Browse Publications Technical Papers 2008-01-0073
2008-04-14

An Optical Study of Spray Development and Combustion of Ethanol, Iso-Octane and Gasoline Blends in a DISI Engine 2008-01-0073

In recent times regulatory pressure to reduce CO2 emissions has driven research towards looking at blending fossil fuels with alternatives such as crop-produced alcohols. The alcohol of interest in this paper is ethanol and it was studied in mixtures with gasoline and iso-octane in an optical spark-ignition engine, running at 1500 RPM at low-load operation with 0.5 bar absolute intake plenum pressure. Specifically, tests involved fuels of 100% gasoline and 100% iso-octane, so that differences between multi and single-component fuels could be compared within this environment. A mixture of 25% ethanol with 75% iso-octane was also tested and compared. Finally, mixtures of high-percentage of ethanol (85% ethanol) in gasoline and in iso-octane were used in the study and compared. Tests were undertaken using a standard port injection system as well as a direct injection system so an appraisal of both mixture preparation methods could be made. Initially, a high-speed imaging study of the in-cylinder spray formation was undertaken with the direct injection system for different injection timings and engine-head temperatures under motoring engine conditions. The engine was also run with continuous firing using all fuels. In-cylinder pressure data were collected at 0.2° crank angle resolution for each cycle and synchronized with simultaneous high-speed flame imaging at 1° crank angle resolution for a series of 100 consecutive cycles for all test points. The flame images were processed to quantify the evolution of an equivalent flame radius.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 43% off list price.
Login to see discount.
Special Offer: With TechSelect, you decide what SAE Technical Papers you need, when you need them, and how much you want to pay.
X