CRC (Coordinating Research Council) Hot-Start and Driveaway Driveability Program at High and Intermediate Temperatures Using Gasoline-Alcohol Blends

Abstract

A cooperative CRC test program was conducted at Failure Analysis Associates Test Track in Phoenix, Arizona, from September 4 through October 4, 1985. The program investigated the hot-start driveability of thirteen 198'-model vehicles with eight hydrocarbon-alcohol blends ant~wo hydr rbon only gasolines at nominal ambient temperatures of 9MF and 70. The driveability procedure was modified to emphasize conditions which may cause fuel foaming. Carburetted, throttle-bodyinjected (TB!), port-fuel-injected (PFI), and port-fuel-injected turbocharged fuel systems were represented in the vehicle fleet. Ambient temperature effects were highly significant for carburetted and throttle-body-injected vehicle fuel-metering systems and for the total fleet. Carburetted vehicles were more sensitive to fuel properties and ambient conditions than fuel-injected vehicles. F1 vehicles consistently gave lower demerits than TBI vehicles. Lo-. volatility fuels gave significantly better hot-start driveability at-high temperatures than the high-volatility fuels. It should be noted, however, that tests of high-volatility fuels at high temperatures (nominal 90F) were not representative of conditions found with commercial fuels. The only significant difference due to oxygenate addition was the poorer performance of carburetted vehicles on lowvolatility-matched gasoline-ethanol and gasoline-methanol:TBA blends. Vehicle performance was generally poorer on oxygenated fuels than on hydrocarbon-only fuels.

Cold-Start and Warmup Driveability Performance of Hybrid Electric Vehicles Using Oxygenated Fuels

“…As might be expected, based on the literature treating fuel interactions with conventional vehicles, the higher DI fuels have higher TWD (99.99% confidence level) and ethanol degrades performance. In addition, GLM results indicate that the effect of 1% ethanol relative to one point of DI (°F scale) is similar to that observed when the main fleet is analyzed in the same fashion (2). While this similarity could not be predicted with certainty a-priori, the fact that HEVs still use a standard internal combustion engine (ICE) makes this result quite reasonable.…”

“…The test fuels were evaluated as prescribed in the CRC Cold-Start and Warm-up Driveability Procedure (E-28-94) (2). Duplicate tests were performed on every vehicle and fuel combination.…”

“…The CRC Cold-Start and Warm-up Driveability Procedure consists of a series of light, moderate, and wide-open-throttle maneuvers mixed in with idles to obtain as many evaluations of driveability in a cold engine as possible (2). Figure 3 shows one of the Insights during an acceleration maneuver at the Renegade Raceway.…”

“…The standard fueling procedure had been developed by the CRC Volatility Group from a study to reduce fuel carryover from one test to the next when flushing vehicle fuel tanks (2,8,9). Changes to the refueling procedure were to address concerns on battery state of charge and time to refuel.…”