Abstract: In a method for recovering energy from the heat dissipated by an internal combustion engine and to an internal combustion engine wherein the pressure and temperature of a liquid working medium are increased from a lower process pressure and a first temperature to an upper process pressure at which the working fluid is heated to a second temperature whereby it is converted to a gaseous phase; the working medium is then expanded back to the lower process pressure whereby mechanical power is generated and the working medium is converted back to a liquid phase, the upper process pressure being adjusted in such a way that the working medium is expanded into the wet steam area close to the saturated steam limit.

Abstract: In a motor vehicle with an internal combustion engine providing a hot exhaust gas flow which is used as heat source for a Clausius-Rankine cycle process, wherein a pump is provided in the cycle for pumping, pressurizing and circulating an operating fluid, the pumping operation is controlled by a controller depending on the exhaust gas mass flow through an evaporator and possibly also the exhaust gas temperature to vaporize the operating fluid and expanding the vapor under pressure in an expander while generating energy. The vapor is condensed in a condenser to form a condensate which is again returned to the pump.

Abstract: In a method for operating a waste heat utilization device comprising a working fluid which is liquefied after expansion in an expander by a condenser of the heat utilization device, by controlling an inflow cross-section to an expander of the waste heat utilization device a low pressure of the working fluid in the region of the condenser for adjusting the condensation temperature of the working fluid in the condenser, to provide for a heat transfer flow from the working fluid to the condenser environment sufficient to ensure the complete liquefication of the working fluid in the condenser.

Abstract: In an exhaust gas heat utilization device of a motor vehicle, comprising an exhaust gas heat utilization cycle in which an operating temperature of an operating fluid of the exhaust gas heat utilization cycle is controlled by adapting a mass flow of the operating fluid through a heat exchanger of the exhaust gas heat utilization cycle in such a way that a maximum permissible operating temperature, in particular the decomposition temperature, of the operating fluid is not exceeded.

Abstract: In a Clausius-Rankine cycle, in particular for mobile applications, comprising a pump for circulating a liquid working fluid in the Clausius-Rankine cycle and pressurizing the working fluid, a heating device for vaporizing the pressurized liquid working fluid and an expansion device for generating mechanical driving power by expanding the hot, compressed vaporized working fluid, a condenser device for condensing the hot, expanded vaporized working fluid is provided to form again liquid working fluid and the condenser device includes integrated therein a collection volume for collecting and storing liquid working fluid.

Abstract: In a motor vehicle with an internal combustion engine providing a hot exhaust gas flow which is used as heat source for a Clausius-Rankine cycle process, wherein a pump is provided in the cycle for pumping, pressurizing and circulating an operating fluid, the pumping operation is controlled by a controller depending on the exhaust gas mass flow through an evaporator and possibly also the exhaust gas temperature to vaporize the operating fluid and expanding the vapor under pressure in an expander while generating energy. The vapor is condensed in a condenser to form a condensate which is again returned to the pump.

Abstract: In a method for recovering energy from the heat dissipated by an internal combustion engine wherein the pressure and temperature of a liquid working medium are increased from a lower process pressure and a first temperature to an upper process pressure and a second temperature by a pump unit; the working medium is heated from the second temperature to a third temperature by transferring heat from a hot medium containing heat dissipated by the internal combustion engine to the working medium, which is thereby converted from a liquid phase to a gaseous phase; the working medium is then expanded to the lower process pressure whereby mechanical power is generated and the working medium is converted from a gaseous phase to a liquid phase and transferred back to the pump unit, the upper process pressure is adjusted in such a way that the working medium is expanded at least approximately to a predetermined saturated steam limit and to an internal combustion engine for carrying out the method.

Abstract: In a needle valve (1) for a high-pressure gas conduit system consisting of two units (2, 3) which are joined and one of which encloses a stepping motor (8) and the other includes gas flow passages and a gas flow control bore (17), a valve needle (10) is supported in the housing unit so as to be movable by the stepping motor and extends into the gas flow control bore (17) in the other housing unit through a guide passage (18) provided with seals to prevent gas from flowing to the housing unit including the stepping motor (8) between a region of the guide bore (18) and a low pressure region of the needle valve (1) a compensation connection is provided for relief of pressure at the sealing region (43) of the guide bore (18). The needle valve is particularly suitable as an expansion valve in an automotive CO2 air conditioning system.

Abstract: In a piston for a compressor, the piston comprises a stem by which the piston may be guided in the housing in an axially displaceable manner, and a force introducing section where an outer drive force can be introduced into the piston. The piston head, the piston skirt and the force introducing section are successively arranged in the direction of the piston axis. The piston head, the piston skirt and the force introducing section are produced as a single element of graphite or a synthetic material, and the piston skirt comprises a solid strut structure and a guide section, the cross-sectional area of the strut structure being smaller than the surface of the piston head. The piston consists of a non-organic, non-metallic material having an average thermal expansion of less than 7×106/° C. in the temperature range of 0° C. to 200° C.