Ford Adopts Particulate Filters

French chemical supplier Rhodia SA says Ford Motor Co. will adopt its “Eolys” fuel-borne catalyst technology on the entire range of diesel engines it manufactures in Europe that are equipped with diesel particulate filters (DPFs).

The technology will debut on a diesel Ford Focus, and Rhodia says the number of passenger vehicles with DPF-Eolys catalyst systems will rise from 400,000 annually in Europe in 2003 to 1 million by 2005.

DPFs are an effective but controversial means of controlling emissions of particulate matter (PM) — soot — in exhaust gas. Soot is considered a growing environmental and health threat, especially in Western Europe, where nearly 40% of new light vehicles are powered by diesels.

Some European OEMs criticize DPFs as being too expensive and are pursuing other strategies to reduce PM. But auto makers such as France's PSA Peugeot Citroen — the first to adopt Rhodia's cerium-based PM filter technology — have won accolades from environmentalists for using the filters.

Rhodia claims the Eolys technology is the most efficient way to virtually eliminate PM and “the only solution available on an industrial scale” for mass production.

The main challenge lies in eliminating the accumulation of soot in the DPF so it can be effective for 50,000 miles (80,000 km) or more without needing to be replaced or cleaned. A typical diesel engine can produce as much as 6.6 lbs. (3 kg) of PM in 50,000 miles, Rhodia says.

In a typical DPF system, Rhodia's Eolys fuel-borne catalyst is contained in an onboard canister and then metered into the fuel tank as the owner refuels. The Eolys, when added to diesel fuel, allows the engine to periodically develop higher-temperature exhaust that burns off the accumulated particulates trapped in the filter.

This DPF concept, developed with Ford, prevents 99% of soot particles from being spewed into the atmosphere, 100 times less than conventional, unfiltered diesel exhaust.

Meanwhile, Engelhard Corp. says Renault SA is the first OEM to use its catalytic soot filter (CSF) for the 2.2L diesel Vel Satis.

Combined with a diesel oxidation catalyst, CSF does not require a separate fuel additive or periodic removal of the filter to clean out ash deposits. Engelhard says CSF cuts diesel carbon monoxide (CO), hydrocarbons (HC) and PM more than 95%.

The Engelhard CSF is based on a porous silicon carbide element coated with a special catalytic material — used in conjunction with cooled exhaust gas recirculation — to cut PM and NOx emissions. Placed just downstream from the turbocharger, the filter is cleaned every 185 to 310 miles (300 to 500 km) by raising exhaust gas temperature briefly to 1,058°F (570°C) with extra injected fuel.
— with Bob Brooks