In 2015 it was found that Volkswagen diesels were rigged to defeat NOx emissions tests. It resulted in a big scandal and Volkswagen will have to pay out a lot of money in damages. But is Volkswagen the only car brand with defeat devices that was ever caught? This week the Dutch government body responsible for authorizing motorized vehicles called RWD published an interesting report. The RWD has tested 30 cars with a especially designed mobile NOx emission detector. This detector allowed the researchers to measure emissions in real-road conditions instead of the usual laboratory test bench. Here is a basic summary of the test results.
The first test car was the Volkswagen Caddy, a car known to have a defeat device. Sure enough emissions were found at two specific levels, low (205 mg/km) in the official RWD tests and high 800 mg/km when the test was performed outside official RWD test specifications, notably the starting test temperature of between 20 and 30 degrees. If a test was run in reverse, from a high temperature to a low one, the emissions remained at a high level. Clearly some cheating is taking place. Then a number of other cars were subjected to tests inside the official test specs and outside. Half the tested cars are now suspected of having a defeat device. Not only the start temperature is relevant but also the test duration: after 20 minutes (the official test duration) the NOx values shoot up. Offenders are the Chevrolet AVEO, the Opel Mokka and the Opel XC90.
Cleverly the RWD asked the manufactures beforehand to solemnly swear their cars were honest which they all did. Now that they appear to be caught red-handed the RWD has one ultimate penalty if they choose to: they have the power to revoke the authorization.