EU-PEMS PM evaluation program : third report, further study on post DPF PM/PN Emissions

This study evaluated the performance of five in total candidate PEMS-PM systems at diesel exhaust PM levels spanning from 20 mg/kWh (Euro V) to post DPF. The different emission levels were simulated by means of a DPF/bypass configuration. The PEMS-PM systems evaluated included Horiba's On Board System with Transient PM measurement (OBS-TRPM), AVL's Micro Soot Sensor (MSS) and Gravimetric Filter Box (GFB), Control Sistem's micro Particulate Sampling System (m-PSS), Sensors Portable Particulate Measurement Device (PPMD) and Dekati's Mass Monitor (DMM). The work focused on the effect of sampling time on the performance of the PEMS-PM instrumentation. To this end, repeated WHTC tests were performed with PM samples taken over a single WHTC but also over three consecutive test cycles. Teflon filters exhibited superior performance from TX40 and Quartz filters, showing little dependence on the sampling time and at the same time resulting in better agreement between the reference instrumentation and the candidate PEMS-PM systems. The study also evaluated the performance of the real time sensors following some revisions and modifications considered by the manufacturers in response to the findings of the previous (phase 2) campaign. The experimental results verified the improved performance of the revised instrumentation but also revealed some areas for further improvements.