EV Powertrain Cooling via Cabin Air Recirculation
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Solution Overview
Problem
Current cooling systems for high voltage powertrain components in battery electric vehicles are inefficient, particularly at low motor vehicle speeds, high ambient temperatures, or under elevated sun loads, as they rely on compromised airflow and a low temperature radiator loop.
Innovation Solution
A control module monitors the temperature of high voltage powertrain components and overrides HVAC system parameters to recirculate cabin air, setting the evaporator temperature to its highest allowable value, ensuring the coldest air is directed to the low temperature radiator for enhanced cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the low temperature radiator is positioned downstream from the condenser with respect to ram air flow, then the HVAC system can effectively cool the passenger cabin, but the cooling efficiency of the high voltage powertrain component suffers when airflow is compromised by low vehicle speeds or high ambient temperatures
Solution Approach 1:
The system dynamically switches between fresh air mode and recirculated air mode based on operating conditions. The climate control module adjusts the air inlet door position and evaporator temperature settings in real-time to optimize cooling efficiency for the high voltage powertrain component under varying vehicle speeds and ambient temperature conditions
Solution Approach 2:
The system changes the evaporator temperature parameter to its highest allowable value when recirculated air mode is activated, which in turn produces the coldest condenser air outlet temperature. This parameter adjustment optimizes the air inlet temperature to the low temperature radiator, thereby improving cooling efficiency of the high voltage powertrain component
2Temperature
If the climate control module overrides HVAC system parameters to recirculate cabin air, then the air inlet temperature to the radiator is reduced improving cooling efficiency, but the system complexity and control logic increase
Solution Approach 1:
The existing climate control module is leveraged to perform dual functions: both passenger cabin temperature control and high voltage powertrain component cooling optimization. By utilizing the already-present control module and air inlet door mechanism, the patent avoids adding separate dedicated cooling systems, thereby minimizing additional complexity while achieving the temperature reduction goal
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 effectively reduces the air outlet temperature at the condenser and air inlet temperature at the radiator, improving the cooling efficiency of high voltage powertrain components without adding cost or complexity, thereby maintaining optimal operating conditions.
Implementation Method 1
a radiator for cooling the coolant with ambient air and particularly ram air as the battery electric vehicle travels along the roadway
Implementation Method 2
a refrigerant circuit adapted to cool the passenger cabin. That refrigerant circuit includes a condenser and an evaporator
Data Source
AI summary
A battery electric vehicle includes a passenger cabin, a refrigerant circuit adapted to cool the passenger cabin, a powertrain including a high voltage powertrain component, a coolant circuit adapted to cool the high voltage powertrain component and a control module. The refrigerant circuit includes a condenser and an evaporator. The coolant circuit includes a radiator downstream from the condenser. The control module is configured to recirculate cabin air to the passenger cabin in response to data indicating temperature of the high voltage powertrain component exceeds a predetermined threshold temperature in order to reduce the air outlet temperature at the condenser and the air inlet temperature at the radiator. A related method to cool a high voltage powertrain component of a battery electric vehicle is also disclosed.