Abstract: In order to increase the closure angle of an interrupter switch connected in series with the primary winding of an ignition coil with increasing engine speeds, a capacitor is connected to the input of a trigger circuit whose output controls this closure angle. The capacitor is charged through a diode while the trigger circuit is switched out. The voltage across the capacitor shifts the threshold of the trigger circuit in a direction increasing the time that the interrupter switch is conductive. The charge on the capacitor is controlled by a signal generator which furnishes an output signal having an amplitude increasing with increasing engine speeds. The closure angle of the interrupter switch therefore also varies as a function of engine speed.

Abstract: When the engine accelerates, the angle over which the ignition switch is closed prior to initiating the spark is automatically increased. Acceleration of the engine is detected by a comparator which compares the value of a speed-dependent signal in sequential cycles and initiate closure of the ignition switch if a predetermined difference is exceeded between the so-compared signals at a predetermined time in the cycle. Under static or decelerating conditions, the speed-dependent signal is compared, in each cycle, to the output of an integrator circuit. The integrator circuit integrates in a first direction at a first rate up to the above-mentioned predetermined time in the cycle and in the opposite direction at a second predetermined rate for the remainder of the cycle. The average value of the integrator output signal corresponds to the engine speed. When the so-compared signals are equal, the second comparator furnishes an output signal which closes the ignition switch.

Abstract: An internal combustion engine crankshaft reference signal pulse corresponding to a selected one engine cylinder pair and a series of crankshaft position signal pulses are generated during each crankshaft revolution and a crankshaft reference signal pulse corresponding to each other engine cylinder pair is synthesized during each crankshaft revolution. In response to each crankshft reference signal pulse and the subsequent crankshaft position signal pulses there is produced an ignition dwell signal effective to initiate ignition coil primary winding energization and later an ignition spark event signal that is effective to terminate ignition coil primary winding energization to thereby produce an ignition spark potential at the engine crankshaft angle at which an ignition spark event is to occur as calculated by an associated external data processor unit.

Abstract: To permit use of shaft position transducers which provide needle pulses at predetermined angular positions of the crankshaft of an engine, such as Wiegand-type, and still enable generation of a counted dwell time even under transient conditions, or under low-speed conditions, the output from the Wiegand transducer is connected to a logic circuit which, under normal operating conditions, by use of a counter counts a predetermined time interval after opening of a switch in series with the ignition coil to determine the dwell period or initiation of current flow for a subsequent ignition event by resetting the counter with a reverse polarity subsequent pulse, thereby passing, upon reset, a predetermined count state which, similar to the normal counting of the count state, initiates closing of the switch.

Abstract: The duty factor of pulses controlling the time throughout which current flows through an ignition coil is increased or decreased depending upon whether the current through the ignition coil at the last ignition time was less than or greater than the desired amplitude required for ignition. A sample--and--hold circuit samples the output of a comparator comparing the actual current to the desired current at ignition time. If the comparator indicates that the actual current amplitude was less than the desired current amplitude, a first counter is set to count downwards. It counds down by one unit and then its count is transferred to another counter. When the count on the other counter reaches a predetermined count, the current through the ignition coil is initiated. The current is interrupted when either the next ignition timing signal or a signal signifying that the actual current through the ignition coil has reached the desired value is received, whichever is later.

Abstract: An ignition apparatus for an internal combustion engine is disclosed in which a current control circuit for so limiting the collector current of a power transistor for controlling the primary current of an ignition coil that the collector current may not exceed a predetermined value, is provided. The current control circuit comprises a circuit for generating a preset reference voltage and a comparison circuit for comparing the reference voltage with a voltage proportional to the collector current of the power transistor, and controls the conductivity of the drive transistor for controlling the drive current for the power transistor in accordance with the output signal of the comparison circuit.

Abstract: A fail-safe coil ingition dwell control system for an internal combustion engine of the type employing a digital ignition advance computer, wherein the computer computes ignition advance angle data and stores current dwell data. The fail-safe system detects the absence of an ignition spark, as may be caused by a computer failure, and in the event thereof produces a control signal capable of triggering the engine power element, i.e. spark plug, and includes an output switching circuit at the output thereof for switching control of the triggering of the engine power element from the computer to the signal generator circuit in the event of a computer failure.

Abstract: A digital spark and dwell ignition control system is disclosed. Maximum advance and reference sensors are utilized to determine positions of maximum and minimum possible advance for spark ignition with respect to the position of the engine crankshaft. For each maximum advance sensor pulse a main counter starts sequentially counting clock pulses wherein the maximum count obtained by the counter is related to engine crankshaft speed. The count of the main counter is utilized by a dwell circuit to determine the time prior to the maximum advance pulse at which spark coil excitation should occur. The main counter count also determines several inputs to a read only memory (ROM) circuit whose output controls a rate multiplier. The rate multiplier receives input clock signals and provides selective frequency division for these clock signals in accordance with the ROM output.

Abstract: An ignition control apparatus for an internal combustion engine is disclosed in which the ignition energy for igniting by means of a spark plug the air-fuel mixture supplied to the internal combustion engine is controlled in accordance with the flow velocity of the air-fuel mixture flowing in the neighborhood of the spark plug. An ignition coil for supplying a spark ignition voltage to the spark plug is energized by a power supply and de-energized at the desired timing of spark generation in accordance with the operating conditions of the internal combustion engine. The rotational speed of the engine representing the flow velocity of the mixture is detected and on the basis of this detected rotational speed, the duration of energization of the ignition coil is variably controlled.