Vehicle Blower Control for Start-Stop Engine Comfort
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Solution Overview
Problem
Conventional Start-Stop technology in vehicles interrupts air conditioning cooling when the engine stops, leading to passenger discomfort and potential loss of fuel economy improvement, as existing solutions like cold storage systems are expensive and energy-intensive, and electric compressors are costly.
Innovation Solution
A method to control the blower speed of the air conditioning system by determining a cutback limit based on ambient temperature and sunload, ramping down the blower speed during engine stops, and restarting the engine when the evaporator temperature reaches a threshold to maintain passenger comfort and optimize engine stop time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine is stopped during idle conditions to improve fuel economy, then fuel consumption is reduced, but the air conditioning cooling action is interrupted causing passenger discomfort
Solution Approach 1:
The system pre-cools the evaporator and stores cold energy in the air conditioning system before the engine stop event. By lowering the evaporator temperature ahead of time, the stored cold energy can maintain passenger comfort during the engine-off period without requiring continuous compressor operation.
Solution Approach 2:
The invention changes the operating parameters of the air conditioning system by reducing blower speed during engine stop events. By controlling the blower to operate at reduced speed rather than shutting it off completely, the system maintains sufficient air circulation and cooling effect while consuming less energy, thus extending the duration the engine can remain stopped.
2Object-affected harmful factors
If cold storage systems with phase change materials are used to maintain cooling during engine stops, then cooling continuity is improved, but system cost and complexity increase
Solution Approach 1:
The system uses the existing evaporator and refrigerant in the air conditioning system as the cold storage medium. Instead of adding separate phase change material systems, the invention leverages the refrigerant already present in the evaporator to store and release cold energy, making the existing system serve the dual purpose of active cooling and thermal energy storage.
Solution Approach 2:
The evaporator is made multi-functional by enabling it to serve both as the active cooling component during engine operation and as a passive thermal energy storage device during engine stop events. This eliminates the need for dedicated cold storage systems while maintaining cooling continuity.
3Object-affected harmful factors
If blower speed is maintained at high levels during engine stops, then passenger comfort is maintained, but energy consumption increases reducing fuel economy benefits
Solution Approach 1:
The system dynamically adjusts the blower speed parameter based on engine operation state. During engine stop events, the blower speed is reduced to a lower operating level that maintains adequate air circulation and cooling effect while significantly reducing energy consumption, thereby preserving fuel economy benefits.
Solution Approach 2:
The blower speed is made dynamic rather than fixed, allowing it to adapt to different operating conditions. The control system adjusts blower speed in response to engine stop/start events and cabin temperature conditions, optimizing the balance between passenger comfort and energy consumption.
Data Source
AI summary
A method and apparatus for controlling blower speed of an air conditioning system in a vehicle having a start/stop engine. When an auto stop event of the start/stop engine is entered, an ambient temperature and a second temperature (e.g., evaporator) of the air conditioning system are measured by sensors. A first cutback limit is determined in response to the ambient temperature. The blower speed is ramped to the first cutback limit by a controller. The engine is restarted and the blower speed is restored in response to the second temperature reaching a restart threshold.