In-line Hydrocarbon (HC) Adsorber System for Cold Start Emissions

In order to meet the strict automobile emission regulations in the U.S.A. and Europe, new aftertreatment technologies such as the EHC and HC Adsorber have been developed to reduce the cold start emissions.

The EHC is obviously effective in reducing emissions, but has the demerits of a large electric power demand and a complicated power control system to support it (13). A by-pass type HC adsorber system has the concerns of unreliable by-pass valves and complicated plumbing (10). A major technical challenge of the in-line type HC adsorber was the difference between the HC desorption temperature and the light-off temperature of the burn-off catalyst.

This paper describes the evaluation results of a completely passive “In-line HC Adsorber System” which can reduce the cold start emissions without the application of any type of mechanical or pneumatic control valve in the exhaust system. In summary, the NGK “In-line HC Adsorber System” has demonstrated a drastic reduction in FTP NMHC emission.