Method for operating a clutch

Abstract

The invention relates to a method for operating a clutch (2) of a motor vehicle (3), wherein the clutch (2) has a multiplicity of clutch linings (29) and has a clutch spring (4) and is connected to a hydraulic pressure system (5) which has a pump (6), a clutch cylinder (7) and a clutch piston (8), wherein the hydraulic pressure system (5) is suitable for delivering, by way of the pump (6), a hydraulic fluid (9) into the clutch cylinder (7) and moving the clutch piston (8), such that the clutch linings (29) can be placed in contact with one another counter to a force of the clutch spring (4), wherein, at the biting point (1) of the clutch (2), an air clearance (10) has been overcome and the clutch linings (29) have been placed in contact, and a further increase of a pressure (11) in the pressure system (5) would directly lead to provision of a torque capacity of the clutch (2), comprising at least the following steps: a) charging the clutch cylinder (7), with a controlled rotational speed (12) of the pump (6) for the purposes of delivering the hydraulic fluid (9) into the clutch cylinder (7), until the biting point (1) of the clutch (2) is reached and exceeded and a motor current (13) of the pump (6) has attained a predetermined minimum value (14); and b) determining, on the basis of a profile of the controlled rotational speed (12) in step a), a first volume (15) of the hydraulic fluid (9) delivered into the clutch cylinder (7) by way of the pump (6) up until the attainment of the minimum value (14); c) reducing the value of the first volume (15) by a predetermined amount (36) such that a second volume (16) is defined; d) using the second volume (16) for clutch processes during the operation of the motor vehicle (3), wherein the second volume (16) is delivered into the clutch cylinder (7), with a high rotational speed (12) of the pump (6), such that the clutch (2) is filled to such an extent that the biting point (1) of the clutch (2) is not quite reached.

Description

technical field [0001] The invention relates to a method for operating a clutch of a motor vehicle. Background technique [0002] This method can be used in particular with all hydraulically actuated clutches. These include clutches in onboard systems (such as boosters), clutches in torque vectoring systems (such as Twinster, BMW-QMVH), clutches in separation systems (PTU with friction diaphragm systems), Clutches in the shift transmission (Volvo2Speed) and clutches in the locking differential (transversal locker in the RDU). [0003] The clutch generally includes a plurality of clutch plates and clutch springs and is connected to a hydraulic pressure system having at least one pump, a clutch cylinder and a clutch piston. In particular, at least one valve is arranged between the pump and the clutch cylinder. The hydraulic pressure system is suitable for feeding hydraulic fluid into the clutch cylinder via a pump and possibly a valve and for moving the clutch piston in a t...

AI Technical Summary

Problems solved by technology

However, this method requires a complex and thus cost-intensive evaluation unit of the sensor system, wherein the time period over which the point of action is reliably reached (but not exceeded) is relatively long due to repeated measurement and control

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