Abstract
In the view of exhaust emission reduction to meet stringent environmental requirements and the efficient supply and use of energy, researches and developments of the alternative fuelled engines are conducted all over the world. The necessity of CNG engine development has increased due to some big cities' proposal of the introduction of CNG engine to city bus. So, on the base of Daewoo Heavy Industries' D2366 diesel engine, was commenced the development of engine fuelled CNG which is one of the most promising alternative fuel. The 11 liter Diesel engine has been converted to a CNG-fuelled and spark-ignited engine for city bus. In the conversion of Diesel engine to CNG engine, its conversion contents, and performance characteristics of CNG engine are introduced.