| 摘要 |
An accurate and low cost sensing apparatus for a swash or wobble plate compressor that requires no modifications in compressor design or operation, and which provides a repeatable and accurate measure of compressor speed and stroke. The apparatus includes a sensor module and a stroke sensing circuit. The compressor has an outer housing formed of aluminum or other non-magnetic material, as is customary in automotive air conditioning systems. The sensor module includes a magnetic field responsive sensor such as a Hall Effect or magneto-resistive (MR) sensor, and is attached to the periphery of the housing in proximity to a reciprocating ferrous element such as a bushing shoe on the swash or wobble plate assembly. The sensor produces a quasi-sinusoidal output voltage signal having a frequency proportional to compressor speed, and the stroke sensing circuit determines the compressor stroke by band-pass filtering, amplifying, and peak detecting the signal. The output of the stroke sensing circuit is substantially insensitive to noise, and the relationship between it and the compressor stroke is substantially linear, resulting in a reliable, accurate and inexpensive sensing apparatus.
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