Patent ID: 7676331

Claim:
A compressor drive torque estimating device able to be utilized for a system provided with a refrigeration cycle in which a refrigerant is circulated by a compressor driven by a drive source carried in a vehicle, said compressor drive torque estimating device provided with: a flow rate detecting means for detecting a flow rate of a refrigerant circulated through said refrigeration cycle, a check valve provided at a discharge pressure region of said compressor and opening only in a refrigerant discharge direction of said compressor, a storage part storing an estimated drive torque characteristic setting a correlation between a drive torque behavior of said compressor and an elapsed time from the start of operation of said compressor, a first estimated drive torque calculating means for calculating a first estimated drive torque of said compressor based on said estimated torque characteristic stored in said storage part, a second estimated drive torque calculating means for calculating a second estimated drive torque of said compressor based on a flow rate of the refrigerant detected by said flow rate detecting means, and an estimated drive torque switching means for switching an estimated drive torque of said compressor from said first estimated drive torque to said second estimated drive torque, wherein said estimated drive torque switching means switches said estimated drive torque of said compressor from said first estimated drive torque to said second estimated drive torque, based on a physical quantity corresponding to a valve opening pressure of said check valve.