Vehicle Air Conditioning Compressor Control for Brake Assist
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Solution Overview
Problem
Existing air-conditioning control methods for vehicles fail to ensure negative pressure inside the vacuum servo when the acceleration pedal is pressed after the brake pedal is released, leading to potential decreases in air-conditioning performance and brake assist force.
Innovation Solution
The air-conditioning compressor is stopped for a first time period after the brake pedal transitions from an operated to a non-operated state, and if the acceleration pedal is operated before this period elapses, the compressor is stopped for an additional second time period, ensuring negative pressure inside the vacuum servo by managing the engine load and throttle valve operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the air-conditioning compressor is stopped to ensure negative pressure in the vacuum servo, then brake assist force is maintained, but air-conditioning performance deteriorates
Solution Approach 1:
The control system dynamically adjusts the compressor operation state based on real-time detection of negative pressure in the vacuum servo and acceleration pedal position. The compressor is stopped only when necessary (when negative pressure is insufficient and acceleration pedal is not pressed), and operates normally when conditions allow, creating a dynamic balance between brake assist force and air-conditioning performance
Solution Approach 2:
The system changes the operational parameters of the compressor based on detected conditions. When negative pressure is insufficient and the acceleration pedal is not pressed, the compressor is stopped (parameter change from running to stopped). When the acceleration pedal is pressed during the first time period, the system extends the stop duration to a second time period, adapting the parameter based on condition changes
2Reliability
If the air-conditioning compressor is stopped for a first time period after brake release, then negative pressure is ensured, but if acceleration pedal is pressed during this period, additional stopping reduces air-conditioning efficiency
Solution Approach 1:
The control system continuously monitors the acceleration pedal position and uses this feedback to adjust compressor operation. When the acceleration pedal is pressed during the first time period, the system receives feedback and responds by extending the compressor stop to a second time period, ensuring negative pressure is maintained while adapting to the driver's acceleration intent
Solution Approach 2:
The system stops the compressor in advance during the first time period after brake release to preemptively ensure negative pressure is sufficient before the driver may need acceleration. This preliminary action prevents potential brake assist force loss while the system monitors for acceleration requests
Data Source
AI summary
A vehicle air-conditioning device is provided for controlling a vehicle air-conditioning of a vehicle in accordance with a control method. The air-conditioning compressor is stopped for a first time period after a brake pedal transitions from an operated state to a non-operated state when negative pressure inside a vacuum servo is insufficient relative to a predetermined pressure while an air-conditioning compressor is operating, and The air-conditioning compressor is stopped for a second time period after the acceleration pedal has come to be in a non-operated state when an acceleration pedal is operated before the first time period elapses.