In 1892 Rudolf Diesel (see Fig. 1) developed the first compressed charge, compression ignition engine, later named the diesel engine.¹  The concept was intended as a mechanical power device for the manufacturing industry.²  After being introduced in shipping, the engine also made its way into road traffic. Since then the diesel engine has been an efficient and highly reliable work horse for supplying the needs especially for people living in densely populated areas. The number of heavy-duty trucks is continuously growing and will by 2030 most likely reach 500 000 in the USA alone.³ 

Emission legislation...