Johnson Matthey has introduced a diesel exhaust aftertreatment system designed to make heavy duty diesel truck and bus engines as clean as those of the latest passenger cars.

The SCRT system builds on the company's Continuously Regenerating Trap technology, which is already extensively used in Europe and is undergoing large scale trials in the U.S. and other parts of the world. This is combined with Selective Catalytic Reduction (SCR), another Johnson Matthey technology which uses the company's own specially formulated catalysts.
By using this combination of technologies, the SCRT is said to cut all four regulated pollutants
contained in the exhaust of heavy trucks and buses. It virtually eliminates carbon monoxide (CO) and hydrocarbon (HC) emissions, while reducing emissions of particulate matter (PM) and oxides of nitrogen (NOx) by between 75 and 90%.
The new system will be launched commercially over the next few years, in line with the introduction of strict emissions standards for heavy duty diesel vehicles in Europe and the U.S. When fully developed and in mass production, it is expected to be small enough to fit in the space occupied by a conventional muffler and will meet industry cost targets for what will be an OEM system.
Dr Barry Cooper, vice president, technology said: "The industry is aware that we have been pursuing this development pathway but this is the first time that details of the system have been made public. It's still early days but we are already within the proposed European Stage 5 limits and all but meet the latest proposals for the US 2007 emissions regulations, when the system is used in combination with sulphur free fuel".