PIV Measurements of Internal Aerodynamic of Diesel Combustion Chamber

Characteristics of the in-cylinder air motion in Diesel engine has been investigated by PIV from intake to exhaust phase. This paper presents the methodology used to perform in cylinder aerodynamics measurements (PIV) using a Renault tansparent single cylinder engine in motored conditions. Measurements have been achieved with exact engine geometry configuration (high compression ratio) even at top dead center (TDC). Two different configurations have been studied: flat and bowl-in-piston. First results, which are high quality, demonstrate that swirl is better centred with bowl-in-piston than flat piston. Nevertheless, swirl still remain dissymetrical. Its evolution during compression measured on experimental engine is close to theory. Finally, squish phenomena is visualized and its intensity appears to be weaker than theory.