Electrically Powered Hydraulic Pump Derating for Thermal Management
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Solution Overview
Problem
Hybrid powertrain systems employing electrically-powered hydraulic pumps face challenges in managing temperature to prevent overheating, which can lead to reduced efficiency and potential damage due to the lack of effective derating mechanisms that balance hydraulic pressure and lubrication flow.
Innovation Solution
A powertrain system that monitors the temperature of the electrically-powered hydraulic pump and derates its power output by decreasing rotational speed while maintaining hydraulic pressure, ensuring adequate lubrication and cooling through a controlled pump derate operating scheme.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the electrically-powered hydraulic pump operates at high power output, then hydraulic pressure is maintained, but temperature increases leading to overheating
Solution Approach 1:
The patent implements dynamic derating of the electric motor's maximum power output based on real-time temperature monitoring. When the pump motor temperature exceeds a threshold, the controller automatically reduces the maximum power output from the rated level to a derated level, preventing further temperature increase while maintaining adequate hydraulic pressure for system operation.
Solution Approach 2:
The patent changes the operational parameters of the electric motor by adjusting the maximum power output level based on temperature conditions. The controller modifies the power parameter from full rated power to a reduced derated power when temperature thresholds are exceeded, thereby resolving the contradiction between maintaining power output and preventing overheating.
2Temperature
If the rotational speed of the hydraulic pump is decreased to reduce power demand, then temperature is controlled, but hydraulic pressure may drop
Solution Approach 1:
The system dynamically adjusts operational parameters based on temperature conditions. When derating is activated due to high temperature, the controller reduces maximum power output while maintaining hydraulic pressure through coordinated control of the electric motor and hydraulic system, ensuring both temperature management and pressure maintenance are achieved simultaneously.
Solution Approach 2:
The patent employs a feedback control mechanism where the controller continuously monitors temperature and hydraulic pressure conditions. Based on this feedback, the controller adjusts the maximum power output of the electric motor to maintain hydraulic pressure within acceptable ranges while preventing temperature from exceeding thresholds, thus resolving the contradiction between temperature control and pressure maintenance.
3Temperature
If the maximum power output is derated to prevent overheating, then temperature is controlled, but productivity decreases
Solution Approach 1:
The patent applies partial derating of power output only when necessary to prevent overheating, rather than continuously reducing power. The derated power level is sufficient to control temperature while maintaining adequate hydraulic pressure and system functionality, thus preserving productivity to the maximum extent possible under thermal constraints.
Solution Approach 2:
The derating mechanism operates periodically based on temperature threshold crossings. When temperature exceeds the threshold, derating is activated; when temperature returns to acceptable levels, full power output is restored. This periodic adjustment allows the system to maintain high productivity during normal operation while preventing overheating through temporary power reduction only when necessary.
Data Source
AI summary
A powertrain system includes a transmission employing an electrically-powered hydraulic pump providing pressurized hydraulic fluid to a hydraulic circuit. A method of operating the powertrain system includes monitoring a temperature of the hydraulic pump. In response to the temperature exceeding a threshold temperature, power output from an electrically-powered motor coupled to the hydraulic pump is derated, which includes decreasing rotational speed of the hydraulic pump and maintaining hydraulic pressure in the hydraulic circuit.