Abstract: An air-conditioning system operated with CO2 for a vehicle has a high-pressure section that is connected to the output of a compressor and includes a gas cooler, a low-pressure section that is connected to the suction side of the compressor and includes an evaporator, and an expansion member connecting the high-pressure section and the low-pressure section. The expansion member has a fixed restrictor with a throttle opening of predetermined length and diameter connected between an inlet from the high-pressure section and an outlet to the low-pressure section whereby under all operating conditions of the system, a pressure of refrigerant in the high-pressure section of the system is limited to values of less than 14 MPa. The restrictor can be connected in parallel with a pressure limiting valve and can include two or more different throttle openings that can be selectively connected for refrigerant flow.

Abstract: A heat exchanger block includes a plurality of block units, located one behind the other, each having a plurality of stacked tube units with tube ducts extending transverse to the block depth and height. The tube ducts are connected at ends to associated collector ducts extending in the block height direction. The tube units can be formed from a multichamber flat tube. At least one collector-duct connection is provided between adjacent block units to form a meandering flow path through the heat exchanger block. The heat exchanger block can be used as an evaporator in a motor vehicle air-conditioning system.

Abstract: A heat exchanger, particularly for a thermal coupling of a glycol/water cooling system circuit and a refrigerant circuit in a motor vehicle includes a plurality of first plates having first flow channels for refrigerant and a first reservoir in fluid communication with the first flow channels integrally formed therein, a plurality of second flow plates having second flow channels for a glycol/water mixture, and a second reservoir mounted to a side of said heat exchanger and in fluid communication with the second flow plates.

Abstract: An air-conditioning system operated with CO2 for a vehicle has a high-pressure section that is connected to the output of a compressor and includes a gas cooler, a low-pressure section that is connected to the suction side of the compressor and includes an evaporator, and an expansion member connecting the high-pressure section and the low-pressure section. The expansion member has a fixed restrictor with a throttle opening of predetermined length and diameter connected between an inlet from the high-pressure section and an outlet to the low-pressure section whereby under all operating conditions of the system, a pressure of refrigerant in the high-pressure section of the system is limited to values of less than 14 MPa. The restrictor can be connected in parallel with a pressure limiting valve and can include two or more different throttle openings that can be selectively connected for refrigerant flow.

Abstract: An optimized CO2 air-conditioning system for a vehicle has individual components designed and/or matched to one another in such a way that if the high pressures in the high-pressure section deviate by up to ±30% from the optimum high pressures, the associated optimum performance figures are reduced by no more than 20%. The individual components include a controllable compressor, a gas cooler, an internal heat exchanger, an evaporator and an accumulator. As a result, a fixed throttle expansion member can be used between the high-pressure and low-pressure sections of the system.

Abstract: An expansion element for a CO2 motor vehicle air conditioner includes a valve unit which can be used particularly for such an expansion element and which has a fixed throttle between an upstream valve high-pressure side and a downstream valve low-pressure side. The expansion element contains a control valve which is acted upon by the low-pressure-side refrigerant pressure or a physical quantity connected therewith as the correcting variable, or valve unit. The valve unit contains a fixed throttle and at least one additional valve component in the form of a pressure control valve which is arranged in a bypass line bypassing the fixed throttle, or in the form of a control vale influencing the passage cross-section of the fixed throttle.

Abstract: A multichannel flat tube for a heat exchanger has a plurality of parallel flow channels aligned in a row, side by side, along a transverse axis of the tube. At least the inner flow channels have oval cross-sections, and major semiaxes of the inner flow channels are inclined relative to the transverse axis of the tube at an acute angle. The flat tube can be designed for high operating pressures with relatively low weight and relatively high heat exchange capability. The construction may be used, for example, in CO2 air conditioners in motor vehicles.

Abstract: An integrated modular collector—heat exchanger unit for motor vehicle air conditioners and the like has a collector housing in which a collecting space and a heat exchanger unit are disposed. The heat exchanger unit includes two separate heat exchanger ducts which are in a thermal contact. One heat exchanger duct has a helical course and is part of a first flow duct which extends from a housing inlet to a housing outlet in the collector housing. The other heat exchanger duct is part of a second flow duct extending between the collecting space and a housing connection. This other heat exchanger duct also has a helical course, its coils in each case being in a thermal contact with at least one adjoining coil of the first of the first heat exchanger duct.

Abstract: A multichannel flat tube for a heat exchanger has a plurality of parallel flow channels aligned in a row, side by side, along a transverse axis of the tube. At least the inner flow channels have oval cross-sections, and major semiaxes of the inner flow channels are inclined relative to the transverse axis of the tube at an acute angle. The flat tube can be designed for high operating pressures with relatively low weight and relatively high heat exchange capability. The construction may be used, for example, in CO2 air conditioners in motor vehicles.

Abstract: A control device is provided for a refrigerant circuit of an air conditioner, divided by a compressor and a vent element into a high-pressure side and a low-pressure side. The control device includes a high-pressure-side control part and a low-pressure-side control part for controlling one or more controllable high-pressure-side or low-pressure-side system components. The two control parts are coupled with one another, with at least one influential parameter of one control part forming a coupling parameter that is coupled into the other control part as an influential parameter that is effective there as well. The control device is useful for carbon dioxide air conditioners of motor vehicles.

Abstract: In an air conditioner for a motor vehicle, an internal heat exchanger is combined with a condenser and a collector.

Abstract: An intake plenum unit is provided for a heat exchanger with a tube block made of a plurality of heat exchanger tubes. The heat exchanger incorporates an intake plenum with a tube wall in which a lengthwise slot is provided for receiving ends of the heat exchanger tubes. The intake plenum is made of one or more individual tubes inserted into one another endwise or fitted together. Each intake plenum has, at least at one individual tube end, a lengthwise slot that is open and made before or after the construction of the intake plenum. This allows problem-free compensation for manufacturing tolerances of the tube ends to be fitted into the lengthwise slot regarding their length in the direction of the lengthwise slot. The intake plenum unit is suitable for use, for example, for gas coolers and evaporators of carbon-dioxide air conditioners.