In the last two weeks, Volkswagen has admitted that it sold 11 million cars with so-called “Clean Diesel” engines worldwide that were equipped with software allowing them to cheat emissions tests. Below are five things you need to know:
- What did Volkswagen do?
Independent automobile researchers report that Volkswagen sold 11 million diesel cars that produced as much as 40 times the E.P.A. allowed limit of nitrogen oxide, a pollutant that contributes to respiratory problems including asthma, bronchitis, and emphysema. The software and devices installed by Volkswagen were programmed to detect when one of its cars was undergoing an emissions test and it triggered equipment that would reduce emissions to legal levels for the duration of the emissions test.
- How did this happen?
Experts say that by the middle of the last decade, it became clear that Volkswagen’s old, less advanced diesel engines could not meet tougher American emissions standards, particularly in California. While Volkswagen made promises of selling “clean” diesel vehicles with ever greater power and fuel economy, its engineers worked on ways to reduce emissions. However, despite Volkswagen’s initial optimism, its engineers could not figure out how to design a catalytic system that would scrub enough nitrogen oxide from the cars’ exhaust. While some diesel car makers used a system that injected a derivative of urea to reduce emissions, Volkswagen concluded that would be too expensive. Other approaches they tried resulted in reduced vehicle performance. When the time came for Volkswagen to begin manufacturing the “clean” diesel vehicles it had promised, it incorporated a defeat device rather than sell cars with lower performance or a more expensive exhaust system.