Abstract
In this study, synthetic gas which is hydrogen rich gas reformed from gasoline fuel was applied to a SI engine to reduce harmful exhaust emissions on cold start condition. Also, ESGI technology, that burns the synthetic gas in exhaust pipe, is developed. ESGI technology applied to raise exhaust gas temperature rapidly so that it leaded fast activation of the catalyst. Synthetic gas fraction of the total supplied fuel varied to 0%, 10%, 25% with various ignition timing at constant excess air ratio(λ=1.2). Exhaust emissions and exhaust gas temperature were measured to investigate the effects of synthetic gas addition on cold start condition. Addition of synthetic gas enlarges the lean flammability limit with a retard of ignition timing. As result, synthetic gas showed that it has ability to extend ignition retard range widely with dramatically reduction of engine out emission. It is supposed that the usage of synthetic gas in the internal combustion engine is an effective solution to meet the future strict emission regulations. As increase of synthetic gas fraction ESGI technology has a good possibility to reduce exhaust emission from gasoline engine. But, to improve ESGI technology, high concentration of oxygen in exhaust pipe and sufficient ignition energy source are needed.
Keywords: Synthetic gas, SI engine, ESGI(Exhaust Synthetic Gas Injection), Light-off, Exhaust gas