Explaining Volkswagenâ€™s Emissions Scandal
Marlene Breverman stashed this in Cheat
The software sensed when the car was being tested and then activated equipment that reduced emissions, United States officials said. But the software turned the equipment down during regular driving, increasing emissions far above legal limits, most likely to save fuel or to improve the carâ€™s torque and acceleration. The company may also have been worried that some parts of the emissions system would break down if used continuously.
Exhaust system of a Volkswagen Golf
Volkswagen has used two basic types of technology to reduce emissions of nitrogen oxides from diesel engines, by either trapping the pollutants or treating them with urea. The first type is shown here.
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 carâ€™sÂ computer couldÂ save fuel by allowing more pollutants to pass through the exhaust system. Saving fuel is one potential reason that Volkswagenâ€™s software could have been altered to make cars pollute more, according to researchers at the International Council on Clean Transportation.