Abstract: To determine an optimum spark advance angle for activation of a spark plug, memory means is provided to previously store a data indicating a plurality of optimum spark advance angles for activation of the spark plug in relation to each amount of air sucked into an engine and each rotation speed of an output shaft of the engine, thereby to simplify construction of the control apparatus.

Abstract: A spark-advance angle of an internal combustion engine is calculated based on at least one electrical signal which indicates an operating condition of the engine. The calculated spark-advance angle is compared with a lower limit of a required spark-advance angle, and then, if the calculated spark-advance angle is less than the lower limit, this calculated spark-advance angle is corrected so that it coincides with the lower limit.

Abstract: To determine an optimum advance angle for activation of a spark plug in relation to an amount of air sucked into an engine, an electronic ignition control method and apparatus comprises a calculation circuit to calculate a linear equation representing a relationship between the optimum advance angle of activation of the spark plug and the amount of the sucked air in consideration with rotation speed of an output shaft of the engine, thereby to simplify the calculation.

Abstract: An electronic ignition control apparatus for an engine comprises a reference signal generator to produce a reference signal corresponding to the top dead center position of a piston, a first sensor to produce a first output signal indicative of the amount of air sucked into a combustion chamber of the engine, a second sensor to produce a second output signal indicative of a predetermined period of time necessary for generating a spark voltage in an ignition coil, and a memory circuit to store a data indicating an optimum period of time for spark advance in relation to the amount of sucked air and responsive to the reference signal to produce a third output signal indicative of a period of time for spark advance relative to the first output signal, a calculation circuit responsive to the reference signal to calculate a timing to start energization of the primary winding of the ignition coil in the following cycle of the reference signal with respect to each period of time represented by the second and third ou

Abstract: In an electronic ignition control apparatus for an engine, an actual optimum spark advance angle for activation of a spark plug is determined as a value defined by a linear equation representing a relationship between an optimum spark advance angle and an amount of air sucked into the engine in consideration with an actual rotation speed by using a stored optimum spark advance angle defined by a reference linear equation representing a relationship between the stored optimum spark advance angle and an amount of the sucked air in consideration with a predetermined rotation speed.

Abstract: In an electronic ignition control apparatus for a combustion engine, a first memory is provided to store a data indicating a first parameter in relation to rotation speed of the engine to read out a value of the first parameter in accordance with an instant rotation speed of the engine, the first parameter defining an ascent of a linear equation representing a relationship between an optimum period of time for spark advance and an amount of air sucked into the engine in consideration with the rotation speed, and a second memory is provided to store a data indicating a second parameter in relation to the rotation speed to read out a value of the second parameter in accordance with the instant rotation speed, the second parameter defining an ordinates' intersection of the linear equation.

Abstract: An ignition system for an internal combustion engine comprising a battery, an ignition coil having a primary and secondary winding, a variable impedance element whose impedance is temperature dependent coupled between the primary of the ignition coil and the battery, and a set of distributor points coupled between the primary and secondary windings of the ignition coil and ground. The variable impedance element prevents deterioration of the ignition efficiency as the temperature of the ignition coil goes up, and can also prevent the temperature of the ignition coil from raising to a point wherein the ignition coil is damaged.