Research on a natural gas engine for use in a series hybrid vehicle drive

摘要

Natural gas engines are very promising for reducing exhaust gas emissions. When implemented in a series hybrid drive, transient engine operation can be avoided, which improves the efficiency of a lambda-1 control, combined with a three-waycatalyst.In the paper a specific small CNG engine and its control system will be described. Since the application was destined to work in a series hybrid drive, research was focussed on steady state operation of the engine. More detailed attention will be paid tothe influence of ignition timing and air/fuel ratio (lambda value) on fuel consumption and exhaust gas emissions. Test results in some working points of the engine in steady state operation will show that the functioning of a three way catalyst can bevery sensitive for small variations of the lambda control settings.