Fundamental studies of liquid fuel fraction and droplet diameter distribution of diethyl ether using a double injection strategy

Optical laser spray investigations have minimally intrusive, simultaneous measurement capabilities with higher spatial and temporal resolution. The microscopic and macroscopic spray parameters of diesel and diesel-diethyl ether blend spray with a split injection strategy were investigated in this experimental study. Lower effective fuel injection pressure due to lower needle lift under the split injection strategy was responsible for the larger droplet sizes in split injection. However, appropriate closing and opening of the injector for a longer dwell time resulted in diluted spray and finer droplet formation. Longer dwell time provided sufficient time for efficient evaporation of fuel droplets, resulting in higher vapor formation. The liquid fuel fraction was lower for longer dwell time and diesel-diethyl ether spray, indicating superior atomization and evaporation characteristics. Higher fuel injection pressure resulted in longer liquid penetration, which can be reduced by using split injection strategies. Diesel-diethyl ether spray was more diluted for fuel concentration and had a lower spray area than diesel. Two high-velocity peaks were observed for split injections. The occurrence of high-velocity peaks improves the fuel–air mixing and droplet vaporization. Diesel-diethyl ether spray showed a higher density of detection of coarser droplets, indicating evaporation of finer droplets. Higher vapor pressure of diethyl ether resulted in rapid evaporation of finer droplets.