Combustion and emission characteristics of DI diesel engine fuelled by ethanol injected into the exhaust manifold

Dual fuel diesel engine operation is an important technique used for combustion control in diesel engines. In this study, ethanol is injected into the exhaust manifold of a single cylinder diesel engine. The exhaust valve opens during the intake stroke, enabling vaporized ethanol to enter the cylinder where it is then ignited by diesel fuel injection. The effects of exhaust gas recirculation (EGR) ratios, ethanol injection timing, and ethanol amount are studied. Furthermore, exhaust and intake manifold injection of ethanol compared under the same conditions. These results reveal that ethanol injection into the exhaust manifold increases the apparent heat release rate (AHRR) at the premixed combustion phase. Additionally, the ignition delay increases with ethanol injection by 0.2° crank angle (CA). The indicated mean effective pressure (IMEP) and total heat released per cycle are increased by 8.2% and 14.2%, while the NOx and soot concentrations are reduced by 88% and 30%, respectively. When compared with exhaust manifold ethanol injection, intake manifold injection results in higher AHRR in the premixed combustion phase, decreased engine performance, an increase in soot production of approximately 35%, and decrease in NOx of 13%. •The ethanol injection into exhaust manifold of diesel engine is investigated.•Influences of EGR ratio, ethanol injection timing and ethanol amount are studied.•Ethanol injection into intake and exhaust manifold are compared at fixed conditions.•Exhaust manifold injection of ethanol reduces the combustion quenching.•Ethanol burning in the late combustion phase improves the soot oxidation.