Abstract: To zero or reference-set or null-set a signal source, typically a distance or rotary angle transducer (10), a closed control loop (11, 12, 13) is connected in the output (E) from the signal source, which includes feedback of the system output signal (A) and comparison thereof with a reference or null or zero-set signal (W) when the signal source or transducer is at the reference position, the closed control loop including a correction element (11), such as an adder, to correct the zero or null-set signal derived from the signal source in accordance with the operation of the control loop. This eliminates individual adjustment of the zero or null-set of the signal source, reducing costs and increasing accuracy of the zero or null-set.

Abstract: In order to produce a transition mixture enrichment during acceleration of an internal combustion engine, a carburettor or other mixture generator 1 of the engine with a mixing chamber 2, a main throttle 4 and a choke valve 5, has the choke valve 5 operated by a quick-acting electric drive 6, for example a two-coil rotary setter, which is controlled by a microprocessor 8. The microprocessor is fed with signals which sense the opening of the main throttle 4 and preferably also other engine operating parameters such as temperature and speed. When the main throttle 4 is opened to accelerate the engine, the microprocessor 8 causes the electric drive 6 to close the choke valve 5 abruptly and temporarily. The extent of closure of the choke valve 5 is dependent upon the extent of the throttle opening and on the other operating parameters to give the required mixture enrichment. This arrangement avoids the necessity to provide an accelerator pump.

Abstract: A method for varying the phase spacing of sequential ignition control pulses emitted by an ignition pulse transducer and an apparatus for performing the method are proposed, wherein it is ascertained in the case of the sequential ignition pulses whether their phase spacing has become shorter. If a shortening of the phase spacing is ascertained, then the ascertained phase difference, or a maximal value of the phase difference, is added to the phase spacing of the ignition pulse at that particular time. In this manner, jerking which occurs particularly at constant rpm, when internal combustion engines with externally-supplied ignition used to operate a motor vehicle are driven in the vicinity of the idling rpm, is avoided by simple means.