A system for controlling a compressor may include an engine controller controlling a fuel injection amount corresponding to an engine load and an opening amount of a throttle by reflecting a required torque required for an air conditioner, an operation information detector for detecting operation information according to driving state of the vehicle, a compressor generating pressure through a piston operation of a cylinder utilizing the power of the engine during operation of the air conditioner, and a controller determining an engine negative pressure of an intake manifold stored in the brake booster at a value, and when the negative pressure of intake manifold is below a first threshold value when the brake is operated, the engine enters a negative pressure recovery mode for predicting an insignificant negative pressure drop condition that falls below a second threshold value which is the A/C cut control condition and reduces the A/C duty.

A vehicle air conditioning system includes an in-vehicle air conditioner that includes a refrigerant circulation circuit including a compressor and an evaporator; a weather information acquiring section configured to acquire weather information at a current location of a vehicle; an evaporator drying determining section configured to estimate a water retention amount of the evaporator based on the weather information acquired by the weather information acquiring section and an operation state of the in-vehicle air conditioner, and to determine whether the evaporator is in a dry state; and a compressor stop permitting section configured to output a permission signal for permitting stop of the compressor on a condition that the evaporator drying determining section determines that the evaporator is in the dry state.

A heating, ventilation, and air-conditioning (HVAC) system in a hybrid or battery-electric vehicle is provided. The HVAC system includes a compressor that has its own dedicated motor to control its speed. The compressor includes an inlet pressure sensor to determine and output the suction pressure, and an outlet pressure sensor to determine and output the discharge pressure of the compressor. At least one controller can be programmed to determine the discharge-to-suction pressure ratio, and limit the operating speed of the compressor in response to the ratio exceeding a pressure-ratio-threshold. The pressure-ratio-threshold can vary based on ambient air temperature. In the event an inlet pressure sensor is not available, the operating speed of the compressor can be reduced in response to the outlet pressure exceeding an ambient-temperature-based variable threshold.

An air conditioning apparatus for recreational vehicles comprises a refrigeration circuit for circulating a refrigerant fluid, said refrigeration circuit including: a condenser, an expansion valve, an evaporator, in heat exchange with a room of the recreational vehicle to be air-conditioned, a compressor, and a leakage detection system, including: a refrigerant fluid sensor, configured to detect a control parameter representative of a physical condition of the refrigerant fluid at the outlet of the evaporator or at the inlet of the condenser; a control unit, connected to the refrigerant fluid sensor, and to the compressor.

A method for determining a level of refrigerant charge in a cooling circuit of an air-conditioning system and a module for leak detection are provided. The method includes determining a total quantity of refrigerant contained in the cooling circuit of the air-conditioning system solely based on data internal to the air-conditioning system.

While a speed of a first compressor during operation is less than a threshold speed, a speed of a second compressor during operation is prevented from falling below a minimum threshold speed that is defined by a sum of the speed of the first compressor and a predefined offset speed delta such that the minimum threshold speed changes as the speed of the first compressor changes.

Methods and systems for providing control of a heat pump of a motor vehicle are presented. In one operating mode, speed of a heat pump compressor is controlled responsive to an outlet pressure of the heat pump compressor. In a second operating mode, speed of the heat pump compressor is controlled responsive to a pressure ratio between an inlet and an outlet of the heat pump compressor.

A vehicle heating, ventilating, and air conditioning (HVAC) system can be configured to reduce and/or prevent condensation build up on one or more elements of the system. Subsequent to a power state of the vehicle being switched from an active state to an inactive state, a fresh mode air source can be selected as an intake for a blower. It can be determined whether an ambient temperature is greater than or equal to a predetermined temperature. It can then be determined whether the compressor was in operation prior to the vehicle having been switched from the active state to the inactive state. It can be determined whether a temperature of an evaporator of the HVAC system is rising. If it is determined that the ambient temperature is greater than or equal to the predetermined temperature value, that the compressor was in operation prior to the vehicle having been switched from the active state tot eh inactive state, and that the temperature of the evaporator is rising, a blower can be activated to blow air from the fresh mode air source across the evaporator.

A transport refrigeration unit system (26) for cooling a trailer compartment (24) is provided. The transport refrigeration unit system (26) includes an engine for controlling a cooling rate capacity, the engine operable at a nominal high speed and a nominal low speed. Also included is a controller (50) in operative communication with the engine to control an engine speed of the engine. Further included is a user interface (52) in operative communication with the controller (50), the user interface (52) providing a high capacity cooling mode to a user, wherein initiation of the high capacity cooling mode includes the engine operating at a speed greater than the nominal high speed to result in a high capacity cooling rate.

This electric compressor control device comprises: a control unit of an inverter which controls a motor that drives a compressor; a physical quantity calculation unit which calculates, on the basis of one or a plurality of predetermined detection values acquired from the inverter, a physical quantity that varies depending on a workload of the compressor; a number-of-revolutions acquisition unit which acquires the number of revolutions of the motor; a storage unit which stores information representing a first threshold that varies depending on the number of revolutions of the motor, and defines whether or not the physical quantity is a normal value; and a refrigerant abnormality determination unit which determines whether or not there is an abnormality in a refrigerant system by comparing the calculated physical quantity with the first threshold, depending on the acquired number of revolutions.