CRC Cold-Start and Warmup E85 Cold Ambient Temperature Driveability Program, 2008

摘要

The 2008 CRC Cold-Start and Warm-Up E85 Cold Ambient Temperature Driveability Program was conducted at the Imperial Oil automotive test centre in Sarnia, Ontario, Canada, from September 25 through December 18, 2008. The objective of the program was to determine the effect of vapor pressure and hydrocarbon content of E75/E85 fuel ethanol on cold-start and warm-up driveability performance under cold ambient conditions in a large group of late-model E85 flexible-fuel (flex-fuel) vehicles equipped with fuel injection systems. There were twenty late-model (2007 2008) E85 flex-fuel vehicles in the program. The test fuel design consisted of eight test fuels: six E75/E85 blends and two hydrocarbon-only fuels. The E75/E85 blends varied in vapor pressure and hydrocarbon content. Two of the E75/E85 blends met the minimum vapor pressure requirements of ASTM Specification D5798 volatility Class 3 but with different hydrocarbon levels. Two E75/E85 blends met midrange Class 2 vapor pressure limits with two hydrocarbon levels. One E85 blend was prepared to represent the volatility of blending the lowest vapor pressure gasoline found in north-central states during the wintertime with denatured fuel ethanol. The last blend, which was not tested, was prepared as a center point fuel to assist in determining linearity of vehicle response. The two gasolines varied in vapor pressure from the maximum vapor pressure (15 psi) allowed in ASTM Specification D4814 to the lowest vapor pressure found in north-central states during the wintertime. It should also be noted that this study is not comprehensive in representing the entire fleet and may not reflect all situations that may be encountered in the legacy fleet. For E75/E85 fuels, cold-start and warm-up driveability improved with increasing ambient temperature, increasing vapor pressure, and increasing hydrocarbon content. For hydrocarbon gasoline (E0), cold-start and warm-up driveability improved with increasing ambient temperature and increasing vapor pressure. The effects of ambient temperature on cold-start and warm-up driveability were more pronounced on the E75/E85 fuels than for E0 fuels. The effects of vapor pressure on cold-start and warm-up driveability were more pronounced at the coldest temperatures with the E75/E85 fuels. At +20DGF, there was no difference in vapor pressure sensitivity between E75/E85 and E0 fuels. Total weighted demerits for the current program at +20DGF were comparable to the total weighted demerits from the 2008 E85 Yakima Program at a similar ambient temperature.