Multiple injection strategy is a vital strategy to reduce the soot and NO_x emissions concurrently. The multiple injection strategy can enhance the air/fuel mixture, combustion and exhaust emission characteristics by providing a small amount of fuel before the main injection. Among all types of alternate fuels, biodiesel has emerged as an eco-friendly fuel for the diesel engines. This paper is focusing on the effect of pilot injection strategies on diesel engine say timing (−30° bTDC to −50° bTDC) and by varying the fuel quantity (5–15%). The performance, combustion and emission characteristics of Palm-munja biodiesel/diesel blend (B20) were investigated on CRDI diesel engine. The experimentations were carried out on a constant speed by varying loads from 0 to 100%. The experimental results show that as an increase in pilot injection timing there is a reduction in the in-cylinder pressure, whereas soot and NO_x emissions decrease as the pilot injection timing increases. As the pilot injection fuel quantity increases, the in-cylinder pressure and NO_x emission increase, whereas soot emission decreases.

The fast depletion of fossil fuels is driving the research toward renewable fuels. Alcohols, which can be produced from agricultural wastes such as sugarcane bagasse and corn stalks, appear to be promising renewable fuels. Among the different alcohols, butanol which is higher chain alcohol is considered in this study. This study deals with the emission and performance characteristics of a direct injection (DI)–compression ignition (CI) engine operating with different butanol/diesel blends. Experiments were conducted with different butanol/diesel blends, with the butanol proportion in the blend varying from 0 to 50% percentage (0, 10, 20, 30, 40, and 50%-by volume designated as Bu00, Bu10, Bu20, Bu30, Bu40, and Bu50). The engine performance with different butanol/diesel blends was compared to the engine performance with pure diesel. The experimental results revealed that as the fraction of butanol in the blend is increased, the emissions of CO, soot, and NOx decreased, whereas the unburned hydrocarbons (UBHC) emissions increased. Similarly, brake thermal efficiency (BTE) of the engine slightly improved with increase in the butanol fraction in the blend compared with diesel operation.

The present paper discusses a comparative study of single- and pilot-injection strategy fuelled with diesel (i.e. Bu00) and 15% of butanol blend (i.e. Bu15). The effects of pilot injection timing (−33° bTDC to −73° bTDC) and pilot injection fuel quantity (5–20%) with 15% of butanol blend were carried out numerically using CONVERGE CFD Code. The results show that in single-injection strategy, NOx, CO and soot emissions reduce, whereas UBHC emission increases with the addition of butanol content. In pilot-injection strategy, when the first fuel injection timing is advanced, the peak value of heat release rate (HRR) for the first injected fuel reduces, but marginally improves for the main injected fuel. Increasing the first injection fuel quantity, the HRR of the peak value for first injected fuel increases but the HRR of the peak value for second injected fuel reduces. Minimum ISFC was obtained at 10% of pilot injection fuel quantity and −53° bTDC of pilot injection timing.

This paper investigates the combined effect of Exhaust gas recirculation (EGR) and Start of Injection (SOI) on the performance and emissions of a caterpillar 3401 CI engine. To study this, the numerical analysis is carried out using CONVERGE CFD software, and the results are validated with experimental data. During the simulation, the SOI is varied from -11° bTDC to -21.5° bTDC and the EGR rate has varied from 10% to 20%. Design of experiments (DOE) is applied to create the numerical experimental array using Central composite design. An optimum case is found out for the combination of advanced SOI and EGR and the results are compared with the baseline case to prove the optimization.