Start your engines.

An automotive system designed to reduce toxic hydrocarbon emissions has received the checkered flag from mechanical engineers who examined the device.

Once an engine reaches its operating temperature, catalytic converters eliminate nearly all hydrocarbon emissions. However, in the first 2 minutes after a car is started, some toxic fuel doesn't burn entirely and gets spit out the exhaust pipe. Up to 95 percent of a vehicle's hydrocarbon emissions occur during this warm-up period.

In 2001, a group of engineers developed a lightweight, inexpensive system, called the on-board distillation system, that converts regular fuel into a highly volatile distillate that vaporizes more easily as the engine warms up (SN: 1/20/01, p. 39). This start-up fuel is kept in a separate tank that's accessed only during the first 20 seconds after ignition.

Researchers tested this start-up tank by installing it on a Lincoln Navigator and running the vehicle through a drive simulation used by the federal government to determine automotive regulations, says Marcus D. Ashford of the University of Alabama in Tuscaloosa. They found that activating the system decreased the car's hydrocarbon emissions by 81 percent.

Ashford and Ronald D. Matthews of the University of Texas at Austin, who were part of the group that developed the system, report these results in the Sept. 15 Environmental Science & Technology.

The technology could be ready for mass production in a few years, but car manufacturers haven't produced the inexpensive system because they are focusing on making better catalytic converters instead of adjusting fuel volatility, Ashford says.--E.J.