Wednesday, November 25, 2015

Many European diesels have high emissions under real driving conditions

It appears that Volkswagen is not the only one with high NOx emissions under real driving conditions. Tests performed by Deutsche Umwelthilfe (DUH) show that Opel and Renault diesels also have increased NOx emissions under normal driving conditions. DUH claims that Renault Espace diesels have up to 25 times higher emissions than allowed in Europe. In a response Renault claims that their diesels pass the test. Of course Volkswagens also pass that test. It's the difference between between emissions under real driving conditions and the test that's disturbing. Volkswagen cheated by using a cheat device. It seems that officially Renault didn't cheat. Instead the cause seems to be that Renault tests with a cold engine. Lower temperatures lead to lower NOx emissions. In real life those engines heat up over time and then emit poisonous NOx emissions that kill people. In real life we need stricter regulations to ban such practices.

Wednesday, November 4, 2015

VW scandal expands to gasoline cars

Only a few hours after I wrote my post yesterday, asking whether Volkswagen's dieselgate scandal would expand to gasoline cars, the news broke that it did. I noted yesterday, that a defeat device that affects engine operation may also be used in gasoline cars. As a consequence performance and fuel economy will be reduced.

In the latest scandal Volkswagen admits overstating fuel economy and as a result CO2 emissions for 800,0000 vehicles. The majority of these vehicles have diesel engines, which implies that at least some gasoline cars were also affected. Volkswagen stated that they don't know yet what caused the irregularities. So they don't know whether a defeat device was installed this time as well, but in light of earlier misdoing this seems to be the most logical explanation.

Tuesday, November 3, 2015

New Volkswagen violation - will scandal expand to gas powerd cars?

Earlier I described the technical details of dieselgate with regard to the EPA's September 18 Notice of Violation (NOV). Sadly Volkswagen Group's (VW) ordeal is not over yet. The EPA released a new NOV which now affects VWs 3.0 liter diesel engines.

There is a serious threat that the scandal will expand to more and more engine types and vehicle models. "ARB and EPA will continue to conduct a rigorous investigation that includes testing more vehicles until all of the facts are out in the open." This time the violation also affects Porsche which was unaffected by the earlier NOV.

Although the number of vehicles is limited (10.000 in 2014, plus an unknown additional number in 2015), the technical details are at least as disturbing as the earlier violation.

Again VW used a cheat device. This time exactly one second after the vehicle completes the initial phase of the standard test procedure, the vehicle changes to normal mode, where NOx emissions increase up to nine times the EPA standard. This time the engine cheats by running in a low NOx "temperature conditioning" mode. Engine temperatures are kept down as high temperatures increase NOx emissions.

The consequences of removing the cheat device would be a broad range of reduced performance, including reduced torque and increased fuel consumption. What's even more worrisome is that this time VW didn't just play with the post-combution exhaust cleanup. They changed the operating parameters of the engine. That method can be applied to a broad range of vehicles including those with gasoline powered engines.