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Envirofit: Retrofitting the Two-Stroke Engine

Two-stroke engines emit as much pollution as approximately 50 conventional automobiles.

A retrofit kit initially designed to reduce the emissions of snowmobiles is now being applied to the ubiquitous two-stroke motorcycle taxis in Philippine cities. Envirofit, an independent nonprofit company started at Colorado State University in 2003, works to develop and disseminate direct injection retrofit kits to improve the efficiency of two-stroke engines, one of the world’s largest sources of vehicular emissions. “It’s a huge amount of pollution, and a very solvable problem,” says Dr. Bryan Willson of Envirofit. The group’s effort earned it the WCEA award in the category of transport and mobility.

A traditional two-stroke engine emits as much pollution as approximately 50 modern automobiles, according to Envirofit. In the retrofit systems, in contrast, the carburetor is eliminated and the fuel is introduced directly into the engine cylinder, so less unburned fuel is wasted. According to Willson, Envirofit’s direct injection kits reduce fuel and oil consumption by 35–50 percent and cut the emissions of a two-stroke engine by as much as 90 percent.

Fuel efficiency can mean big savings for taxi drivers with little earned income. According to Envirofit, the typical Filipino taxi driver makes only US$3–5 per day. The organization’s kits pay for themselves in fuel savings alone within 10 months, says Willson. The Philippine cities of Vigan and Puerto Princesa, home to Envirofit’s pilot projects, offer microfinancing to help individuals afford the retrofits. But it is important the loans are structured in a way that ensures taxi drivers take home more income the very first day they pay for their retrofit, Willson stresses.

“There are real challenges in selling to the Base of the Pyramid,” says Willson. “In many cases you’re developing products for people who really have very little available income.” It is necessary to appreciate the risk people take when they choose to retrofit their engines, he says, and to make sure your product is “extremely well-engineered and affordable.” Envirofit also works with local partners to develop self-sustaining businesses to install and service the kits.

The Asian Development Bank estimates there are some 100 million two-stroke vehicles in Southeast Asia. Envirofit hopes to expand its engine retrofit program to Bangladesh, Sri Lanka, Pakistan, and India, where demonstrations of the product will take place this year. Willson believes the WCEA award may help in this endeavor, because it “provides validation of the concept” of retrofitting two-stroke engines.

Alana Herro writes for Eye on Earth (e²), a service of World Watch Magazine in partnership with the blue moon fund. e² provides a unique perspective on current events, newly released studies, and important global trends.

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