Control apparatus for variable capacity compressor and method of calculating torque of variable capacity compressor

Abstract

An apparatus for calculating torque of a variable capacity compressor is provided. The compressor includes a suction chamber, a discharge chamber, a piston to draw coolant from the suction chamber, compress the drawn coolant, and discharge the compressed coolant into the discharge chamber, a clutch to be turned on to transmit driving force from a driving source to the piston so that the piston operates and to be turned off to disconnect the driving force of the driving source from the piston so that the piston stops, and a pressure adjuster to adjust a back pressure introduced from the discharge chamber to the back of the piston and thereby adjust a piston stroke. The apparatus comprises a counter configured to count an OFF time when the clutch is tuned off from an ON state until the clutch is next turned on, a determiner configured to determine whether or not the OFF time is less than a predetermined time, and a start torque calculator configured to calculate a start torque of the compressor depending on the determination of the determiner.

Description

CROSS REFERENCE TO RELATED APPLICATIONS AND INCORPORATION BY REFERENCE [0001] This application is based on and claims the benefit of priority from the prior Japanese Patent Application No. 2005-153188 filed on May 25, 2005; the entire contents thereof are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a method of and an apparatus for calculating and controlling torque of a variable capacity compressor arranged in a refrigeration cycle. [0004] 2. Description of Related Art [0005] A variable capacity compressor is utilized in a refrigeration cycle of, for example, an air conditioner of a vehicle. In the vehicle, the compressor is connected to a vehicle engine by an endless belt. The belt connects a main pulley fixed to a drive shaft of the engine to a follower pulley fixed to a drive shaft of the compressor. The engine serves as a driving source for driving the compressor. If the compressor varies ...

AI Technical Summary

Benefits of technology

[0009] A first aspect of the present invention provides a method of calculating torque of a variable capacity compressor. The compressor includes a suction chamber, a cylinder bore, a discharge chamber, a piston to draw coolant from the suction chamber into the cylinder bore, compress the drawn coolant, and discharge the compressed coolant into the discharge chamber, a clutch configured to transmit driving force from a driving source to drive the piston and configured to disconnect the driving force of the driving source so that the piston is not driven, and a pressure adjuster to adjust a back pressure introduced from the discharge chamber to the back of the piston and thereby adjust a piston stroke. The method includes counting an OFF time when the clutch is tuned off from an ON state until the clutch is next turned on, determining whether or not the OFF time is less than a predetermined time, and calculating a start torque of the compressor depending on the determination.

[0010] According to a second aspect of the present invention provides a method of calculating torque of a variable capacity compressor. The compressor includes a suction chamber, a cylinder bore, a discharge chamber, a piston to draw coolant from the suction chamber into the cylinder bore, compress the drawn coolant, and discharge the compressed coolant into the discharge chamber, a clutch configured to transmit driving force from a driving source to drive the piston and configured to disconnect the driving force of the driving source so that the piston is not driven, and a pressure adjuster to adjust a back pressure introduced from the d

Problems solved by technology

In a short period at the start of operation of the variable capacity compressor, for example, in a period of about four seconds after the start of the compressor, the flow of coolant is unstable, and therefore, it is impossible for the related art to estimate torque based on a coolant flow rate.

During the pressure changing period, a piston in the compressor is moving, and therefore, it is difficult to estimate the position of the piston, and therefore, it is impossible to estimate a start torque of the compressor when the compressor is restarted soon after being stopped.

This is inconvenient in terms of free control of the compressor.

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