Albert Widmann with the car engine running. He had nearly died of carbon monoxide poisoning from the exhaust fumes. This engine exhaust testing inspired the development of gas vans. Back in Berlin, Reinhard Heydrich immediately set to work within the RSHA for the development of, in the words of Heydrich's subordinate Walter Rauff, a "more humane method of execution" than the "Einsatzgruppen" firing squads which had been used. When a prototype gas van was driven to KTI, Widmann explained to his young chemists that by adjusting the timing of the ignition, one could maximize the amount of poisonous carbon monoxide in the
Diesel exhaust process result in significant production of gaseous nitrogen oxides (NO), an air pollutant that constitutes a unique challenge with regard to their reduction. While total nitrogen oxides from petrol cars have decreased by around 96% through adoption of exhaust catalytic converters as of 2012, diesel cars still produce nitrogen oxides at a similar level to those bought 15 years earlier under real-world tests; hence, diesel cars emit around 20 times more nitrogen oxides than petrol cars. Modern on-road diesel engines typically use selective catalytic reduction (SCR) systems to meet emissions laws, as other methods such as exhaust gas recirculation (EGR)