An Innovative Optical Diagnostics for Injection Process in CI Engines

Diesel engines are continuously developing in order to meet ever more stringent emissions regulations. The understanding of injection and combustion phenomena has a primary role in this process. Different techniques have been set up in order to reduce the exhaust emission of diesel engines. On one side, experimental activities allow to enlarge the knowledge of these phenomena; on the other side, modeling supports experimental activities with time and cost reduction. This book presents a combination of the experimental and the modeling approaches to deeply understand the high pressure injection process in a modern diesel engine. The first part concerns the tuning of a 1d model of fuel injection to the engine environment. Potential and limitation of spray simulation are illustrated. In the second part, the model is used to help understanding and to develop a new optical diagnostics performed in the infrared spectrum. The use of a thermal-camera has allowed to detect both the liquid- and vapor- phase of diesel fuel so providing an innovative and simple tool for the analysis of sprays.