A refrigeration cycle device includes: a variable displacement compressor including a discharge capacity varying part to change a refrigerant discharge capacity; a controller that outputs a capacity control signal to the variable displacement compressor to change the refrigerant discharge capacity; a heat exchanger that condenses or cools refrigerant discharged from the variable displacement compressor; a decompressor that decompresses and expands refrigerant flowing out of the heat exchanger; an evaporator that evaporates refrigerant decompressed and expanded by the decompressor; and a high load determiner that determines whether the compressor is in a high load operational status based on the capacity control signal.

An air conditioner for a vehicle has a compressor, a radiator, a first pressure reducer, a gas-liquid separator, a second pressure reducer, an exterior heat exchanger, an intermediate pressure refrigerant passage, a switching device, and a controller. The controller operates the switching device to switch from a refrigerant circuit of a two-stage compression mode to a refrigerant circuit of a single-stage compression mode when a compressor stop signal is output in the two-stage compression mode. The single-stage compression mode is a mode that blocks at least a flow of an intermediate-pressure refrigerant into the intermediate pressure refrigerant passage and makes refrigerant remained in the intermediate pressure refrigerant passage to flow out of the intermediate pressure refrigerant passage. The controller stops the compressor after controls the compressor to continue operating for a specified time in the single-stage compression mode. The controller restarts the compressor when the compressor stop signal is canceled.

A method for adaptive power engine control of a transport refrigeration unit (TRU) is provided. The method includes determining a current compressor power of a compressor of the TRU. The method also includes determining an adaptive compressor power error of the compressor. Also, the method includes calculating and setting a target compressor power of the compressor based on the current compressor power and the adaptive compressor power error. Further, the method includes determining a suction pressure control point of the compressor based on the target compressor power and a compressor curve map. Moreover, the method includes operating the compressor with the suction pressure control point of the compressor.

A system is disclosed. The system includes a climate condition determination module that is configured to determine a climate condition associated with a vehicle based upon an external air temperature or a dew point temperature. The system also includes a compressor operational state control module that is configured to control a plurality of operational states of a variable displacement compressor of a heating, ventilation and air conditioning system within the vehicle. The compressor operational state control module is configured to cause the variable displacement compressor to selectively transition from a variable displacement operational state to a fixed displacement-like operational state when the climate condition exceeds a climate threshold to cause an evaporator of the heating, ventilation and air conditioning system to provide evaporator air having an air temperature corresponding to a target evaporator air temperature.

A method of operating a transport refrigeration system is provided. The method includes electrically powering a first plurality of components of a first refrigeration unit and a second plurality of components of a second refrigeration unit, wherein electrically powering comprises operating a prime mover and an electric generation device. The method also includes monitoring a plurality of operating parameters of the first refrigeration unit. The method further includes monitoring a plurality of operating parameters of the second refrigeration unit. The method yet further includes calculating a combined power load of the first refrigeration unit and the second refrigeration unit. The method also includes comparing the combined power load to a maximum available power of the prime mover.

An air-conditioner may include an evaporator, a compressor configured to compress refrigerant supplied to the evaporator and a clutch configured to transmit power needed to operate the compressor to the compressor or to prevent power from being supplied to the compressor, wherein the clutch prevents power from being supplied to the compressor when an actual measurement temperature of the evaporator reaches a lower limit threshold temperature selected among the lower limit threshold temperature and an upper limit threshold temperature and the lower limit threshold temperature is changeable, and the upper limit threshold temperature is relatively higher than the lower limit threshold temperature and is changeable.

A method and an apparatus for controlling a compressor are provided. The method includes measuring a vehicle speed, an engine speed, a position value of an accelerator pedal, and an external air temperature and comparing the vehicle speed with a predetermined speed. A basic operation rate of the compressor is then determined based on the engine speed and the position value of the accelerator pedal when the vehicle speed is equal to or less than the predetermined speed. A final operation rate of the compressor is determined based on the external air temperature and the determined basic operation rate and the compressor is operated based on the determined final operation rate.

An externally-controlled variable displacement compressor (EVDC) cold-start method is described including, during an EVDC cold-start procedure, iteratively alternating an amount of a control current supplied to an electronic control valve (ECV) associated with the EVDC between no control current and a full control current. Systems for implementing the described method are provided.

A valve in which a small driving force of a drive source is required when the valve is closed. A valve includes a valve housing and a valve body to be driven by a drive source, and controls a flow rate of a fluid flowing through a through-flow passage in a direction opposite a closing direction of the valve body, by moving the valve body from a control region to a closing region. The valve body has an effective pressure-receiving area where a pressure of the fluid acts on the valve body. The effective pressure-receiving area is switched between the effective pressure-receiving area in the control region and the effective pressure-receiving area in the closing region. The effective pressure-receiving area is smaller than the effective pressure-receiving area.

Embodiments are disclosed that relate to controlling a compressor. In one example, method of controlling a compressor comprises regulating a discharge capacity of the compressor via a control current supplied to a control device, holding the control current supplied to the control device at substantially zero amperes for a first duration, and stepping the control current from substantially zero amperes to a sustainable current that provides a sustainable level of a performance parameter of the compressor.