Abstract: An input/output unit modifiable engine ignition control apparatus for controlling ignition timing for engine cylinders at optimum values based on reference position pulses, crank angle pulses generated and a vacuum signal produced by reference position sensors, a crank angle sensor and a vacuum sensor mounted in an engine. The engine ignition control apparatus is divided into an input-output unit and a control unit. The control unit having a control capacity for an engine having a maximum number of the sensors and engine cylinders, so that the control unit can be shared by a variety of engines for their ignition control simply by changing the input-output unit.

Abstract: A control unit modifiable engine ignition control apparatus for controlling ignition timing optimally for each cylinder by processing reference position pulses, crank angle pulses and a vacuum signal generated by a reference position sensor, a crank angle sensor and a vacuum sensor which are mounted on the engine. The engine ignition control apparatus is divided into an input-output section including an input-output unit and a controller comprising a single or a combination of control units each having a minimum capacity to control a single ignition coil.

Abstract: An engine ignition interpolation apparatus including three reference position sensors, a single crank angle sensor and a counter resettable by outputs from the reference position sensors and used for counting output pulses from said crank angle sensor. Also included are a decoder for generating an output when the counter produces a count output which exceeds a preset value, flip-flops connected respectively to the reference position sensors in a ring arrangement and triggerable by the outputs from the reference position sensors for synchronous operation therewith, and a logic circuit for seeking conformity between the output from the decoder and set outputs from the flip-flops to produce a quasi or replacement pulse for one of the reference position sensors which fails to produce an output, thereby interpolating a reference position pulse.

Abstract: An engine ignition system connected between an engine crank and ignition coils includes a reference position signal generating device having reference position sensors, and a crank angle sensing device. The ignition system also includes a signal processing device which receives both the reference position signals and crank angle signals, and when one of the reference position signals is absent continues to generate ignition control signals which activate the ignition coils. The signal processing device includes a counter which counts the crank angle signals and which is reset by the reference position signals, and a decoder which produces a signal when a count value reaches a predetermined count. The signal processing device also includes a logic circuit and a flip-flop for producing either primary ignition control signals or replacement ignition control signals. The replacement ignition control signals are generated when one of the reference position signals is absent.