Turbocharging a small displacement diesel engine for urban vehicles

Turbochargers are widely used in automotive industry to enhance the engine power output without the need to increase the engine displacement, thus allowing the adoption of smaller powerful engines. This paper presents a development of a naturally aspirated small displacement diesel engine, a light and compact engine that has a leading role in micro-cars in urban areas. The engine was equipped with a small turbocharger in order to improve its power output with the objective of letting this engine equip not only microcars but also urban vehicles. The engine operative range was extended aimed at including engine speed values where the turbocharger has the positive effect of increasing the engine volumetric efficiency. An experimentation was performed in the complete engine operative field of both naturally and turbocharged configurations. The engine performance and emissions were analyzed. The impact of engine configuration on the total number and size distribution of particle emissions was investigated.