Parametric investigation the particle number and mass distributions characteristics in a diesel/natural gas dual-fuel engine

Considering the negative effects on human health, the number of particles has been limited in the current standard emissions regulation. So an experimental study has been carried out to explore the behavior of the particles in a diesel/natural gas dual-fuel engine. In this paper the particle emissions characteristic of a diesel/natural gas dual-fuel engine with varying engine loads at constant engine speed was experimentally studied using the electrical low-pressure impactor. The effects of pilot injection pressure, natural gas percentage energy substitution and brake mean effective pressure on the particle number and mass as well as particle size distributions were analyzed. The experimental results indicated that the particle number and mass are significantly influenced by the pilot injection pressure, brake mean effective pressure and percentage energy substitution, but the particle size distribution is not sensitive to the variation of those parameters. Furthermore, the particle number concentration (in particular to the ultrafine particle) could be reduced dramatically with increased pilot injection pressure and the percentage energy substitution as well as engine loads. In addition, over 60% number of particle emitted from a diesel/natural gas dual-fuel engine is ultrafine particle while they just provide no more than 10% particle mass.