Patent Number: 6,166,479

Title: Spark plug having a spark discharge portion with a specific composition

Abstract: A spark plug includes a center electrode, an insulator provided outside the center electrode, a metallic shell provided outside the insulator, a ground electrode disposed to oppose the center electrode, and a spark discharge portion fixed on at least one of the center electrode and the ground electrode for defining a spark discharge gap. The spark discharge portion is formed from an alloy containing Ir as a main component, Rh in an amount of 0.2 to 10 wt. %, and Pt in an amount not greater than 10 wt. %. The ratio WPt/WRh of the Pt content to the Rh content falls within the range of 0.1-1.5.

Inventors: Matsutani; Wataru (Nagoya, JP), Gonda; Ichiro (Konan, JP)

Assignee: NGK Spark Plug Co., Ltd.

International Classification: H01T 13/39 (20060101); H01T 013/20 ()

Expiration Date: 12/26/2017