초록 ▼

A compressor protector system is an air conditioning system that includes a compressor driven by an engine through an electromagnetic clutch. If the refrigerant charge is below the level necessary for proper compressor cooling and lubrication a pressure or temperature responsive switch cycles at an

A compressor protector system is an air conditioning system that includes a compressor driven by an engine through an electromagnetic clutch. If the refrigerant charge is below the level necessary for proper compressor cooling and lubrication a pressure or temperature responsive switch cycles at an excessive rate. A digital counter adds the number of cycles occuring over a given time, compares the rate of switch pulses to a predetermined maximum and operates to disengage the clutch and signal the vehicle operator that corrective action to restore the refrigerant charge is required.

대표청구항 ▼

In an air conditioning system including a refrigerant compressor driven by an engine, a compressor protector comprising: first means for establishing and disestablishing a driving connection between the compressor and the engine according to whether the magnitude of an operating parameter of the sys

In an air conditioning system including a refrigerant compressor driven by an engine, a compressor protector comprising: first means for establishing and disestablishing a driving connection between the compressor and the engine according to whether the magnitude of an operating parameter of the system is greater or less than a predetermined value; second means responsive to the frequency at which said first means changes state for disestablishing the driving connection between the compressor and the engine when said frequency equals or exceeds a predetermined frequency; said second means comprising a current detector for sensing discontinuous current flow in an electrical circuit that supplies power to said first means; comparator means for comparing the number of occurrences of current flow in the electrical circuit during a specific period of time to a predetermined number; means for disestablishing the driving connection between the compressor and the engine when the number of occurrences of current flow equals or exceeds the predetermined number; said comparator means including: an oscillator producing a pulsetrain having a constant frequency; a flip-flop set to the ON state for the period of the pulsetrain produced by said oscillator; an AND gate having one input terminal connected to the output of said current detector and a second input terminal connected to the output of said flip-flop whereby said gate is open for the period of said flip-flop output pulsetrain; a counter adapted to incrementally count the number of pulses received from the output of said AND gate during discrete periods when said gate is open; a comparator adapted to produce a signal when the pulse count received from said binary counter attains a predetermined value, the signal operating to disestablished the driving connection between the compressor and the engine; said current detector further including a zero crossing detector for converting the output waveform of said current detector to an undirectional pulsetrain which is supplied to said AND gate; and a low-pass filter for eliminating noise from the output signal of said current detector, the output signal of said filter being supplied to said zero crossing detector.