Abstract
The paper deals with recent work at Fiat Research Centre regarding the development of a very small unit displacement 4-cylinder, turbocharged, intercooled Direct Injection Diesel engine for passenger car applications. The engine displacement is 1.25 litres with maximum power output of the order of 50 kW while emissions are well within Euro III standards with no particular exhaust gas aftertreatment technologies. In this paper, a number of combustion system, as well as overall engine design issues are addressed and results of engine performance tests are presented.