In order to reduce the spray tip rich mixture observed in conventional “rectangle” injection, “inversed-delta” injection rate shaping (i.e., progressive reduction of injection rate during injection period) diesel spray flame is investigated using simultaneous high-speed imaging technique. The experiments are conducted in a constant volume combustion chamber CVCC at 17% O2 concentration, 1050 K and 23.8 kg/m3, equivalent to a modern diesel engine conditions using a novel injection rate shaping TAIZAC - TAndem Injectors Zapping ACtivation injector. In 175 MPa inversed-delta injection, optically thinner spray tip mixture, shorter spray tip penetration and more even UV emissions spatial distribution compared to than that of 175 MPa rectangle injection profiles likely due to less following spray catch-up motion. Meanwhile, the differences are less apparent in 120 MPa rectangle injection. For 135 MPa inversed-delta injection profile, broad and thick rich mixture, intense UV emissions and long soot luminosity residence are observed, suggesting poor atomization and mixing likely caused by excessive near-zero injection pressure reduction. Hypothesized inversed-delta injection trend such as the spray tip rich mixture suppression and even fuel distribution are well captured from the high-speed images however, exact combustion duration timing cannot be pinpointed.
|Publication status||Published - 1 Jan 2019|
|Event||12th Asia-Pacific Conference on Combustion, ASPACC 2019 - Fukuoka, Japan|
Duration: 1 Jul 2019 → 5 Jul 2019
|Conference||12th Asia-Pacific Conference on Combustion, ASPACC 2019|
|Period||1/07/19 → 5/07/19|