Electric Oil Pump Cooling Control for Erroneous Fault Detection
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Solution Overview
Problem
Existing cooling systems for electric vehicles often lead to erroneous detection of electric oil pump faults or restrict the operating temperature range, causing the electric oil pump to be deactivated unnecessarily, especially at low outside air temperatures.
Innovation Solution
A cooling system with an electric oil pump, outside air temperature sensor, and oil temperature sensor, controlled by a CPU that permits actuation based on specific temperature thresholds for both oil and air temperatures, allowing continued operation without fault judgment in certain conditions to prevent erroneous detection and expand the operable range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric oil pump is operated at low outside air temperature, then the motor cooling function is maintained, but mileage per charge is reduced
Solution Approach 1:
The control device changes the activation temperature threshold parameter dynamically based on outside air temperature. When the outside air temperature is low, the system raises the oil temperature threshold required for pump activation, preventing operation in conditions where the oil viscosity is too high regardless of motor temperature, thus avoiding unnecessary energy consumption.
Solution Approach 2:
The system transitions from a static temperature-based activation criterion to a dynamic one that considers both outside air temperature and oil temperature. The activation condition becomes adaptive, changing based on environmental conditions to optimize between cooling reliability and energy efficiency.
2Use of energy by moving object
If the electric oil pump is kept inactive at low outside air temperature to save energy, then mileage per charge is improved, but erroneous fault detection occurs
Solution Approach 1:
The system introduces a dynamic temperature threshold parameter that adjusts based on outside air temperature. This prevents the pump from being activated when oil viscosity is too high due to cold conditions, thereby avoiding false fault detections while still allowing operation when conditions are suitable.
Solution Approach 2:
The outside air temperature acts as an intermediary parameter that mediates between energy conservation goals and fault detection accuracy. By using this external environmental parameter, the system can make informed decisions about pump activation that prevent erroneous fault detection without unnecessarily sacrificing energy efficiency.
3Adaptability or versatility
If the activation temperature threshold is lowered to allow pump operation in cold conditions, then the operable region is expanded, but the pump may fail to activate due to high oil viscosity
Solution Approach 1:
Rather than lowering the activation threshold, the system raises it dynamically based on outside air temperature. This ensures that even though the pump can operate in a broader temperature range, activation only occurs when environmental conditions indicate the oil viscosity is suitable, maintaining high activation success rates.
4Measurement precision
If a temperature sensor is installed in the electric oil pump to directly measure oil temperature, then activation judgment accuracy is improved, but system complexity increases
Solution Approach 1:
The system uses outside air temperature as an intermediary parameter to infer oil temperature conditions. Instead of directly measuring oil temperature with a sensor in the pump, the control device uses the relationship between air temperature and oil temperature to determine suitable activation conditions, avoiding the need for additional sensors and reducing system complexity.
Solution Approach 2:
The system leverages existing sensor data (outside air temperature) to make activation decisions without requiring additional measurement infrastructure. The control device self-sufficiently determines activation suitability using environmental parameters already available in the system.
Data Source
AI summary
A cooling system 100 includes an electric oil pump 18, an outside air temperature sensor 22, an oil temperature sensor 21, and a controller 30. The controller 30 permits the actuation of the electric oil pump 18 in one of a first case where an oil temperature To is equal to or greater than a first threshold (A) and where an outside air temperature Ta is equal to or greater than a second threshold (B), a second case where the outside air temperature Ta is less than the second threshold (B) and where the oil temperature To is equal to or greater than a third threshold (C) higher than the first threshold (A), and a third case where the oil temperature To is less than the first threshold (A) and where the outside air temperature Ta is equal to or greater than a fourth threshold (D) higher than the second threshold (B).