Compressor Clutch Intermittent Start to Prevent A/C Slugging
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Solution Overview
Problem
Air conditioning systems in vehicles experience noise and component stress due to liquid slugging, where refrigerant and lubricant pool in low areas and cause vibration and clutch failure when the compressor is restarted after a period of inactivity.
Innovation Solution
An apparatus with a microcontroller and switching transistor that intermittently grounds the compressor clutch for a predetermined period upon startup, using a power transistor and voltage regulator to manage the clutch's operation, ensuring the compressor purges liquid refrigerant and lubricant before normal operation, thereby reducing wear and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the compressor is operated continuously after a period of inactivity, then the A/C system can maintain cooling function, but liquid slugging occurs causing noise, vibration and component stress
Solution Approach 1:
The control system performs preliminary intermittent operation of the compressor for a predetermined period before normal continuous operation. This preliminary action purges accumulated liquid refrigerant from the compressor, preventing liquid slugging during subsequent normal operation while maintaining system reliability
Solution Approach 2:
The control system implements periodic on/off cycling of the compressor clutch during the predetermined period after system shutdown. This periodic action allows the compressor to purge liquid refrigerant in cycles, eliminating harmful liquid slugging effects before transitioning to continuous operation
2Object-affected harmful factors
If the compressor is intermittently started to purge liquid, then slugging is reduced, but wear and noise are generated during the purging cycles
Solution Approach 1:
The intermittent purging operation is performed as a preliminary action only during the predetermined period after shutdown, before normal continuous operation begins. This limits the wear and noise generation to a brief initial period while effectively eliminating liquid slugging
Solution Approach 2:
The control system rushes through the purging process by implementing a predetermined time limit for intermittent operation. After this brief period, the system transitions to continuous operation, minimizing the duration of wear and noise generation while still achieving effective liquid removal
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 solution effectively prevents slugging by ensuring the compressor purges liquid refrigerant and lubricant, reducing noise and stress on components, and can be retrofitted into existing vehicles for enhanced performance.
Implementation Method 1
controlling the clutch operation... the magnetic clutch driving the compressor to be intermittently engaged
Data Source
AI summary
A switch (10, 200) is provided for installation in the air conditioning (A/C) system (12) in a vehicle (16) for intermittently operating the clutch (20) in the A/C system (12) each time the control (44) in the A/C system (12) provides power to operate the clutch (20) to prevent slugging. This turns the compressor (14) a few turns each time the clutch (20) is energized during intermittent operation to purge liquid refrigerant and lubricant from the compressor (14) to prevent slugging. The switch (10, 200) can be installed in existing vehicles by connecting the switch (10, 200) in the wiring harness (18) of the A/C system (12) to the power lead (38) from the control (44) to the clutch (20) and between the ground lead (40) from the clutch (20) and a ground. The switch (10, 200) can include a microcontroller (52) for controlling the operation of a power transistor (70) to intermittently ground the clutch to provide the intermittent operation. A battery (202) can be provided to power the microcontroller (52) for a set period of time after an initial intermittent operation. This prevents additional intermittent operation for the set period of time.