Method for controlling a thermal management device of a motor vehicle
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Solution Overview
Problem
Thermal management devices in electric and hybrid vehicles take a long time to reach setpoint temperature and are inefficient at outside temperatures below 5°C, leading to icing issues and prolonged heating times.
Innovation Solution
A control method for thermal management devices that uses an electric heating device to preheat internal air until a target temperature is reached, then engages the refrigerant circuit to accelerate heating, reducing icing and improving efficiency by adjusting electric power based on outside temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If only heat pump mode is used, then energy consumption is reduced, but heating time is prolonged and comfort is delayed
Solution Approach 1:
The electric heating device performs preliminary heating of the internal air flow before the heat pump reaches full operational capacity. This preheating action addresses the slow start-up phase of the heat pump, providing immediate thermal comfort while the heat pump gradually ramps up, thereby reducing overall heating time without excessive energy consumption.
Solution Approach 2:
The system dynamically switches between electric heating mode and heat pump mode based on real-time temperature feedback. The control unit monitors the internal air flow temperature and adjusts the heating strategy accordingly, transitioning from electric heating to heat pump operation as conditions change, optimizing both response time and energy efficiency.
2Productivity
If electric heating device is added to reduce heating time, then heating speed improves, but energy consumption increases
Solution Approach 1:
The electric heating device operates at partial capacity rather than full power continuously. It provides just enough supplemental heating during the critical start-up phase to achieve acceptable comfort levels, then transitions to heat pump operation. This partial action approach achieves sufficient heating speed improvement without the excessive energy consumption of continuous full-power electric heating.
Solution Approach 2:
The system ensures continuous useful heating action by seamlessly coordinating electric heating and heat pump operation. The electric heater provides immediate thermal output while the heat pump simultaneously builds up capacity, ensuring uninterrupted heating throughout the transition period. This continuity maintains heating speed without the need for excessive peak power consumption.
3Reliability
If heat pump operates at low outside temperature, then heating function is maintained, but icing occurs at evaporator
Solution Approach 1:
The electric heating device applies preliminary anti-icing action by heating the internal air flow that passes over the evaporator. This pre-heating of the air stream prevents moisture condensation and freezing on the evaporator surfaces, countering the icing tendency before it can develop and compromise heat pump operation at low outside temperatures.
Solution Approach 2:
The internal air flow acts as an intermediary medium between the electric heating device and the evaporator. The electric heater warms this air stream, which then flows across the evaporator surfaces, providing thermal protection against icing. This intermediary approach allows the heat pump to operate reliably in cold conditions without direct heating of the evaporator components.
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 method reduces heating time, prevents icing, and maintains comfort temperature with reduced energy consumption, enhancing user comfort and battery autonomy in electric and hybrid vehicles.
Implementation Method 1
direct or indirect heating of the internal air flow only by the electric heating device until the internal air flow reaches a target temperature
Implementation Method 2
starting the compressor so that the refrigerant circuit takes heat energy from the external air flow at the level of the second heat exchanger and releases said heat energy at the first heat exchanger
Implementation Method 3
the refrigerant circuit comprises in the direction of circulation of the refrigerant fluid in heat pump mode: a compressor, a first heat exchanger intended to exchange heat energy directly or indirectly with an internal air flow, an expansion device, a second heat exchanger intended to be crossed by an external air flow
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention relates to a method for controlling a thermal management device (1) of a motor vehicle comprising a refrigerant-fluid circuit comprising a compressor (3), a first heat exchanger (5), an expansion device (7) and the second heat exchanger (9), said thermal management device (1) further comprising an electric heating device (60), said control method involving, upon a starting of the thermal management device (1) from cold, the following steps: direct or indirect heating of the internal air flow (20) by the electrical heating device (60) alone until said internal air flow (200) reaches a target temperature and/or until a predetermined timer has run out, - when the internal air flow (200) has reached its target temperature and/or when the timer has run out, starting the compressor (3) so that the refrigerant-fluid circuit draws heat energy from the external air flow (100) at the second heat exchanger (9) and gives up said heat energy at the first heat exchanger (5).