Air Conditioning Compressor Clutch Slippage Control
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Solution Overview
Problem
Existing methods for controlling electromagnetic clutches in air conditioning compressors lack precision in detecting slippage, leading to energy inefficiencies and potential engine stall conditions due to the reliance on parameters influenced by multiple factors, rather than direct slippage monitoring.
Innovation Solution
Incorporating a slippage sensor to detect slippage by measuring the difference in RPM between the clutch and drive shaft, with a pulse width modulation controller adjusting the electric current to the clutch coils based on this feedback, ensuring reliable torque transmission and reduced energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If low clutch forces are used to save energy, then electrical energy consumption is reduced, but slippage occurs when torque load exceeds holding force
Solution Approach 1:
The patent implements a feedback control system where a slippage sensor continuously monitors the rotational speed of the drive shaft and compares it with the clutch pulley speed. When slippage is detected (difference exceeds threshold), the control system automatically increases the clutch current to restore proper engagement. This closed-loop feedback enables the system to maintain reliability while using minimal clutch force during normal operation, thus saving energy.
Solution Approach 2:
The clutch force is made dynamic rather than static. The system continuously adjusts the clutch current based on real-time slippage detection. During normal operation, low clutch force is applied to save energy. When slippage conditions arise, the system dynamically increases the clutch force to prevent engine stall. This dynamic adaptation resolves the contradiction between energy saving and reliability.
2Device complexity
If thermal fuse is used for slip protection, then device complexity is reduced, but trigger time is too long to prevent engine stall
Solution Approach 1:
The patent replaces the passive thermal fuse mechanism with an active electronic sensing and control system. The slippage sensor electronically detects speed differences between the clutch pulley and drive shaft in real-time, triggering immediate corrective action. This substitution of mechanical/thermal protection with electronic sensing reduces the detection time from seconds (thermal fuse) to milliseconds (electronic sensor), preventing engine stall while maintaining reasonable system complexity.
3Device complexity
If existing control methods monitor parameters like engine rpm and discharge pressure, then device complexity is minimized, but measurement precision of slippage detection is insufficient
Solution Approach 1:
The patent introduces a slippage sensor as an intermediary measurement device that directly monitors the actual slippage condition by measuring the rotational speed difference between the clutch pulley and drive shaft. Rather than inferring slippage from indirect parameters like engine RPM or discharge pressure, the sensor provides direct, precise measurement of the actual slippage phenomenon, enabling accurate detection and control.
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 approach enables precise detection and prevention of slippage, improving fail-safe behavior, reducing fuel consumption, and lowering CO2 emissions by optimizing clutch force adaptation.
Implementation Method 1
a slippage sensor by which slippage is monitored, such that a presence of slippage can be detected directly and precisely. Depending on whether slippage is detected or not an electromagnetic clutch force of an electromagnetic clutch the compressor comprises is adjusted.
Implementation Method 2
The clutch coil produces an electromagnetic force that engages the clutch driver to the rotating pulley. The amount of transmittable torque usually depends on an electric current, which electric clutch coils are supplied with as to generate an electromagnetic clutch force
Implementation Method 3
the pulse width of the electric current being fed to the clutch coils. The pulse width modulation controller is electrically attached to the clutch coils and modulates a pulse width of the electric current being fed to the clutch coils.
Data Source
AI summary
An electromagnetic clutch (1) of an air conditioning compressor (2), in particular for a motor vehicle (11), transmits a torque to a drive shaft (3) of the compressor (2) depending on an electric current (I) being fed to clutch coils (4) of the electromagnetic clutch (1) to generate an electromagnetic clutch force. According to a control method (10), a slippage of the electromagnetic clutch (1) is determined by a difference between the rpms of the electromagnetic clutch (1) and of the drive shaft (3), and is monitored by a slippage sensor (5). The electric current (I) and the resulting clutch force are adjusted dependent on slippage by a pulse width modulation controller (6) of the compressor (2). The pulse width modulation controller (6) is electrically connected to the clutch coils (4) and modulates a pulse width of the electric current (I) fed to the clutch coils (4).