emissions testing

“Smoking gun” found in Volkswagen’s vehicle software used to evade regulators

The software mechanism used in Volkswagen (VW) vehicles to artificially lower their emissions output when being tested by regulators has been discovered by a team of international researchers.

The implementation of the software workaround allowed VW to circumvent US and European emission tests over at least six years before the Environmental Protection Agency put the company on notice in 2015 for violating the Clean Air Act.

During a year-long investigation, researchers found code that allowed a car’s onboard computer to determine that the vehicle was undergoing an emissions test.

The computer then activated the car’s emission-curbing systems, reducing the amount of pollutants emitted. Once the computer determined that the test was over, these systems were deactivated.

When the emissions curbing system wasn’t running, cars emitted up to 40 times the amount of nitrogen oxides allowed under EPA regulations.

“We were able to find the smoking gun,” said Kirill Levchenko, a computer scientist at the University of California San Diego. “We found the system and how it was used.”

Computer scientists obtained copies of the code running on Volkswagen onboard computers from the company’s own maintenance website and from forums run by car enthusiasts. The code was running on a wide range of models, including the Jetta, Golf and Passat, as well as Audi’s A and Q series.

“We found evidence of the fraud right there in public view,” Levchenko said.

During emissions standards tests, cars are placed on a chassis equipped with a dynamometer, which measures the power output of the engine.

The vehicle follows a precisely defined speed profile that tries to mimic real driving on an urban route with frequent stops.

The conditions of the test are both standardised and public. This essentially makes it possible for manufacturers to intentionally alter the behaviour of their vehicles during the test cycle.

The code found in Volkswagen vehicles checks for a number of conditions associated with a driving test, such as distance, speed and even the position of the wheel. If the conditions are met, the code directs the onboard computer to activate emissions curbing mechanism when those conditions were met.

The cars’ onboard computers, known as Engine Control Units were checked for vulnerabilities. The team examined 900 versions of the code and found that 400 of those included information to circumvent emissions tests.

A specific piece of code was labelled as the “acoustic condition”—ostensibly, a way to control the sound the engine makes. But in reality, the label became a euphemism for conditions occurring during an emissions test. The code allowed for as many as 10 different profiles for potential tests.

When the computer determined the car was undergoing a test, it activated emissions-curbing systems, which reduced the amount of nitrogen oxide emitted.

“The Volkswagen defeat device is arguably the most complex in automotive history,” Levchenko said.

Researchers found a less sophisticated circumventing ploy for the Fiat 500X. That car’s onboard computer simply allows its emissions-curbing system to run for the first 26 minutes and 40 seconds after the engine starts—roughly the duration of many emissions tests.

Researchers note that for both Volkswagen and Fiat, the vehicles’ Engine Control Unit is manufactured by automotive component giant Robert Bosch. Car manufacturers then enable the code by entering specific parameters.

Figures in January showed that 1.7 million cars were produced in Britain in 2016, representing a 17-year high. 

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