Control apparatus and method for controlling a volume flow of a fluid in a drive train of a motor vehicle

A hydraulic conveying system for a motor vehicle comprising:

• a conveying device having a pump and a drive motor coupled to the pump;
• a rotational speed detection unit configured to detect a variable representing a current rotational speed of the drive motor;
• a torque detection unit configured to detect a variable representing a current torque of the drive motor;
• and a control device including:
• a rotational speed specification input for receiving a target rotational speed signal representing a target rotational speed of a drive motor for driving a pump for conveying a fluid;
• a power output for connection to the drive motor;
• a torque monitoring unit configured to (i) determine, based on a characteristic diagram of the pump that describes a functional dependency between a torque to be applied by the drive motor and a rotational speed of the drive motor for a predetermined fluid state of the fluid, a current torque deviation occurring between the current torque and a torque given by the characteristic diagram for a current rotational speed of the drive motor, and (ii) generate a torque deviation signal representing the current torque deviation;
• a rotational speed regulation unit configured to generate, based on the target rotational speed signal and the current rotational speed signal, a first power setting signal that represents a target torque of the drive motor;
• a correction unit configured to correct the first power setting signal in accordance with the torque deviation signal and to provide a corrected first power setting signal;
• and a power regulation unit configured to generate a second power setting signal based on of the corrected first power setting signal and the current torque signal and to provide the second power setting signal at the power output to actuate the drive motor according to the second power setting signal;
• wherein the power output of the control device is connected to a power input of the drive motor;
• wherein the rotational speed detection unit is connected to the rotational speed specification input of the control device;
• and wherein the torque detection unit is connected to a torque input of the control device.

A method for regulating a volume flow of a fluid conveyed through a drive train of a motor vehicle by a pump driven by a drive motor, the method comprising:

• detecting a current rotational speed of the drive motor;
• detecting a current torque of the drive motor;
• determining, based on a characteristic diagram of the pump that describes a functional dependency between a torque to be applied by the drive motor and a rotational speed of the drive motor for a predetermined fluid state of the fluid, a current torque deviation between the detected current torque and a torque given by the characteristic diagram for the current rotational speed;
• determining a target torque of the drive motor based on a target rotational speed and the detected current rotational speed;
• correcting the target torque in accordance with the detected current torque deviation;
• and regulating the current torque of the drive motor to the corrected target torque.