Abstract: In operation of an internal combustion engine, exhaust gases of the internal combustion engine are directed through an oxidation catalyzer and thereby heat the catalyzer. Subsequently the engine is stopped, and the catalyzer is regenerated by supplying reducing gas to the catalyzer while the catalyzer is still sufficiently hot for regeneration to occur.

Abstract: Spark gap measuring and monitoring method and device, for providing, during operation, a signal indicative of the intended performance of the spark gap (1), in particular a spark plug of a combustion engine. The device includes an electrical detecting element which is coupled inductively to a connecting lead (4) of the spark gap (1), for example a toroidal coil (8), which detecting element is connected to a processing circuit (9-11) for the purpose of converting the electrical signal produced by the detecting element into a measuring signal indicative of the spark gap (1) performance, for example the spacing (d) between the electrodes (2, 3). Measurement results obtained from an initial measurement can be established as reference data by means of memory elements and circuit elements. The measuring signal is then analyzed by means of an analyzing circuit (14) as a function of the reference data.

Abstract: Piston position detector for generating an electrical signal varying linearly with piston travel of a piston machine. The device comprises a metal cylinder rotating about an eccentric axis synchronously with the crankshaft of the piston machine, the ratio of eccentricity to cylinder radius being substantially equal to the ratio of crank length to connecting rod length of the piston machine. The cylinder surface is faced by the probe of an eddy-current distance meter, the arrangement being such that the desired linear relation is obtained.