Transient particle number emissions from diesel engines with biodiesel fuel

Particle number emissions from a light-duty vehicle diesel engine during transient state operating conditions were studied. Test fuels were petroleum diesel, pure Jatropha biodiesel, B20 and B50 biodiesel blend fuels. The results show the number of nucleation mode particles from the engine increases when using petroleum diesel during the transient operating condition (Increasing torque at constant speeds). The number of accumulation mode particles increases at the initial stage of transient process, and then descends with increasing torque. The total particle number increases continuously with torque during the transient operating condition, and accumulation mode particles play an important role in the beginning, and nucleation mode particles dominate the later part of the transient operating condition. Dynamic characteristics of particle number using lower biodiesel blend during the transient process is similar to that of petroleum diesel, whereas higher biodiesel blends show distinct differences, and the total particle number and nucleation mode particle number using B50 and pure biodiesel fuels are obviously larger than pure diesel from beginning to end, while the accumulation mode particle number keeps smaller. For the pure biodiesel fuel, the nucleation mode particle number rapidly ascends until the end of the transient process, and accumulation mode particle number continuously descends.