Drive Train Fluid Flow Control Using Torque-Based Pump Correction
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Solution Overview
Problem
Existing systems for regulating hydraulic fluid volume flow in motor vehicle drive trains lack accuracy and are prone to errors, as they require direct measurement of volume flow, which increases costs and susceptibility to errors, and do not effectively account for fluid viscosity changes.
Innovation Solution
A control device that regulates hydraulic fluid volume flow by monitoring the torque and rotational speed of the drive motor using a characteristic diagram, allowing for closed-loop regulation and detection of viscosity changes without direct volume flow measurement, thereby correcting the torque to achieve the target volume flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct volume flow measurement is used to regulate hydraulic fluid flow, then regulation accuracy is improved, but system cost and error susceptibility increase
Solution Approach 1:
The patent uses torque and rotational speed as intermediary parameters to indirectly determine volume flow. Instead of directly measuring volume flow with complex and error-prone sensors, the system measures torque (via current) and rotational speed, then uses the characteristic diagram to calculate volume flow. This intermediary approach simplifies the measurement system while maintaining regulation accuracy.
Solution Approach 2:
The patent replaces direct mechanical volume flow measurement with an electrical/control-based calculation system. By using the relationship between torque, rotational speed, and volume flow stored in a characteristic diagram, the system substitutes complex mechanical flow sensors with simpler electrical measurements and computational methods.
2Extent of automation
If direct volume flow measurement is implemented, then closed-loop regulation is achieved, but system complexity and cost increase
Solution Approach 1:
The patent extracts the essential information needed for closed-loop regulation (volume flow) from the complex direct measurement approach. By taking out only the necessary measurements (torque and rotational speed) and using the pre-stored characteristic diagram, the system achieves closed-loop control without the complexity of direct volume flow sensors.
Solution Approach 2:
The characteristic diagram is prepared in advance, storing the relationship between torque, rotational speed, and volume flow. This preliminary action allows the control system to perform quick lookups and calculations during operation, enabling closed-loop regulation without real-time complex measurements.
3Manufacturing precision
If torque correction based on characteristic diagram is used, then volume flow regulation accuracy is improved, but computational requirements increase
Solution Approach 1:
The characteristic diagram is pre-calculated and stored in memory during system setup or manufacturing. This preliminary computation of the torque-speed-flow relationship eliminates the need for complex real-time calculations during operation, reducing computational power requirements while maintaining high regulation precision through simple lookup and correction operations.
Data Source
AI summary
A control device for regulating a volume flow of a fluid in a drive train of a motor vehicle includes a torque monitoring unit, set up to determine, on the basis of a characteristic diagram of the pump which describes a functional dependency of the torque to be applied by the drive motor on the rotational speed of the drive motor for a predetermined fluid state of the fluid, a current torque deviation occurring between the current torque and the torque given by the characteristic diagram for the current rotational speed, and a correction unit, set up to correct a power setting signal for the drive motor in accordance with the current torque deviation and to provide a corrected power setting signal, and a power regulation unit, set up to generate a second power setting signal for actuating the drive motor on the basis of the corrected power setting signal.