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The role of Spark Ignition (SI) and Diesel engines as nanoparticles sources in urban area was investigated. Detection, sizing and counting of particles were realized at the exhaust of a Port Fuel Injection Spark Ignition (PFI SI) engine equipped with a Three-Way Catalyst (TWC) and a Unijet Common Rail (CR) Diesel engine equipped first with an Oxidation Catalyst (OC) and then with a Catalyzed Diesel Particulate Filter (CDPF). Engine operating conditions in high road traffic were considered. Electrical Low Pressure Impactor (ELPI) was used as real-time measurements device for particle size distribution in the range from 7 nm up to 10000 nm. Broadband UV-Visible Extinction and Scattering Spectroscopy (BUVESS) allowed investigating the chemical and physical nature of emitted particles. It was observed that the major contribution to particulate mass is due to Diesel engine equipped with the OC, the other engines contribute only in terms of number concentration.

Ethanol is the most promising alternative fuel for spark ignition (SI) engines, that is blended with gasoline, typically. Moreover, in the last years great attention is paid to the dual fueling, ethanol and gasoline are injected simultaneously. This paper aims to analyze the better methods, blending or dual fueling in order to best exploit the potential of ethanol in improving engine performance and reducing pollutant emissions. The experimental activity was carried out in a small displacement single cylinder engine, representative of 2-3 wheel vehicle engines or of 3-4 cylinder small displacement automotive engines. It was equipped with a prototype gasoline direct injection (GDI) head. The tests were carried out at 3000, 4000, and 5000 rpm full load. The investigated engine operating conditions are representative of the European homologation urban driving cycle.

The aim of the paper is the comparison of the performance, gaseous and particle emissions from different injection configurations and fuels. The engine was operated in port fuel injection (PFI), direct injection (DI) and dual fuel (DF). For DF, ethanol DI-gasoline PFI and gasoline DI-gasoline PFI strategies were performed to discern the effect of injection strategy from the effect of the fuel. The experimental activity was carried out in a small displacement single cylinder engine, representative of 2-3 wheel vehicle engines or of 3-4 cylinder small displacement automotive engines. It was equipped with a prototype gasoline direct injection (GDI) head. The tests were carried out at 3000 rpm, 4000 rpm and 5000 rpm full load. The investigated engine operating conditions are representative of the homologation urban driving cycle. The gaseous and particle emissions were measured at the exhaust by means of a gas analyzer and a smoke meter.