Torque estimating device of compressor

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,
• said 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 based on a physical quantity corresponding to a valve opening pressure of said check valve.