Vehicle Cabin Thermal Management with Single Loop
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Solution Overview
Problem
Vehicle thermal management systems often engage the air conditioning system to cool high voltage batteries even when passengers request climate control or air conditioning to be off, leading to undesired cooling of the vehicle cabin.
Innovation Solution
A single thermal loop system with a controller that manages thermal conditions for both the vehicle cabin and high voltage battery, using a blower, evaporator, and chiller to maintain predetermined temperatures while minimizing impact on cabin temperature, and includes a control strategy to direct airflow and refrigerant flow without shut-off valves, ensuring comfortable cabin temperatures even when the air conditioning is off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the air conditioning system is engaged to cool the high voltage battery, then the battery temperature is maintained within a predetermined range, but the vehicle cabin experiences undesired cooling when the climate control system is off
Solution Approach 1:
The system divides the thermal management function into two independent control paths: one for the high voltage battery (using the chiller and coolant loop) and one for the vehicle cabin (using the evaporator and climate control system). This segmentation allows the battery cooling to operate independently without necessarily affecting the cabin temperature when the climate control is off.
Solution Approach 2:
The chiller acts as an intermediary component that couples the battery coolant loop with the refrigerant loop. By using the chiller as a heat exchange intermediary, the system can cool the battery through coolant circulation while allowing the climate control system to remain off, as the chiller enables thermal management of both systems through a single integrated loop without direct conflict.
2Device complexity
If a single thermal loop is used to manage both battery and cabin thermal conditions, then device complexity is reduced, but control precision for maintaining both temperatures becomes more difficult
Solution Approach 1:
The system employs dynamic control strategies where the controller adjusts operational parameters in real-time based on detected temperature conditions. The controller can vary coolant flow rates, refrigerant flow rates, and blower speeds dynamically to maintain precise temperature control for both the battery and cabin despite using a single thermal loop configuration.
Solution Approach 2:
The controller modifies operational parameters such as coolant flow rate through the chiller, refrigerant expansion valve positioning, and blower motor speed to achieve precise temperature control. By changing these parameters dynamically based on sensor feedback, the system maintains accurate temperature regulation for both battery and cabin while using a simplified single loop architecture.
3Temperature
If shut-off valves are used to control refrigerant flow to evaporators, then temperature control is improved, but noise, vibration, and harshness increase
Solution Approach 1:
The system removes the shut-off valve component from the refrigerant flow control path. Instead of using mechanical shut-off valves that generate noise and vibration, the system extracts this function and replaces it with electronic control mechanisms that regulate refrigerant flow smoothly without mechanical interruption, thereby eliminating the associated NVH issues.
Solution Approach 2:
The patent replaces the mechanical shut-off valve system with an electronic control system that uses electronic expansion valves or electronically controlled flow regulation. This substitution eliminates the mechanical operation that causes noise and vibration, while maintaining precise temperature control through electronic actuation and control algorithms.
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 effectively maintains comfortable cabin temperatures while cooling the high voltage battery, reducing noise, vibration, and harshness, and providing cost savings by eliminating unnecessary components and noise from shut-off valves.
Implementation Method 1
The chiller is for facilitating fluid communication between the evaporator and a high voltage battery
Implementation Method 2
output a control signal to the blower to move air across a heat source and to the vehicle cabin
Implementation Method 3
maintaining refrigerant flow through the evaporator
Implementation Method 4
direct the blower to push air through a heater core to the vehicle cabin at a predetermined temperature
Data Source
AI summary
A vehicle thermal management system including an electric powertrain, a single thermal loop, and a controller is provided. The electric powertrain includes a high voltage battery. The single thermal loop is for managing thermal conditions of the high voltage battery and a vehicle cabin and may include a climate control system, a blower, and a front evaporator in fluid communication with the vehicle cabin. The controller is programmed to, responsive to detection of a climate control system off request, output a command to direct the blower to push air through a heater core to the vehicle cabin at a predetermined temperature such that a temperature within the vehicle cabin is maintained at a predetermined temperature and refrigerant continues to flow through the front evaporator. The system may include a vehicle cabin temperature sensor and an ambient temperature sensor, each in electrical communication with the controller.