A study of spray strategies on improvement of engine performance and emissions reduction characteristics in a DME fueled diesel engine

This paper investigated the impact of injection angle and advance injection timing on combustion, emission, and performance characteristics in a dimethyl ether (DME) fueled compression ignition engine through experimentation on spray behaviors and the use of numerical methods. To achieve this aim, a visualization system and two injectors with different injection angles were used to analyze spray characteristics. The combustion, emission, and performance characteristics were analyzed by numerical methods using a detailed chemical kinetic DME oxidation model. Each of five injection angles and timings were selected to examine the effect of injection angle and timing. It was revealed that the injected spray with narrow injection angles was impinged on the bottom wall after the SOI of BTDC 60°, and most of the fuel spray and evaporation with the wide injection angles had a distribution at the crevice region when the injection timing was advanced. In addition, NOx emissions at the SOI of BTDC 20° and TDC had higher values, and the soot emission quantities were extremely small. The narrow injection angles had good performance at the advanced injection timing, and the injection timing over a range of BTDC 40–20° showed superiority in performance characteristics.

Research highlights
► Recently, dimethyl ether (DME) has been investigated, among many alternative fuels, as it has a high cetane number and DME also has the advantage of soot-free combustion.
► The analysis for the spray, combustion and emission characteristics of DME fuel according to the various conditions is essential.
► The influence of the spray angle and advanced injection timing on the combustion and emission characteristics in a DME fueled compression ignition engine was analyzed.
► Spray and combustion characteristics according to injection timing/angle were obtained using experimental apparatus and model validation were conducted based on the measured spray and combustion characteristics.
► The combustion, emission, and performance characteristics under various experimental parameters in a DME fueled CI engine were analyzed by using numerical methods with a KIVA-3 V code.