Gas van Gas van A gas van or gas wagon ( ("dushegubka"); ) was a vehicle reequipped as a mobile gas chamber. The vehicle had an air-tight compartment for the murdered victims, into which exhaust fumes were transmitted while the engine was running. The murdered victims were gassed with carbon monoxide, resulting in death by carbon monoxide poisoning and suffocation. The gas van was used by the Soviet secret police in 1930s. During World War II Nazi Germany used gas vans on a large scale as an extermination method to murder inmates of asylums, Romani people, Jews, and prisoners in occupied Poland,
Exhaust gas recirculation the engine was running. Difficult starting, rough idling, and reduced performance and fuel economy resulted. By 1973, an EGR valve controlled by manifold vacuum opened or closed to admit exhaust to the intake tract only under certain conditions. Control systems grew more sophisticated as automakers gained experience; Chrysler's "Coolant Controlled Exhaust Gas Recirculation" system of 1973 exemplified this evolution: a coolant temperature sensor blocked vacuum to the EGR valve until the engine reached normal operating temperature. This prevented driveability problems due to unnecessary exhaust induction; NOx forms under elevated temperature conditions generally not present with a cold engine. Moreover, the