Particle emissions have been generally associated to diesel engines. However, spark-ignition direct injection (SI-DI) engines have been observed to produce notable amounts of particulate matter as well. The upcoming Euro 6 legislation for passenger cars (effective in 2014, stricter limit in 2017) will further limit the particulate emissions from SI engines by introducing a particle number emission (PN) limit, and it is not probable that the SI-DI engines are able to meet this limit without resorting to additional aftertreatment systems.In this study, the solid particle emissions of a SI-DI passenger car with and without an installed Particle Oxidation Catalyst (POC®) were studied over the New European Driving Cycle (NEDC) on a chassis dynamometer and over real transient acceleration situations on road. It was observed that a considerable portion of particle number emissions occurred during the transient acceleration phases of the cycle. The application of the POC resulted in a reduction of those emission peaks and, as a conclusion, the car was able to meet the 2017 Euro 6 particle number emission limit with the POC.The on-road measurement confirms the results obtained on the chassis dynamometer in that the majority of particle number emissions associated with SI-DI engines arise from transient acceleration situations. The POC efficiency was verified also on road by significantly reducing the particle number emission peaks caused during accelerations.