The FORD 2.5 Litre DI Engine entered volume production in January 1984, as the World's first high speed naturally aspirated direct injection diesel. Producing 52 KW at 4000 RPM the engine achieves a 15% fuel saving over indirect engines of similar size and rating. The direct injection engine is inherently less thermally active than pre-chamber engines and this, together with other design features, provides a power unit with extended durability for the medium van market.
Based on controlled swirl air management, the otherwise conventional combustion system depends heavily on the fuel injection system for control throughout the speed load and temperature ranges. This paper describes the key elements of the design and performance development of the 2.5 litre DI engine, discusses the experience gained and examines the possibilities of a second generation of engines based on this system.