechanism itself is normal, the above-mentioned defect may lead to permanent destruction, which is not desirable in terms of vehicle maintenance.

This invention was made to solve the above-mentioned problems, and it is an object of the present invention to provide a control device for a vehicle electromagnetic clutch that can prevent permanent destruction of the output transistor used in the clutch current control means. purpose.

[Means for solving problems]

A control device for a vehicle electromagnetic clutch according to the present invention is provided with an overcurrent detector or an overvoltage detector for detecting overcurrent or overvoltage of an output transistor.

[Effect]

In this invention, an overvoltage detector or an overcurrent detector for the output transistor is provided, and when an overcurrent or overvoltage of the output transistor is detected, measures such as opening the clutch are taken depending on the condition of the engine speed. Off etc.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram, and FIGS. 2 and 3 are explanatory diagrams. In FIG. 1, 100 is a current detector, 101 is a positive current detection resistor, and 102 to 10
9, 111 to 113, 115 are resistances, 110, 1
14 is a house current detector.

In the above configuration, the current of the positive side transistor 11 is detected by the positive side current detector resistor 101, this detected current is shaped by the current detector 100, and the overcurrent detector 110 receives this shaped output and detects the overcurrent. Detect and obtain overcurrent detection signal S _C1 . Further, the current of the negative side transistor 12 is detected by the current detection resistor 13, and whether or not this detected current is an overcurrent is detected by the overcurrent detector 114. In the case of an overcurrent, an overcurrent detection signal S _C2 is sent. obtain. The overcurrent detection signals S _C1 and S _C2 serve as control input information for the clutch current calculating means 2, as shown in FIG. Of course, travel control information S _D and engine control information S _E are also input. Further, the clutch current control means 2 outputs a current command signal S _I and a clutch 4 release signal S _O. The basic on/off operation of the output transistors 11 and 12 is the same as the conventional one.

FIG. 3 shows a flowchart of the protective operation of this embodiment. In step 301, it is determined whether there is an overcurrent, and if there is no overcurrent, the fail safe is canceled in step 303, and the transistors 11 and 12 are
performs normal on/off operation. If there is an overcurrent, the engine speed is determined in step 302, and the following three cases are handled individually. If the engine speed increases abnormally and the vehicle does not accelerate even though there is an overcurrent and the driver has not requested acceleration, the latch may be open due to a short circuit or ground fault, for example. Conceivable. If this state continues, the output transistor will be destroyed due to overcurrent, so the corrective action is to open the clutch and cut off the current. When the driver releases the accelerator, coasts, or decelerates, and the engine speed is in the normal speed range, it is abnormal but not a complete short circuit, so engine braking must be applied to ensure driving safety. Directly connected to clutch. Also, if the engine speed falls below the idle speed near the vehicle stop,
Release the clutch. If the clutch remains directly engaged when starting the engine or stopping the vehicle, the engine will stall, so the clutch should be released. In order to intentionally open the clutch, the current command signal S _I is set to zero, the clutch release signal S _O is set to open, and the output transistors 11 and 12 are turned off.

FIG. 4 shows a second embodiment of the invention, 12
0,140 is a logic circuit, 121-125,12
7,129,130,132,141~145,
148, 149, 151 are resistances, 128, 146
is a capacitor, 126, 147 is a voltage detector, 1
31,150 is an overvoltage detector.

In the above configuration, when an overcurrent flows through the transistors 11 and 12, the voltage drop across the transistors 11 and 12 increases. Voltage detectors 126 and 147 receive reference values input from pulse width modulator 15 via logic circuits 120 and 140 and transistors 11 and 1.
In addition to comparing the feedback values from the transistors 11 and 12, it also serves as a filter to eliminate ripples caused by the on/off of the transistors 11 and 12. Overvoltage detector 13
1 and 150 are voltage detectors 126 and 147, respectively.
If the output is large, it is determined that there is an overvoltage, and overcurrent (overvoltage) detection signals S _C1 and S _C2 are output. Other operations are the same as in the previous embodiment.

〔Effect of the invention〕

As described above, according to the present invention, overcurrent or overvoltage of the output transistor of the clutch current control means is detected, and measures such as opening the clutch are taken in conjunction with the status of the engine speed, and the output transistor is turned off. This protects the output transistor, thereby preventing permanent damage to the output transistor due to faulty vehicle wiring, faulty clutch power supply mechanism, faulty coil view, etc.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a first embodiment of the device of the present invention, FIG. 2 is an explanatory diagram of input and output of the clutch current calculation device of the present invention, and FIG. 3 is a flowchart of the protection operation of the device of the invention. FIG. 4 is a block diagram of a second embodiment of the inventive device, FIG. 5 is a block diagram of a conventional device, and FIG. 6 is a flowchart showing the operation of the conventional clutch current calculating device. 1... Clutch current control means, 2... Clutch current calculation means, 4... Electromagnetic clutch, 11, 12
... Output transistor, 14 ... Deviation amplifier, 1
5... Pulse width modulator, 110, 114... Overcurrent detector, 131, 150... Overvoltage detector.
Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1 Clutch current calculation means that calculates the current of the vehicle electromagnetic clutch in response to engine control information and travel control information; upon receiving the output of the clutch current calculation means, current is passed through the electromagnetic clutch through the output element and transmitted to the vehicle. A control device for an electromagnetic clutch for a vehicle is provided with a clutch current control means for controlling the torque of the clutch, and includes an overcurrent detector or an overvoltage detector for detecting overcurrent or overvoltage of the output element, The vehicle is characterized in that the means detects a failure based on the detection output of the overcurrent detector or the overvoltage detector, the engine control information, and the traveling control information, and releases the electromagnetic clutch when the failure is detected. Control device for electromagnetic clutches.