Breakthrough for cars as Daimler tests SCR

The decision by the German car maker Daimler Chrysler to do field trials of Selective Catalytic Reduction (SCR) looks set to be a breakthrough in the battle to reduce nitrogen oxides emissions from diesel cars.

Sketch of some documents (default image for news

[mailchimp_signup][/mailchimp_signup]Since environmental factors first became an issue for car buyers, the choice has generally been between petrol-fuelled cars which reduce emissions of pollutants but use more fuel (thereby emitting more carbon dioxide), and diesel cars which reduce fuel consumption per kilometre but emit more pollutants, notably hydrocarbons, nitrogen oxides and particulates.

SCR, which reduces NOx while leaving fuel consumption largely unchanged, has in recent years been developed for lorries, but the automotive industry has always said SCR is a long way away for cars.

Daimler Chrysler now says it is field testing diesel cars which reduce NOx emissions by 80% at the same time as allowing the engine to be optimised for fuel economy and particulate emissions.

“Daimler Chrysler has broken the industry front,” said T&E director Jos Dings. “If the trials confirm the claims the company is making, it will mean the industry can no longer claim that low NOx comes at the cost of higher fuel consumption.

“It could be that Daimler is looking to prepare its diesel engines for the stricter emissions standards that apply to the US market. If that is right, we could have a repeat of the situation in the 1980s, when EU car makers argued that three-way catalytic converters were not feasible while they were in widespread use in America.”

Signs of that happening emerged as the Commission presented its first draft Euro-5 proposal to the Cars 21 “sherpa” group earlier this month. It contains a target to reduce NOx by 20%, a figure which could soon look outdated when Daimler is ready to offer the market technology that can reduce NOx by 80%.

This news story is taken from the July 2005 edition of T&E Bulletin.