Nitrogen oxide trap
This system traps nitrogen oxides, reducing toxic emissions. But the engine must regularly use more fuel to allow the trap to work. The car’s computer could save fuel by allowing more pollutants to pass through the exhaust system. Saving fuel is one potential reason that Volkswagen’s software could have been altered to make 11 million cars pollute more, according to researchers at The International Council on Clean Transportation.
Illustration by Guilbert Gates|Source: Volkswagen, The International Council on Clean Transportation