Judge Charles Breyer of the U.S. District Court for the Northern District of California on Oct. 25 granted final approval for a massive settlement of just under $15 billion for using software in the computers that control the diesel engines in some of its cars that allowed those cars to cheat on emissions tests.
The settlement is the largest class-action settlement in U.S. automotive industry history. Volkswagen has begun the process of buying back cars containing the offending engines.
The decision is the result of revelations in September, 2015, in which researchers found that Volkswagen vehicles with 2.0-liter diesel engines produced far more pollutants when driven on the road then they did when undergoing emissions tests. Once the cheating was revealed, Volkswagen admitted it and worked with negotiators to develop a settlement for owners now stuck with cars that produce illegal amounts of air pollution.
The settlement means that VW will either fix the illegal engines or it will buy the cars back from owners who had purchased what they believed were efficient "clean" diesels. At this point, the repairs proposed for the most recent versions of the VW diesel engine have not been approved by the U.S. Environmental Protection Agency (EPA) or the California Air Resources Board (CARB). Repair proposals for older versions of those engines have not yet been submitted.
The problem with the VW diesel engines began with the 2009 model year, when engineers were trying to find a way to silence the distinctive clattering sound such engines typically exhibit. In the process, the emissions level of those diesels went up significantly, but rather than abandoning the noise reduction effort, VW engineers changed the engine control software so that it only functioned while the engine was being tested for emissions.
The cheating software, which the EPA calls a "defeat device," monitored the speed of the front and rear wheels of the car being tested. When the software found that the front wheels of the car being tested were turning, but the rear wheels were stationary, it then changed the fuel injection settings to meet emissions requirements. Otherwise, the fuel injection computer returned to settings that were more efficient and produced less noise, but which produced high levels of nitrogen oxides.
The reason the defeat device worked was emissions testing takes place on a dynamometer, where only the front wheels turn because the Volkswagens in this case are front-wheel drive cars. The cheating was uncovered when researchers performed testing while the cars were actually being driven on the road and thus had all four wheels turning.
During the six years that VW cars were cheating on emissions tests, the computer software went through three iterations.