Vehicle Thermal Management System Battery Engine Warming Strategy
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Solution Overview
Problem
Hybrid vehicles face inefficiencies in heating the vehicle interior using waste heat from engines or power-train devices, as existing cooling systems are complex and dissipate heat without effectively utilizing it for heating purposes.
Innovation Solution
A thermal management system that includes a refrigeration cycle with a compressor, heat exchangers, and a controller to prioritize battery warming-up over engine warming-up, reducing the required heating capacity and enhancing the operating efficiency of the electric motor by efficiently managing heat distribution between the battery, engine, and vehicle interior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a refrigeration cycle with large heating capacity is used to warm up both battery and engine simultaneously, then both devices can be warmed up, but the device complexity and energy consumption increase significantly
Solution Approach 1:
The thermal management system divides the warming-up process into separate time stages: first warming up the battery using waste heat from the engine, then warming up the engine using the refrigeration cycle. This segmentation avoids the need for a large-capacity refrigeration cycle to handle both warming-up tasks simultaneously, thereby reducing system complexity and energy consumption.
Solution Approach 2:
The system performs preliminary warming-up of the battery using engine waste heat before the engine itself needs warming-up. By doing the battery warming-up in advance during engine operation, the system eliminates the need for simultaneous warming-up operations, reducing the required heating capacity of the refrigeration cycle.
2Use of energy by stationary object
If waste heat from engine is used to heat vehicle interior, then heating function is provided, but the heat is insufficient and cannot adequately heat the interior
Solution Approach 1:
The system continuously utilizes engine waste heat to warm up the battery during engine operation, maximizing the continuous extraction and use of waste thermal energy. This continuous useful action ensures efficient waste heat utilization without requiring additional heating capacity from the refrigeration cycle.
3Power
If heat pump cycle is used to absorb heat from outside air for heating, then vehicle interior can be heated, but waste heat from engine is dissipated without being used
Solution Approach 1:
The system converts the harmful waste heat that would otherwise be dissipated into a useful resource by directing it to warm up the battery. This transformation of waste heat into a beneficial heating source for the battery eliminates energy loss while maintaining adequate heating capacity for the vehicle interior.
Solution Approach 2:
Instead of discarding waste heat from the engine into the environment, the system recovers this thermal energy and directs it to the battery warming-up process. This recovery mechanism prevents energy loss and improves overall thermal efficiency of the vehicle system.
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 reduces the heating capacity needs of the refrigeration cycle, prioritizes battery warming to improve electric motor performance, and enhances fuel efficiency while ensuring comfortable interior heating.
Implementation Method 1
a heat-medium heating heat exchanger that heats the heat medium by exchanging heat between the refrigerant discharged from the compressor and the heat medium drawn into and discharged from the second pump
Implementation Method 2
a heat-medium cooling heat exchanger that cools the heat medium by exchanging heat between the refrigerant decompressed and expanded by the decompressor and the heat medium drawn into and discharged from the first pump
Implementation Method 3
a heat medium-outside air heat exchanger that exchanges heat between the heat medium cooled by the heat-medium cooling heat exchanger and outside air
Implementation Method 4
an air heating heat exchanger that heats ventilation air into a vehicle interior by exchanging sensible heat between the heat medium heated by the heat-medium heating heat exchanger and the ventilation air
Implementation Method 5
an engine heat transfer portion that transfers heat between an engine outputting a traveling driving force and the heat medium
Implementation Method 6
a battery heat transfer portion that transfers heat between a battery supplying electric power to a traveling electric motor and the heat medium
Data Source
AI summary
A controller of a thermal management system for a vehicle controls a first switching valve and a second switching valve to set a battery warming-up state in which a heat medium circulates between a battery-temperature adjustment heat exchanger and a heat-medium heating heat exchanger, and the heat medium does not circulate between a coolant-coolant heat exchanger and a heat-medium heating heat exchanger when both a battery and an engine need to be warmed up. In contrast, the controller controls the first switching valve and the second switching valve to set an engine warming-up state in which the heat medium circulates through between the coolant-coolant heat exchanger and the heat-medium heating heat exchanger while the heat medium does not circulate between a battery-temperature adjustment heat exchanger and the heat-medium heating heat exchanger when a temperature of the battery exceeds a target battery warming-up temperature in the battery warming-up state.