Audi faced the challenge of finding a way to make the RS6, which is very popular in the US and Canada, meet new "transient low emission vehicle" (TLEV) exhaust emission regulations.
The RS6 met the regulations until the end of 2003. But in January, the level of exhaust pollutants -- such as hydrocarbons -- allowed in the US was cut in half by new emission standards.
Audi decided against making major changes to the RS6's engine or the car itself because the RS6 uses the body shell of the A6, which is due to be replaced worldwide within a year. The new A6 is already available in Germany.
Emitec developed a new catalyst technology that significantly reduces the RS6's emission levels.
Usually catalytic converters have open channels that are not connected to each other. Emitec designed a catalytic converter in which there is a high level of gas exchange between the channels.
Emissions can move to the sides of the catalyzer and swirl around the edges. Experts call it a "turbulent" catalyst. Its efficiency has so far not been equaled by other methods.
Another advantage is that the catalyst heats up extremely quickly after a cold start. The "turbulent" catalyzer reaches 300 degrees Celsius 18 seconds earlier than a conventional filter system. The high temperature is necessary to convert engine emissions into less harmful gases.
The new system means that the RS6's emission levels have fallen far below the levels prescribed by US legislators.
Wolfgang Maus, Emitec's head of the business, said that several manufacturers of sports cars will start using the catalysts in series production within the coming year.