Abstract: A method of controlling an engine speed for an internal combustion engine and an apparatus therefor which are capable of significantly improving transient response characteristics and controlling the engine speed with high accuracy. The method and apparatus are adapted to keep the actual engine speed at a set engine speed by proportional control action and derivative control action wherein a derivative control engine speed range is set about the set engine speed to stop derivative action to allow only proportional action to operate an engine speed adjusting operation unit when the actual engine speed is out of the range.

Abstract: An ignition system for an internal combustion engine having a transistor switch means connected across a primary winding of an ignition coil wherein a base current input terminal of the transistor switch means is connected through a coil to an igniting exciter coil to supply a base current through the coil to the base current input terminal thereby decreasing a power loss at the interruption of a primary current flowing through an ignition coil and operating a transistor in a low power loss region, so that a high voltage may be induced across a secondary winding of an ignition coil.

Abstract: An ignition system for an internal combustion engine comprises a primary current control switch provided in parallel with an exciter coil and the primary of the ignition coil, energized by an exciter coil producing an AC voltage in time with rotation of the engine crank shaft. The primary current control switch is made conductive in advance of the ignition angle to permit a current to flow therethrough, and is made nonconductive at the ignition angle to cause sudden increase in the primary current. The ignition system is characterized in that the core of the ignition coil has a magnetic retentivity and by comprising resistor means for providing a path for a current through the primary in the opposite direction to the current which flows through the primary at the ignition angle.

Abstract: A current interruption type ignition system for an internal combustion engine comprises an ignition coil including a primary coil portion and a secondary coil portion; an exciter inducing an AC voltage in synchronism with rotation of the engine to be supplied to the primary coil portion of the ignition coil; a first semiconductor switch provided in parallel to the primary coil portion to conduct a current from the exciter therethrough; a second semiconductor switch provided on a controlled terminal of the first semiconductor switch so that the second semiconductor switch, upon conduction, causes the first semiconductor switch to be turned off so as to abruptly conduct a primary current into the primary coil portion of the ignition coil; and a signal source generating an ignition signal at the ignition position of the engine.

Abstract: An ignition system for a multicylinder engine comprising a magneto having an igniting exciter coil to induce an AC voltage in synchronism with rotation of the engine; ignition coils having secondary coil portions respectively connected to ignition plugs for cylinders of the engine, to supply a high voltage to the respective ignition plugs; and a primary current controlling semiconductor switch connected to the igniting exciter coil in parallel therewith to be turned on in advance of respective igniting positions of the cylinders so that a current flows through the semiconductor switch.