Studying the behavior of ethanol-diethyl ether-based flex fuels in a direct injection SI engine

In the modern era, biofuel-based flex-fuels are preferred over conventional fuels in the transportation sector due to their vast socio-economic impact. The present study also confers similar flex fuels based on ethanol and diethyl ether (DEE) experimentally in a direct injection SI engine. The DEE strength was varied from 0 % to 20 %, under wide-open throttle conditions at 1500 rpm–2000 rpm. The outcomes indicate that the DEE lowers delay, improves volatility, and increases flame speed, which increases peak cylinder pressure by 3.18 % at 7–8°CA advanced position. However, low heat content shows 16.23 % higher brake specific fuel consumption (BSFC) than gasoline at 37 % lower cost. A higher heat release rate also improves the BSFC of ethanol. While the DEE share increased above 12.5 %, combustion faced irregularities that increased cyclic variations by 23.17 %, and larger variations in HRR were noticed the net carbon emissions (CO₂ and CO) were reduced by16.45 % by the flex fuel than gasoline; simultaneously, the lower T_max due to low mean gas temperature resulted in lower NO_x emissions than gasoline for a larger range of DEE share. The NO_x improvements were reduced at higher speeds, while the adversaries of high DEE dominated; overall, E85D15 exhibited the best outcomes.