METHOD OF OPERATING INTERNAL COMBUSTION ENGINE AND INTERNAL COMBUSTION ENGINE OPERATED BY SAME

摘要

PROBLEM TO BE SOLVED: To achieve NOx reduction in exhaust gas of an internal combustion engine.SOLUTION: An internal combustion engine uses exhaust gas recirculation. The engine is operated at times in an environment with a first emission standard and at other times in another environment with a second more strict emission standard. The engine is operated with a first fuel 27 or with a second fuel 28 having a second lower calorific value when operating in another environment having the second emission standard, which second lower calorific value is lower than the first lower calorific value of the first fuel. The engine is operated with a first degree of exhaust gas recirculation when operated with the first fuel 27 and with a second, higher degree of exhaust gas recirculation when operated with the second fuel 28.