• Energy Research
• 11. Sustainability close

The implementation of environmentally friendly internal combustion engines (ICEs) has become an urgent need in recent years due to the strict current legislation. The high pollutant emissions such as particulate matter (PM) exhausted from ICE has driven many researchers to explore the possible advantages of alternative fuels. Ethanol is one of the most suitable alternative fuel for spark-ignition (SI) engines due to its higher heat of evaporation, octane number and larger oxygen content that allow to obtain positive effects on engine performance and particle formation and emissions. The main goal of the experimental research is the study of the effect of the different methods of ethanol fueling on particulate matter by means of the correlation between the in-cylinder soot formation and the exhaust particle emissions. The experimental investigation was carried out in a 4-stroke small displacement optical spark ignition engine operated at 2000 and 4000 rpm under full load conditions. The engine was fueled with gasoline and ethanol pure, blended (E30) and dual fueled (EDF). For both E30 and EDF configurations, 30 vol% of ethanol in gasoline was supplied. An optical technique based on 2D-digital imaging was used. Two-color pyrometry theory was applied to assess the in-cylinder soot formation. Particle emissions were measured at the exhaust by means of a smoke meter. The particle size distribution function (PSDF) was measured in the range from 5.6 to 560 nm with an Engine Exhaust Particle Sizer (EEPS). The research has shown that the effect of ethanol on soot formation and particle emission depends not only on ethanol fuel properties, but also on engine configuration and engine operating conditions.

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. Engine performance and gaseous and particle emissions were measured at the exhaust by means of a gas analyzer and a smoke meter. Particle size distribution function was measured in the range from 5.6 to 560 nm by means of an Engine Exhaust Particle Sizer (EEPS). The gaseous and particle measurements were performed upstream and downstream of a three way catalyst (TWC), respectively. The results show that the dual fuel configuration allows an improvement of the engine performance and a reduction of exhaust emissions

The objective of this paper is the evaluation of the effect of the fuel properties and the comparison of a PFI and GDI injection system on the performances and on particle emission in a Spark Ignition engine. Experimental investigation was carried out in a small single cylinder engine for two wheel vehicles. The engine displacement was 250 cc. It was equipped with a prototype GDI head and also with an injector in the intake manifold. This makes it possible to run the engine both in GDI and PFI configurations. The engine was fuelled with neat gasoline and ethanol, and ethanol/gasoline blends at 10% v/v, 50% v/v and 85% v/v. The engine was equipped of a quartz pressure transducer that was flush-mounted in the region between intake and exhaust valves. Tests were carried out at 3000 rpm and 4000 rpm full load and two different lambda conditions. These engine points were chosen as representative of urban driving conditions. The gaseous emissions and particle concentration were measured at the exhaust by means of conventional instruments. Particle size distribution function was measured in the range from 5.6 nm to 560 nm by means of an Engine Exhaust Particle Sizer (EEPS). The effect of ethanol blending on particle emission depends on engine configuration and ethanol percentage. A strong increase of particle emission for E50 was observed in PFI configuration. For GDI configuration a larger particle emissions with respect to gasoline fuel was measured for E10. Moreover, for blends fuelling, particle emissions decrease with the ethanol percentage.