Abstract: An ion sensor glow plug assembly includes a metal shell for attachment to a cylinder head of a compression ignition engine. The ion sensor glow plug assembly also includes a center terminal at least partially disposed in the metal shell and connected to a source of power to create a heating circuit. The ion sensor glow plug assembly includes a metal glow sheath disposed at least partially in the metal shell and about the center terminal. The ion sensor glow plug assembly further includes an insulator disposed about the metal glow sheath and at least partially in the metal shell and extending axially into a glow area of the metal glow sheath to clean off soot on the insulator by glowing.

Abstract: An ion sensor glow plug assembly includes a shell for attachment to a cylinder head of a compression ignition engine and having a passageway extending axially therethrough. The ion sensor glow plug assembly also includes a center terminal disposed at least partially in the passageway of the shell and connected to a source of power to create a heating circuit. The ion sensor glow plug assembly includes a glow sheath disposed at least partially in the passageway of the shell and about the center wire to create an ion sensing circuit. The ion sensor glow plug assembly further includes a coating disposed about a portion of the glow sheath between the glow sheath and the shell to isolate the shell from the glow sheath and extending axially into a glow area of the glow sheath to clean off soot on the glow sheath by glowing.

Abstract: A firing tip for a spark plug assembly comprises an iridium-rhodium alloy. The firing tip is resistance welded to an electrode for use with a long life spark plug. A thermal expansion dividing layer can be bonded between the electrode surface and iridium-rhodium firing tip to prevent peeling, cracking and/or spalling due to thermal stress fatigue. The thermal expansion dividing material can be a platinum-nickel alloy having a coefficient of thermal expansion compatible with both the electrode material and iridium-rhodium alloy.

Abstract: A firing tip for a spark plug assembly comprises an iridium-rhodium alloy. The firing tip is resistance welded to an electrode for use with a long life spark plug. A thermal expansion dividing layer can be bonded between the electrode surface and iridium-rhodium firing tip to prevent peeling, cracking and/or spalling due to thermal stress fatigue. The thermal expansion dividing material can be a platinum-nickel alloy having a coefficient of thermal expansion compatible with both the electrode material and iridium-rhodium alloy.

Abstract: The spark plug assembly comprises a pair of electrodes, a pair of resistance welded thermal expansion divider layers affixed to the electrodes, and a pair of resistance welded firing tips affixed to the thermal expansion divider layers, such that the firing tips are coaxially aligned to form a spark gap. The thermal expansion divider layers further comprise an electrically conductive alloy comprising a combination of metals selected from the group consisting of iron, chromium, aluminum, manganese, and silicon. The thermal expansion divider layer reduces thermal stress fatigue, and eliminates the premature failure of the firing tips due to cracking, peeling and/or spalling.

Abstract: An ion sensor glow plug assembly includes a shell for attachment to a cylinder head of a compression ignition engine and having a passageway extending axially therethrough. The ion sensor glow plug assembly also includes a center terminal disposed at least partially in the passageway of the shell and connected to a source of power to create a heating circuit. The ion sensor glow plug assembly includes a glow sheath disposed at least partially is the passageway of the shell and about the center terminal to create an ion sensing circuit. The ion sensor glow plug assembly further includes an insulator disposed at least partially in the passageway of the shell and about a portion of the glow sheath and extending axially therefrom to clean off soot on the glow sheath. The ion sensor glow plug assembly includes a coating disposed about a portion of the glow sheath between the glow sheath and the shell to isolate the shell from the glow sheath.

Abstract: An ion sensor glow plug assembly includes a metal shell for attachment to a cylinder head of a compression ignition engine. The ion sensor glow plug assembly also includes a center terminal at least partially disposed in the metal shell and connected to a source of power to create a heating circuit. The ion sensor glow plug assembly includes a metal glow sheath disposed at least partially in the metal shell and about the center terminal. The ion sensor glow plug assembly further includes an insulative seal disposed at least partially around the metal glow sheath to isolate the metal shell from the metal glow sheath to create an ion sensing circuit.

Abstract: An ion sensor glow plug assembly includes a shell for attachment to a cylinder head of a compression ignition engine and having a passageway extending axially therethrough. The ion sensor glow plug assembly also includes a center terminal disposed at least partially in the passageway of the shell and connected to a source of power to create a heating circuit. The ion sensor glow plug assembly includes a glow sheath disposed at least partially in the passageway of the shell and about the center wire to create an ion sensing circuit. The ion sensor glow plug assembly further includes a coating disposed about a portion of the glow sheath between the glow sheath and the shell to isolate the shell from the glow sheath.

Abstract: An ion sensor glow plug assembly includes a shell for attachment to a cylinder head of a compression ignition engine and having a passageway extending axially therethrough. The ion sensor glow plug assembly also includes an insulator disposed at least partially in the passageway of the shell and having an aperture extending axially therethrough. The ion sensor glow plug assembly includes a glow bulb made of an insulative material and including a heating element disposed therein. The glow bulb extends through the aperture and into the passageway of the shell and is operatively connected to a source of power to create a heating circuit. The ion sensor glow plug assembly further includes a conductive material extending axially along the glow bulb and operatively connected to a source of power to create an ion sensing circuit.

Abstract: A glow sensor which combines functions of a diesel engine glow plug with an ion sensor for sensing engine combustion initiation and characteristics includes a ceramic rod retained in a supporting ceramic sleeve carried by a metal shell mountable in an engine cylinder head. The ceramic rod includes a heating element in a glow tip at the inner end of the rod which, in use, extends into an engine combustion chamber or pre-chamber. A conductive material such as platinum or palladium is coated on the lower end of the glow tip and connected by a conductor with a source of electric voltage. In use, the voltage produces a current carried by electrons generated by ionization of the combustion chamber gases during combustion. The current varies with the degree of ionization and the amount of electrons generated during various phases of the combustion event. The resulting information is usable in controlling engine operation or evaluating its operation for test purposes.

Abstract: A glow sensor provides functions of both a diesel engine glow plug and an ion sensor for sensing engine combustion initiation and characteristics. A ceramic flat plate glow sensor element is carried by a tubular ceramic sleeve and insulating material in a metal shell. The element includes a ceramic flat plate having a glow tip, on an inner end with a heating element on one side and an ion sensor electrode on the other printed in electrically conductive ink. Printed conductors on both sides connect the heating element and ion sensor with an outer end of the glow sensor element for connection with an electric power source. An insulating coating protects the heating element and conductors from exposure to combustion gases. Various flat plate mounting embodiments are disclosed.

Abstract: A glow sensor provides functions of both a diesel engine glow plug for aiding fuel ignition during starting and low temperature operation and an ion sensor for sensing engine combustion initiation and characteristics. Compact glow sensor components may be assembled directly in combination with an engine combustion chamber defining component, such as a cylinder head, to provide a combination in which separate housings or shells for the glow sensors are not needed. Thus, the glow sensor elements and insulation may be made larger to provide greater electrical resistance in the ion sensor electrical circuit and enhance the operation of the ion sensor function. Various forms of glow sensors may optionally be used in such a combination including, for example, metal sheath type glow sensors with either isolated or non-isolated coils and ceramic rod or flat plate type glow sensors. Exemplary embodiments of glow sensor components mounted in a cylinder head are disclosed.

Abstract: A spark plug is provided which is suitable for use in a spark ignition system for an internal combustion engine. The spark plug is equipped with a specially configured firing tip on each of its electrodes for the purpose of minimizing the demand voltage of the spark plug, as well as extending the life of the spark plug by maximizing the time over which the demand voltage will remain within an acceptable level. For this purpose, the firing tips are configured such that their firing surfaces include at least three edges and three corners which serve as arc initiation sites of a relatively low resistance arc path between the electrodes.