VW Manipulates Emission Control System
Experimental evidence confirms that VW manipulated its emission control system for Diesel engines. The manipulation has been classified by the US officials as a ‘defeat device’. A defeat device conceals the true emissions during an emissions test.
Up to now, car manipulations have only be discussed with respect to attackers like researchers or like the Jeep hacking earlier this summer. The insight produced by US officials revealed that VW has systematically manipulated 500k vehicles in the US and probably 11M vehicles worldwide to illegally pass emissions tests. This is a manipulation at an unprecedented scale.
Why would they do it?
Bluntly, to increase performance. A car would accelerate slower having a more rigorous setting in the emission control system. It would also run hotter and thereby decrease the lifetime of the engine. The car might also be less reliable. The rules in the US are much stricter than those in Europe. Settings that would work in Europe might not conform to American regulations.
How are emission tests working?
Emission tests (smog tests) are mandatory to perform for each vehicle every couple of years. This test is important to identify malfunction exhaust systems and to reduce air pollution. Emission tests are performed in garages. A technician connects a test device to the vehicle’s diagnostics port and a sensor to the exhaust system. The test device then starts a test procedure. The test procedure sets the engine in different operating conditions. For each operating condition, a exhaust values are recorded. Finally, these values are compared to the allowed values. If they violate the norm, the vehicle may not operated on the road.
How did they do it?
The ‘defeat device’ recognized, if the car is under test. For instance, if the steering wheel is not moved and the throttle position does not change, but the engine speed goes up, it is likely that a test procedure has been started. If the vehicle assumes that it is in test mode, it changes the emission control parameters. This effects inserting more exhaust fluid in the catalytic converter during the test. The result are emission values conforming to the regulations.
What follows from the manipulation?
It is crucial that vehicles are continuously monitored and tested. It is not sufficient to only tested before the vehicle is delivered to the customer. The MODESEC project researches methods to effect this monitoring and control of a vehicle to recognize violations of specifications and regulations.