Abstract: A glow plug assembly is disclosed having a plug body for mounting the assembly into an engine. A sheath extends from the plug body and has a distal tip portion spaced from the plug body. A first heating element having a fixed resistance is disposed within the sheath and extends from the plug body into the tip portion. A second heating element having a variable resistance is located next adjacent the tip portion separated from the plug body by the first heating element and connected in series with the first heating element. A terminal extends outwardly from the plug body and a power supply is connected to the terminal. A controller between the power supply and the terminal intermittently applies voltage to the terminal for a predetermined time period to maintain an operating temperature. A sensor senses a combined resistance of the first heating element and the second heating element to maintain the combined resistance with the controller by intermittently applying the voltage.

Abstract: A glow plug assembly is disclosed having a plug body for mounting the assembly into an engine. A sheath extends from the plug body and has a distal tip portion spaced from the plug body. A first heating element having a fixed resistance is disposed within the sheath and extends from the plug body into the tip portion. A second heating element having a variable resistance is located next adjacent the tip portion separated from the plug body by the first heating element and connected in series with the first heating element. A terminal extends outwardly from the plug body and a power supply is connected to the terminal. A controller between the power supply and the terminal intermittently applies voltage to the terminal for a predetermined time period to maintain an operating temperature. A sensor senses a combined resistance of the first heating element and the second heating element to maintain the combined resistance with the controller by intermittently applying the voltage.

Abstract: A rapidly heated glow plug which concentrates its heat at the tip of the protective sheath of the plug so that the tip is the first part to heat to the ignition temperature. The plug is heated by a coil of positive temperature coefficient resistance material such as nickel, and the method of manufacturing the plug results in there being a mass of PTC material at the tip of the protective sheath, with the coil being connected to this mass. The preferred mass is formed by melting several coils of wire within a hole formed in the tip of the sheath to close the hole and expose a large surface area of positive temperature coefficient resistance material at the very tip of the sheath to be heated first.

Abstract: A resistor capable of being used as an RC network can be constructed using an electrically conductive metal sheet coated with a dielectric coating serving as a substrate. The dielectric coating supports two separate resistor terminals and a resistance element extending between these terminals. A third terminal is provided for use in connecting the metal sheet to one of the resistor terminals so that the resistor may be used as an RC network.