Compressor Piston Stroke Sensing via Magnetic Intermediary
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Solution Overview
Problem
Variable swash plate type compressors face challenges in accurately measuring the stroke of the piston, leading to inadequate load compensation and reduced sensing accuracy, which affects engine load management.
Innovation Solution
The compressor design includes a sensor part that senses the speed and stroke of the piston through a position determination part and a diameter maintenance part, with a coating to maintain surface evenness, allowing for accurate digital signal conversion and real-time operation, enabling precise load control and torque compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a variable swash plate type compressor is used to adjust cooling capacity, then adaptability to different cooling loads is improved, but measurement precision of piston stroke deteriorates
Solution Approach 1:
A non-magnetic marker is introduced as an intermediary element on the piston, which can be detected by a magnetic sensor without requiring direct magnetic properties from the piston itself. This intermediary marker enables precise stroke measurement while maintaining the variable swash plate compression mechanism.
Solution Approach 2:
The patent replaces direct mechanical measurement methods with a magnetic sensing system. Instead of using mechanical linkages or direct contact measurement, a magnetic sensor detects the position of a non-magnetic marker through magnetic field interactions, enabling non-contact precise measurement.
2Manufacturing precision
If the piston surface is made rough for coating adhesion, then manufacturing precision of coating application is improved, but measurement precision of piston position deteriorates
Solution Approach 1:
The piston surface is designed with different local qualities: the measurement surface remains smooth for accurate magnetic sensing, while other surfaces can have rough coatings for adhesion. This localized differentiation allows both coating adhesion and precise measurement to coexist.
Solution Approach 2:
A non-magnetic marker serves as an intermediary between the piston body and the magnetic sensor. This marker can be applied with adhesive coatings on its non-sensing surfaces while maintaining a smooth surface on the sensing side, resolving the conflict between coating adhesion and measurement precision.
3Device complexity
If the swash plate angle is constantly fixed for simple structure, then device complexity is reduced, but adaptability to varying engine loads deteriorates
Solution Approach 1:
The swash plate mechanism is designed to be dynamically adjustable rather than fixed. The swash plate angle can be varied in real-time to match changing engine load conditions, enabling the compressor to adapt its displacement and cooling capacity dynamically throughout the engine operating range.
Solution Approach 2:
A magnetic sensor provides feedback on piston position and stroke length to a control system. Based on this feedback and detected engine load conditions, the control system adjusts the swash plate angle optimally, creating a closed-loop control system that adapts to varying operating conditions.
Data Source
AI summary
A compressor having a front housing in which a crank chamber is formed. A cylinder block is coupled to an opposite surface facing the front housing and includes reciprocating pistons in a plurality of cylinder bores. A rear housing is coupled to an opposite surface facing the cylinder block, the rear housing includes a suction chamber and a discharge chamber formed therein. A rotating shaft 400 is inserted via centers of the front housing and the cylinder block, the shaft inserted into a swash plate. A diameter maintenance part is configured to constantly maintain a diameter based on an axis direction of the piston 220. A sensor part is configured to sense a speed and a stroke of the piston in accordance with a change in position of a position determination part positioned on one side of the diameter maintenance part.