Ash deposited in the DPF cannot be burnt, which will affect the service life of DPF. However, previous works focused on the effect of ash on the engine exhaust emissions are limited. Therefore, the influence of ash on the emissions was studied in this work. The particle emissions, the gaseous emissions, and the unregulated emissions (carbonyl compounds and volatile organic compounds) were measured by an AMA4000 gaseous analyzer, ELPI, HPLC, and GC-MS, respectively. Research results indicate that the filtration efficiency decreases by 0.57-4.49% for accumulation mode particle of particulate matter, while it has very little effects on the other type and the particle number in the presence of ash. For regular gaseous pollutions, ash has no influence on CO2 and NOx emission, while CO and THC increase by 68.2% and 91.0%, respectively. For unregulated emissions, overall, carbonyl compounds increase by 41-150% and the BTEX decreases by 8.6-23.6% after ash formed. The change is mainly caused by the increase in the exhaust backpressure that plays a key role.
Keywords: Ash; DPF; Gaseous emissions; Particle emissions; Unregulated emissions.