There is provided a vehicle air conditioner which is capable of smoothly achieving a dehumidifying and heating mode without using an evaporation pressure adjustment valve, so that cost reduction is achievable. A controller executes a normal mode to control an operation of a compressor 2 on the basis of a radiator pressure PCI and control a valve position of an outdoor expansion valve 6 on the basis of a heat absorber temperature Te, and in this normal mode, when the valve position of the outdoor expansion valve 6 is maximized but the heat absorber temperature Te falls, the controller shifts to a heat absorber temperature control mode to control the operation of the compressor 2 on the basis of the temperature of a heat absorber 9 and generate heat from an auxiliary heater 23.

A vehicle air-conditioning apparatus is provided which is capable of expanding an effective range of a dehumidifying and heating mode to achieve comfortable vehicle interior air conditioning. A control device (controller) executes a dehumidifying and heating mode to let a refrigerant discharged from a compressor 2 radiate heat in a radiator 4, let a part of the refrigerant flow from a bypass circuit (refrigerant pipe 13F) to an indoor expansion valve 8, and let the residual refrigerant flow through an outdoor expansion valve 6. In the dehumidifying and heating mode, the control device has a state of controlling the operation of the compressor 2, based on a heat absorber temperature Te and executes a radiator temperature priority mode which enlarges a capability of the compressor when heat radiation in the radiator is insufficient.

Disclosed is a vehicle air conditioning device including a heat pump cycle configured to compress and expand a refrigerant; a heater core; a high pressure side pressure sensor configured to detect a pressure on the high pressure side of the heat pump cycle; and a heater core inlet water temperature sensor configured to detect a temperature of cooling water at an inlet of the heater core as a heater core inlet water temperature. The heat pump cycle includes a compressor; a condenser; a water refrigerant heat exchanger and an evaporator; and a heating expansion valve and a cooling expansion valve. An estimated outside air temperature is calculated based on the high pressure side pressure detected by the high pressure side pressure sensor and the heater core inlet water temperature detected by the heater core inlet water temperature sensor.

There is disclosed a vehicle air conditioning device of a heat pump system which delays proceeding of frosting onto an outdoor heat exchanger, thereby eliminating or inhibiting deterioration of a heating capability due to the frosting. The vehicle air conditioning device executes a heating mode in which a controller lets a refrigerant discharged from a compressor 2 radiate heat in a radiator 4, decompresses the refrigerant by which heat has been radiated, and then lets the refrigerant absorb heat in an outdoor heat exchanger 7, and on the basis of a difference TXO=(TXObaseTXO) between a refrigerant evaporation temperature TXObase of the outdoor heat exchanger 7 in non-frosting and a refrigerant evaporation temperature TXO of the outdoor heat exchanger 7, the controller corrects a target subcool degree TGSC that is a target value of a subcool degree of the refrigerant in the radiator 4 in an increasing direction in accordance with increase of the difference TXO.

There is disclosed a vehicle air conditioning device of a heat pump system which delays proceeding of frosting onto an outdoor heat exchanger, thereby eliminating or inhibiting deterioration of a heating capability due to the frosting. The vehicle air conditioning device executes a heating mode in which a controller lets a refrigerant discharged from a compressor 2 radiate heat in a radiator 4, decompresses the refrigerant by which heat has been radiated, and then lets the refrigerant absorb heat in an outdoor heat exchanger 7, and on the basis of a difference TXO=(TXObaseTXO) between a refrigerant evaporation temperature TXObase of the outdoor heat exchanger 7 in non-frosting and a refrigerant evaporation temperature TXO of the outdoor heat exchanger 7, the controller corrects a target subcool degree TGSC that is a target value of a subcool degree of the refrigerant in the radiator 4 in an increasing direction in accordance with increase of the difference TXO.

An air conditioner for a vehicle includes: a condenser that includes a core for allowing heat exchange between a refrigerant discharged from a compressor of a refrigeration cycle and air; and a switching unit that switches a refrigerant passage in the condenser. The switching unit switches the refrigerant passage between a first refrigerant passage that allows the refrigerant to flow throughout the core, and a second refrigerant passage that allows the refrigerant to flow through a part of the core by allowing the refrigerant discharged from the compressor to flow into a middle part of the core.

A vehicle air conditioner is provided which is capable of detecting a refrigerant lack accompanying a refrigerant leakage and the like over time at the earliest possible stage and protecting a compressor. The vehicle air conditioner is provided with a compressor 2, a radiator 4, an outdoor expansion valve 6, and a heat absorber 9. The vehicle air conditioner holds normal time data indicating a relation between the number of revolutions NC of the compressor and a discharge refrigerant temperature Td thereof when a sufficient amount of refrigerant is filled in a refrigerant circuit R. The present invention calculates a discharge refrigerant temperature estimated value Tdst in normal time from the normal time data on the basis of a current number of revolutions NC and compares the discharge refrigerant temperature estimated value Tdst with a current discharge refrigerant temperature Td to determine a refrigerant lack of the refrigerant circuit.

Methods and systems are provided for controlling an air conditioning compressor clutch. In one example, a method includes monitoring a clutch of an air conditioning system in a vehicle when the air conditioning system is activated, and responsive to determining that the clutch is not engaged, increasing a current flow to the clutch. In this way, engagement of the compressor clutch may be dynamically maintained with a reduced usage of electrical power.

A transport refrigeration system including a method for fault tolerant power management. The system includes a first sensor identified as required for operation of the transport refrigeration system and a second sensor operable as a backup for the first sensor. The system also includes a first power supply operably connected to the first sensor and configured to operate the first sensor and a second power supply operably connected to the second sensor and configured to operate the second sensor. The system further includes a controller operably connected to at least the first power supply as well as the first sensor and the second power supply as well as the second sensor, the controller configured to monitor at least the first power supply and the second power supply, if a fault is detected in the first power supply, operate the transport refrigeration system from the second sensor.

A method for operating a coolant circuit of a refrigeration system of a vehicle having multiple system sections. A single pressure sensor is located in each system section. A temperature sensor is arranged downstream at each component to be balanced in the system sections, such as heat exchangers and a coolant compressor. The sensor signals of the pressure and temperature sensors are supplied to a control unit for the control or regulation of the refrigeration system. Furthermore, a pressure approximation value at the position of the temperature sensor is calculated by a pressure loss value determined using a pressure loss calculation function starting from the position of the pressure sensor arranged in the system section of the component up to the position of the temperature sensor if the temperature sensor and the pressure sensor are arranged at different positions in the system section.