In the last years increased interest in pollution control focused on the particulate emission from real combustion systems. These particles are usually not relevant for the total mass of particulate emitted, but become predominant in a concentration number analysis. Measurements have been conducted at the exhaust of an EUR05 diesel engine, in order to investigate the mechanisms of particle formation and the influence of combustion characteristics on particle size distribution in diesel engine combustion. Particles characterization has been performed upstream the particulate filter. In particular, it has been investigated the effect of EGR in three engine points representative of a low, medium and high load engine operative conditions. To investigate the effect of engine combustion, EGR has been varied from zero to a value comparable to the current EUR05 engine calibration. A TapCon (or Vienna type) differential mobility analyzer (DMA), a differential mobility spectrometer (DMS) of Cambustion and an AVL Microsoot sensor have been employed to have a complete description of particle size distribution function (PSDF) and soot mass concentration at the exhaust of a real engine. Moreover gas analysis has been performed in all the operative conditions. Focusing the attention in the size range l-100nm, it is generally possible to distinguish two peaks in the particles size distribution function: the first peak is around 2-4nm, the second one is located at about 50-60nm. These two modes in the particle size distributions are present simultaneously in some combustion conditions, whereas in other cases only the second one is found. This behaviour suggests that the combustion condition can be responsible for the production of particles belonging to the first mode. So future high-EGR engine calibration for very low-NOx emission vehicles will require special attention in ultrafine particle emission control. Copyright © 2010, AIDIC Servizi S.r.l.
Ultrafine particle emission from modern diesel engines: Effects of the EGR and engine calibration
Beatrice C;Di Iorio S;Guido C;Fraioli V;Lazzaro M;
2010
Abstract
In the last years increased interest in pollution control focused on the particulate emission from real combustion systems. These particles are usually not relevant for the total mass of particulate emitted, but become predominant in a concentration number analysis. Measurements have been conducted at the exhaust of an EUR05 diesel engine, in order to investigate the mechanisms of particle formation and the influence of combustion characteristics on particle size distribution in diesel engine combustion. Particles characterization has been performed upstream the particulate filter. In particular, it has been investigated the effect of EGR in three engine points representative of a low, medium and high load engine operative conditions. To investigate the effect of engine combustion, EGR has been varied from zero to a value comparable to the current EUR05 engine calibration. A TapCon (or Vienna type) differential mobility analyzer (DMA), a differential mobility spectrometer (DMS) of Cambustion and an AVL Microsoot sensor have been employed to have a complete description of particle size distribution function (PSDF) and soot mass concentration at the exhaust of a real engine. Moreover gas analysis has been performed in all the operative conditions. Focusing the attention in the size range l-100nm, it is generally possible to distinguish two peaks in the particles size distribution function: the first peak is around 2-4nm, the second one is located at about 50-60nm. These two modes in the particle size distributions are present simultaneously in some combustion conditions, whereas in other cases only the second one is found. This behaviour suggests that the combustion condition can be responsible for the production of particles belonging to the first mode. So future high-EGR engine calibration for very low-NOx emission vehicles will require special attention in ultrafine particle emission control. Copyright © 2010, AIDIC Servizi S.r.l.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
