Combustion and emission characteristics of a direct injection diesel engine fueled with biodiesel and PODE/biodiesel fuel blends

- Blending PODE and biodiesel achieves a complementary in both physical properties.
- B85P15 exhibits lower premixed heat release rate and higher diffusion heat release rate.
- B85P15 has a potential to save a DPF compared with diesel for the same emission standard.
- B85P15 exhibits both high combustion and thermal efficiency.

Biodiesel is a promising alternative fuel for diesel engines. Polyoxymethylene Dimethyl Ethers (PODE), which features high cetane number, low viscosity and high oxygen content, is often used as a fuel additive. In this study, PODE is blended with biodiesel as a major components of the fuel to improve the low-temperature flow properties and the viscosity of biodiesel, aiming to achieve superior engine emission characteristics and efficiency compared with the baseline operation working with neat diesel. The experiments are conducted using diesel (D100), biodiesel (B100) and biodiesel/PODE blend fuel (B85P15) in a direct-injection diesel engine operating at different loads. Combustion data, fuel consumptions and gas emissions are measured. The results show that the engine operates smoothly with B100 and B85P15, at high load B85P15 has obviously higher diffusion combustion heat release rate, and the total combustion duration of B85P15 is 5 CAD shorter than that of D100. B85P15 produces the lowest soot emissions (<0.01 g/kW.h) and the highest combustion efficiency and the highest indicated thermal efficiency during the load sweep.