(Particle) Emissions of Small 2-& 4-Stroke Scooters with (Hydrous) Ethanol Blends 2010-01-0794

The objectives of the present work are to investigate the regulated and unregulated (particle) emissions of a classical and modern 2-stroke and a typical 4-stroke scooter with different ethanol blend fuels. There is also comparison of two different ethanol fuels: pure ethanol (E) ^*) and hydrous ethanol (EH) which contains 3.9% water and is denatured with 1.5% gasoline. Special attention is paid in this research to the hydrous ethanol, since the production costs of hydrous ethanol are much less than those for (dry) ethanol.

The vehicles are with carburettor and without catalyst, which represents the most frequent technology in Eastern Asia and offers the information of engine-out emissions. Exhaust emissions measurements have been performed with fuels containing ethanol (E), or hydrous ethanol (EH) in the portion of 5, 10, 15 and 20% by volume. During the test systematical analysis of particle mass (PM) and nano-particles counts (NP) were carried out.

The most important results are:

• there are no significant differences of results between the blends with pure ethanol (E), or hydrous ethanol (EH), except of some cases, where EH improves slightly the emissions (CO, HC, PM, NP) and reduces the fuel consumption,
• addition of ethanol to the gasoline provokes a leaner tuning of the engine operation,
• for the investigated newer 2-S scooter with leaner tuning the irregularities of combustion and increased emissions of PM & NP were remarkable with higher ethanol content, there was a poor driveability,
• the older 2-S scooter showed good performances and reduction of CO and of fuel consumption up to E15; no impact on or reduction of (nano-) particles and reduction of particle mass emissions with growing ethanol content,
• the operation of 4-S scooter was without problems, the leaning by ethanol caused: lowering of CO, HC & fuel consumption, increase of NOx, no effect on PM and reduction of nanoparticles count concentrations especially at transient operation,
• there are no significant differences of results between the blends with pure ethanol (E), or hydrous ethanol (EH).

The present investigations did not concern the durability of parts exposed to the chemical influences of ethanol. Also the cold start, particularly in extreme conditions and the lube oil dilution were not addressed.