|
|
It might seem the antithesis to good fuel management but the Wellington Institute of Technology says mixing water with diesel creates a more efficient fuel and it has completed trials to prove it.
To prevent this, diesels are equipped with fine fuel filters capable of removing water in addition to particles of micron levels. Diluting diesel with up to 30 percent water by using a surfactant to reduce the surface tension in both the water and the combustible fuel, so they mix freely in the same way laundry soaps work in breaking down the surface tension of water to increase its penetration, is not new. Adding water to diesel not only cheats on the overall cost of the fuel, but also produces a cleaner fuel. Adding clean water (distilled or rain water) with an emulsifier (other additives can be added to help keep the mix from freezing) achieves a leaner burning fuel with lower nitrogen oxides and carbon dioxide, says the Wellington Institute of Technology (WelTec). The institute teamed up with Ian Choard (previously of Chevron) to develop an ‘engine performance and emissions’ testing laboratory on its campus. “There is a real need to test biofuels for emission rates so WelTec has provided the space and equipment for the testing lab,” says Paul Mather, director for the Centre for Smart Product at WelTec. As the school trains automotive engineers, the facilities have proved perfect for the institute’s automotive engineering students who are specialising in future vehicle technologies. By emulsifying diesels and bio-diesels, significant environmental benefits have been achieved with measured reductions of particulate matter, nitrogen oxides (NOx) and carbon dioxide, he says. “We set up a sophisticated emission testing laboratory in association with Ian Choard and his team based in Wellington under the name of Beranis Corporation.” WelTec’s purpose-built lab uses a state-of-the-art dynamometer to replicate engine performance and gather data in controlled conditions. “The end goal is ultimately to produce significant reductions in emissions by developing a customised low emission fuel which can be run in diesel vehicles. This sort of technology has world-wide implications,” says Mather. “They have got through to the point where they can make a stabilised emulsified fuel, which has been run on static dynamo testing and testing in the field, both on a generator and large diesel machinery.” The research team has been using rainwater and a percentage of between 12-15 percent water to diesel has proved the best combination, Mather says. Through the emulsion the fuel is locked inside a water globule, which is turned to steam in the combustion chamber. The process factures the fuel globule into much smaller particles to get a cleaner burn and the engine also runs cooler. Further research will look at a different fuel stocks and adding trade waste oil. “We hope to have a lot more field testing done to identify any issues,” say Mather. “One problem was that the filter system on diesel engines are very fine and designed to take water out. So we had to developed a bolt-on pump system that captures any free water in the fuel line, emulsify it and return it back to the line.” And what about the engine warranty? “This has been a problem, but when you are looking at big bus fleets that have been operating around the country for up to 25 years and with engines long out of warranty, this is not an issue,” he says. “We are particularly keen to get fuel with better emissions into school bus fleets,” he adds. “At the moment we are lining kids up next to an idling bus and effectively gassing them.”
Energy NZ Vol.4 No.5 September-October 2010 |
Diesel machinery users have long been taught the benefits of keeping their diesel pure and free of water because it rusts and corrodes finely machined injector parts, or will even blow the tip of an injector if there’s enough of it.