Monitoring particle emission for non-road diesel machineries equipped with particulate filters

Diesel particulate filters (DPF) are a very effective means to reduce emissions of soot particles contained in the exhaust gases of diesel engines for non-road mobile machineries. However, DPF can be damaged, leading to particle emission levels exceeding the regulatory limits. Verification of the particle number PN should normally be performed in line with the Particle Measuring Program (PMP) protocol for the measurement of the “solid” particles ≥ 23 nm. The current method used on-site to monitor particle emissions is based on measurement of the light-attenuation using opacimeters. But opacimeters are not sufficiently sensitive and not able to detect small DPF leakages. Therefore a new test procedure requiring practical and not too expensive instruments is needed. In this study, various methods to measure particulate emission in terms of PN and particle mass PM were investigated in different configurations: with and without removal of volatile compounds by thermo-dilution, with and without DPF. The use of a diffusion charge classifier (DISCmini) for PN determination and an aethalometer for the black carbon mass concentration was studied. These techniques used in combination appear promising for the verification of DPF functioning.