Abstract: A dwell angle control has three counting devices for detecting acceleration. In a first UP/DOWN counter (17), the count in one direction takes place throughout the time the current in the primary circuit of an ignition coil (25) exceeds a current threshold value (I1). The count in the other direction is constant with respect to time. The counts on the first counter are taken over into a second UP/DOWN counter (11) in response to the input signal, the counting direction also being determined by the input signals. When the count in the second counter (11) reaches an adjustable trigger threshold value, the closure time is initiated, the actual ignition time being fixed by an edge of a sensed signal, or the edge of the signal from an ignition computer. The adjustable trigger threshold value is advantageously determined by a third UP/DOWN counter (12) which is set to a fixed value (X) by an edge of the sensed signal and whose counting direction is also determined by the sensed signals.

Abstract: An ingition system for internal combustion engines has dwell angle control apparatus for controlling the switching times of an electronic switch (21) in the primary circuit of an ignition coil (22) in dependence on the signals of a rotating sensor (10) or an ignition computer (11). Specifically, speed dependent counting values are periodically generated in a counting apparatus (13) each being counted down in a further counting apparatus (14) controlled by an edge of the sensed signal or a computed signal. Upon reaching a presettable triggering counting value, the electronic switch (21) is closed (start of dwell period). This triggering value is set by periodic up and down counting processes in a control counter (17) the upwards counting being constant with respect to time and the count-down process being determined by the length of time of current flow above a settable current value through the ignition coil (23).

Abstract: Clock pulses are counted to provide a count indicative of speed in a counter that is reset with every revolution of a reference mark. The difference between successive counts is multiplied by a fractional factor, which is not necessarily the same for acceleration and deceleration, then added algebraically to the current count value. The acceleration-corrected speed value is then multiplied by a parameter-dependent digital value obtained from a summing circuit to which various engine condition parameters are supplied and the output of the last-mentioned multiplier is supplied to a comparator to which the current count of clock pulses beginning with the reference mark passage is compared. When the comparator finds the match, spark ignition takes place. Another counter counts the clock pulses following each reference mark for sequencing multiplexers that enable some components to serve in more than one operation, in effect controlling the flow of digital values around various loops in the circuit.

Abstract: Adapter plugs are proposed for electronic circuits in motor vehicles which normally receive plug-in units. The adapter plug is interposed between the circuits and the plug-in units and contains circuits which improve the operation of such units. Specifically, in ignition control circuits, the circuitry in the adapter plug can contain a thyristor which is normally blocked, but which shunts energy from the ignition capacitor when the ignition switch is open while the interrupter switch is closed. This prevents the generation of undesired sparks.

Abstract: In order to control the spark advance of an internal combustion engine in the idling domain, the invention provides circuitry for increasing the spark advance below an upper rpm limit and returning the ignition timing to normal when the engine speed drops below a second lower limit. The continuous temporal shift of an output signal which may be used for engaging the ignition control system of the engine is provided by a very small number of elements, in particular only two timing elements, a flip-flop and a number of logical gates. The two flip-flops are triggered by the respective leading and trailing edges of the engine speed transducer signal. One of the flip-flops defines the upper engine speed limit while the second timing element defines the lower engine speed limit. Two embodiments of the invention are described.