Behr Gmbh & Co.

Luk Fahrzeug-hydraulik Gmbh & Co. Kg

Behr Gmbh & Co. Stuttgart

Michael Sickelmann

Hans-Joachim Krauss

Christoph Walter

Harald Raiser

Karl-Heinz Staffa

Hagen Mittelstrass

Walter Demuth

Martin Kotsch

Volker Kirschner

Wolfgang Geiger

Rainer Heilig

Frank Obrist

Karl Lochmahr

Georg Weber

Wilhelm Baruschke

Jochen Schumm

Ottokar Kunberger

Tilo Schäfer

Hagan Mittelstrass

Sascha Lindauer

Thomas Gerken

Wolfgang Schmidt

Herbert Bimboes

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 (dT&#xfc;) 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 (p) lies below a minimum pressure value (p) or the temperature (T) lies above a maximum saturation temperature value (T) with the pressure being outside a predefinable intended pressure range ([p,p]).

Method of monitoring refrigerant level

A safety device limits the pressure in an axial-piston compressor with variable piston displacement. The compressor has as wobble plate or swash plate whose tilt angle can be variably controlled by the pressure differential between the high pressure in the discharge pressure zone and the pressure in the piston-drive chamber. The safety device consists of a valve arranged in a connector channel between the discharge pressure zone and the pressure zone of the piston-drive chamber. When the discharge pressure exceeds a given pressure limit, the safety device responds by allowing an increased flow of pressure medium from the discharge pressure zone to the piston-drive chamber. The influx of pressure medium into the piston-drive chamber causes a reduction of the tilt angle of the swash plate or wobble plate.

Safety device to limit pressure in an axial-piston compressor housing

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.

Method of forming flat-tube insertion slots in a header tube

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 (dT&uuml;) 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 (p ) lies below a minimum pressure value (p ) or the temperature (T ) lies above a maximum saturation temperature value (T ) with the pressure being outside a predefinable intended pressure range (&lsqb;p ,p &rsqb;).

The invention relates to a serpentine heat exchanger having a first serpentine tube block ( ) comprising one or more adjacent first serpentine tube sections with parallel through-flow and a second serpentine tube block ( ) 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 ( ) to a first serpentine tube section lying adjacent thereto.

Serpentine heat exchanger

The invention relates to a method and system for controlling a compressor in a refrigerant circuit of an air-conditioning system of a motor vehicle. The instantaneous load torque is determined and compared with a maximum limiting torque prescribed by an engine controller, and the compressor is controlled depending on the comparison value resulting therefrom. In order to avoid complete shutdown of the compressor, the instantaneous load torque is represented as a function of variables, such as compressor speed and high pressure of the refrigerant, and, using an inverted function belonging to this function, a control signal for the compressor, for example, a set-point value for the high pressure of the refrigerant, is determined as a function of the maximum limiting torque and employed to control the compressor.

Method and system for controlling a compressor

A heat-exchanger tube block is disclosed having at least two header tubes ( ), which are C-shaped in cross section and each of which has a continuous longitudinal slot ( ). Flat tubes ( ) are inserted into the header-tube longitudinal slots. A cover-plate element ( ) is provided which has a plurality of C-shaped openings and is fitted over one end of the at least two header tubes, so that the header tubes respectively fit into one of the openings and are secured in a fluid-tight manner. The tube-block can be used, for example, in an evaporator of CO air-conditioning installations for a motor vehicle.

Heat-exchanger tube block with a plurality of slotted header tubes

The invention relates to an air conditioner with a refrigerant loop containing a compressor, an evaporator, an accumulator positioned on the low-pressure side between the evaporator and the compressor, and an internal heat exchanger with a high-pressure side heat transfer channel and a low-pressure side heat transfer channel. According to the invention, the internal heat exchanger has a multichannel tube wound into a radial spiral or a meander shape. In addition or alternatively, the internal heat exchanger contains a multichannel tube which is positioned in the air current path of a cool air current of a high-pressure side condenser/gas cooler. Utilization, for example as a CO air conditioner in motor vehicles.

Air conditioner with internal heat exchanger and method of making same

The invention relates to a filling device for motor vehicle air-conditioning systems which can be operated with harmless and natural refrigerants, in particular CO . 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 ( ) for connecting the device ( ) to the air-conditioning system, a drainage line ( ), containing a drainage valve ( ), for draining off the refrigerant of the air-conditioning system in a defined manner, a pumping-off line ( ) which has a pump ( ) and is connected to the connection ( ), for completely pumping off refrigerant residues and any other impurities, and a refrigerant feed line ( ), connected to the connection ( ), for filling the air-conditioning system with refrigerant from a refrigerant reservoir ( ).

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Stuttgart, Germany

Michael Sickelmann