Abstract: An electronic throttle control system for a vehicle accommodates situations where ice forms on one or more throttle assembly components. Rapid movement is induced in the throttle assembly to generate a high torque for a short period of time to break up any ice formation. A controller preferably induces motion at a resonant frequency of the assembly for a controlled period of time. In a disclosed embodiment, a first frequency is used when the throttle blade is in a first position while a second frequency is used when a throttle blade is in a second position. The preferred embodiment includes a vibration enhancing element.

Abstract: An ignition timing control system for a two-cycle internal combustion engine compares a first reference signal which rises to a predetermined level as a first pulse signal is generated corresponding to a predetermined crank angle and which thereafter decays at a predetermined slope, and a second reference signal of generally trapezoidal shape and having a pulse width corresponding to the pulse width of a second pulse signal corresponding to a predetermined crank angle. When the signal level of the second reference signal rises above that of the first reference signal, an ignition signal is generated.

Abstract: Automatic control of spark advance in an electronic ignition system for an internal combustion engine is effected by using a first electromagnetic pick-up cooperating with a protuberance which is phase-displaced on a rotary part (flywheel) relative to top dead center by the maximum advance angle required, and a second pick-up which cooperates with peripheral teeth on the rotary part. Pulses from the second pick-up are counted during a predetermined interval (T) initiated by a pulse from the first pick-up to provide a count which is stored as a reference value representing the required spark advance angle, this stored reference value being subsequently compared with the number of pulses from the second pick-up counted with the commencement of the next pulse from the first pick-up to provide a spark-triggering pulse upon parity of the number of these subsequently counted pulses with the reference value.

Abstract: A device for automatically varying the ignition spark advance angle in an electronically controlled ignition system for an internal combustion engine, in which there is a first sensor for producing a train of pulses the pulse repetition frequency of which represents the engine speed and a second sensor for producing a single pulse once each revolution of the engine when the crankshaft is at the top dead center position.

Abstract: In an ignition system wherein an ignition timing signal generated in synchronism with the engine rotation is detected by a detecting transistor and a base current of a power transistor adapted to control a primary current of an ignition coil is controlled by the detected ignition timing signal thereby to generate a high voltage across a secondary side of the ignition coil; the primary current of the ignition coil is controlled by the power transistor not to exceed a predetermined value, a time interval during which the primary current of the ignition coil is restricted to the predetermined value is detected by a change in collector voltage of the power transistor, i.e. an output thereof, and a conduction starting point for the primary current of ignition coil is controlled by the output of the power transistor.