Champion Spark Plug Company

Richard E Callahan

Frank John Raeske

Sam J Green

Robert A Mahaney

Switch-controlled apparatus for actuating a power switch to enable application of power from an associated power supply to a heater filament of a glow plug in a diesel engine is disclosed. The filament is one which is heated to a predetermined design temperature when a specified voltage is applied thereto. The power source has a supply voltage greater than the specified voltage of the filament. A switch accessible to an operator of the engine is operable in a first position to prevent the application of the supply voltage to the apparatus, operable in a second position to apply the supply voltage through a first terminal of the apparatus, and operable in a third position to apply the supply voltage through the first terminal and through a second terminal of the apparatus and to a starter for the engine. The apparatus comprises means operable, after the switch has been turned from the first to the second position, to actuate the power switch for a preheat time period which varies as an inverse function of available supply voltage and equals the time required to raise the temperature of the filament from ambient temperature to the design temperature. The apparatus also includes means operable, after the preheat time period, to alternately actuate and then deactuate the power switch in a cyclic fashion to maintain the design temperature of the filament for a prestart time period. The apparatus also includes means operable, after turning the switch from the second to the third position, to continue the cyclical actuation and deactuation of the power switch for an afterglow time period predetermined by the amount of time required for smooth engine idling and to minimize engine noise and white smoke emission.

Glow plug control circuit

An improved high voltage pulse power supply for a spark plug test fixture. AC line voltage is applied through a voltage step-down transformer, a half wave rectifier and an electronic switch to the primary winding of a conventional ignition coil. During the rise time of positive half cycles, the rectified voltage is applied through the electronic switch to the ignition coil primary. As the positive half cycle begins to fall towards the zero crossover, the electronic switch is opened. The magnetic field collapse in the ignition coil produces a high voltage negative pulse which is applied to a spark plug under test. The peak voltage of the negative pulse is adjusted by controlling the peak current in the ignition coil primary.

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Toledo, OH, United States of America

Richard E Callahan