Last night I tried an experiment with ethanol usage in a Prius. I used a 36% ethanol/64% gasoline mix, and drove a round trip of 120 miles. No problems overall. There was a perceptible increase in power and a 9% decrease in gas mileage.
Details:
The Prius is designed to use up to a 10% ethanol/90% gas mix. This is needed for operation in some states that use ethanol as an oxygenate instead of MTBE. From this I concluded that the Prius fuel system had been designed to accomodate some amount of ethanol without degradation, and the surfaces in the catalytic converters would not be degraded by combustion products involving small amounts of ethanol.
Then I took a look around the web, and found a study done by Minnesota State University where they ran a Prius on E85 (85% ethanol, 15% gas) and measured emissions results. They discovered a reduction in three pollutants (HC, NOx, and CO) an increase in power of 20% and a reduction in overall gas mileage. They also discovered that after approx 140 miles they would get a check engine light. They used a diagnostic tool to check the error code; apparently the error was due to the computer having to increase the richness of the mixture by 32% to deal with the added oxygenate in the fuel. The computer did not have a problem making this adjustment but did set an error code since it was outside its expected range. See link below for more information.
I thought that perhaps a less aggressive mix of ethanol and gasoline would bring some of the benefits of ethanol operation (i.e. decreased reliance on petroleum, increased power) without setting the error light. A 36% mix would only require a 14% mixture adjustment; this might be within the 'legal' range of the mixture adjustment.
To get the right mix I filled several 5 gallon cans with E85 from a local gas station. (They made me sign a waiver saying I wouldn't sue them if I damaged my vehicle, which I thought was funny.) E85 cost was $2.10 a gallon; local gas costs around $2.50 a gallon. I filled the Prius from one of the cans and topped it off with regular (87 octane) gas from a local gas station. Calculating the amounts got me a 36% ethanol mix.
I then drove a 120 mile round trip with one passenger. No error lights, and my mileage, as determined by the car's computer, dropped off by about 9% while giving me a noticeable increase in power. This leads to a fuel cost of 5.4 cents per mile with normal gas and 5.6 cents per mile with the E36 mixture I used.
So overall a bit of a pain to mix the fuel manually, but it seemed to work well. I may try a mixture up to 50% ethanol next.
Link to study:
http://66.102.7.104/search?q=cache:...rid%20report.doc+ethanol+prius+test+E85&hl=en
Details:
The Prius is designed to use up to a 10% ethanol/90% gas mix. This is needed for operation in some states that use ethanol as an oxygenate instead of MTBE. From this I concluded that the Prius fuel system had been designed to accomodate some amount of ethanol without degradation, and the surfaces in the catalytic converters would not be degraded by combustion products involving small amounts of ethanol.
Then I took a look around the web, and found a study done by Minnesota State University where they ran a Prius on E85 (85% ethanol, 15% gas) and measured emissions results. They discovered a reduction in three pollutants (HC, NOx, and CO) an increase in power of 20% and a reduction in overall gas mileage. They also discovered that after approx 140 miles they would get a check engine light. They used a diagnostic tool to check the error code; apparently the error was due to the computer having to increase the richness of the mixture by 32% to deal with the added oxygenate in the fuel. The computer did not have a problem making this adjustment but did set an error code since it was outside its expected range. See link below for more information.
I thought that perhaps a less aggressive mix of ethanol and gasoline would bring some of the benefits of ethanol operation (i.e. decreased reliance on petroleum, increased power) without setting the error light. A 36% mix would only require a 14% mixture adjustment; this might be within the 'legal' range of the mixture adjustment.
To get the right mix I filled several 5 gallon cans with E85 from a local gas station. (They made me sign a waiver saying I wouldn't sue them if I damaged my vehicle, which I thought was funny.) E85 cost was $2.10 a gallon; local gas costs around $2.50 a gallon. I filled the Prius from one of the cans and topped it off with regular (87 octane) gas from a local gas station. Calculating the amounts got me a 36% ethanol mix.
I then drove a 120 mile round trip with one passenger. No error lights, and my mileage, as determined by the car's computer, dropped off by about 9% while giving me a noticeable increase in power. This leads to a fuel cost of 5.4 cents per mile with normal gas and 5.6 cents per mile with the E36 mixture I used.
So overall a bit of a pain to mix the fuel manually, but it seemed to work well. I may try a mixture up to 50% ethanol next.
Link to study:
http://66.102.7.104/search?q=cache:...rid%20report.doc+ethanol+prius+test+E85&hl=en