Analysis of combustion and emissions characteristics of a DI diesel engine fuelled with diesel/biodiesel/glycerol tert-butyl ethers mixture by altering compression ratio and injection timing

Abstract

In this present research, glycerol tert-butyl ethers mixture was utilized as a biofuel with a diesel-canola oil biodiesel blend to experimentally investigate its effect on combustion and emissions characteristics of a stationary diesel engine run at different compression ratios (16, 17.5, and 18) and fuel injection timings (25 °CA bTDC, 23 °CA bTDC, and 18 °CA bTDC). Diesel fuel (D), B20G0 (80% v/v diesel + 20% v/v canola oil biodiesel + 0% v/v glycerol tert-butyl ethers mixture), and B18G2 (80% v/v diesel + 18% v/v canola oil biodiesel + 2% v/v glycerol tert-butyl ethers mixture) were used in the experiments. Engine tests were conducted on a 4-stroke single-cylinder diesel engine at distinct loads and an engine speed of 1500 rpm. The results showed that NOX emission decreased while HC emission increased at all compression ratios with the use of B18G2. The maximum increase in average HC emission and the maximum mean reduction in NOX emission was determined by 173% and 68% at compression ratios 16 and 17.5, respectively. B18G2 caused a longer ignition delay period and higher combustion duration compared to other fuels. The great enhancement in B18G2 regarding emissions was detected at original injection timing wherein an average decrease in NOX and CO emissions by 68% and 34% occurred. It is concluded that glycerol tert-butyl ethers mixture can be utilized as a biofuel by 2% v/v of the mixing ratio with a diesel–biodiesel blend. This blending ratio can provide a simultaneous decrease in NOX and CO emissions at the original engine settings.