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
Exhaust gas recirculation the increase in particulate emissions that corresponds to an increase in EGR. Particulate matter (mainly carbon) that is not burned in the power stroke is wasted energy. Stricter regulations on particulate matter (PM) call for further emission controls to be introduced to compensate for the PM emission increases caused by EGR. The most common is a diesel particulate filter in the exhaust system which cleans the exhaust but causes a constant minor reduction in fuel efficiency due to the back pressure created. The nitrogen dioxide component of NOx emissions is the primary oxidizer of the soot caught in the diesel