In order to achieve the desired fuel consumption values at the test stand, the engineers made use of a variety of tricks. For example, they increased the tyre pressure to 3.5 bar to reduce friction and mixed additives into the engine oil before the vehicles were tested.
According to the report, the fraud started in 2013 and continued to spring 2015. The overarching motivation for their activities was that the fuel consumption goals set by former VW CEO Martin Winterkorn could not be reached with legal means. Out of fear of reprisals, the engineers did not dare to communicate the actual values. A “culture of fear” reigned at the carmaker, the report says.
In 2012, then VW CEO Martin Winterkorn announced to reduce the fleet CO2 emission by as much as 30 percent. Recently the company was forced to admit publicly that its CO2 emission values were disguised. Worldwide, some 800.000 vehicles are affected. In addition, Volkswagen sees itself amidst a scandal about an in-car software that detected if the vehicle was tested on a test stand and then reduced the NOx emission to the legal limit; under normal driving conditions, the software allowed the car to exceed these limits. The consequences of this incident are far from being foreseeable. Winterkorn stepped back shortly after the issue became public.
As a consequence of these scandals, the German federal minister of transport, Alexander Dobrindt, announced to establish tougher exhaust gas tests that include real driving.