Control system for a clutch for a vehicle

Claim 1

In control system for controlling and electromagnetic clutch for a motor vehicle having an engine with a throttle valve operatively connected to an accelerator pedal, a transmission operatively transmitting the power of the engine to wheel through a power transmitting path, sensing means for sensing operating conditions of the engine and transmission and for producing condition signals dependent on the operating conditions, start mode providing means for providing a start mode and for producing a start clutch current at depression of the accelerator pedal, drag mode providing means responsive to release of the accelerator pedal for providing a drag mode and for producing a drag clutch current to produce a drag troque on the electromagnetic clutch, and mode deciding means for deciding one of the modes responsive to the condition signals, the improvement in the control system comprising; transient state deciding means for deciding a transient state responsive to an output signal of the more deciding means at the release of the accelerator pedal for producing a transient signal, clutch current detecting means responsive to an output signal of the start mode providing means for detecting clutch current just before the release of the accelerator pedal, clutch current control means responsive to an output signal of the clutch current detecting means for quickly reducing the clutch current to a first predetermined value and thereafter gradually reducing the clutch current to a second predetermined value lower than the first predetermined value to disengage the clutch, and engine speed control means gradually reducing the speed of the engine upon the release of the accelerator pedal, so as to prevent oscillation of the power transmitting path.