COORDINATING RESEARCH COUNCIL QUANTIFYING PERFORMANCE OF KNOCK-SENSOR EQUIPPED VEHICLES WITH VARYING OCTANE LEVEL FUELS

A pilot study was conducted under the auspices of the Coordinating Research Council, Inc. (CRC) to assess the potential effects of gasoline octane quality on acceleration performance, fuel economy and driveability in vehicles equipped with electronic spark control systems (knock sensors). Fourteen vehicles were tested by five participating laboratories, representing both the oil and automotive industry, on CRC unleaded reference fuels of varying octane quality (78 to 104 RON). The test vehicles included nine naturally-aspirated and five turbocharged models. The results showed that acceleration performance was the parameter most sensitive to octane quality changes, particularly in the turbocharged models. No significant improvements in fuel economy were found with increasing octane. Drive-ability was not affected by fuel octane within the commercial fuel range, but three vehicles showed degraded driveability with sub-commercial octane fuels. Additional testing is planned within CRC to further quantify the effects of octane quality on acceleration performance in a wider variety of vehicles.