Disclosed are climate systems for vehicles and methods for controlling the climate systems. In some implementations, a climate system includes: (1) a temperature sensor configured to measure a temperature within the compartment of the vehicle; (2) a user interface configured to receive a desired temperature from a user; (3) a first compressor powered by an engine of the vehicle to compress a refrigerant; (4) a second compressor driven by an electric motor to compress the refrigerant; and (5) a controller electrically coupled to the first compressor and the second compressor. The controller configured to: (1) calculate a thermal load of the compartment based on a difference between a desired temperature and a measured temperature; and, (2) based on the calculated load, selectively activate: (i) the engine, (ii) the first compressor, and/or (iii) the second compressor.

A system for a vehicle includes an air conditioning compressor, and a controller configured to operate the compressor based on temperature value, responsive to the temperature values being faulty and refrigerant pressure values exceeding a first threshold, operate the compressor based on the refrigerant pressure values, and responsive to the refrigerant pressure values falling below a second threshold, deactivate the compressor for a rest of a drive cycle.

An air conditioning system of a vehicle having an internal combustion engine includes a condenser configured to receive refrigerant output by an electric compressor and transfer heat from the refrigerant within the condenser to air passing the condenser. A first evaporator is configured to receive refrigerant from the condenser when a first control valve is open and transfer heat from air passing the first evaporator to the refrigerant within the first evaporator. A first blower is configured to blow air across the first evaporator to a first section of a cabin of the vehicle. A second evaporator is configured to receive refrigerant from the condenser when a second control valve is open and transfer heat from air passing the second evaporator to the refrigerant within the second evaporator. A second blower is configured to blow air across the second evaporator to a second section of the cabin of the vehicle.

A heat pump and a heater core are provided at a heating coolant water circuit connected to an engine. As heating thermal amount control, the control of decreasing the output of the heat pump and increasing the output of the engine with an increase in an engine outlet water temperature detected by an engine outlet water temperature sensor, thereby ensuring a target heating thermal amount. Thus, in response to a decrease in a heat generation efficiency of the heat pump with an increase in the engine outlet water temperature, the output of the heat pump is decreased so that fuel economy can be improved while the output of the engine is increased so that the target heating thermal amount can be ensured.

A method for operating a cooling circuit. It is provided that a) the actuation signal ST of the coolant compressor is provided so as to increase over time from a minimum value (ST.sub.min) in order to generate a start-up phase of the coolant compressor, b) a control signal maximum value (ST.sub.max) and a control signal threshold (ST.sub.SW) are provided, where ST.sub.SW<ST.sub.max, c) the actuation signal (ST) is limited to the control signal maximum value (ST.sub.max) if the actuation signal (ST) reaches the control signal threshold (ST.sub.SW) and the measured high and/or low-pressure value (PHD, P.sub.ND) satisfies a condition.

A vehicle heating, ventilating, and air conditioning (HVAC) system can reduce a load applied to a vehicle powertrain during certain conditions. The system can include a fixed compressor operable between an ON state and in an OFF state. Systems and methods can determine whether an engine water temperature meets a forced HVAC recirculation intake threshold. Responsive to determining that the engine water temperature meets the forced HVAC recirculation intake threshold, it can be determined if the engine water temperature meets a high water temperature threshold. Responsive to determining that the engine water temperature meets the high water temperature threshold, it can be determined if a vehicle pitch meets a vehicle pitch threshold. Responsive to determining that the vehicle pitch does not meet the vehicle pitch threshold, the compressor can be operated according to an AC cut cycle.

A method of controlling a cooling fan in a cooling system in a vehicle includes detecting presence/absence of abnormality in a communication state, measuring an output voltage level of an air-conditioner pressure transducer (APT) sensor when the abnormality in the communication state is detected, determining a cooling fan control condition based on the measured output voltage level, and controlling a cooling fan motor according to the determined cooling fan control condition.

A vehicle includes a controller configured to determine when an HVAC system is providing at least one of heating, ventilating and air conditioning to a primary zone and to determine when a drivetrain is providing energy to a power source or the power source is providing surplus energy to the drivetrain, and in response, to activate a low cost energy mode wherein the HVAC system is operated to provide the at least one of heating, ventilating and air conditioning to at least one secondary zone.

Methods and systems are provided for a vehicle adapted to be operated based on fuel combustion or electric power. In one example, an accessory train of the vehicle, including an air conditioning pump and a power steering pump, may be operated according to a first mode or according to a second mode based on a power system of the vehicle. When in the second mode, the vehicle may be instructed to coordinate operation of the air conditioning pump and the power steering pump.

An air conditioning device for a vehicle has a compressor, an evaporator, a driving condition detector, a temperature detector, and a controller. The driving condition detector detects a driving condition of the vehicle. The evaporator has a cold storage portion storing the heat from the refrigerant and having phase-change energy in at least two different temperature ranges. The controller (i) maintains the compressor being stopped while a temperature detected by the temperature detector is lower than or equal to the first temperature when the vehicle is in a coasting operation and (ii) maintains the compressor being stopped while the temperature is lower than or equal to the second temperature when the vehicle is stopped. The coasting operation is a driving condition in which a vehicle speed is lower than or equal to a specified speed and an acceleration device of the vehicle is not operated.