Nanotech company to test fuel additive in Asian buses

By Genevieve Oger
Small Times Correspondent

Dec. 27, 2001 — Issues of smog and air pollution have left urban planners scratching their heads for years. But small tech may have a hand in reducing some of the vehicle emissions that poison the atmosphere of large cities the world over.

An Oxford-based British startup is developing a fuel additive that reduces the particulates diesel and gasoline engines leave in the air. To do this, Oxonica is working to improve the combustion process of fuel. The results of its research will be put to a real-world test this spring, when Oxonica’s fuel additive will keep Hong Kong city buses running and, if all

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The city of Hong Kong has decided to give Oxonica’s
additive-enhanced fuel a try. The city’s buses and
government vehicles are to be equipped with the fuel
for several months beginning in April 2002. Other
Asian cities may follow.

goes well, reduce their emissions.

“When fuel combusts perfectly, it turns into carbon dioxide and water and brings you energy,” said Gareth Wakefield, Oxonica’s vice president of research. “But you never get a perfect reaction. That’s why you get all this added junk in the exhaust.”

Oxonica looked for a very small solution to this big problem. Scientists had already tried to inject additives into fuel to make it burn cleaner. But the units used were too big and tended to sink to the bottom.

“The concept of adding materials to improve combustion is over 20 years old, but science has improved and allows us to make additives much, much smaller,” said Kevin Matthews, Oxonica’s chief executive.

Oxonica put nanotechnology to work by breaking the additive down to allow it to disperse evenly inside the fuel. The material has been broken down to 5 or 10 nanometers and coated with a fatty acid. Small enough to mix with fuel, but big enough to be effective.

Oxonica is one of the many spinouts of Oxford University, which finds commercial applications for discoveries made by its engineering and biochemistry departments. In addition to fuel additives, the company’s nanoresearch currently focuses on sunscreen, anti-counterfeiting phosphor products and biotags.

Oxonica says the composition of the fuel additive in question must remain secret for now, as patents are pending. “What we can say is that the material can function in both an oxygen rich and oxygen poor environment,” Wakefield said. “It can flip between the two and can compensate for whatever shortages or excesses of oxygen there are.”

It all happens during the combustion process in the vehicle’s combustion chamber. As in all engines, when a drop of fuel gets to the combustion chamber, there is a spark and a bang. That’s when energy is created. The presence of oxygen is what causes the reaction. If the environment is oxygen rich, the exhaust will emit carbon monoxide. If it is oxygen poor, the vehicle will release noxious oxides. “The presence of this additive has been found to convert what comes out into less harmful gases,” Wakefield said.

Trials conducted in Britain are encouraging. According to assessments performed at bus depots and government emissions testing sites, the presence of the additive reduced air emissions by 65 percent and improved fuel consumption by 10 percent.

But Oxonica needs to test the product in a real-world environment to get more reliable figures. The city of Hong Kong has decided to give the additive-enhanced fuel a try. The city’s buses and government vehicles are to be equipped with the fuel for several months beginning in April 2002. Other Asian cities may follow.

But some observers warn that Oxonica’s efforts must be viewed with prudence, keeping the mistakes of history in mind. “We have seen so many additives used in the past,” said Peter Widerkehr, project manager of the OECD’s Environmentally Sustainable Transport Initiative. “We have seen lead, MTB [methyl tertiary butyl ether] and magnesium added, and every time there has been a negative effect.”

Lately, much of the effort to reduce worldwide pollution has focused on diesel. It is the main source of power around the world for engines of up to 5,000 horsepower, like city buses. According to the International Energy Agency, diesel buses make up 93 percent of the U.S. bus fleet and a similar share of the European fleet. However, they typically emit more particulate matter than gasoline engines equipped with catalytic converters.

Reducing the amount of sulfur in diesel fuel has been found to diminish the amount of particulates a vehicle produces by up to 90 percent if an adequate exhaust filter is in place. For this reason the European Union, Canada and the United States are proceeding with aggressive legislation to reduce sulfur content.

In this context, any further emissions reduction becomes marginal in the case of diesel. In 2005, when the new European laws kick in, diesel engine particulate emissions will be reduced by 90 percent, explains Lew Fulton, of the International Energy Agency. “Some other approaches to particulate reduction may not matter as much at that point.”

However, Oxonica may find a market in the developing world. There, older buses, whose emissions are greatest, are expected to continue running for years to come. It is estimated a second-hand bus in the developing world costs between $10,000 and $40,000, while a new diesel bus, which meets current E.U. standards, costs at least $100,000 to $150,000. For a developing economy with limited resources, the choice is a simple one.

However, air quality concerns both rich and poor. Oxonica has found Asian cities to very keen to try the enhanced fuel. “The pollution is so high there that cities want to do the tests right away and not waste any time,” Wakefield said. According to the deal with the city of Hong Kong, Oxonica will supply the fuel for the trial this spring. It will then take another three to six months to verify and tabulate the results.

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