Heater Core Cold Storage for Extended Engine Auto-Stop
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Solution Overview
Problem
The HVAC system in vehicles loses its ability to cool the cabin effectively when the engine is automatically stopped, leading to passenger discomfort in warm conditions and reduced system efficiency.
Innovation Solution
A method is introduced to control coolant flow through a bypass valve, allowing the heater core to act as a cold storage device by charging it when predetermined conditions are met, such as high outside air temperature, and using it to maintain cabin temperature during extended engine auto-stop periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine is automatically stopped to improve fuel economy, then fuel consumption is reduced, but the HVAC system loses its ability to cool the cabin effectively leading to passenger discomfort
Solution Approach 1:
The system pre-cools the heater core coolant and stores cold energy in the heater core before engine auto-stop occurs. This preliminary cooling action enables the HVAC system to maintain cabin cooling capability during the extended auto-stop period without requiring the engine to run continuously, thus resolving the contradiction between fuel economy and cooling effectiveness
Solution Approach 2:
The heater core acts as an intermediary cold storage device between the evaporator and the cabin air. By storing cold energy in the heater core coolant and using it to cool cabin air during auto-stop, the system bridges the gap between engine shutdown and maintained cooling capability, allowing longer auto-stop periods while preserving passenger comfort
2Ease of operation
If the engine runs continuously to maintain cabin cooling, then passenger comfort is maintained, but fuel economy deteriorates
Solution Approach 1:
Instead of continuous engine operation, the system uses periodic cooling cycles where the engine runs intermittently to recharge the heater core cold storage. This periodic action pattern allows the engine to stop for extended periods while maintaining cooling capability through the stored cold energy, significantly reducing fuel consumption while preserving cabin comfort
Solution Approach 2:
The heater core serves dual functions: it normally heats the cabin using engine coolant, but in this system it also serves as a self-contained cold storage device. By utilizing the existing heater core infrastructure for cold energy storage and release, the system eliminates the need for additional complex cooling systems, maintaining cabin comfort during auto-stop with minimal energy input
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 extends the engine auto-stop period, maintaining cabin comfort and improving fuel economy by utilizing the heater core as a cold storage device to cool the cabin air.
Implementation Method 1
Refrigerant flowing through coils in the evaporator absorbs heat from air flowing across coils in the evaporator, thereby cooling the air
Implementation Method 2
Engine coolant flowing through the heater core rejects heat to air flowing through the heater core, thereby heating the air
Implementation Method 3
The condenser cools refrigerant as the refrigerant flows through coils in the condenser
Data Source
AI summary
A method for controlling coolant flow and cooling of a heater core to be used as a cold storage device or “heater core cold storage” (HCCS) cooling of a vehicle to extend an engine auto-stop period includes determining if at least one predetermined condition is met for HCCS cooling, and charging a heater core for a predetermined charge period in preparation for HCCS cooling when the at least one predetermined condition is met. The charge is held in the heater core until a trigger event occurs and HCCS cooling is initiated. HCCS cooling is then performed until a predetermined use period expires.