Abstract: An intake port for air for air conditioning in an air conditioning device is switched when an engine is stopped, by forcibly displacing an internal/external air switching door so as to block an external air duct. As a result, an air flow area of the external air duct becomes substantially zero. Accordingly, intake of external air to the air conditioning device as air for air conditioning is inhibited, and it becomes less liable that an air condition (e.g., a temperature) within a passenger compartment will deviate from a required state.

Abstract: The present invention provides a cooling fan control device configured to use a single cooling fan instead of a double cooling fan for cooling an air conditioner and a radiator. The cooling fan control device comprises a vehicle operation state detecting unit; an electronic control unit to output a cooling fan control signal according to a preset program; a first power supply unit for supplying a high fan speed driving power to a cooling fan motor; and a second power supply unit for supplying a low fan speed driving power to the cooling fan motor according to the cooling fan control signal output from the electronic control unit.

Abstract: A method of control for preventing warm air from being exhausted during a fuel cut when driving an air-conditioning system by a vehicle engine comprising, when it is judged that the fuel has been cut when the engine is decelerating and the engine speed has fallen to a first judgement value, causing the amount of discharge and torque of the refrigerant compressor to fall once to for example zero or a value close to zero, then causing them to gradually rise in a pattern of torque control of the refrigerant compressor and, when it is judged that the engine speed has fallen to a second judgement value, causing the fuel cut of the engine to end so as to secure the minimum necessary cooling capacity and extend the fuel cut time simultaneously.

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: The present invention relates to a method and an apparatus for controlling an electric motor by regulating at least the current Iout, the voltage Uout and the frequency fout to an input of said motor, where the number of revolutions of said electric motor is proportional to said frequency fout. If an available power Pin from an energy source is greater than or equal to the nominal requested power Pnom of said electric motor, the current Iout, voltage Uout and frequency fout are set to there corresponding nominal values Inom, Unom and fnom, respectively, to achieve said requested power Pnom and frequency fnom. If said available power Pin is less than the requester power Pnom, the voltage Uout and the frequency fout are reduced such that the relation between the voltage Uout and the frequency fout is essentially constant while said current Iout is kept at its nominal value Inom.

Abstract: A controller for a vehicle air conditioner which includes a control unit, a fuel cutoff control unit capable of stopping supply of fuel to an engine, an engine rpm detecting unit capable of detecting engine revolutions per minute, and a brake signal detecting unit capable of detecting a brake signal is provided. The control unit is adapted to alter the evaporator temperature setting during fuel cutoff, when a detected change of engine rpm is less than a predetermined value, and brake signal detector does not detect a brake signal.

Abstract: In a control unit of a vehicle air conditioner, a necessary time period T1, between the present time and a time at which the vehicle is stopped next, and a vehicle stopping time period T2, between the time at which the vehicle is stopped next and a time at which the vehicle is re-started, are estimated based on vehicle-travel state information and traffic signal information in a vehicle traveling. Further, a necessary cold release amount Q required for cooling in the vehicle stopping time period T2 is calculated based on the vehicle stopping time period T2, and a cold storage operation is controlled so that the necessary cold release amount Q is stored for the necessary time period T1.

Abstract: An air conditioning system for a vehicle includes a compressor driven by a first drive source or a second drive source, or a combination thereof, and an evaporator operationally connected to the compressor via a refrigerant circuit. The system also includes a blower for dispensing air into an interior of the vehicle via the evaporator. The blower is driven by the first drive source or the second drive source, or a combination thereof. Moreover, the system includes a controller for controlling the first drive source and the second drive source. Specifically, when a temperature of air dispensed from the evaporator is greater than a predetermined temperature and a speed of the vehicle is greater than a predetermined speed, the first drive source drives the compressor and the blower.

Abstract: A control device for a motor fan of a vehicle, which controls the motor fan to cool a radiator for engine coolant and a condenser for air conditioner refrigerant, includes: a first command value calculation section which calculates a first command value for control of the motor fan according to refrigerant pressure; a second command value calculation section which calculates a second command value for control of the motor fan according to coolant temperature; a first target value setting section which sets the greater of the first command value and the second command value as a first target value; a second target value setting section which obtains a second target value for control of the motor fan which corresponds to a total torque which is smaller than a total torque of a torque of an alternator and a torque of a compressor corresponding to the first target value; and a control section which controls the motor fan according to the second target value.

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: The object of the present invention is to provide a method of controlling a refrigeration cycle such that maximum refrigerating capacity can be educed when the refrigeration cycle is started, the driving torque of a variable displacement compressor can be reduced when an automotive vehicle performs standing start or acceleration, and the refrigeration cycle can be operated with the maximum efficiency in a steady operating condition.

Abstract: A control method for a motor vehicle HVAC system categorizes potentially conflicting override commands for at least one control parameter in order to assign a priority of control. Override commands are categorized as being related to occupant safety, vehicle safety or occupant comfort. Highest priority is assigned to override commands categorized as being related to occupant safety, second-highest priority is assigned to override commands categorized as being related to vehicle safety, and third-highest priority is assigned to override commands categorized as being related to occupant comfort. An HVAC controller carrying out the control method then regulates the control parameter in accordance with the override command that has been assigned the highest priority.

Abstract: A vehicle air-conditioning system calculates and indicates the remaining time of effective cooling by cold air discharge from its cold storage unit during a vehicular eco-run halt. In cold discharge cooling mode, a first cold discharge cooling remaining time tx1 is calculated from the remaining cold heat of a cold storage medium. A second cold discharge cooling remaining time tx2 is calculated from temperature changes of the cold storage unit. The second remaining time tx2 is set to zero when the cold storage unit temperature rises to a cooling upper target temperature. The first remaining time tx1 is selected in the cold discharge cooling mode as long as the temperature of the cold storage unit is below a temperature near the solidifying point of the cold storage medium. The second remaining time tx2 is selected when the cold storage unit temperature exceeds the temperature near the solidifying point.

Abstract: In a vehicular air conditioning control apparatus having a compressor and an electric cooling fan of an externally controlled type, a fan motor control for increasing fan motor load is carried out in a compressor discharge capacity region lower than in normal control in below-listed cases.

Abstract: The method for controlling a hybrid air conditioning system of a direct coupled motor-driven hybrid electric vehicle includes detecting operating conditions of the air conditioning system; and controlling the hybrid air conditioning system. The hybrid air conditioning system includes a mechanical air conditioner driven by an engine and an electric air conditioner driven by electric power of a battery.

Abstract: A hybrid compressor apparatus for a refrigerant cycle is mounted on a vehicle having an engine that stops in accordance with driving conditions of the vehicle. The apparatus includes an electrical motor, a compressor driven by at least one of the engine and the motor for compressing refrigerant in the refrigerant cycle, a controller for controlling operation of the motor and the compressor and for selecting a driving source between the engine and the motor so as to drive the compressor, and a switch for manually setting a normal mode and an economy mode in the refrigerant cycle. The motor drives the compressor when the economy mode is selected while the engine stops. Therefore, an operation load of the compressor can be reduced in the economy mode, and fuel consumption can be reduced.

Abstract: A compressor device for a refrigerant cycle includes a compressor and a control unit. The compressor is provided with a displacement changing mechanism for changing its displacement. The control unit changes a current value supplied to the displacement changing mechanism, thereby relatively changing the displacement of the compressor. In the compressor device, when a rotational speed of a vehicle engine is lower than a predetermined rotational speed, the control unit controls an upper limit of the current value between a first predetermined value and a maximum value. Accordingly, a displacement specification of the compressor device can be normalized for vehicle engines having different power outputs, while engine stall can be prevented.

Abstract: An apparatus and method for drying condensate from the heat exchanger of a vehicle's air conditioning system after operation in order to thwart odor buildup is provided. The apparatus and method operate regardless of whether the system's blower control circuit is positively or negatively switched. The apparatus includes relays that bypass the normal operating electrical routing to the air conditioning system's blower motor to operate the blower directly. The method comprises determining that the engine of the vehicle has been switched off and that the air conditioning system of the vehicle was in operation prior to the engine being switched off. If the conditions are met, the air conditioning system's blower is operated on a predetermined time schedule to circulate air in the air conditioning system to dry condensate therefrom. In this way, growth of odor-causing fungus and bacteria is inhibited.

Abstract: If a motor breaks down, an appropriate measure is taken according to the type pf the breakdown. If the breakdown is judged to be due to abnormal energization of the motor by electrical abnormality judgment means, a drive source for a hybrid compressor is secured while preventing an engine for traveling from stopping by compressor operation continuation means. If it is judged that the driven state of the motor is abnormal, the hybrid compressor is disconnected from the engine to protect the engine from mechanical abnormality of the hybrid compressor.

Abstract: In an air conditioner for use in vehicles comprising a compressor that is connected to an engine driving a vehicle and operated by a driving force provided by the engine during operation of the engine, connection between the engine and the compressor is released in response to stopping of the engine, as well as an electric motor driving the compressor is connected to the compressor in response to stopping of the engine; and the compressor is operated by the electric motor during stopping of the engine.

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: An electrically actuated clutch assembly for a compressor in an automotive air conditioner is described wherein clutch engagement to and disengagement with the compressor are momentary events with no electrical current being required to maintain the on and off states of the clutch.

Abstract: In a vehicle air conditioner, a control unit includes determining means for determining a first start of a compressor for compressing refrigerant in a refrigerant cycle after being mounted on the vehicle, and control means for controlling operation of the compressor so that the compressor is operated for a predetermined time by a rotation speed equal to or lower than a predetermined rotation speed when the determining means determines the first start of the compressor. Accordingly, breaking-in operation of the compressor can be accurately performed for the predetermined time by an automatic control.

Abstract: A composite auxiliary machine for a vehicle has proper startup performance in starting an engine. The composite auxiliary machine has a compressor for compressing a refrigerant inside a refrigeration cycle device, a rotary machine connected to the compressor and rotated together therewith, a drive pulley for operating the rotary machine in response to a driving force from the vehicle engine, and a clutch device for transmitting and terminating the driving force of the drive pulley. The rotary machine functions as a generator and an electric motor. A variable displacement mechanism is provided in the compressor to vary an amount of discharge per revolution. A control unit controls to engage the clutch device in starting the vehicle engine, and actuates the rotary machine as an electric motor to actuate the vehicle engine. Then, an amount of discharge of a refrigerant is controlled to become smaller than that necessary in the refrigeration cycle device.

Abstract: A composite auxiliary machine for a vehicle and an accompanying control unit to control a compressor. The composite auxiliary machine for a vehicle includes a compressor for compressing refrigerant, a rotary machine that acts as an electric motor and a generator, and a torque and power distributing mechanism for distributing engine torque and power from a drive shaft to a compressor shaft and a rotary machine shaft, and from the rotary machine shaft to the drive shaft and compressor shaft. An intermittent mechanism is provided to the torque and power distributing mechanism so as to connect and disconnect any two of the drive shaft, the compressor shaft, and the rotary machine shaft. A locking mechanism is provided for restricting rotation of the compressor shaft. The compressor includes variable displacement mechanism for varying the amount of discharge per turn of the compressor shaft.

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: Device for detecting a risk of misting of a motor-vehicle window, and installation including such a device. Measurements are taken and associated with chosen models giving access to an average temperature (on the surface) of the window, for instance the windscreen, and to a dew temperature of the air in the passenger compartment of the vehicle. A comparison between the two temperatures represents a risk of misting of the window.

Abstract: A method of powering a refrigeration system. The method includes providing a mover and an alternator, the alternator being coupled to the mover and generating a power signal. The method also includes monitoring at a control a plurality of system parameters and sending a control signal based on the system parameters from the control. The method further includes receiving the power signal and the control signal at an inverter-based device which has a plurality of inverters, converting the power signal into a controlled power signal based on the control signal, and driving a plurality of components of the refrigeration system with the controlled power signal, which are also controlled by the control.

Abstract: The invention relates to a method and system for controlling a compressor in a refrigerant circuit of an air-conditioning system of a motor vehicle. The instantaneous load torque is determined and compared with a maximum limiting torque prescribed by an engine controller, and the compressor is controlled depending on the comparison value resulting therefrom. In order to avoid complete shutdown of the compressor, the instantaneous load torque is represented as a function of variables, such as compressor speed and high pressure of the refrigerant, and, using an inverted function belonging to this function, a control signal for the compressor, for example, a set-point value for the high pressure of the refrigerant, is determined as a function of the maximum limiting torque and employed to control the compressor.

Abstract: A housing of a compressor supports a rotary shaft. The rotary shaft is coupled to a pulley with a pulley one-way clutch and is coupled to a rotor of an electric motor with a motor one-way clutch. The pulley is supported by the housing with a pulley bearing. The electric motor overlaps a power transmission portion in the axial direction of the rotary shaft. At least two of the bearing, the pulley one-way clutch, the motor one-way clutch, and a brush device of the electric motor overlap each other in the axial direction of the rotary shaft. As a result, the size of the compressor is reduced in the axial direction of the rotary shaft.

Abstract: A method for controlling cycling of an air conditioning compressor coupled to an internal combustion engine interrupts normal cycling based on operation conditions. In addition, normal engaged and disengaged cycling durations are adaptively estimated in real-time. The method of the present invention achieves improved fuel economy and improved drive feel. As an example, improved fuel economy is achieved by engaging the compressor during braking or when the engine is being driven by the vehicle. As another example, improved drive feel is achieved by engaging the compressor during transient conditions when drive feel is unaffected.

Abstract: A method of control for preventing warm air from being exhausted during a fuel cut when driving an air-conditioning system by a vehicle engine comprising, when it is judged that the fuel has been cut when the engine is decelerating and the engine speed has fallen to a first judgement value, causing the amount of discharge and torque of the refrigerant compressor to fall once to for example zero or a value close to zero, then causing them to gradually rise in a pattern of torque control of the refrigerant compressor and, when it is judged that the engine speed has fallen to a second judgement value, causing the fuel cut of the engine to end so as to secure the minimum necessary cooling capacity and extend the fuel cut time simultaneously.

Abstract: When air passing through a condenser and a radiator passes through a cooling fan in a state where a driving circuit controls a voltage applied to a motor to be constant in accordance with a motor application voltage instructed by a control signal Sa, a motor current Im decreases. A comparator compares the motor current Im with a reference current set on the basis of a motor voltage Vm. When the motor current Im decreases to a value equal to or lower than the reference current, a switching circuit is switched to select an output signal of an operational amplifier. The operational amplifier performs a feedback control so that the motor voltage Vm coincides with a minimum application voltage VL.

Abstract: An electrically actuated clutch assembly for a compressor in an automotive air conditioner is described wherein clutch engagement to and disengagement with the compressor are momentary events with no electrical current being required to maintain the on and off states of the clutch.

Abstract: An arrangement and a method for controlling a compressor of an airconditioning arrangement for a motor vehicle, whereby the compressor is optionally driven through activation of a clutch arrangement. The compressor has an input shaft which, via a first wobble plate, acts through bearing elements on a second wobble plate. The second wobble plate is arranged to transmit a wobbling motion designed to drive pistons of a number of compressor units of the piston and cylinder type. A control circuit is designed for brief activation of the clutch arrangement at selected times to cause periodic movement of the bearing elements. The control circuit may be activated by the vehicle starter motor, the reverse gear or a timing circuit.

Abstract: A control unit takes in a set temperature, a vehicle-internal temperature, an ambient temperature, an engine-water temperature, a sun load and a vehicle speed from a means for setting a temperature of the air inside a vehicle and sensors. The control unit determines whether a failure has occurred in the internal-air-temperature sensor and the external air temperature sensor. If a failure is determined in any of the sensors, the control unit fetches a substitute value registered in advance in the substitute-value table. Then, the outlet temperature as well as the difference between the vehicle-internal temperature and the set temperature are determined from the signals generated by the sensors. A driving voltage of the FAN motor and switching position of the outlet flap are subsequently computed. If a failure in either of the internal-air-temperature sensor and the external air temperature sensor is determined, an opening of the air-mix flaps is then set.

Abstract: In a vehicle air conditioner, a control unit includes determining means for determining a first start of a compressor for compressing refrigerant in a refrigerant cycle after being mounted on the vehicle, and control means for controlling operation of the compressor so that the compressor is operated for a predetermined time by a rotation speed equal to or lower than a predetermined rotation speed when the determining means determines the first start of the compressor. Accordingly, breaking-in operation of the compressor can be accurately performed for the predetermined time by an automatic control.

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 shaft of a planetary gear mechanism is connected via a lock mechanism to an air-conditioner compressor. A shaft is connected to an engine, and a shaft is connected to a motor-generator. The shaft or the shaft of the motor-generator is linked to the shaft through a clutch mechanism. A control unit reduces shock by changing the rotation speed of the motor-generator on the basis of the engine speed and reducing a speed difference between the input shafts of the clutch mechanism and a speed difference between the input shafts of the lock mechanism before engaging of the clutch mechanism and releasing of the lock mechanism.

Abstract: An air conditioning apparatus includes a refrigerant circulation circuit that has a compressor. A driving status of the compressor is detected by first detector. A first calculator calculates a theoretical torque and a driving efficiency of the compressor based on information from the first detector. A second calculator calculates a necessary torque required for driving the compressor. The second calculator calculates the necessary torque based on the theoretical torque.

Abstract: A vehicle air conditioning system controls an engine and an air conditioner according to an air-conditioner load to thereby improve fuel economy and drivability of the vehicle. A higher compressor torque between a first estimated compressor torque, which is estimated according to the outside air temperature and the vehicle speed, and a second estimated compressor torque, which is estimated according to the refrigerant pressure, is adopted as an estimated compressor torque. When an air conditioner control switch is ON, an operational status of an engine and a compressor are controlled according to the adopted estimated compressor torque.

Abstract: A displacement control device comprises a control valve. The control valve controls the pressure in a crank chamber. The control valve includes a valve body, and an electromagnetic actuator. A power source supplies the current to the actuator. A switch device located between the actuator and the power source. A controller determines a target value of the current supplied to the actuator in accordance with an external condition. When the target value is changed to a new value, the controller controls the switching of the switch device such that the current is intermittently supplied from the power source to the actuator before the current is set to the new target value. This permits the displacement of the compressor to be smoothly and rapidly changed.

Abstract: In a hybrid vehicle including an engine and an electric motor both for running the vehicle, an air conditioner includes a compressor driven by the engine, and an engine controller controls the operation of the engine based on a condition of the air conditioner and a condition of the vehicle except the air conditioner. While the air conditioner performs a defrosting control for a windshield, the engine controller drives the engine irrespective of the condition of the vehicle except the air conditioner. On the other hand, when the defrosting control is not performed, the operation of the engine is controlled in accordance with the condition of the vehicle, for example.

Abstract: A displacement control apparatus is used for a variable displacement compressor. The compressor is driven by an internal combustion engine. The compressor has an inclining swash plate and a piston, which is reciprocated by the swash plate. The stroke of the piston is changed in accordance with the inclination angle of the swash plate. The displacement of the compressor is changed between a minimum displacement and a maximum displacement in accordance with the stroke of the piston. The apparatus includes an actuator coupled to the swash plate. The actuator is actuated by exhaust pressure or intake pressure from the engine. A controller changes the inclination angle of the swash plate by actuating the actuator.

Abstract: A controller for controlling the displacement of a variable displacement compressor that does not require an engine ECU to presume the load torque of the compressor and thus does not require the preparation of a load torque presumption map for each type of vehicle. The displacement controller includes a control valve arranged in the compressor to vary the displacement of the compressor in accordance with an instruction signal. A first computer is connected to the control valve. The first computer provides the instruction signal to the control valve to adjust a torque of the compressor to a target torque that is in accordance with a torque target signal.

Abstract: A vehicle air conditioner including a refrigerant circuit that incorporates a variable displacement compressor driven by an engine of the vehicle. The air conditioner includes a control valve for varying the displacement of the compressor and an ECU for controlling the control valve. The control valve has a bellows, a valve body, and a coil. The ECU varies the displacement of the compressor by energizing the coil to apply a force, which counters the movement of the bellows, to the valve body to move the valve body. This alters the moved amount of the bellows. The air conditioner control unit gradually changes the force applied to the valve body by the coil to adjust the pressure difference and vary the displacement of the compressor when the engine is running at an idle speed.

Abstract: A vehicle air conditioning system controls an engine and an air conditioner according to an air-conditioner load to thereby improve fuel economy and drivability of the vehicle. A higher compressor torque between a first estimated compressor torque, which is estimated according to the outside air temperature and the vehicle speed, and a second estimated compressor torque, which is estimated according to the refrigerant pressure, is adopted as an estimated compressor torque. When an air conditioner control switch is ON, an operational status of an engine and a compressor are controlled according to the adopted estimated compressor torque.

Abstract: A displacement control apparatus controls the displacement of a variable displacement controller. A drive shaft of the compressor is driven by an engine. Torque acting on the drive shaft represents the displacement. The apparatus includes a control valve, an air conditioner controller and a compressor controller. The control valve changes the compressor displacement. The air conditioner controller produces a torque setting signal, which represents a target torque, to the compressor controller. The compressor controller changes the valve opening based on the torque setting signal such that the actual load torque matches the target torque value. Accordingly, the compressor is controlled according to the torque. The air conditioner controller may send the torque setting signal to an engine controller, which eliminates the need for load torque maps.

Abstract: A vehicle air conditioning apparatus includes a refrigerant circuit. The air conditioning apparatus is driven by an engine. The air conditioning apparatus includes a variable displacement compressor. An external information detector detects external information used for the air conditioning. An E/G-ECU controls the output of the power source. An A/C-ECU is connected to the E/G-ECU via a communication line. The A/C-ECU computes a target value of the displacement of the compressor based on the external information. The A/C-ECU sends the computed target value to the E/G-ECU. The E/G-ECU controls the displacement of the compressor based on the computed target value. This is capable of rapidly changing the discharge displacement in accordance with the driving condition of the engine.