Glow plug having a conductive film heater

Claim 2

A glow plug for a diesel engine comprising: a metal body having a cylindrical bore; an electrode concentrically disposed in said cylindrical bore and insulated therefrom; a heater member having a conductive film heater element disposed on the external at least one surface of a cylindrical substrate, said heater member circumscribing said electrode and having one end of the conductive film heater element in electrical contact with said metal body; a cap connected to the end of said electrode fixedly captivating the other end of heater member and providing electrical contact between the other end of said heating element and said electrode; resilient means for urging said heater member toward said cap to assure said electrical connection is maintained between said metal body, conductive film heater element and cap with changes in temperature; a protective dielectric film disposed over said surface film heater element.

Claim 3

The glow plug of claim 1 wherein said conductive film heater element is a transition metal film.

Claim 4

The glow plug of claim 1 wherein said conductive film heater element is a transition metal film selected from the platinum family comprising platinum, palladium, iridium and rhodium.

Claim 5

The glow plug of claim 1 wherein said conductive film heater element is a metal alloy film containing at least one metal selected from the platinum family comprising platinum, palladium, iridium and rhodium.

Claim 6

A glow plug of the type having a hollow metal base, and an axial electrode passing through said base and electricaly insulated therefrom, and a heater member electrically connected between said base and said axial electrode, an improved heater member characterized by: a heater member substrate having at least one end structurally supported by said base, and; a conductive surface film heater element disposal on at least one surface of said substrate having one end in electrical contact with said base and the other end in contact with said axial electrode; means for electrically connecting one end of said heater element to said base; channel means for electrically connecting the other end of said heater element to said axial electrode; resilient means for urging said heater member substrate toward said channel means to assure said electrical connection is maintained between said base and axial electrode with changes in temperature; and a protective dielectric film disposed over said surface film heater element.

Claim 7

A glow plug of the type having a hollow metal base, and an axial electrode passing through said base and electricaly insulated therefrom, and a heater member electrically connected between said base and said axial electrode, an improved heater member characterized by: a heater member substrate having at least one end structurally supported by said base, and; a conductive surface film heater element disposal on at least one surface of said substrate having one end in electrical contact with said base and the other end in contact with said axial electrode; means for electrically connecting one end of said heater element to said base; channel means for electrically connecting the other end of said heater element to said axial electrode; resilient means for urging said heater member substrate toward said channel means to assure said electrical connection is maintained between said base and axial electrode with changes in temperature; and a protective dielectric film disposed over said surface film heater element.

Claim 8

The glow plug of claim 5 wherein said substrate is a ceramic cylinder.

Claim 9

The glow plug of claim 5 wherein said substrate is a planar ceramic substrate.

Claim 10

The glow plug of claim 5 wherein said conductive film heater element is a metal film substantially covering said at least one surface of the substrate.

Claim 11

The glow plug of claim 8 wherein said metal film is a transition metal film selected from the platinum family comprising platinum, palladium, iridium and rhodium.

Claim 12

The glow plug of claim 8 wherein said metal film is an alloy containing at least one transition metal selective from the platinum family comprising platinum, palladium, iridium and rhodium.

Claim 13

A heater member for a glow plug of the type having a hollow cylindrical metal body, an axial electrode and an insulator supporting said axial electrode in said body, said heater member comprising: a non-conductive substrate supported between said body and said axial electrode; an electrically conductive surface film heater element disposed on the surface of said substrate having one end of said conductive surface film in electrical contact with said metal body and the other end in electrical contact with said axial electrode; resilient means for urging said substrate toward said axial electrode to assure said electrical contact is maintained between said metal body, film heater and axial electrode with changes in temperature; and a thin protective dielectric surface film disposed over said heater element.

Claim 14

A heater member for a glow plug of the type having a hollow cylindrical metal body, an axial electrode and an insulator supporting said axial electrode in said body, said heater member comprising: a non-conductive substrate supported between said body and said axial electrode; an electrically conductive surface film heater element disposed on the surface of said substrate having one end of said conductive surface film in electrical contact with said metal body and the other end in electrical contact with said axial electrode; resilient means for urging said substrate toward said axial electrode to assure said electrical contact is maintained between said metal body, film heater and axial electrode with changes in temperature; and a thin protective dielectric surface film disposed over said heater element.

Claim 15

The heater member of claim 1 wherein said conductive surface film is a conductive cermet film substantially covering at least one surface of said substrate.

Claim 16

The heater member of claim 11 wherein said planar substrate is a flat ceramic plate.

Claim 17

The heater member of claim 11 wherein said metal film is a metal alloy film containing at least one transition metal.

Claim 18

The heater member of claim 14 wherein said conductive cermet film includes at least one transition metal selected from the platinum family comprising platinum, palladium, iridium and rhodium.

Claim 19

The heater member of claim 11 wherein said conductive surface film is a metal film substantially covering at least one surface of said substrate.

Claim 20

The heater member of claim 16 wherein said metal film is a transition metal.

Claim 21

The heater member of claim 17 wherein said transition metal is selected from a member of the platinum family comprising platinum, palladium, iridium and rhodium.

Claim 22

The heater member of claims 16, 17, 14 or 15 wherein said substrate is a cylindrical substrate.