Method for checking the actuating accuracy of a clutch when an electric or hybrid motor vehicle is at a standstill

A system for checking positional accuracy of a clutch comprising:

• an electric machine (2);
• a shaft (5,6) operatively coupled to and driven by the electric machine (2);
• a clutch (7,8) arranged in a force flow between the electric machine (2) and the shaft (5,6);
• and
• a control unit configured to check the positional accuracy of the clutch (7, 8);
• wherein the shaft (5,6) is configured such that it can be controlled to be held stationary;
• wherein, when the shaft (5,6) is held stationary:
• the control unit accelerates the electric machine (2) to a defined speed,
• the control unit sets a defined setpoint torque at the clutch (7, 8) to be checked,
• the control unit compares the torque of the electric machine (2) which is needed to maintain a constant speed with the setpoint torque set at the clutch (7, 8),
• wherein the control unit determines a torque difference between the torque reached and the setpoint torque;
• and
• the control unit automatically identifies an altered friction coefficient in the clutch based on the torque difference.

A system for checking positional accuracy of a clutch comprising:

• an electric machine (2);
• a shaft (5,6) operatively coupled to and driven by the electric machine (2);
• a clutch (7,8) arranged in a force flow between the electric machine (2) and the shaft (5,6);
• and
• a control unit configured to check the positional accuracy of the clutch (7, 8);
• wherein the shaft (5,6) is configured such that it can be controlled to be held stationary;
• wherein, when the shaft (5,6) is held stationary:
• the control units sets a defined setpoint torque at the clutch (7, 8) to be checked,
• the control unit accelerates the electric machine (2) to a threshold measurement level, and
• the control unit compares a needed torque of the electric machine (2) which is needed to satisfy the threshold measurement level with the setpoint torque set at the clutch (7, 8) and the control unit determines a torque difference therebetween;
• and
• wherein the control unit identifies an altered friction coefficient based on the torque difference and corrects for the altered friction coefficient.