Abstract: A variable speed drive control system operates a variable speed drive to power a first load from a power source simultaneously powering a second load. An AC reactive power is monitored which may comprise or consist of an AC reactive power of the second load. Responsive to the monitored AC reactive power, the variable speed drive is controlled to counter the AC reactive power of the second load.

Abstract: Disclosed are an apparatus and a method for controlling the operation of an air conditioner, in which one or more compressors are operated so that the total refrigerant compression capacity of the operating compressors is variably changed according to a cooling or heating load to be eliminated, and an opening degree of an electronic expansion valve is controlled between minimum and maximum values set according to the total refrigerant compression capacity of the operating compressors, thus stably operating the air conditioner and preventing the refrigerant in a liquid state from being introduced into the compressors and the compressors from overheating.

Abstract: A refrigeration circuit (1) sequentially connected to a compressor (10), a condenser (11), an electric expansion valve (13), an evaporator (17), and an intake proportional valve (21). When the freezing capability of the refrigeration device is to be suppressed, a control means (30) will restrict the intake proportional valve (21) in order to place refrigerant in a discharge side of the evaporator (17) in a wet saturated steam state, and the electric expansion valve (13) will be set to an aperture such that the refrigerant in the interior of the evaporator (17) will be placed in the wet saturated steam state.

Abstract: A control system is provided to maintain stable operating conditions for centrifugal compressors operating in parallel when one of the centrifugal compressors enters into an unstable operating condition. The control system determines an unstable operating condition in response to signals indicating the motor current or power consumption of each compressor and the position of the pre-rotation vanes of the compressors. Once an unstable operating condition is determined, the control system closes the pre-rotation vanes to each compressor until the unstable operating condition has been corrected.

Abstract: Disclosed herein is a system and method for controlling the degree of superheat of an air conditioner. The air conditioner includes a compressor controlled in a pulse width modulation manner according to duty control signals, a condenser, an electronic expansion valve and an evaporator so as to form a refrigeration cycle. An entrance temperature sensor situated at the entrance of the evaporator and an exit temperature sensor situated at the exit of the evaporator are connected to a control unit. The control unit calculates the degree of superheat of the evaporator using the difference between mean entrance and exit temperatures of the evaporator sensed by the entrance temperature sensor and the exit temperature sensor for a period of time corresponding to a duty cycle period of the compressor, and regulates the opening of the electronic expansion valve according to the calculated degree of superheat.

Abstract: Disclosed are an apparatus and a method for controlling the operation of an air conditioner, in which one or more compressors are operated so that the total refrigerant compression capacity of the operating compressors is variably changed according to a cooling or heating load to be eliminated, and an opening degree of an electronic expansion valve is controlled between minimum and maximum values set according to the total refrigerant compression capacity of the operating compressors, thus stably operating the air conditioner and preventing the refrigerant in a liquid state from being introduced into the compressors and the compressors from overheating.

Abstract: A variable displacement type compressor circulates a refrigerant in an air conditioning circuit. The compressor has a compression mechanism and a displacement controller. The compression mechanism compresses and discharges the refrigerant. The displacement controller controls the discharge amount of the refrigerant of the compressor. The displacement controller further includes a normal control means and a protective control means. The normal control means controls the displacement based on a cooling load. The protective control means controls the displacement based on the value in connection with the rotational speed of the compressor and the actual operating information of the compressor.

Abstract: In a vehicle air conditioner, a refrigerant cycle system is constructed to switch a cooling refrigerant cycle where an interior heat exchanger is used as an evaporator, and a hot gas heater cycle where the interior heat exchanger is used as a radiator. Further, determining means of a control unit determines whether the interior heat exchanger has a quantity of retained water in a heating mode with the hot gas heater cycle. When the determining means determines that the interior heat exchanger has the quantity of retained water in the heating mode while a blower stops, operation of the heating mode is stopped. On the other hand, when the determining means determines the interior heat exchanger does not have the quantity of retained water in the heating mode while the blower stops, the operation of the heating mode is performed.

Abstract: In a vehicle air conditioner, a compressor is driven by a vehicle engine, and a displacement of the compressor is controlled based on a cooling load. When a post-evaporator air temperature (TE) is higher than a predetermined value (TEO+&bgr;), it is determined that the cooling load is large, and the compressor is forcibly controlled at maximum displacement that is larger than a control value controlled based on the cooling load. Accordingly, the post-evaporator air temperature (TE) can be rapidly reduced to be lower than the predetermined value (TEO+&bgr;), so that a driving time of the vehicle engine can be made shorter. As a result, fuel consumption efficiency of the vehicle engine can be effectively improved.

Abstract: A refrigerating apparatus including three compressors (2A, 2B, 2C) and application side heat exchangers (41) (45, 51) for two channels is formed so that a first compressor (2A) is used only for the application side heat exchangers (45, 51) in a first channel of a circuit, a third compressor (2C) is used only for the application side heat exchanger (41) in a second channel of the circuit, and a second compressor (2B) is used in a switchable manner between the application side heat exchangers (45, 51) in the first channel of the circuit and the application side heat exchanger (41) in the second channel of the circuit. Thus, not only the pipe arrangement at suction side is simplified, but also operation control is streamlined.

Abstract: An air conditioning system for a vehicle includes a controller for periodically increasing the stroke and output of the pistons in a variable stroke compressor for periodically reducing the amount of refrigerant resident in the evaporator. The controller includes a timer for establishing predetermined time periods between the momentary spikes of periodic increases of stroke. Normally, the stroke is spiked only when the compressor is operating at a low load condition.

Abstract: The object of the present invention is to provide a method of operating a refrigeration cycle which is capable of preventing oil from staying in an evaporator and ensures high coefficient of performance as well as sufficient circulation of oil. An electronic expansion valve is controlled such that during normal operation, refrigerant is always in a superheated state at the outlet of an evaporator, and the refrigerant is periodically forced to have negative superheat for a predetermined time by a superheat control device. Thus, during normal operation, the refrigerant sucked into a variable displacement compressor always has superheat, whereby the refrigeration cycle can operate with high coefficient of performance and an engine driving the variable displacement compressor can be operated at high fuel efficiency. Also, the refrigerant is temporarily controlled so as to have negative superheat.

Abstract: Disclosed are an air conditioner in which one or more compressors are operated so that the refrigerant compression capacity of the operating compressor(s) is variably changed in accordance with a cooling or heating load for cooling or heating air in a room, and a method for controlling an electronic expansion valve of the air conditioner.

Abstract: Disclosed is a method for controlling the aperture ratio of a linear expansion valve (LEV) so as to control the flow rate of refrigerant circulating in an air conditioning system. The LEV aperture ratio is controlled to range from the minimum value to the maximum value, which are determined according to the compressor's capacity and the cooling and heating modes. The LEV aperture ratio is controlled also based on the compressor's operating status, the change of the indoor fan's air volume, and whether or not the indoor fan operates. Such LEV control enables refrigerant to always be circulated at a suitable flow rate, improving the cooling and heating efficiencies, and also prevents liquid refrigerant from flowing into the compressor, securing high reliability of the compressor.

Abstract: Disclosed are an apparatus and a method for controlling compressors of an air conditioner. The apparatus includes a temperature sensor, a comparison unit, and a controller. The temperature sensor is installed close to an outdoor unit and serves to sense an outdoor temperature. The comparison unit compares the outdoor temperature sensed by the temperature sensor to a predetermined temperature. The controller determines a heating load when the comparison unit determines that the outdoor temperature is more than the predetermined temperature, and controls the operation of the plural compressors based on the determined heating load. The apparatus determines the heating load by means of the outdoor temperature, and properly operates the plural compressors depending the determined heating load, thereby improving the heating efficiency of the air conditioner.

Abstract: In a refrigerating apparatus (1) having application-side heat exchangers (41, 45, 51) for a plurality of systems for air-conditioning, for cold-storage/freezing and the like and a four-way switch valve (3C) and a plurality of check valves (7) on suction sides of compression mechanisms (2D, 2E) and formed from three compressors (2A, 2B, 2C) to allow the operation states to be switched, the number of compressors (2A, 2B, 2C) used at air-conditioning side and cold-storage/freezing side is limited to two at maximum, thereby achieving a simple circuit configuration in which the number of the check valves (7) to be provided in the suction sides of the compression mechanisms (2D, 2E) is reduced to one or two, suppressing the occurrence of chattering noise in check valves (7) and, also, preventing an ability from reducing due to a suction-side pressure loss.

Abstract: Disclosed herein is an air conditioner and method of controlling the same. The air conditioner includes a compressor having a capacity variable according to a duty control signal. The duty control signal controls the compressor to undergo a loading time for maintaining a loading state in a cycle and an unloading time for maintaining an unloading state in a cycle. The air conditioner further includes a control unit for determining the loading time and the unloading time according to the variation of a total required cooling capacity to generate the duty control signal even before a corresponding cycle is over, if the total required cooling capacity has been varied in a corresponding cycle while the compressor is operated, and controlling the compressor according to the duty control signal.

Abstract: A vehicle refrigerating cycle device capable of preventing the air-conditioning from becoming inadequate and capable of improving vehicle fuel economy is installed in a vehicle having both, a vehicle engine capable of carrying out stratified combustion and a brake booster. Negative pressure generated in an intake system of the engine is accumulated as brake negative pressure, which drives the brake booster. The refrigerating cycle device has a variable displacement type compressor driven by the vehicle engine and a negative pressure detection means for detecting the brake negative pressure. In the stratified combustion operation and at the time of the brake operation to cause the vehicle to stop, the volume in the compressor is controlled to reduce the load on the compressor by a prescribed amount when the detected brake negative pressure is below a prescribed value. Then, the volume in the compressor is gradually increased.

Abstract: The object of this invention is to provide an air conditioner with a variable capacity compressor (2) parallely connected to a fixed capacity compressor (4), and a method of controlling the operation of such an air conditioner. When it is required to start the fixed capacity compressor (4) in addition to an operation of the variable capacity compressor (2) due to an increase in the sum of the required cooling capacities of indoor units (9), an outdoor control unit (13) starts the fixed capacity compressor (4) during an unloading mode operation of the variable capacity compressor (2) where the pressure difference between the outlet side and inlet side of the variable capacity compressor is minimized. The fixed capacity compressor (4) is thus smoothly started without causing an induction of excessive starting current, and improves the operational reliability of the air conditioner.

Abstract: An air conditioner for air conditioning the interior of a compartment includes a compressor and an electric motor. The compressor compresses refrigerant gas and changes the displacement. The electric motor drives the compressor. A motor controller rotates the motor at a constant reference speed. A detection device detects information related to the thermal load on the air conditioner. A current sensor detects the value of current supplied to the electric motor. A controller controls the compressor based on the detected thermal load information and the detected current value. The controller computes a target torque of the compressor based on the thermal load information. In accordance with the computed target torque, the controller computes a target current value to be supplied to the electric motor. The controller further controls the displacement of the compressor such that the detected current value matches the target current value.

Abstract: An air conditioner for vehicle has a refrigeration cycle with a variable displacement type compressor. A fuel cut control is carried out in response to a vehicle deceleration. In the fuel cut control, the displacement is first increased so that an evaporator performs as a cold storage. Then, if an engine speed is decreased to a certain level, the displacement is decreased to decrease an engine load. The displacement is kept in the decreased level for a predetermined time period or until the end of the fuel cut control. Even when the displacement is decreased, the evaporator can cool air, since the evaporator performs as the cold storage. Further, the time period for keeping the displacement in the decreased level is limited. Therefore, it is possible to prevent an excessive temperature rise and to keep comfortable air conditioning.

Abstract: In a vehicle air conditioner, a variable displacement compressor has a control valve for continuously changing a discharge capacity of the compressor, and a control unit calculates an electrical value DT to be applied to the control valve based on the following formula of DT=DT(n−1)+Kp[(En−En−1)+C/(Ti×En)]. In this formula, En=Te−Teo, Kp=Kp′/(Ph×Ph′), Ti=Ti′/(Ph×Ph″), C is a sampling cycle, n is a positive number, Kp′, Ti′, Ph′and Ph″ are constants, Ph is a refrigerant pressure at a high pressure side, Te is a detected air temperature at an air outlet of the evaporator, and Teo is a target evaporator air temperature that is calculated based on an outside air temperature Tam. Accordingly, the compressor can be stably controlled in a wide thermal load range.

Abstract: Disclosed is a method for controlling the aperture ratio of a linear expansion valve (LEV) so as to control the flow rate of refrigerant circulating in an air conditioning system. The LEV aperture ratio is controlled to range from the minimum value to the maximum value, which are determined according to the compressor's capacity and the cooling and heating modes. The LEV aperture ratio is controlled also based on the compressor's operating status, the change of the indoor pan's air volume, and whether or not the indoor pan operates. Such LEV control enables refrigerant to always be circulated at a suitable flow rate, improving the cooling and heating efficiencies, and also prevents liquid refrigerant from flowing into the compressor, securing high reliability of the compressor.

Abstract: An improved compressor capacity control method selectively overrides a normal capacity control during periods of vehicle acceleration to reduce engine exhaust emissions. The capacity override is invoked when the rate of engine throttle movement exceeds a predefined rate, provided that the load imposed by the compressor is sufficiently high and the vehicle speed is greater than a minimum value. Once invoked, the override reduces the compressor capacity to a predetermined level, and measures the elapsed time. The override is maintained for at least a minimum time period that ensures an emission benefit, after which the vehicle speed is monitored to determine the extent of the acceleration. The override is terminated when the rate of increase in vehicle speed falls below a reference rate, or when the elapsed time exceeds a reference time, whichever occurs first.

Abstract: To provide an air conditioning system which simultaneously eliminates shortage of lubricating oil of a variable displacement compressor and degradation of cooling efficiency of the system. An air conditioning system is configured to have a variable displacement compressor under flow rate control by a proportional flow rate control solenoid valve forming a variable orifice in a discharge-side refrigerant flow passage, and a constant differential pressure valve for controlling a differential pressure (PdH−PdL) across the variable orifice, developed depending on a flow rate Qd of refrigerant, to a constant level, and an expansion valve of a normal charge type. By providing the expansion valve of the normal charge type, it is possible to always hold refrigerant at an outlet of an evaporator in a superheated state, whereby even during low load operation, high cooling efficiency can be maintained.

Abstract: A control valve is fluidly coupled to chambers containing fluid of different pressures for regulating flow therebetween. The control valve has a valve housing having a chamber fluidly coupled to a first chamber, a second chamber, and a third chamber. A fluid flow regulation member is disposed in the chamber and is configured to regulate fluid flow between the second chamber and the third chamber. A diaphragm is disposed substantially perpendicular to a longitudinal axis of the chamber in which longitudinal deflection of diaphragm is representative of the pressure in the first chamber.

Abstract: An apparatus for controlling compressor discharge capacity includes a variable capacity compressor, a capacity adjustment device, a signal processing device, a capacity setting device, and a signal comparing device. The capacity adjustment device regulates a discharge capacity of the variable capacity compressor. The signal processing device receives a signal corresponding to a discharge capacity of the variable capacity compressor. The capacity setting device sets a first discharge capacity target value for the variable capacity compressor. The signal comparing device compares the discharge capacity signal to the fist discharge capacity target value and sends an activation signal to the capacity adjustment device, such that the discharge capacity signal approaches the first discharge capacity value.

Abstract: A refrigeration system comprises a condenser, an evaporator, and a plurality of compressors in fluid communication. The plurality of compressors has a current run pattern with a current run capacity. The refrigeration system further comprises a controller operable to control the plurality of compressors. One method of operating the refrigeration system includes, at the controller, determining whether to increase or decrease the current run capacity and, when an increase or decrease in the current run capacity is required, creating a new run pattern to replace the current run pattern.

Abstract: A control unit for a clutchless variable displacement compressor with a solenoid is used in an air conditioning system for vehicles. The control unit includes a solenoid drive for adjusting a current flowing in the solenoid, a voltmeter for detecting a voltage applied to the solenoid, an ammeter for detecting the current of the solenoid, and a control for supplying current to the solenoid drive during a first predetermined time period when the air conditioning system is not in operation, and current has been prevented from flowing to the solenoid during a second predetermined time period. A resistance of a coil of the solenoid is calculated from the detected voltage and the detected current.

Abstract: A variable displacement compressor includes a housing assembly having a control pressure chamber. A drive shaft is rotatably supported by the housing assembly. Cylinder bores, each accommodating a piston, are formed about the drive shaft. Each piston defines a compression chamber inside the corresponding cylinder bore. Each piston compresses refrigerant drawn into the corresponding compression chamber from a suction pressure zone and discharges the refrigerant to a discharge pressure zone. The inclination of a swash plate changes in accordance with the pressure in the control pressure chamber. A supply passage connects the control pressure chamber to the discharge pressure zone. A pressure release passage connects the control pressure chamber to the suction pressure zone. A shutter, which is made of synthetic resin or rubber and includes a restricting passage, closes one of the supply passage and the pressure release passage.

Abstract: A control valve has a valve housing and a valve chamber defined in the valve housing. A valve body is accommodated in the valve chamber for adjusting the opening degree of a supply passage. A pressure sensing chamber is defined in the valve housing. The pressure at a pressure monitoring point in a refrigerant circuit is applied to the pressure sensing chamber. A bellows is located in the pressure sensing chamber. The bellows has a movable end. A transmission rod is slidably supported by the valve housing. The transmission rod includes the valve body. A support spring is located between the inner wall of the pressure sensing chamber and the movable end of the bellows. The spring supports the movable end such that the movable end can be displaced. The movable end of the bellows includes a protrusion such that the spring and the movable end of the bellows are fitted to each other.

Abstract: A method of operating a refrigeration system having a discharge port that guides conditioned air from the system to a conditioned space and a return port that guides air from the conditioned space back to the system. The method comprises providing a first control algorithm and second control algorithm for controlling the system. The first control algorithm is a function of the air temperature at the discharge port, and the second control algorithm is a function of the air temperature at the return port. The method further comprises operating the system using the first control algorithm when a first condition is met, operating the system using the second control algorithm when a second condition is met, and automatically switching between the first control algorithm and the second control algorithm depending on the status of the first and second conditions.

Abstract: Refrigerant fluid such as CO2, compressed to the supercritical pressure by a compressor, is delivered selectively through a three-way valve, either into a branch of the circuit containing a cooler, an expansion device and an evaporator for cooling the cabin of a vehicle, or into a branch containing another expansion device and a heat exchanger for the purpose of heating the cabin.

Abstract: A refrigerant cycle system includes a variable displacement compressor, and first and second evaporators disposed in parallel. In the refrigerant cycle system, it is determined whether a refrigerant flow amount from the compressor is in a low flow amount area when first and second blowers for blowing air to the first and second evaporators are operated at the same time. When it is determined that a predetermined time passes after the refrigerant flow amount is determined to be in the low flow amount area, the operation of the compressor is forcibly switched between a large discharge capacity and a small discharge capacity. Accordingly, it can prevent oil returning to the compressor from being short due to the operation of the compressor in the low flow amount area.

Abstract: An air conditioning system for a vehicle includes a controller for periodically increasing the stroke and output of the pistons in a variable stroke compressor for periodically reducing the amount of refrigerant resident in the evaporator. The controller includes a timer for establishing predetermined time periods between the momentary spikes of periodic increases of stroke. Normally, the stroke is spiked only when the compressor is operating at a low load condition.

Abstract: Disclosed are compressor-controlling device and method for an air conditioner comprising a plurality of compressors. In case several compressors selected from the plural compressors are stopped for a long period of time according to cooling or heating load, the refrigerant contained in a higher-pressure state inside of the stopped compressors moves toward a refrigerant pipe of a lower-pressure inlet port, and oil used to operate the compressors leaks toward the inlet port, thus lowering the oil level within the stopped compressors. Since the stopped compressors are operated during a second designated time when stopped time of the stopped compressors exceeds a first designated time, the stopped compressors are protected from damage due to poor lubrication.

Abstract: A control valve is used for a variable displacement compressor. The compressor has a crank chamber and a bleed passage. The control valve includes a valve housing. A valve chamber is defined in the valve housing. A valve body is accommodated in the valve chamber for adjusting the opening size of the bleed passage. A pressure sensing chamber is defined in the valve housing. A pressure sensing member separates the pressure sensing chamber into a first pressure chamber and a second pressure chamber. The pressure at a first pressure monitoring point is applied to the first pressure chamber. The pressure at a second pressure monitoring point located is applied to the second pressure chamber. The pressure sensing member moves the valve body in accordance with the pressure difference between the first pressure chamber and the second pressure chamber such that the displacement of the compressor is varied to counter changes of the pressure difference. The pressure sensing member is a bellows or a diaphragm.

Abstract: A refrigeration system and method for controlling defrost includes a refrigeration case, an evaporator disposed in the refrigeration case, and a condenser and compressor coupled in fluid communication with the evaporator. The condenser is disposed on the refrigeration case and the compressor is a pulse width modulated variable capacity compressor. The system also includes a controller responsive to a load sensor disposed in the refrigeration case and is coupled to the compressor for providing a variable duty cycle control signal to the compressor, wherein the compressor is modulated between a first capacity and a second capacity while operating to adjust the operating capacity of the refrigeration system. The system further includes a module for periodically defrosting the refrigeration system as a function of duty cycle.

Abstract: A vehicle air conditioning system mountable on a vehicle has the control function of stopping a vehicle engine automatically when the vehicle stops (eco-run vehicle). The system includes a variable displacement compressor driven by the vehicle engine, and a stop time of the vehicle engine is ensured when the vehicle stops. When the engine is running, the displacement of the variable displacement compressor is adjusted to control the temperature of an evaporator. When the vehicle engine stop request is issued when the vehicle is stopped, the compressor is kept at its maximum displacement and the vehicle engine is either stopped or activated depending on the temperature of the evaporator to control the on and off modes of the compressor.

Abstract: An air-conditioning system for a vehicle including a refrigerant circuit and an engine, has a compressor in the refrigerant circuit, a battery, an electric motor and a mechanism operative to controllably connect and disconnect a power transmitting path between the engine and the motor. The motor is connected to drive the compressor when energized by the battery. A first controller is operative to control the electric power supplied to the motor from the battery. A capacity control mechanism is responsive to the controller to maintain the discharge capacity of the compressor below a predetermined value upon starting the engine by the motor.

Abstract: A control valve has a valve housing. A valve chamber and a pressure sensing chamber are defined in the valve housing, respectively. A pressure sensing member is located in the pressure sensing chamber. A pressure sensing rod is slidably supported by the valve housing. A valve body is accommodated in the valve chamber. An end of the pressure sensing rod is connected to the pressure sensing member and the other end of the pressure sensing rod contacts the valve body. A solenoid chamber is defined in the valve housing. A stationary iron core is located between the valve chamber and the solenoid chamber. A solenoid rod extends through and is slidably supported by the stationary iron core. An urging force applied to the pressure sensing member by an actuator through the solenoid rod corresponds to a target value of the pressure difference. The pressure sensing member moves the valve body such that the pressure difference seeks the target value.

Abstract: A vehicle refrigerating cycle device capable of preventing the air-conditioning from becoming inadequate and capable of improving vehicle fuel economy is installed in a vehicle having both, a vehicle engine capable of carrying out stratified combustion and a brake booster. Negative pressure generated in an intake system of the engine is accumulated as brake negative pressure, which drives the brake booster. The refrigerating cycle device has a variable displacement type compressor driven by the vehicle engine and a negative pressure detection means for detecting the brake negative pressure. In the stratified combustion operation and at the time of the brake operation to cause the vehicle to stop, the volume in the compressor is controlled to reduce the load on the compressor by a prescribed amount when the detected brake negative pressure is below a prescribed value. Then, the volume in the compressor is gradually increased.

Abstract: An air conditioner for vehicle has a refrigeration cycle with a variable displacement type compressor; A fuel cut control is carried out in response to a vehicle deceleration. In the fuel cut control, the displacement is first increased so that an evaporator performs as a cold storage. Then, if an engine speed is decreased to a certain level, the displacement is decreased to decrease an engine load. The displacement is kept in the decreased level for a predetermined time period or until the end of the fuel cut control. Even when the displacement is decreased, the evaporator can cool air, since the evaporator performs as the cold storage. Further, the time period for keeping the displacement in the decreased level is limited. Therefore, it is possible to prevent an excessive temperature rise and to keep comfortable air conditioning.

Abstract: A pull-down control algorithm for an HVAC refrigeration system is provided. The control algorithm utilizes a fuzzy logic methodology to automatically adjust a flow of refrigerant in the system during a pull-down to maintain a desired pull-down rate. The desired pull-down rate is decreased proportionately as the temperature of the fluid being pulled down approaches a desired operating setpoint to avoid or minimize any overshoot of the operating setpoint. The desired pull-down rate is obtained by adjusting a rate sensitivity factor used in the control algorithm. When the temperature of the fluid being pulled down is above a predetermined value from the operating setpoint, the control algorithm uses a fuzzy logic methodology to determine a rate sensitivity that results in the desired pull-down rate that approaches the operating setpoint without overshoot.

Abstract: A scroll compressor comprises an operating state detection part (27) detecting an operating state, a variable-speed motor (28), a control part (26) and an unloading mechanism (12) serving as capacity control means. The control part (26) controls operation of the unloading mechanism (12) and the rotational frequency of the motor (28) in response to the operating state detected by the operating state detection part (27). An air conditioner comprises the aforementioned scroll compressor, a condenser (23), an expansion valve (24) and an evaporator (25).

Abstract: A control valve is used for a variable displacement compressor installed in a refrigerant circuit of a vehicle air conditioner. The control valve has a valve housing. A valve chamber is defined in the valve housing. A valve body is accommodated in the valve chamber. A pressure sensing chamber is defined in the valve housing. A pressure sensing member separates the pressure sensing chamber into a first pressure chamber and a second pressure chamber. The pressure at a first location in the refrigerant circuit is applied to the first pressure chamber. The pressure at a second location in the refrigerant circuit, which is downstream of the first location, is applied to the second pressure chamber. The pressure sensing member moves the valve body in accordance with the pressure difference between the first pressure chamber and the second pressure chamber such that the displacement of the compressor is varied to counter changes of the pressure difference.

Abstract: A refrigeration circuit (1) sequentially connected to a compressor (10), a condenser (11), an electric expansion valve (13), an evaporator (17), and an intake proportional valve (21). When the freezing capability of the refrigeration device is to be suppressed, a control means (30) will restrict the intake proportional valve (21) in order to place refrigerant in a discharge side of the evaporator (17) in a wet saturated steam state, and the electric expansion valve (13) will be set to an aperture such that the refrigerant in the interior of the evaporator (17) will be placed in the wet saturated steam state.

Abstract: Saturated or sub-cooled liquid is supplied to the expander of an expressor. Starting just prior to the end of the inlet process or just after the completion of the inlet process, high pressure vapor from the expressor compressor discharge is supplied to the cavity defining a trapped volume under going expansion.

Abstract: An improved cooling system for an original machine comprised of a temperature controller, a linear temperature sensor, a cooling liquid tank provided with a heat exchanger and a refrigeration frequency variable compressor; hot liquid of the original machine being detected by the sensor with data transmitted to the temperature controller for comparison with the preset temperature to control the refrigeration output of the compressor for the tank temperature to reflect as required by the original machine without causing excessive fluctuation of temperature difference, thus to achieve zero error in the positioning of the main shaft of the original machine in process.

Abstract: A control valve used for a variable displacement type compressor. The compressor has a crank chamber, a discharge pressure zone, and a supply passage. The supply passage connects the crank chamber to the discharge pressure zone. The control valve is located in the supply passage. The control valve has a valve body. The valve body adjusts the size of the opening of the supply passage in accordance with the discharge pressure. The valve body is exposed to the pressure of the supply passage. The valve body moves in accordance with the discharge pressure such that the displacement is varied to counter changes of the discharge pressure. The direction in which the valve body moves in response to an increase of the discharge is the same as the direction in which the valve body moves when the pressure of the supply passage increases.