3-D Analysis of the Flow Through a Multihole V.C.O. Nozzle for D.I. Diesel Engine

A 3-D analysis of the flow through a multihole, V.C.O. (Valve Covered Orifice) nozzle for D.I. Diesel Engine has been carried out. The analysis was performed by means of a finite element code. The nozzle comprises five injection holes.

Aims of the analysis were:

• the investigation of the pressure drops along the conical clearance between the needle and the nozzle;
• the evaluation of the energy losses in the injection holes;
• the disclosure of the velocity profile at the injection hole outlets.
• the differences of flowrate for each hole with geometrical asymmetries.

This kind of analisys is the first step of a more complete spray analysis; in fact, the spray from an injection hole is influenced by the injection pressure and the velocity profile. In particular, the needle lift and the needle tip deviation have been parametrized.

The analysis betters both the theoretical knowledge of this kind of nozzle and the hydraulic phenomena occurring inside. The work is still in progress as for different geometries of the needle tip deviation.