Vehicle Thermal Management With Heat Pump for Low Waste Heat Heating
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Solution Overview
Problem
Modern vehicles face challenges in efficiently heating the occupant compartment due to reduced waste heat from energy-efficient propulsion systems, including internal combustion engines and electric propulsion systems, which often generate insufficient heat for traditional heating arrangements.
Innovation Solution
A thermal management system that includes a propulsion coolant circuit, a heating circuit, and a heat pump circuit with a connecting conduit and a first valve to control coolant flow, allowing the heating circuit to operate at a higher temperature than the propulsion coolant circuit, thereby enhancing heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a traditional heating arrangement is used that relies on waste heat from the propulsion system, then the system structure is simple, but the heating capability is insufficient because modern energy-efficient propulsion systems generate less waste heat
Solution Approach 1:
A heat pump circuit is introduced as an intermediary system between the propulsion coolant circuit and the heating circuit. The heat pump includes a compressor, condenser, expansion device, and evaporator to actively transfer heat from the propulsion system to the heating circuit, enabling sufficient heating capability even when waste heat from the propulsion system is insufficient
Solution Approach 2:
The system changes the temperature parameter relationship between circuits by using a heat pump to raise the temperature of coolant in the heating circuit above the temperature in the propulsion coolant circuit. This allows the heating circuit to operate at higher temperatures and provide adequate heating despite reduced waste heat availability
2Device complexity
If the heating circuit is directly connected to the propulsion coolant circuit without a heat pump, then the system complexity is low, but the temperature control flexibility is limited and heating performance is insufficient
Solution Approach 1:
A heat pump circuit serves as an intermediary between the propulsion coolant circuit and heating circuit, containing a compressor, condenser, expansion device, and evaporator. This intermediary system enables active heat transfer and temperature elevation, allowing the heating circuit to achieve higher temperatures than the propulsion coolant circuit
Solution Approach 2:
The heat pump system changes the temperature parameters by compressing the refrigerant to raise its temperature, then condensing it to transfer heat to the heating circuit. This parameter transformation enables the heating circuit to operate at elevated temperatures independent of the propulsion system temperature
3Productivity
If a heat pump circuit is added to transfer heat from the propulsion system to the occupant compartment, then the heating efficiency is improved, but the system complexity increases
Solution Approach 1:
The heat pump circuit is designed to perform multiple functions: heating the occupant compartment, cooling the propulsion system components, and potentially providing climate control. By integrating these functions into a single system with shared components like the condenser and evaporator, the overall system complexity is managed while achieving high heating efficiency
Solution Approach 2:
The heating circuit and propulsion coolant circuit are merged through the heat pump system, where the condenser of the heat pump serves as a heat exchanger with the propulsion coolant. This merging allows heat transfer between circuits while reducing the total number of separate components needed
4Ease of operation
If the internal combustion engine is started to increase available heat for heating the occupant compartment, then the heating capability is improved, but fuel consumption and emissions increase
Solution Approach 1:
The heat pump circuit acts as an intermediary that can efficiently transfer available heat from the propulsion system to the heating circuit without requiring the engine to run. This eliminates the need to start the internal combustion engine solely for heating purposes, thereby reducing fuel consumption and emissions while maintaining adequate heating capability
Solution Approach 2:
The heat pump system changes the temperature parameters to maximize heat transfer efficiency from available propulsion heat to the heating circuit, extracting sufficient heating energy even at lower propulsion system temperatures, thus eliminating the need to run the engine for heating
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
The system provides a more efficient transfer of heat from the propulsion system to the occupant compartment, improving heating performance and reducing the need for fuel consumption and emissions by allowing the heating circuit to operate independently of the propulsion system's temperature.
Implementation Method 1
a heat pump circuit comprising a first evaporator in the propulsion coolant circuit and a condenser in the heating circuit
Implementation Method 2
provides a more efficient transfer of heat from the propulsion system to the occupant compartment
Data Source
AI summary
A thermal management system for a vehicle is disclosed, wherein the vehicle comprises an occupant compartment and a propulsion system configured to provide motive power to the vehicle. The system comprises a propulsion coolant circuit configured to cool at least a portion of the propulsion system, a heating circuit configured to heat the occupant compartment, and a heat pump circuit comprising a first evaporator in the propulsion coolant circuit and a condenser in the heating circuit. The propulsion coolant circuit comprises a connecting conduit connecting the propulsion coolant circuit to the heating circuit at a position upstream of the condenser, and a first valve configured to control flow of coolant through the connecting conduit. The present disclosure further relates to a powertrain for a vehicle, as well as a vehicle.