Ion sensor glow plug assembly

A self-cleaning ion sensor glow plug assembly for a compression ignition engine comprising:

• a metal shell for attachment to a cylinder head of a compression ignition engine and having a passageway extending axially therethrough;
• a center terminal disposed at least partially in said passageway of said metal shell and connected to a source of power to create a heating circuit;
• a metal glow sheath disposed at least partially in said passageway of said metal shell and about said center terminal to create an ion sensing circuit;
• an insulator disposed at least partially in said passageway of said metal shell and about a portion of said metal glow sheath and extending axially therefrom to clean off soot on said metal glow sheath;
• and
• a first coating disposed about a portion of said metal glow sheath between said metal glow sheath and said metal shell to isolate said metal shell from said metal glow sheath.

A self-cleaning ion sensor glow plug assembly for a diesel engine comprising:

• a metal shell for attachment to a cylinder head of a compressive ignition engine and having a passageway extending axially therethrough;
• a metal center terminal disposed at least partially in said passageway of said and connected to a source of power to create a heating circuit;
• a metal glow sheath disposed at least partially in said passageway of said metal shell and about said metal center terminal;
• an insulator disposed about said metal glow sheath and at least partially in said passageway of said metal shell and extending axially therefrom to clean off soot on said metal glow sheath;
• a first coating disposed about a portion of said metal glow sheath and at least partially in said passageway of said metal shell and extending axially therefrom to clean off soot on said glow sheath;
• a second coating disposed over said first coating to retain said metal glow sheath to said metal shell;
• a first terminal attached to said metal glow sheath and a source of power to create an ion sensing circuit;
• an electrical coil disposed about a portion of said metal center terminal having a heating portion connected to said metal center terminal and a current regulating portion connected to said heating portion;
• an inner tube disposed about a portion of said metal center terminal and connected to said current regulating portion;
• and
• a second terminal attached to said inner tube and to a source of power to create a heating circuit.