ENERGIZATION INDICATION CONTROL FOR DIESEL GLOW PLUG

摘要

ENERGIZATION INDICATION CONTROL FOR DIESEL GLOW PLUG An indicating lamp and a PTC thermistor are connected in series across an electric power source by an ignition switch which simultaneously actuates apparatus to intermittently energize a diesel engine glow plug. Further apparatus is effective to make and break a low resistance shunt path around the indicating lamp in response to deenergization and energization of the glow plug. The indicating lamp and PTC thermistor both are electrically energized to self heat and both have electrical resistances increasing sufficiently with temperature to drop substantially most of the supply voltage when hot and prevent energization of the cold other. The indicating lamp heats much faster than the PTC thermistor and so energizes during the initial energization of the glow plug to signal the vehicle operator to not attempt starting of the engine. However, upon the first making of the low resistance shunt path, the PTC thermistor increases its resistance to drop substantially most of the supply voltage and maintains this condition through further cycling to prevent further energization of the indicating lamp.