Comparison of diesel spray with small injection amount between single-hole and multi-hole injectors: Results under same rail pressure and similar injection rate

Abstract

A comparison of diesel spray for injectors with single-hole (SH) and multi-hole (MH) nozzles has been conducted under same rail pressure and similar injection rate (30 MPa for SH and 100 MPa for MH) conditions. The result showed that the spray of SH injector has a longer penetration under same rail pressure condition caused by the faster build-up process of sac pressure. The spray of MH injector has a larger spray angle resulted from the complicated nozzle flow. These further affect the evaporation rate and mixture formation process. Regarding the same rail pressure condition, the spray of SH injector shows a fast evaporation rate, as well as the MH injector, although the spray angle of SH injector is quite small. For the entire mixture formation process, more spray vapor of SH is distributed in the thin area. For similar injection rate condition, the effect of different spray tip penetration can be eliminated while the advantage of the large spray angle of MH injector becomes apparent. The evaporation rate and mixture formation process of the SH injector are much worse than those of the MH injector. The complex nozzle internal flow of MH injector is responsible.