Abstract: An improved control apparatus for controlling the displacement of a variable displacement compressor. A control valve includes an operating rod, which is urged by a force based on a differential pressure between two pressure monitoring points, which are located in a refrigeration circuit. The control valve causes the compressor to seek a target displacement. A computer limits the target displacement when the demand for cooling is decreasing to improve fuel economy and to extend the life of the compressor.

Abstract: The control settings of a vehicle climate control system are adjusted in accordance with a relative ambient humidity correction to compensate for variations in relative ambient humidity, and the correction is based on normally measured system operating parameters. The ambient humidity correction value is determined according to a difference between the cooling performance of the system and the ambient heat energy absorbed by the system. The cooling performance of the system is determined during an initial period of vehicle operation based on the time required to reduce the initial evaporator temperature by a predetermined amount. Once steady-state operation of the system is achieved, the cooling performance of the system is determined by the steady-state deviation of the evaporator outlet air temperature from a target temperature of the system. The ambient heat energy absorbed by the system is determined based on the temperature of the ambient air and the flow rate of air through the evaporator.

Abstract: An apparatus and system for manipulating the air temperature within an interior compartment of a vehicle, the apparatus cycles a compressor between an off and on position based upon a temperature reading of the evaporator fins positioned to cool the air of the vehicle. The system employs a control algorithm wherein the evaporator fin temperature of the evaporator determines the operational status of the compressor.

Abstract: A controller controls a displacement of a compressor which is installed in a refrigerant circuit of an air-conditioning system. The controller has a pressure difference detector. An air conditioning switch turns the air conditioning system on. A temperature detector detects the temperature in a compartment. A control valve controls the displacement of the compressor such that the pressure difference detected by the pressure difference detector approaches a target value. A computer determines the target value. The computer changes the target value, depending on the detected temperature. The computer limits the target value to a target value limit. After a predetermined time expires from when the air conditioning switch is turned on, the computer changes the limit. This permits the displacement of the compressor to be promptly and reliably changed.

Abstract: When a solenoid 42 of a flow-rate control valve drive mechanism is demagnetized, a pilot valve 41 is closed for introduction of working pressure into a pressure chamber 35 of a flow-rate control valve 31 to be stopped, and a spool valve 33 is closed for a low-pressure side refrigerant path 25 to be closed and for a refrigerant suction rate to a refrigerant suction chamber 7 to be reduced to a zero.

Abstract: A refrigerated merchandiser system (10) includes a compressor (20), a condenser (30), a display case (100) having an evaporator (40), an expansion device (50), and an evaporator pressure control device (60) connected in a closed refrigerant circuit via refrigerant lines (12, 14, 16 and 18). The evaporator pressure control device (60) operates to maintain the pressure in the evaporator at a set point pressure so as to maintain the temperature of the refrigerant expanding from a liquid to a vapor within the evaporator (40) at a desired temperature. A controller (90) operatively associated with the evaporator pressure control device (60) maintains the set point pressure at a first pressure for the refrigerant equivalent to a first refrigerant temperature during a first refrigeration mode and at a second pressure for the refrigerant equivalent to a second refrigerant temperature about 2 to about 12 degrees warmer than the first temperature during a second refrigerant mode.

Abstract: An improved vehicle climate control system in which the passenger compartment temperature and humidity are controlled without requiring a humidity sensor. The control is based on the recognition that the air temperature at the evaporator outlet represents the dew point of the air supplied to the passenger compartment, and may be specified based on the desired passenger compartment air temperature to achieve a desired relative humidity in the vehicle once the desired passenger compartment temperature has been achieved. In a first mechanization, the desired relative humidity is predetermined, and the corresponding values of evaporator outlet air temperature are determined as a function of the desired passenger compartment temperature.

Abstract: In a refrigerant cycle system for a vehicle air conditioner, when a continuous operation time of a compressor elapses a predetermined time after the compressor operates, operation of the compressor is forcibly interrupted so that a refrigerant pressure at a suction side of the compressor is changed. Thus, even when the compressor operates continuously in a long time when only a front evaporator operates among front and rear evaporators, the refrigerant pressure at a low-pressure side is forcibly changed so that a rear thermal expansion valve of the rear evaporator is forcibly opened. As a result, lubrication oil staying in the rear evaporator and a low-pressure pipe is introduced into the suction side of the compressor by a refrigerant flow due to a valve opening of the rear thermal expansion valve of the rear evaporator.

Abstract: In an air-conditioning system having two air-conditioning passages serving two different air-conditioning zones but having a cooling degree detector provided in only one of the passages to reduce cost, with the degree to which air is cooled in the other passage being estimated based on a cooling degree detected by the detector and the difference between flows of air passing through the passages or an intake temperature of air entering the passages. On the other hand, when an evaporator is possible to be frosted in one of the passages, air flow amount in the one of the passages is corrected to be increased. Therefore, it can prevent a windshield from being fogged while preventing the evaporator from being frosted.

Abstract: A control system for mobile air conditioning systems for controlling the rate at which the system compressor or clutch is cycled between operational and decreased refrigerant flow, by selectively controlling the response time of certain system control signals to flow demand changes including de-icing control, from interactions between de-icing control and flow control valves, as well as system overall control. Upon the detection of an icing condition, the response of the control system is delayed to a degree to control the rate at which the capacity of the compressor can be cycled with in design limits. The delay feature allows the differential used in differentiating between icing and non-icing conditions to be significantly reduced over that required in the prior art and thereby improving the performance of the air conditioning system.

Abstract: The invention concerns a method for controlling the temperature of a refrigeration unit (1) with a refrigerating compartment (3), a freezing compartment (2) and a common evaporator (4) of a cooling circuit, and a corresponding temperature control arrangement. In a first mode (normal operation) the compressor (5) of the cooling circuit is turned ON when cooling is required and turned OFF when cooling is not required, in dependence of the refrigerating compartment temperature (T.sub.2). In a second mode, in spite of no cooling requirement in the refrigerating compartment (3), the compressor (5) is forced ON for a predetermined operating time (t.sub.1), when the OFF-time of the compressor has exceeded a threshold value (t.sub.2). The forced turning ON is repeated as often as the OFF-time exceeds the threshold value. A return to the first mode occurs as soon as the refrigerating compartment (3) requires cooling.

Abstract: A self-regulating device for controlling refrigerating appliances, such as refrigerators or freezers, preferably domestic, which comprise a refrigerating circuit with compressor, evaporator, condenser and controlling means of the compressor with a temperature sensor placed in contact with the evaporator, where said means of controlling the compressor is a microprocessor device which records and processes the temperature of the evaporator and at least one of the following two parameters: the compressor functioning time and the time during which the compressor is inactive and compares said time(s) with one or more tabulated values, in order to ensure that the disconnection time (t.sub.r) of the compressor reaches and maintains, by self-regulation, a constant predetermined tabular value (t.sub.r1).

Abstract: Disclosed is a refrigerator comprising: a compressor having a driving motor with controllable rotation speed, an exterior sensor for sensing an exterior temperature, an evaporator sensor for sensing an evaporator temperature, a selection part for selecting an operation mode, and a control part for controlling operations of a driving motor. Where a quick-cooling mode is selected by the user through the selection part, the control part controls the driving motor, considering exterior conditions influencing the efficiency of cooling. The control part increases the rotation speed of the driving motor as the exterior temperature detected by the exterior sensor is higher. The control part increases the rotation speed of the driving motor as the evaporator temperature detected by the evaporator sensor is higher.

Abstract: In a method for the temperature regulation of an air conditioning system having a condenser, an evaporator, an expansion device and a compressor, the stroke of which can be set via a valve, the temperature in the region of the air outlet of the evaporator is measured and a desired temperature is set by a controlling of the valve. The temperature regulation additionally takes place in dependence on the refrigerant pressure.

Abstract: A refrigeration system having a modulatable compressor and a Rankine cycle refrigeration circuit having at least two evaporators. The flow rate of the compressor is modulated in response to the sensed temperature of the masses being cooled, and the control circuit switches valves to control the refrigerant flow path and modulates the flow rate of the compressor to optimize the efficiency of the refrigeration system.

Abstract: A method for controlling the evaporator temperature of an air conditioner as a function of the outside dew point, in which the air temperature and the dew point temperature of the incoming air drawn in from outside by the air conditioner for air conditioning an interior are determined. An evaporator demand temperature without reheating is determined from the interior temperature setpoint information. On the one hand, the evaporator temperature is set to a setpoint that, within presettable temperature limits, is selected as the smaller value of the evaporator demand temperature. On the other hand, the evaporator temperature is set to a setpoint that, within presettable temperature limits, is the difference between the air temperature and the dew point temperature of the incoming air on the other. A typical use of the method, for example, is in the air conditioners of motor vehicles.

Abstract: A control system for mobile air conditioning systems for controlling the rate at which the system compressor or clutch is cycled between operational and decreased refrigerant flow, by selectively controlling the response time of certain system control signals to flow demand changes including de-icing control, from interactions between de-icing control and flow control valves, as well as system overall control. Upon the detection of an icing condition, the response of the control system is delayed to a degree to control the rate at which the capacity of the compressor can be cycled with in design limits. The delay feature allows the differential used in differentiating between icing and non-icing conditions to be significantly reduced over that required in the prior art and thereby improving the performance of the air conditioning system.

Abstract: A process and an arrangement for controlling an air conditioner utilize an evaporator protected against icing and a refrigerant circulating system which includes at least one compressor and the evaporator. The evaporator temperature is sensed continuously and the compressor is deactivated when the evaporator temperature falls below a defined switch-off temperature. The compressor is activated again when the evaporator temperature exceeds a defined switch-on temperature which is at least equal to the switch-off temperature. The evaporator temperature gradient is determined by a corresponding control unit from the continuous sensing of the evaporator temperature.

Abstract: A refrigerant circulation system of the present invention includes a compressor, a condenser, a evaporator, a throttle device and a control unit. The control unit controls a composition of a refrigerant circulating in the refrigerant circulation system based on a temperature and pressure of the refrigerant of an inlet and outlet portion of the compressor, condenser, evaporator and throttle device. The control unit controls to open and close the throttle device to change the composition of the refrigerant circulating in the refrigerant circulation system.

Abstract: A replacement kit allows the replacement of a pressure operable valve of a vehicle air conditioning circuit, from a mechanically operated valve to an electrically actuated switch. The kit includes a replacement cylinder, a sensor controlled electrical switch coupling to the vehicle adjacent to the evaporator with the sensor probe coupled to the refrigerant flow from the evaporator, and a conductor means for electrically coupling the sensor controlled electrical switch to the clutch cycling system of the vehicle.

Abstract: This invention provides an air conditioner for simultaneously cooling or heating a plurality of rooms by using a single outdoor unit and at least two and more indoor units connected to the outdoor unit, the air conditioner including indoor heat exchangers installed in each room, for heat-exchanging a room air, a unit for detecting varying temperatures of conduit during the air conditioning, a control unit for controlling low temperature, high temperature, and defrosting operations for respective indoor units on the basis of the detected conduit temperature, and for coding operation states of respective indoors to input/output the coded communication signals, a communicating unit for transmitting and receiving the coded communication signals through input/output ports provided with the control unit for communicating between any indoor units.

Abstract: An automotive air conditioner which is capable of suppressing periodic torque variation in an engine-driven refrigerant compressor while ensuring performance of returning oil thereto to circumvent periodic variation in a rotational speed of an engine, thereby preventing degradation in motor power performance and drivability of an automobile. A value of target blowout temperature is calculated using a set temperature, indoor air temperature, outdoor air temperature and intensity of solar radiation. A value of first target post-evaporation temperature (TEO1) is calculated according to a determined value of target blowout temperature. Then, a value of second target post-evaporation temperature (TEO2) corresponding to a limit level for ensuring oil return performance is calculated according to the outdoor or indoor air temperature.

Abstract: A method and circuit are provided for on/off control of the compressor of a motor vehicle air conditioner, in which the compressor is shut off when the evaporator temperature measured by an evaporator temperature sensor drops below a presettable shutoff temperature value located above 0.degree. C. The shutoff temperature value is set to fall as a function of the evaporator blower power and/or the temperature of the air drawn in by the evaporator blower with rising blower power or with rising intake air temperature. The circuit includes a control stage whose output signal is fed to an on/off switching element of the compressor and depends on the voltage level at an input node, which varies with the supply voltage of the evaporator blower and/or the output voltage of the intake air temperature sensor.

Abstract: The present invention is a method for operating an air conditioner chiller system under high ambient air conditions. When the temperature of the standard discharge saturation temperature increases above a first predetermined temperature as a result of a rise in ambient air temperature, an expansion valve is throttled to reduce the capacity of the system compressor. The amount of throttling can be made to be dependent on the amount that the discharge temperature exceeds the first predetermined temperature so that compressor capacity is reduced by an amount no more than is necessary to assure that a maximum operating design pressure is not exceeded.

Abstract: A refrigeration system having a modulatable compressor and a Rankine cycle refrigeration circuit having at least two evaporators. The flow rate of the compressor is modulated in response to the sensed temperature of the masses being cooled, and the control circuit switches valves to control the refrigerant flow path and modulates the flow rate of the compressor to optimize the efficiency of the refrigeration system.

Abstract: Freezing is prevented when either of two blow ports of a bidirectional blow air-conditioner is closed. A first blowing fan is disposed on one of the sides of a heat exchanger on the utilization side and a second blowing fan is disposed on the other side. First and second blow ports are so disposed as to correspond to these showing fans, respectively, and a flap is operable to close the first blow port. The blow quantity of the second blowing fan, when the flap closes the first blow port, is controlled to a value greater than the blow quantity of the second blowing fan when the flap does not close the first blow port.

Abstract: An air conditioning apparatus for an electric vehicle includes an electrically-driven compressor. A desired temperature is set which relates to one of a temperature of air discharged into a vehicle interior and a temperature within the vehicle interior. Detection is given of a temperature related to a heat exchanger. An inverter connected to the compressor is operative for driving the compressor at a variable speed corresponding to a desired rotational speed. A target temperature related to the heat exchanger is calculated in response to the desired temperature. Calculation is given of a difference between the detected temperature and the target temperature. Also, calculation is given of a variation in the detected temperature for every given period. A corrective rotational speed is calculated from the temperature difference and the temperature variation for every given period.

Abstract: A method and an apparatus are provided for variably controlling the temperature at which the clutch of an air conditioner compressor is engaged and disengaged. The temperature at which the compressor clutch is engaged and disengaged is based on an average minimum temperature at the evaporator over a clutch cycle, wherein the clutch disengage temperature is increased if the average minimum temperature is below a first predetermined temperature and is decreased if the average minimum temperature is above a second predetermined temperature, thus maintaining the average minimum temperature within a temperature range. Further, the clutch disengage temperature is adjusted based on user operated air conditioner control settings. The clutch disengage temperature is adjusted to a higher temperature if a low blower speed is selected by the user and is adjusted to a lower temperature if a high blower speed is selected.

Abstract: A mass flow control apparatus and method for use in combination with a heat transfer system having a compressor, condenser, expansion valve, evaporator and working fluid in a fluid circuit. The mass flow is controlled using a quality sensor for the working fluid exiting the evaporator, and a high side pressure sensor. A control circuit is provided that monitors the quality sensor and the high side pressure sensor, and controls operation of the compressor, condenser fan and valve in response thereto. A flow reduction mode is used to reduce high side pressure at the valve inlet without excessive compressor cycling by changing the quality sensor set point when the high side pressure exceeds the condenser fan turn-on pressure but is less than the compressor disengage pressure.

Abstract: A system for preventing fogging in air conditioning systems is disclosed. The system employs a strategy whereby if fogging conditions are present, the temperature of the evaporator is stepped downwardly in increments which allow the surface of the evaporator to stabilize thereby eliminating localized cold spots.

Abstract: A method and software/firmware fixed capacity compressor control system for varying the set point temperature of a evaporator in response to changes in ambient temperature in order to produce optimum cooling in the passenger compartment of a vehicle while preventing frost from accumulating on the fins of the evaporator. The system includes an evaporator probe and an outside ambient sensor and firmware for computing set-point steady state temperatures values over a wide range of ambient temperature. Also circuits are provided for cycling ON and OFF a fixed capacity compressor in a manner to achieve optimum cooling in the passenger compartment of the vehicle in response to the computed evaporator set point temperatures.

Abstract: An automatic control for an air conditioner having a compressor motor and a fan motor and a method for its operation are provided. While the control operates both motors to cool an enclosed space, a temperature indicative of the air temperature in the space is sensed and compared with a first preselected temperature value. When the sensed temperature is no longer greater than the preselected temperature, operation of the compressor motor is terminated. Thereafter the fan motor is operated for a first preselected time period. During the first time period, a currently sensed temperature indicative of the air temperature in the space is compared with a second preselected temperature value. When the sensed temperature is no longer less than the second preselected temperature during the first time period, operation of the compressor motor is resumed and the process described above with respect to cooling the space is repeated.

Abstract: A method and apparatus of controlling an air conditioner. The discharge temperature of a compressor and the indoor heat exchanger temperature are steadily controlled to set temperatures as close as possible, suppressing hunting of the frequency of an inverter. A temperature sensor is provided for detecting the temperature of the indoor heat exchanger or the discharge temperature of the compressor. A control unit is further provided, and judges as to in which temperature zone among at least preset four temperature zones the detected temperature is.

Abstract: An environmental control system disclosed includes a refrigeration loop including a variable speed compressor having an inlet and an outlet, a condenser having an inlet connected with the compressor outlet and an outlet, and an evaporator having an inlet connected with the condenser outlet and an outlet connected with the compressor inlet. The system also includes a variable speed evaporator fan and evaporator fan control for controlling the speed of the evaporator fan and a monitor for monitoring the superheat condition of the refrigerant at the compressor inlet wherein the evaporator fan control controls the speed of the evaporator fan as a function on the value of the superheat condition. A variable speed condenser fan is controlled by a condenser fan speed control that functions in part on the value of the superheat condition.

Abstract: A modular (unitary) refrigerated condiments container is provided for use in a conventional restaurant-type salad bar. The modular refrigerated condiments container comprises a housing having a recessed cold pan in the top thereof and a removable condiment support plate for mounting above the bottom surface of the recessed pan. At least one upstanding wall extends across the recessed pan to divide it into two or more sections for enhanced cooling of condiment holders supported by the condiment support plate. A refrigeration condensing unit is provided and includes refrigerant-containing cooling coils in heat exchange communication with the recessed pan so as to cool the space defined between the recessed pan and the condiment support plate and thereby to cool the condiment holders supported by the condiment support plate.

Abstract: An electronic controller receives an evaporator inlet (or outlet) temperature sensor signal and measures the time required for the evaporator to be heated from compressor clutch cut-out to compressor clutch "ON". Depending upon the elapsed time, the controller selects from a predetermined schedule, a new value CLHOFF of the evaporator inlet temperature at which the compressor is next cut-out, raising CLHOFF for lighter thermal loading to prevent evaporator icing and freeze-up and lowering CLHOFF for heavy thermal loading to prevent unwanted compressor cycling.

Abstract: Method and apparatus for controlling a prior art refrigeration system of the type having an evaporator, a variable capacity compressor arrangement, and switching apparatus between a control unit and the compressor arrangement. The compressor arrangement thereof has adding and subtracting inputs which translate input signals to respectively increase or decrease step by step the effective capacity of the compressor arrangement. The switching apparatus thereof has adding and subtracting inputs and outputs and a reset output which is made effective after each increase or decrease of the effective capacity of the compressor arrangement. The method and apparatus herein involves processing a data signal which is indicative of the temperature status of the evaporator.

Abstract: A microprocessor based control for an automotive air conditioner receives inputs from transducers which measure suction gas pressure and temperature and ambient air temperature and provides outputs for compressor clutch control and instrument panel lights. The control includes a table of warning temperatures and critical temperatures of suction gas for various ranges of ambient temperature. The control is programmed to carry out the process of comparing compressor on times to a threshold and shutting down the compressor when the on times are repeatedly less than the threshold, looking up table values for warning temperature and critical temperature for the current ambient temperature, comparing suction gas temperatures to the table values and shutting down the compressor when the temperature is repeatedly above the critical temperature and giving a warning when the temperature is repeatedly above the warning temperature.

Abstract: A device for preventing evaporation of liquefied gas in a liquefied gas reservoir used to cool an EDS detector of an electron microscope or the like is disclosed. A cold head of a cryogenic refrigerator is disposed so as to fit an opening of the top of the liquefied gas reservoir and moreover a temperature measuring instrument or a level gauge is disposed within the liquefied gas reservoir so that the cryogenic refrigerator is automatically operated depending on the temperature within the liquefied gas reservoir or on change in the liquid level of liquefied gas. In the manner vaporized gas is condensed and reliquefied, thus suppressing wasteful dissipation of vaporized gas.

Abstract: In an air conditioning system, thermistors measure evaporator inlet and outlet temperatures and compressor body temperature. When the differential between inlet and outlet temperatures is below a first threshold and the compressor temperature is above a second threshold, very low refrigerant charge is indicated and the compressor is turned off. Also, if compressor temperature reaches a critical value, the compressor is turned off regardless of the temperature differential across the evaporator.

Abstract: In an automotive automatic air conditioning system having at least a variable displacement compressor, a condenser, an expansion valve, and an evaporator; an improvement comprising a refrigerant temperature sensor disposed between the outlet of the expansion valve and the inlet of the evaporator for detecting a refrigerant temperature, and a controller for setting a target refrigerant temperature are disclosed. The controller controls the discharge of refrigerant from the compressor such that the refrigerant temperature reaches the target refrigerant temperature. Thus, the system provides optimum dehumidification under conditions of high humidity and relatively low ambient temperature, such as a rainy spell in autumn.

Abstract: A refrigerating cycle apparatus has, in a sealed casing, a compressor including first and second compressor means driven simultaneously. A refrigerating cycle circuit is constituted by connecting this compressor, a condenser, a pressure-reducing device, and an evaporator. Counterflow checking means is provided on the suction side of the first compressor means, for checking the counterflow of the refrigerant from the first compressor means to the evaporator. Switching means is provided on the discharge side of the second compressor means.

Abstract: A remotely changeable thermostat for a refrigeration or air conditioning system and method and system employing same. The thermostat has a fluid filled capsule with a diaphragm movably responsive to fluid expansion and contraction for actuating, via lever means, a compressor power switch. The capsule senses temperature via a fluid filled capillary. A separate remote user activated switch energizes an electrical actuator for moving the fulcrum of the lever means to change the sensed temperature of the evaporator at which the power switch is actuated. The user activates a remote switch to energize an electrical heater coil for heating a bimetal strip which moves the fulcrum for the lever means between a high or low temperature setting for compressor power switch actuation in response to user opening or closing the remote heater switch.

Abstract: A control system for an automotive air conditioning system includes temperature sensors at the evaporator and at the compressor of the air conditioning system and a controller responsive to signals from the sensors to control cycling of the compressor clutch. The controller is operative to monitor the cycle rate of the compressor clutch (i.e., the duration for which the clutch is engaged in any given cycle) and to provide command signals to control air conditioning system when the clutch cycle rate exceeds or falls below predetermined values. The controller is programmed so that at a predetermined level of sensed humidity in the vehicle to change the predetermined evaporator temperature values at which the clutch is engaged or disengaged so as to change the moisture content in the air flowing across the evaporator before it is supplied to the interior of the vehicle.

Abstract: A heat pump diagnostic and control system for controlling indoor coil freeze-up when in the cooling mode is provided. A low indoor coil temperature is sensed, the indoor fan speed is increased in steps up to a maximum to thaw the frost on the indoor coil. If this is not sufficient, the compressor speed is then reduced in steps until it is turned off and if necessary, it is held off until such time as the temperature sensor indicates thawing of the indoor coil of the heat exchanger. Diagnostic flow chart and control circuitry for accomplishing this control are disclosed.

Abstract: A refrigeration system (10) having a compressor rotor (20) rotatably supported by a plurality of hydrodynamic bearings (22 and 24) lubricated by oiless pressurized liquid refrigerant and pressurizing refrigerant which flows to a condenser (34) providing liquid refrigerant which flows to an evaporator (68) in fluid communication with the condenser and the compressor in accordance with the invention includes a refrigeration circuit (36) coupled to the compressor, for providing pressurized refrigerant to the hydrodynamic bearings from the compressor and to the evaporator; a bearing pump (26), coupled to the refrigerant circuit and to the condenser, for providing pressurized refrigerant to the refrigeration circuit; a first temperature sensor (101) sensing a temperature Tsink of a heat exchange fluid at the condenser and providing a temperature signal representative of the temperature Tsink of the heat exchange fluid at the condenser; a second heat exchange sensor (103) sensing a temperature Tsource of a heat exc

Abstract: A refrigerating system including a refrigerant circuit having a condenser, evaporator and wobble plate type compressor with a variable displacement mechanism. Two passages communicate between the crank chamber and the suction chamber in the cylinder block. A bellows is disposed in a first passage and controls the communication between the crank chamber and the suction chamber response to crank chamber pressure. A control valve is disposed in the second passage and controls communication between the crank chamber and the suction chamber in the second passage in response to a signal generated outside of the compressor. A control circuit controls the generation of the signal in response to thermodynamic characteristics related to the evaporator. The signal activates or deactivates the second control valve when the characteristic indicates a value beyond a predetermined range of values.

Abstract: A refrigeration cycle is a closed cycle constituted by a variable power compressor, a four-way valve, an indoor heat exchanger, an expansion valve and an outdoor heat exchanger. Air-conditioned air is supplied from the refrigeration cycle to a plurality of rooms to be subjected to air conditioning through a supply duct at a portion near a supply opening for supplying the air-conditioned air to a corresponding one of the rooms and controls a flow amount of the air-conditioned air supplied from the supply opening. Air is returned from each room to the refrigeration cycle through a return duct. The indoor heat exchanger of the refrigeration cycle has a temperature sensor for detecting the temperature of the indoor heat exchanger. A system controller controls a drive frequency of the variable power compressor of the refrigeration cycle in accordance with a difference between the temperature of the indoor heat exchanger detected by the temperature sensor and a preset temperature of the indoor heat exchanger.

Abstract: A vapor control system (10) utilizes a variable speed compressor (11) driven by a motor (12) or the like. A condenser (13) is provided downstream of the compressor (11). Multiple evaporators (14, 15, etc.) are arranged in parallel with stepper motor controlled thermal expansion valves (16, 17, etc.) located upstream thereof. Refrigerant exit temperatures (T.sub.r1, T.sub.r2, etc.) are sensed at the exits of the evaporators (14, 15, etc.) and source exit temperatures (T.sub.S1, T.sub.S2, etc.), are also sensed. A function generator (18) calculates refrigerant dewpoint temperature (T.sub.dew) is subtracted from each of the refrigerant exit temperatures (T.sub.r1, T.sub.r2, etc.) to determine a minimum superheat temperature which is used to calculate an error signal for providing a speed signal (N.sub.c). The loads on the evaporators (14, 15, etc.) are individually controlled with the thermal expansion valves (16, 17, etc.) whose positions are responsive to signals (X.sub.C1, X.sub.C2, etc.

Abstract: An update kit allows the conversion of a suction throttling valve of a vehicle air conditioning circuit, from a mechanically operated switch to an electrically actuated thermostatic switch, without destroying the authenticity of the air conditioning circuit. The kit includes a substantially rigid planar plate for coupling in the suction throttling valve in place of a diaphragm, a gasket for coupling adjacent to the planar rigid plate to prevent leakage of refrigerant, a thermostatic electrical switch having a flexible elongated temperature probe from coupling to the vehicle adjacent to the evaporator with the flexible elongated temperature probe in contact with the evaporator, a faster means for securing the elongated temperature probe in place, thermically insulating tape for wrapping around the flexible elongated temperature probe, and a conductor means for electrically coupling the thermostatic electrical switch to the clutch cycling system of the vehicle.