Abstract: A heating/air-conditioning device includes a high-performance heat exchanger for providing air-conditioning of the vehicle cab of passenger cars and is designed and optimized for the large-scale production of passenger cars concerning quantity and costs. The construction size of a heat exchanger, which is already designed as a high-performance heat exchanger and has a soldered matrix, is enlarged beyond the previously known size, so that the vehicle delivers the same heating power as the previous basic series including a much more expensive PTC auxiliary heater. In addition to cost savings, fuel is saved in an order of 0.5-1.01/100 km, compared to an operation with a PTC auxiliary heater and at the same heating power.

Abstract: A method is provided for monitoring the regulation of smooth running of a multi-cylinder internal combustion engine. The smooth running is regulated using at least one manipulated variable, which can be controlled by a control device, to influence the smooth running behaviour, and in which the measurement signals which correspond to temperatures on the catalytic converter are obtained.

Abstract: The invention relates to a process for heating the passenger compartments of motor vehicles by means of the heat given off by the engine (1) via the coolant which is taken back to the engine (1) through coolant lines via a heat exchanger to heat the passenger compartment, and a device for implementing the process. The heating capacity provided for the passenger compartment can be markedly increased by the use of a counterflow heat exchanger (3) and reducing the coolant flow through the engine (1) and/or the heat exchanger (3) by a proportion determined by the permissible limit values of engine cooling. A counterflow characteristic can be obtained, in particular, by the series connection of conventional cross-flow heat exchangers. Further improvements are possible by specially designing the heat exchanger fins and the dimensions and insulation of the coolant lines (2, 4).