Mazda Successfully Reduces Diesel Emissions

- PM emission reduced by more than 75 percent, monitor test drives commence in preparation for commercial production -

Mazda Motor Corporation has developed a clean diesel engine that significantly reduces the amount of particulate matter (PM) and nitrogen oxides (NOx) in exhaust gas emissions. Using small commercial Bongo vans powered by the new diesel engine, the automaker will begin monitor test drives today, aimed at commercial production. This is the first time such tests have been carried out for the small commercial vehicle segment.

New Diesel Engine 'Bongo Van' (test model)

The newly developed engine is a 2.0-liter, inline-4 cylinder, common-rail direct injection turbo diesel. Based on the "MZR-CD," mounted in the European specification Mazda6, the new engine is equipped with an all-new diesel particulate filter (DPF) and an improved engine control unit. This has resulted in a more than 75 percent reduction of PM and 25 percent reduction of NOx, compared to diesel engines used in the current Bongo.

In order to reduce the amount of PM emitted in the air, Mazda used a DPF that is specially coated with an oxidation catalyst. The ceramic DPF traps PM, and when the amount of PM in the filter has reached the designated level, it is removed through the combined effect of the catalyst and combustion temperature controlled by the common-rail injection system. In an effort to reduce NOx, the combustion temperature is optimally controlled through "Cooled EGR.^*" It is also helped by improved combustion efficiency with fuel injected at high pressure from the common-rail.

As part of the development process, the engine's performance will be monitored in tests conducted on public roads using the small commercial Bongo van. Mazda will test one van itself, while enlisting the help of business partners to monitor additional vehicles. This will allow Mazda engineers to collect a variety of data under different driving conditions. The results will then be utilized to further enhance the engine in preparation for commercial production.

Under new, stricter emissions regulations for diesel engines, the first of which will come into force in Japan this October, automakers are being asked to reduce NOx and PM emissions by about 30 percent of levels set in the current standards. Mazda is aiming to meet these standards, those of the 'Automobile NOx/PM Law' covering metropolitan areas, and the Tokyo Metropolitan Government's diesel vehicle regulations with its cleaner new diesel engine.