Experimental Study of Fuel Injection Timing and Exhaust Gas Recirculation for Combustion Control in Diethyl Ether-Diesel Blend Fuelled Tractor Engine

Tuning an existing engine for adopting a new alternative fuel is the most attractive strategy for Internal Combustion (IC) engine researchers and automotive companies. This approach's advantages include minimal hardware modification requirements, reduced dependence on conventional petroleum-based fuels, and emissions reduction benefits from low-carbon fuels. Diethyl Ether (DEE) is considered one of the most suitable alternate fuels for diesel engines in blended form. In our previous study, 30 % (v/v) DEE blended with mineral diesel (DEE30) was found to be a suitable DEE blend for engine applications, offering numerous benefits. This study aims to optimise the engine control parameters, namely, fuel injection timing and exhaust gas recirculation (EGR), to achieve improved overall engine performance from DEE30. Initially, the effect of the start of fuel (DEE30) injection (SoI: 15 degrees, 20 degrees and 25 degrees bTDC) on overall engine characteristics was investigated. The fuel injection timing sweep was decided based on OEM-configured injection timing. Results showed that advancing the SoI to 25 degrees bTDC resulted in a higher rate of pressure rise, while retarding the SoI to 15 degrees bTDC led to higher NOx and particulate emissions. SoI of 20 degrees bTDC showed minimum NOx and particulate emissions and comparable engine performance. Then, the effect of varying EGR (15 % and 30 %, v/v) was investigated. The experimental results showed that 30 % EGR was the most suitable for the DEE30-fuelled compression-ignition (CI) engine, drastically reducing NOx emissions without any deterioration in the fuel economy. However, the CO and particulate emissions were slightly higher. Nevertheless, these can be controlled via oxidation catalysts in the exhaust particulate filter systems. DEE30 can be used in multi-cylinder engines without significant hardware modification and deliver diesel-equivalent power and performance.