The invention relates to a thermoplastic composition for a monolayer tube (T1, T2), and particularly to an air-conditioning circuit for a motor vehicle comprising tubes transporting a refrigerating fluid.

The composition comprises in weight fractions: more than 20% and up to 40% of a PA 6.10 and/or a PA 6.12, from 45% to less than 60% of a polyphthalamide having a Tg higher than 120° C. and selected from PA 6.I/6.T, PA 9.T, PA 10.T, PA 10.T/X, and from 10% to 20% of a compatibilizing system comprising a reaction product between (a) a polymer of olefin comprising an unsaturated epoxide and (b) a polymer of olefin comprising an unsaturated carboxylic acid, with weight ratio (a):(b) greater than 1.

A refrigeration system has: (a) a fluid tight circulation loop including a compressor, a condenser and an evaporator, the evaporator having at least three evaporator zones, each evaporator zone having an inlet port, the circulation loop being further configured to measure the condition of the refrigerant with a refrigerant condition sensor disposed within the evaporator upstream of the evaporator outlet port; and control the flow of refrigerant to the evaporator based upon the measured condition of the refrigerant within the evaporator, and (b) a controller for controlling the flow rate of refrigerant to the evaporator based upon the measured condition of the refrigerant within the evaporator upstream of the evaporator outlet port.

A heat pump system with a refrigerant flow path comprising, in the heating mode of operation: a compressor coupled to receive refrigerant from a heating mode first refrigerant stream and a heating mode second refrigerant stream of the refrigerant flow path; the condenser coupled to receive refrigerant from the compressor; and a heat exchanger for transferring heat between the heating mode first refrigerant stream and the heating mode second refrigerant stream, wherein the heating mode first refrigerant stream comprises: the first expansion valve coupled to receive refrigerant from the condenser; the first evaporator coupled to receive refrigerant from the first expansion valve; and the heat exchanger coupling the heating mode first refrigerant stream from the first evaporator to the compressor, wherein the heating mode second refrigerant stream comprises: the second expansion valve; the heat exchanger coupling the heating mode second refrigerant stream from the condenser to the second expansion valve; and the second evaporator being coupled to communicate refrigerant from the second expansion valve to the compressor, wherein the first evaporator is in a first air flow conduit with a first air inlet for receiving a first air flow, and the second evaporator is in a second air flow conduit coupled to receive the first air flow.

An air-conditioning device includes a heater unit that heats the air to be lead to a vehicle cabin using the heat of the refrigerant compressed by a compressor, a liquid receiver arranged at the downstream side of an outside heat exchanger, a liquid receiver separating the refrigerant lead from the outside heat exchanger into a liquid-phase refrigerant and a gaseous-phase refrigerant and storing the liquid-phase refrigerant, and a restrictor mechanism provided between the heater unit and the outside heat exchanger, the restrictor mechanism decompressing and expanding the refrigerant. When there is a dehumidification request, the operation mode is temporarily switched from a dehumidifying cabin-heating mode which evaporates the refrigerant by an evaporating unit and radiates heat by the heater unit in the state in which the restrictor mechanism restricts the flow of the refrigerant, to the cabin-cooling mode which evaporates the refrigerant by the evaporating unit while promoting the storage of the liquid-phase refrigerant in the liquid receiver.

A method for cooling air in an HVAC system includes moving refrigerant through a closed refrigeration circuit having, inter alia, an expansion device subsystem, which includes a full-load pathway and at least one partial-load pathway and a flow selector for directing refrigerant flow from the condenser to either the partial-load pathway or the full-load pathway. The method also involves directing refrigerant flow from the condenser to the full-load pathway when the refrigerant pressure is greater than or equal to a first preselected activation pressure and stepping down a refrigerant pressure with a set orifice and directing refrigerant flow from the condenser to the partial-load pathway when the refrigerant pressure is less than a second preselected activation pressure and stepping down a refrigerant pressure with a variable expansion device configured for partial loads. Refrigerant is delivered from the full-load pathway or partial-load pathway to the evaporator.

An air conditioning system for motor-vehicles includes a thermally controlled expansion valve unit for regulating the expansion of the fluid upstream of the evaporator, depending upon the temperature downstream of the evaporator. An intermediate heat exchanger provides a heat exchange between the conduit upstream of the evaporator and the conduit downstream of the evaporator. The expansion valve unit is arranged in such a way that its temperature sensor detects a temperature of the fluid along the conduit downstream of the evaporator at a portion of this conduit which is located downstream also with respect to the intermediate heat exchanger. A connecting flange is interposed between the evaporator and the thermally controlled expansion valve unit.

A refrigeration system has: (a) a fluid tight circulation loop including a compressor, a condenser and an evaporator, the evaporator having at least three evaporator zones, each evaporator zone having an inlet port, the circulation loop being further configured to measure the condition of the refrigerant with a refrigerant condition sensor disposed within the evaporator upstream of the evaporator outlet port; and control the flow of refrigerant to the evaporator based upon the measured condition of the refrigerant within the evaporator, and (b) a controller for controlling the flow rate of refrigerant to the evaporator based upon the measured condition of the refrigerant within the evaporator upstream of the evaporator outlet port.

An expansion valve includes: a body having an insertion hole in a partition separating a first passage from a second passage; a power element configured to generate a drive force for opening or closing a valve section; a shaft extending through the insertion hole and configured to transmit the drive force to a valve element; a vibration-proof spring coaxially supporting the shaft and biasing the shaft radially inward to apply a sliding resistance thereto; and a flexible O-ring supported by one of an inner surface of the support part defining the insertion hole and an outer surface of the shaft and being in close contact with the other thereof. The O-ring, sliding portions of the shaft and the support part, and the vibration-proof spring are arranged in this order from a first passage side toward a second passage side in an axial direction of the shaft.

A temperature sensitive rod is communicated with a diaphragm that is displaceable in response to a pressure difference between an internal pressure of a sealed space, in which a temperature sensitive medium is sealed, and a pressure of a low pressure refrigerant outputted from an evaporator. A blind hole, which opens to the sealed space, is formed in an inside of the temperature sensitive rod. The temperature sensitive medium is a mixture gas of the refrigerant and an inert gas. A mixing ratio of the inert gas in the temperature sensitive medium corresponds to a ratio of an equivalent diameter of the blind hole relative to a depth of the blind hole in such a manner that a time constant of heat conduction from the temperature sensitive rod to the temperature sensitive medium is kept within a desired time constant range.

A refrigerant/heat medium heat exchanger that heats a heat medium which circulates in a heater core of an HVAC unit is provided in a discharge pipe of a cooling refrigerant circuit, a heating bypass circuit that extends to a receiver is connected to a downstream side of the refrigerant/heat medium heat exchanger through a switching means, a second circuit having a second decompression means is provided between an outlet of the receiver and a first end of a vehicle exterior heat exchanger, and a third circuit having a solenoid valve is provided between a second end of the vehicle exterior heat exchanger and an intake circuit. In a vehicle air-conditioning system, a heating refrigerant circuit is configured by an electric compressor, a refrigerant/heat medium heat exchanger, a switching means, a heating bypass circuit, a receiver, a second circuit, a vehicle exterior heat exchanger, and a third circuit. Consequently, while simplification of a configuration and the like are attained by diverting cooling refrigerant circuit and an HVAC of a current system, cooling/heating capacity can be ensured by diversifying heating heat sources, and operation in a frost formation delay mode or the like is possible during heating.