DIESEL SCANDAL : Diesel cars on the virtual test bench


Instead of expensive test bench tests and meticulous search, manipulations and switch-off devices can be detected by software.


Long-term investigations: Previous procedures to prove exhaust gas manipulations to manufacturers often took months.
Photo: panthermedia.net/Corepics

Up to now, diesel vehicles had to be put to the test stand in order to test exhaust gas values ​​and identify irregularities. Computer scientists from Bochum as well as in San Diego now developed a software that can analyze 926 engine control programs from Volkswagen and Fiat within two minutes. Of these, 406 contained potential cut-off devices.
The exhaust gas companies are far from over: last week, over 230 police officers and 23 prosecutors searched the offices of Daimler. They were looking for clues as to whether Daimler had tampered with the exhaust gas values ​​of its diesel engines or had merely used the legally permissible margins. The differences between the laboratory and the road values ​​were strikingly large for different models.

The exhaust gas aftertreatment can be switched off in the European Union if the engine could be damaged if the outside temperature is too cold. This is already under ten or seven degrees Celsius. This "thermofilter" is used generously by car manufacturers. The question at Daimler is now whether too generous.
Last week, the US authorities filed a lawsuit against Fiat Chrysler. The group is said to have used a software that switches off the exhaust gas purification, in order to spare the engine - according to its own data. The US environmental agency complains that the Group has not disclosed at least eight software programs for the approval of SUVs of the Jeep Grand Cherokee type and pick-up trucks of the Chrysler brand Ram of the 2014 to 2016 model years.
Fiat Chrysler threatened severe sanctions. In the US, Volkswagen already paid $ 22.6 billion in penalties and compensation for customers. As in the case of VW, Fiat Chrysler's supplier Bosch was also involved in the development of the control software.
Until now, the various vehicle models had to be brought to the test rigs and tested with real-drive emission meters on the road. This lasted for months. There was no way to search the software specifically in the devices for shutdown codes. One and a half years after the acquaintance of exhaust gas fraud by Volkswagen, however, there is now for the first time a possibility to digitally check the code of the shutdown device in these "black boxes".
Scientists at the Bochum Horst-Görtz Institute of the Ruhr University Bochum as well as the University of California in San Diego developed a test software in the course of a year to control the program code of the engine controls.The researchers drew over 926 different versions of the engine control software from Volkswagen and Fiat Chrysler from the last eight years by car manufacturers and tuning companies.
The result of their test: 406 codes contained a shutdown device. With it, the exhaust gas cleaning can be activated on the test stand and switched off again under normal driving conditions. "We were able to find the smoking colt," says Kirill Levchenko of the University of California.This means the active automatism of the test bench detection, which has also been used in many models such as the Jetta, the Golf, the Passat but also in the Audi A and Q series.
A new feature, however, is the evidence for a passive automatism for the Fiat 500 X system. The EU Commission did not initiate proceedings against the Italian government until mid-May 2017, as it did not look at Fiat enough. The researchers showed for the first time that a type of time switch acts as a defect device: after exactly 1600 s or 26 min and 40 s after the engine start, the exhaust gas purification is switched off - a test run takes about 20 min. "Fiat is particularly crude," says Thorsten Holz from the Horst-Görtz Institute.
With its "active" shut-off device, Volkswagen went a little more refined: the test bench identification evaluated, among other things, acceleration phases and steering angles. Systemintern was placed in a function block for "customer-specific acoustic condition" - the "customer" refers to the automobile manufacturer, thus Volkswagen.
The function block should obviously control the motor sound, but also controlled the conditions during an exhaust test. The software took into account ten different test profiles to push down the exhaust gas values ​​in test situations. "The Volkswagen shut-off device is probably the most complex in the history of the automobile," Levchenko notes dryly.
The scientists point out that "we were able to find strong evidence that both Bosch cut-off devices were created and then activated by Volkswagen and Fiat for their respective vehicles." Both manufacturers use the EDC17 diesel engine control unit from Bosch. The researchers combined reverse engineering techniques from binary firmware and technical documentation from manufacturers that are traded in the tuning community to identify the shutdown devices.

Felix Domke from the Chaos Computer Club is also involved in the research group, which has already demonstrated proof of a switch-off device in the Opel Zafira. Jürgen Resch, Managing Director of the German Environment Agency, criticized in the German radio, however, that the German authorities, despite the proof, did not work with their own follow-up measures: "One simply takes care that a former head of government, Roland Koch, as Opel lawyer With the Minister of Transport appears and there is a way to prevent such a clear violation from being implemented. "
The shutdown devices can vary, as shown by the two exampled examples. In the 1990s, General Motors allowed more fuel to be injected into the engine in the Cadillacs when the air-conditioning system ran, aware that emission tests were always carried out with the air-conditioning system switched off. Because General Motors had not informed the Audit Authority about this, a fine of $ 11 million was due and half a million vehicles had to be recalled.
The aim of the scientists is to be able to automatically check the motor control software of any manufacturer.However, an up-to-date software check is becoming increasingly important when approval authorities and other testing facilities have to monitor and check the increasingly complex vehicle systems.
That the publication of the researchers coincides with the raid of the Stuttgart public prosecutor's office at Mercedes, however, is pure coincidence. The allegations against Daimler differ from those against Volkswagen.This is about a deficient after-treatment of the particle emissions. However, the consequences could be similarly serious for Daimler.
Link: VDI News

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