THREE DIMENSIONAL CALCULATION OF THE FLOW IN A DI DIESEL ENGINE WITH VARIABLE SWIRL INTAKE PORTS

The objective of this paper is to analyse the flow characteristics inside the cylinder of a DI Diesel engine at variable swirl number. Initially, the cylinder head is characterised by means of three-dimensional calculations of the steady flow through the intake ports. These calculations have been made for several positions of the throttles, from wide open, to closed, using the STAR-CD commercial CFD code. They have been validated with steady flow experimental data measured with torque-meter. Next, 3D calculations of the compression stroke are presented and compared with experimental measurements. The initial conditions inside the cylinder in the TDC have been estimated using the head characterisation tests and a zero-dimensional model. The results obtained are in good agreement with the experiments.