Effects of RVP, T50, and Oxygenates on Hot-Start and Driveability Performance at High and Low Altitude
Abstract
A two-phase test program was conducted during July and August 1992 in Longmont, Colorado, and Phoenix, Arizona. The program was designed to investigate the effects of Reid vapor pressure, T50, and oxygenates on hot-start and driveability performance of vehicles operated at high and low altitude in high and intermediate ambient temperature ranges. The temperature ranges had means of 70 deg F and 84 deg F in Longmont and 99 deg F in Phoenix. Twenty 1983 - 1992 model-year vehicles were tested on a set of eighteen fuels which included six hydrocarbon-only fuels, six gasoline-ethanol blends, and six gasoline-MTBE blends. Fuel-injected vehicles produced only about one-third the demerits of the carbureted vehicles and were insensitive, in most cases, to T50 and the other fuel variables studied. For carbureted vehicles, decreasing T50 had no effect with high-RVP fuels, but reduced-T50 fuels degraded driveability with low-RVP fuels. In carbureted vehicles, gasoline-oxygenate blends showed generally improved driveability at high altitude with high-RVP fuels. An alternative driveability procedure that emphasized stop-and-go driving showed no significant fuel effects
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1993
- Accession Number
- ADA266382