Diesel Catalysts – Recent Adverse Publicity

6 November 2015

Diesel engines are used worldwide as fuel-efficient internal combustion engines for both on-highway and off-highway vehicles. Medium and heavy-duty vehicles, buses, military vehicles and construction plant worldwide rely on the diesel engine, and it has also become the fuel of choice for passenger cars in Europe.

Recent publicity over the admission that certain diesel-engined vehicles fail to legitimately meet emission-control testing has occasioned several enquiries about whether MEL, known for its ceria-zirconia technology applied in gasoline-engined vehicles globally, might have products that could help improve matters.

Over recent years, diesel emissions legislation has focussed on the reduction of NOx (oxides of nitrogen) and particulates, with North America, Europe and Japan leading the way with the most-demanding emission standards. With Climate Change concerns about the effect of greenhouse gases such as CO2, and health concerns over NOx and particulates, ever-tightening emission limits are constantly driving the need for new catalyst technologies to control vehicle emissions.

MEL Chemicals has a deep understanding of the functionality of the various technologies used to control CO2, NOx, and particulate emission levels for both existing and upcoming regulations. As stated above, to date the vast majority of our automotive products have gone into gasoline catalyst systems. We have, however, developed materials that are suitable for use in the NOx traps, Passive NOx adsorbers, urea-based Selective Catalytic Reducers (SCR), and Diesel Particulate Filters (DPF) used variously in diesel catalyst systems.

A further challenge is expected to come from World Harmonised Test Cycles and Real World Driving Emissions standards. With the adoption of these testing protocols, vehicles’ emission control systems will need to meet emissions standards throughout the whole of a ‘real-life driving’ cycle, rather than just at a bench or on a rolling-road. Existing exhaust treatment systems may well need to be re-designed to cope with these new requirements.

Development in this area is increasingly focusing on simplifying the number of ‘boxes’ in the system through the combination of previously-separate technologies, for example SCR on DPF. MEL Chemicals has high-temperature, thermally-stable, materials able to combine NOx reduction with passive or active particulate capture in such a combination system.

We believe that MEL Chemicals ceria-zirconia mixed oxide technology has much to offer towards improving diesel engine NOx emissions, probably in combination with the zeolite technology used today, and we are offering our technology to the major automotive catalyst manufacturers.

For more information on MEL’s automotive catalysis products, please visit www.zrchem.com where contact information is available.