Motor Unit Pump Control Using Coil Temperature Estimation
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Solution Overview
Problem
Conventional motor units without an oil temperature sensor face challenges in driving control of the electric oil pump, especially in low temperature environments, where inappropriate activation can lead to the pump being deemed defective due to limited self-starting processes.
Innovation Solution
A control device for a motor unit that includes a motor controller and a pump controller, which estimates oil temperature based on ambient temperature and coil temperature, determining the start timing of the electric oil pump to ensure proper activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an oil temperature sensor is installed to enable accurate driving control of the electric oil pump, then the reliability of the oil pump control is improved, but the device complexity and cost increase
Solution Approach 1:
The patent uses the coil temperature sensor as an intermediary to indirectly obtain information about the oil temperature. Instead of directly measuring oil temperature with a dedicated sensor, the system uses the coil temperature (which correlates with oil temperature) as a substitute measurement, thereby avoiding the need for an additional oil temperature sensor while still enabling reliable control decisions.
Solution Approach 2:
The coil temperature sensor serves multiple functions: it monitors the motor coil temperature for motor control purposes and simultaneously provides indirect information about the oil temperature for oil pump control. This multi-functional use of the existing sensor eliminates the need for a separate oil temperature sensor, reducing device complexity while maintaining control reliability.
2Speed
If the electric oil pump is activated early in low temperature environments, then the operational readiness is improved, but the pump may not activate properly and be deemed defective, worsening the reliability
Solution Approach 1:
The system continuously monitors the coil temperature and uses this feedback to dynamically adjust the activation timing of the electric oil pump. By comparing the coil temperature (which reflects oil temperature conditions) against predetermined thresholds, the control device determines the appropriate moment to activate the pump, ensuring activation occurs only when conditions are suitable for reliable operation.
Solution Approach 2:
The system performs preliminary monitoring of the coil temperature before activating the oil pump. This preliminary action allows the system to assess whether the temperature conditions are appropriate for pump activation, preventing premature activation that would lead to failure while still enabling timely activation when conditions permit.
3Device complexity
If no oil temperature sensor is equipped to reduce size and cost, then the device complexity is reduced, but the ability to perform adequate driving control in low temperature environments deteriorates
Solution Approach 1:
The system uses the existing coil temperature sensor to serve the additional function of oil temperature monitoring. The coil temperature data, which would otherwise be used solely for motor control, is repurposed to also inform oil pump control decisions. This self-service approach allows the system to maintain adequate driving control capability without adding dedicated oil temperature sensing equipment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables reliable operation of the electric oil pump even in low temperature environments without an oil temperature sensor, improving operational reliability and efficiency by accurately determining the start timing based on estimated oil temperature.
Implementation Method 1
a coil temperature sensor detecting a temperature of the coil
Implementation Method 2
an electric oil pump delivering oil stored in the housing
Data Source
AI summary
A control device for a motor unit provided in a vehicle is disclosed. The motor unit includes a motor including multiple coils provided side by side around a motor axis; a transmission mechanism transmitting power of the motor to an axle; a housing housing the motor and the transmission mechanism; an electric oil pump delivering oil stored in the housing; and a coil temperature sensor detecting a temperature of the coil. The control device includes a motor controller driving and controlling the motor; and a pump controller driving and controlling the electric oil pump. The pump controller estimates an oil temperature according to an ambient temperature and the temperature of the coil, and determines a start timing of the electric oil pump based on an estimated oil temperature.