Spray Characteristics of Single- and Two-Spring Diesel Fuel Injectors

The spatial and temporal characteristics of the non-evaporating diesel sprays injected into the atmosphere through two pump-pipe-nozzle systems used in small DI diesel engines have been investigated by laser-single-beam deflection and phase-Doppler anemometry (PDA). The injectors used for these tests comprised a single-spring and a prototype two-spring multihole-type nozzle. The results provided quantitative information about the effect that the second spring exerts on injection duration and spray characteristics, i.e. it increases injection duration and, at the same time, improves fuel atomisation during the main injection period.