Vehicle Thermal Management Pump Control for Compressor Restart Cooling
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Solution Overview
Problem
When the compressor in a vehicle's thermal management system is stopped, the secondary cooling circuit's external heat exchanger quickly terminates cooling, leading to a high temperature at the refrigerant-coolant heat exchanger, increasing refrigerant pressure and power consumption upon restart, which degrades cycle efficiency.
Innovation Solution
A thermal management system that includes a first pump to continue circulating a heat medium even after the compressor is stopped, using a heat medium-outside air heat exchanger to cool the heat medium, thereby preventing temperature and pressure increases, and a pump control unit to manage this operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the pump stops at the same time as the compressor, then the system operation is simplified, but the refrigerant-coolant heat exchanger temperature increases rapidly, causing high pressure and increased power consumption
Solution Approach 1:
The pump continues to operate after the compressor stops, performing preliminary cooling action on the coolant before the compressor restarts. This preliminary action prevents the refrigerant-coolant heat exchanger temperature from rising, thereby reducing the starting torque and power consumption when the compressor restarts.
Solution Approach 2:
The pump operation is extended continuously beyond the compressor operation cycle. By maintaining coolant circulation and cooling even after the compressor stops, the system ensures continuous heat dissipation, preventing temperature and pressure buildup that would otherwise occur during the idle period between compressor cycles.
2Speed
If the external heat exchanger quickly terminates cooling when the compressor stops, then the system responds rapidly to compressor shutdown, but the refrigerant pressure remains high, degrading cycle efficiency
Solution Approach 1:
The pump continues operating after compressor shutdown to perform preliminary cooling of the coolant. This maintains the cooling capability of the external heat exchanger during the transition period, preventing refrigerant pressure from rising and avoiding energy loss when the compressor restarts.
Solution Approach 2:
The cooling action of the external heat exchanger is maintained continuously through extended pump operation. By keeping the coolant flowing and being cooled even after the compressor stops, the system maintains efficient heat dissipation capability, preventing energy loss and maintaining high cycle efficiency during compressor restart.
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
This approach prevents the refrigerant-coolant heat exchanger from maintaining high temperatures, reducing the starting torque and power consumption of the compressor upon restart, thus suppressing the degradation in cycle efficiency.
Implementation Method 1
a heat medium-outside air heat exchanger that exchanges heat between the heat medium circulated by the first pump and outside air
Implementation Method 2
a high-pressure side heat exchanger that exchanges heat between a high-pressure side refrigerant in the refrigeration cycle and the heat medium circulated by the first pump
Data Source
AI summary
A thermal management system for a vehicle includes a high-temperature side pump that draws and discharges a heat medium, a compressor that draws and discharges a refrigerant in a refrigeration cycle, a high-pressure side heat exchanger that exchanges heat between a high-pressure side refrigerant in the refrigeration cycle and the heat medium circulated by the high-temperature side pump, a heat medium-outside air heat exchanger that exchanges heat between the heat medium circulated by the high-temperature side pump and outside air, and a pump control unit that controls an operation of the high-temperature side pump such that the operation of the high-temperature side pump is continued even after the compressor is stopped. Thus, the cycle efficiency exhibited when restarting the compressor can be improved.