Fill ’er up — with vegetable oil?
Student’s cross-country bus trip to test viability of alternative fuel
Photos by Dan Addison
|Luke Scruby shows off the vegetable oil tank
By Charlotte Crystal
When your fritters are fried and you’ve got a vat full of fat, who ya gonna call?
Call Luke Scruby, the rising fourth-year mechanical engineering student at U.Va., who is turning gritty grease into filtered fuel to power an old school bus on a cross-country trip this summer.
Scruby, 21, his sister Emily Scruby, 23, and his high school pal Scott Wilcox, 21, have just embarked on a 13,000- to 15,000-mile trip to
Alaska to demonstrate the effectiveness of recycled vegetable oil as an environmentally sound fuel. They also plan to spend time enjoying the wilds of Alaska, hiking and fishing in the 49th state's Denali and St. Elias national parks.
Along the way, they will pull in behind fast-food joints and other eateries, “wherever people run deep fat fryers,” to fill their fuel tanks with waste vegetable oil. The bus's tanks can hold up to 230 gallons of grease, which
the travelers hope to tap for free or at a fraction of the cost of conventional diesel fuel.
“We want to show the viability of alternative fuels, of substitutes for petroleum,” Scruby said.
The trio snagged the 20-year-old, 54-passenger school bus with a $2,600 bid at a North
| With sister Emily and friend, Scott Wilcox, who will be joining him on the trip to Alaska.
Carolina school bus auction. They converted the bus’s interior into living quarters that include a galley kitchen complete with a propane stove, a sink and a cooler, though lacking a toilet or shower. They painted the bus’s exterior a vibrant green in keeping with the vehicle’s environ-
The bus came with a diesel engine and a 50-gallon tank for diesel fuel. Scruby, a third-generation engineer, spent $1,200 for parts to build a parallel fuel system that incorporates five large tanks for vegetable oil — two 55-gallon tanks and three 40-gallon tanks — and a filtration system that eliminates water and food particles, leaving the recycled oil ready to use.
“What’s unique about our project is the mobile filtration system that we have on board,” Scruby said. “Other filtering systems have to be stationary for the water and particles to settle out. But if you don’t have time to let them settle, you need a more sophisticated filtration system, which is what we’ve got.”
The system works like this. The driver starts the engine and runs it on diesel fuel for about five minutes. During that time, heated engine coolant circulates in coils around two of the vegetable oil tanks and the fuel line. When the engine reaches about 180 degrees Fahrenheit and the oil in the tanks warms to about 150 degrees, thinning it enough to pass through the fuel injection device, the driver flicks a simple tank selector valve to switch from diesel fuel to vegetable oil.
“My pie-in-the-sky goal is to go cross-country on one tank of diesel fuel,” Scruby said.
Scruby, his sister and his friend are riding a small-but-growing international trend.
The University’s Department of Parking and Transportation Services recently launched a biodiesel pilot project, fueling two of its buses with a mixture of 80 percent conventional diesel fuel and 20 percent vegetable oil. Elsewhere in Virginia, Harrisonburg and Arlington have shifted their city bus fleets to biodiesel fuels as have other U.S. cities, from Bangor, Maine, to Berkeley, Calif.
The manufacturers of Audi, Mercedes and Volkswagen all have announced that their diesel models can safely run on biodiesel fuels. And in Western Europe, biodiesel fuels are becoming increasingly available at the gas pumps.
One disconcerting aspect of biodiesel fuel made from recycled vegetable oil is the smell of the exhaust fumes, which can range from French fries, to doughnuts, to Chinese food, fish or chicken — whatever was cooked in the oil.
Charlottesville’s intrepid trio left town on Sunday, May 29. They expect to spend the better part of June and July sightseeing in Alaska, and head for home around July 25.
Scruby began his studies in mechanical engineering at Virginia Tech, but transferred to U.Va. so he also could study Arabic. Emily is enrolled in a master's program at Tech in early childhood education. Wilcox is studying agriculture at Auburn University. They have formed a company, Alternate Transport, which owns the bus that they hope to use again in the future.
While promising the possibility of better engine performance and thousands of miles of clean-burning combustion, the recycled oil appeared unlikely to boost the bus’s speed above 50 miles per hour, Scruby said. “Getting a speeding ticket is one of our lesser concerns,” he said.
Meanwhile, the success of their trip will depend on the kindness of strangers with gallons of gunk to go.