The electrically-heated catalyst ( EHC ) has been established as an effective technology for lower-emission regulations.High electrical power consumption was a major concern for the EHC system in the past. This issue was addressed through the development of the EHC design and the alternator-powered EHC system combined with a light-off ( L/O ) catalyst.The subsequent challenges have been to prove the EHC's reliability and durability. NGK has developed a durable, extruded EHC for very severe exhaust system installations. In addition, the EHC's electrical connector system is required to meet high performance and reliability objectives under extreme environmental conditions unique to this application.This report describes the design concept of NGK's EHC including our new electrical connector system and durability results. In summary, the NGK EHC design concept has been confirmed to have excellent durability performance.