Effect of Intake Charge Preheating and Equivalence Ratio in a Dual Fuel Diesel Engine Run on Biogas and Ethanol-Blended Diesel

Dual fuel diesel (DFD) engines have been gaining popularity due to the flexibility of using both bio and fossil liquid and gaseous fuels. Further, the efficient combustion in DFD mode with bio liquid and gaseous fuel can greatly reduce the greenhouse gas emissions as well as the dependency on fossil diesel. In recent times, a host of investigation has been done in normal dual fuel diesel (nDFD) mode with pure diesel and biogas. However, the engines with ethanol blended with diesel and intake charge (biogas–air mixture) with preheating have not been studied. In the present study, 5% ethanol blended with diesel (E5) and biogas with preheating are used in dual fuel engine (DFD-E5) to find their performance and emission characteristics. In order to have a direct comparison of performances, an engine with pure diesel (E0) and biogas with preheating is also tested in dual fuel mode (DFD-E0). In all the cases, the effect of total equivalence ratio on engine overall performance has also been investigated. In DFD-E5 mode, and at the maximum torque of 21.78 N·m, the brake thermal efficiency (BTE) increases by 2.98% as compared to nDFD mode. At the same torque, there is no trace of carbon monoxide (CO), whereas there is a reduction of hydrocarbon (HC) emission by 62.22% with respect to pure diesel (PD) mode. The nitrogen of oxides (NO_x) is found to decrease in DFD modes in contrast to PD mode.