Development of Extruded Electrically Heated Catalyst System for ULEV Standards

Into the early-part of the next century, automotive emission standards are becoming stricter around the world. The electrically-heated catalyst (EHC) is well known as an effective technology for the reduction of cold-start hydrocarbon emissions without a significant increase in back pressure. Our extruded, alternator powered EHC (APEHC) manufactured with a unique canning method and equipped with a reliable, water proof electrode has demonstrated excellent durability and reliability, as stated in our previous SAE paper (#960340).

The APEHC system discussed in this paper has achieved the Ultra-Low-Emission Vehicle (ULEV) standards, after 100,000 miles of fleet testing, without any failure. This is the final milestone in addressing the EHC as a realistic-production technology for ULEV.

With the ability to meet ULEV/Stage III emission targets without a significant increase in back pressure, the EHC will be applied to an especially high performance vehicle with a large displacement engine. For the operating characteristics of this application, higher durability and emission performance of the EHC is required. A newly-designed EHC with a smaller element diameter eliminated substrate deformation and increased the natural frequency.

The EHC system with an extruded-APEHC has become a viable technology for MY99 production to meet ULEV/Stage III standards.