Abstract: The invention relates to a filling device for motor vehicle air-conditioning systems which can be operated with harmless and natural refrigerants, in particular CO2. The filling device is to have a high safety standard, while at the same time being simple to operate and having a cost-effective makeup. For this purpose, the filling device comprises a connection (12) for connecting the device (10) to the air-conditioning system, a drainage line (18), containing a drainage valve (24), for draining off the refrigerant of the air-conditioning system in a defined manner, a pumping-off line (20) which has a pump (36) and is connected to the connection (12), for completely pumping off refrigerant residues and any other impurities, and a refrigerant feed line (22), connected to the connection (12), for filling the air-conditioning system with refrigerant from a refrigerant reservoir (44).

Abstract: The invention relates to a method for forming at least one flat-tube insertion slot in a header tube. A sawcut is introduced into the header tube during a sawing step, and the slot is configured, during a subsequent punching step, by means of a slot punch, which punches into the region of the sawcut. A rimmed opening can be configured during the punching step by using a slot punch with a larger width and/or length relative to the sawcut. The sawcut is preferably introduced to a depth less that the wall thickness of the header tube. The respective web region(s) between chamber of a multi-chamber header tube can be compressed during the punching operation to a level lower than that of a header-tube wall region functioning as a flat-tube insertion stop, in order to form a chamber-connecting duct.

Abstract: The invention relates to a method of refrigerant level monitoring in a refrigerant circuit of an air-conditioning or heat-pump system having a compressor and a refrigerant which may, depending on the operating point, be operated in the supercritical range. The method includes standstill level monitoring with the compressor switched off and/or in-operation level monitoring with the compressor switched on. In the case of in-operation level monitoring, the refrigerant overheat (dTü) at the evaporator is registered and, in the event of excessive overheat, it is concluded that there is underfilling. At a standstill, the pressure and temperature of the refrigerant are registered, and it is concluded that there is an improper refrigerant filling level if the pressure (pKM) lies below a minimum pressure value (pmin) or the temperature (TKM) lies above a maximum saturation temperature value (TS) with the pressure being outside a predefinable intended pressure range ([pu,po]).

Abstract: The invention relates to a serpentine heat exchanger having a first serpentine tube block (12a) comprising one or more adjacent first serpentine tube sections with parallel through-flow and a second serpentine tube block (12b) disposed behind the first and comprising one or more adjacent second serpentine tube sections with parallel through-flow. According to the invention, at least one of the second serpentine tube sections is connected in series for flow purposes via a diversion section (10, 11) to a first serpentine tube section lying adjacent thereto.

Abstract: The invention relates to a filling device for motor vehicle air-conditioning systems which can be operated with harmless and natural refrigerants, in particular CO2. The filling device is to have a high safety standard, while at the same time being simple to operate and having a cost-effective makeup. For this purpose, the filling device comprises a connection (12) for connecting the device (10) to the air-conditioning system, a drainage line (18), containing a drainage valve (24), for draining off the refrigerant of the air-conditioning system in a defined manner, a pumping-off line (20) which has a pump (36) and is connected to the connection (12), for completely pumping off refrigerant residues and any other impurities, and a refrigerant feed line (22), connected to the connection (12), for filling the air-conditioning system with refrigerant from a refrigerant reservoir (44).