Abstract
For the future promotion of the co-generation systems, it is necessary to reduce initial cost and improve power generation efficiency with low NOx emission. The primary target is set to the 200 [kW] output class co-generation system whose prospective markets are office buildings and small-scale industries. To realize a low cost system, a mass-production diesel engine for a truck has been converted to a gas engine. Furthermore, open chamber lean burn combustion is adopted owing to its potential of simultaneously accomplishing low NOx and high thermal efficiency with the least complex structure. To improve thermal efficiency while maintaining low NOx, following techniques were attempted. Optimization of combustion chamber geometry Application of Miller cycle Optimization of the turbocharger These efforts have achieved brake thermal efficiency exceeding 39 [%] with a NOx emission level below 150 [ppm] (in O2=0%). This is the highest performance gained in 200 [kW] output class gas engines.
