Combustion and emissions in a methane DI stratified charge engine with hydrogen pre-mixing

Characteristics of combustion and emissions in a methane direct injection stratified charge engine premixed with hydrogen lean mixture were analyzed. Results showed the combustion system achieved a higher thermal efficiency due to higher flame propagation velocity and lower exhaust emissions. An increase in the amount of premixed hydrogen stabilizes the combustion to reduce HC and CO exhaust emission, and increases the degree of constant volume combustion and NOx exhaust emission. The increase in NOx emission can be maintained at a lower level with retarded ignition timing without deteriorating the improved thermal efficiency, (C) 2000 Society of Automotive Engineers of Japan, Inc. and Elsevier Science B.V. All rights reserved.