Candid Cameron

Candid Cameron

Q A short article at RealTechNews (www.realtechnews.com) links to a much longer article that explains how acetone can boost fuel mileage in cars. It would be interesting to see if such a boost can be had with motorcycles, too. My Yamaha Seca II gets about 60 mpg right now, but with the rise in gas prices, it would be nifty to increase that by 10 or so more mpg. I’m a bit skittish about trying this, however, since the Seca is my primary transportation on my 70-mile daily commute. Michael Domingo Vista, California

A The usual mileage improvement schemes under development center on such things as the increased efficiency of high compression (diesel engines) or on boosting the conversion of heat into pressure by lowering combustion temperature (lean burn, gasoline direct injection, stratified charge, etc.)

The acetone treatment sounds to me as though it is based on the fact that some small percentage of the gasoline supplied to an engine may not burn completely because the larger fuel droplets evaporate down to a residue that passes through the engine unburned. Fuel droplets are broken up initially by hitting the fast-moving engine intake airflow, and their ultimate size depends in part on their surface tension. Acetone reduces surface tension, thus perhaps making formation of smaller, faster-evaporating droplets more likely. Another low-surface-tension liquid is xylene. An interested person could make careful mileage experiments, if the effect were small or nonexistent, he might conclude that his engine’s unburned fuel fraction is small. If the effect were substantial, it would indicate a significant unburned fuel fraction. I would be surprised, though, if many good dinners could be bought on the money saved in this way. Recognized but boring or even dangerous means of saving fuel are to ride at 30 mph or inflate one’s tires to 50 psi—neither of which are we willing to do. -Kevin Cameron