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Statement of the Adam Opel GmbH on the Current Diesel Discussion

May 20, 2016

Opel News - Statement of the Adam Opel AG

Rüsselsheim. On Wednesday, May 18, 2016, Opel had the opportunity to answer questions of the investigative committee of the Federal Ministry of Transport that were the result of the misleading coverage of last weekend. We want to share the explanations of the technical matters with the public for the sake of transparency.


As a matter of principle, it needs to be made clear that modern engine control systems are highly complex and include more than 17,000 adjustable parameters that need to be taken into consideration. Not only Opel but every automotive manufacturer, without exception, uses various parameters – including amongst others speed, air pressure and engine speed - to regulate the emissions control system.

The Most Important Questions and Answers

Where does Opel stand on the accusations brought forward by DUH, Monitor and Spiegel?


Deutsche Umwelthilfe (DUH), Monitor and Spiegel create the impression that they found new illegal defeat devices. These allegations are wrong!


As we have stated before, we at Opel do not have any illegal software. Our engines are in compliance with the legal requirements.


The accusations are based on misleading oversimplifications and misinterpretations of the complicated interrelationships of a modern emissions control system of a diesel engine.


Has the hacker revealed something sensational?


Certainly not. The information is not surprising for experts. The findings align to the physical conditions of the system that are essential for it to work.


We have discussed the parameters on which the hacker has focused openly with the KBA.


The hacker may have succeeded in obtaining certain control parameters from the emissions control system. However, individual parameters are not sufficient to evaluate the functionality of an extremely complex exhaust gas cleaning system in general.


Emissions control systems are complex, not only at Opel. A modern engine control system contains more than 17,000 adjustable parameters to ensure the functionality of the propulsion system. Every automotive manufacturer, without exception, uses various parameters such as speed, air pressure or engine speed to regulate the emissions control system.


These parameters are known and commonly acknowledged by experts. They have a technical background and are the result of the fact that modern emissions control systems are integrated software and hardware systems, that need to react to the attendant physical conditions and cannot be broken down into individual parameters. None of the parameters as used by Opel is designed to break or avoid legal requirements.


Has Opel got any illegal defeat devices? The DUH diagnosed four such illegal defeat devices in the Zafira 1.6 CDTI.


Every engine control system contains numerous control functions that are vital for the functionality of an emissions control system.


Every automotive manufacturer, without exception, uses various parameters including speed, air pressure or engine speed to regulate the emissions control system. We are absolutely convinced that we do not use any illegal defeat devices in this complex field.


We at Opel do not use any illegal software. Our engines are in compliance with the legal requirements.


The hacker is isolating individual parameters of the engine control system and is coming to misleading conclusions. However, individual parameters are not enough to evaluate the function of a very complex emissions control system in general. A modern engine control system contains more than 17,000 functional parameters to ensure the functionality of the propulsion system. Emissions control systems are extremely complex and highly integrated. This demonstrates the necessity for the 17,000 values used by the software. The hacker only pointed out four, and there is no accompanying understanding of the physical realities the system must deal with in the conclusions around these four values. These challenges are regulated by the constantly evolving and overlapping legal requirements, and the physics encountered by the vehicle.


Background information: The internal-engine measures for the emissions control take place within the combustion process – this has a direct impact on the torque that the engine can make available. The extent of exhaust gas recirculation (EGR) for NOx reduction is limited by the stability of the combustion process based on the amount of oxygen flowing into the engine. Based on this physical reason, consistent amounts of exhaust gas cannot be redirected back into the combustion chamber. Moreover, an adapted amount of exhaust gas is recirculated depending on each operation situation of the engine. This ensures that enough oxygen for the combustion process is present. Furthermore, a higher level of exhaust gas recirculation can lead to excessive soot or particle generation in certain situations. This needs to be avoided as it can lead to malfunctions in the engine or increase other emissions.


The exhaust gas recirculation is constantly adapted: The engine control unit permanently needs to calculate the oxygen set point based on various input values such as:


  • Engine speed and load (how much oxygen for combustion enters the engine)
  • Ambient temperature (which affects combustion and the chemical reactions in the gas cleaning process)
  • Intake manifold temperature (to protect overheating of the intake manifold)
  • Engine coolant temperature (combustion stability)
  • Air pressure (which affects combustion and the chemical reactions in the gas cleaning process)


In summary: Emissions control systems are highly complex and integrated systems. Various parameters such as engine speed, load, temperature and altitude/air pressure play a major role and are linked. Such a complex system cannot be broken down into individual parameters. The interactions must be considered holistically and in combination with the prevailing conditions, the underlying physical conditions and the operation of the engine management system. The findings of a hacker, who derived these in isolation from the software, do not reflect the complex interdependencies of a modern emissions control system.


In detail: What about the system switching off at certain temperatures?


The “temperature range” has been discussed a great deal in recent weeks. It aims to protect the engine and meets legal requirements. Our continuous endeavors to innovate will make it possible for us to implement considerable improvements soon. That is why we announced our large-scale transparency offensive in December already.


What about the systems allegedly switching off at speeds over 145 km/h?

Environment-impairing and poisonous ammonia gas can be released at excessive catalytic converter temperatures. This needs to be prevented. Ammonia, created by the injected AdBlue additive, can no longer be stored in the catalytic converter at temperatures above 400°C, this can lead to ammonia slip from the exhaust pipe. The speed values were chosen as representative for a critical combination of exhaust gas mass flow rate and exhaust gas temperature of around 350°C at 140km/h and 400°C at 145km/h. The increase of exhaust gas temperature is thus exponential to the increase in speed. AdBlue dosage is reduced at temperatures above 400°C as the SCR catalytic converter loses its storage capability at high temperatures. This is also done to avoid ammonia slip and releasing it into the environment. The fact that NOx catalytic converters follow these laws of physics is very common in the industry.

And what about the system switching off at a certain air pressure?

Internal combustion requires an adequate air/fuel balance to ensure stable operation at altitude and to avoid excessive sooting which is regulated in addition to NOx. Even at higher altitudes, the engine needs to be supplied with sufficient oxygen to prevent extensive sooting. This effort to protect the engine renders it an appropriate mechanism within the system. Our voluntary improvement measure that we announced last year and will implement as of the summer, will improve the system performance up to an ambient pressure of 840 mbar. We are thus even exceeding future strict RDE requirements.


And what about switching off exhaust gas recirculation at engine speeds above 2,400 rpm?


Once again the criticism is based on a misinterpretation. In the control system, we have low-speed and high-speed values and we switch between them at 2,400 rpm. We assume the hacker misinterpreted the switch as the end of operation. The EGR system does not switch off at 2,400 rpm but instead continues to higher engine speeds.


The functionality of the exhaust gas recirculation physically depends on the operating states of the EGR system components, the turbo charger with variable turbine geometry, the temperature in the inlet manifold and the heat dissipation of the vehicle cooling system. Furthermore, the use of EGR under certain circumstances in the combustion chamber can lead to unwanted emissions effects or an instability of the combustion.


In this case, the rotation speed is an important indicator and therefore it is obvious that it plays an important part in exhaust gas recirculation.


Is it true that Opel lied to the KBA by claiming that the emissions control systems “works fully at temperatures between 20 and 30 degrees”?


No. We informed the KBA and the investigative commissions extensively and truthfully at our first meeting, and we did so again at the second. The discussion was about the parameter outside the 20 to 30 degree C window. The statement “fully” was related to the NEDC test schedule which is the regulated cycle. We already provided the KBA with documentation last October. We also pointed out other parameters such as air pressure in the written statement we provided during the hearing. By the way, we already suggested at the end of last year that all manufacturers in Europe should disclose their calibration philosophy to the authorities and we are working to do so as part of all our future type approvals.


Is it true that Opel permanently and illegally switches off the emissions control system in many situations?


The allegation is simply wrong.


Many factors influence the balance between the functionality of a modern diesel engine and the level of emissions. According to the governing regulations, therefore, the efficiency of the emissions control can be reduced partially to protect the engine and for physical reasons. At times, this also applies to Opel. Every automotive manufacturer uses various parameters such as vehicle speed, air pressure or engine speed to regulate the emissions control system.


What should people think about an emissions control systems that, according to the DUH, does not work 80 percent of the time? According to the Spiegel the Astra is programmed in such a way that its exhaust emissions are only cleaned as of outside temperatures of 17 degrees.


DUH’s claim that the system does not work 80 percent of the time is grossly misleading.  The claim that the emissions control systems of our cars switch off at 17 degrees is false. Exhaust gas recirculation remains active at temperatures below 17 degrees – however, for physical reasons related to engine protection as permitted by the regulations, with differing rates.


Incidentally, the efficiency of the EGR and the SCR system at temperatures of minus 7°C are amongst others proven within the scope of the Euro 6 type approval.


How do you evaluate the measurements conducted by the DUH?


We cannot evaluate them because the measurement protocols are still being withheld. We believe this is intentional. Previous measurements conducted by the DUH on Opel vehicles had no scientific objectivity. The latest measurements conducted by the DUH from May 18 also show that this private organization is either not able to or not willing to conduct tests that conform to the regulations and lead to comparable results.


How do you explain the persistence of the DUH. The examination conducting by the DUH in cooperation with Monitor and Spiegel seems to have been at least five months in the making. What is your position on the cease-and-desist declaration based on apparent false statements?


In our opinion, the DUH is a private organization with commercial interests.


Appreciating that the current debate has fundamentally altered the consumer’s trust in the automotive industry, and given this changed landscape, we have agreed to withdraw two of the ten phrases that DUH identified, not because they are necessarily deceiving but rather to make sure that the public does not misinterpret them given recent events. As to the remaining phrases at issue, Opel disagrees with the DUH’s cease and desist claim.


Why did Opel have to appear in front of the investigative committee of the German Ministry of Transport?


The misleading coverage raised some questions and we are happy that we could immediately answers these questions. We have again indicated to the KBA and the commission that we will always cooperate transparently and fully with them and with other authorities in Europe. We have been in touch with the KBA for months regarding our engine control logic and are coordinating the further development of our engine control with them. We look forward to continued cooperation with the KBA and the Ministry of Transport.


Why are you still backing the diesel?


The diesel has many strengths, the main one being that it emits considerably less carbon dioxide and plays an important role in meeting future CO2 goals. Furthermore, customers benefit from much lower fuel consumption compared to a car with a gasoline engine. We really hope there will an objective discussion on the future of the diesel engine.

Opel’s share of diesel vehicles is around 37 percent of overall sales (based on the first quarter of 2016).


That means that Opel will carry on as before?


Progress is part of Opel’s DNA and is a constant process. Modern cars are also more efficient, safer and more environmentally friendly than previous generations. We have learned further things in the last weeks and months. That is why, as we already announced in December 2015, we once again lead the way with a big step towards future legislation:

- We will improve our SCR diesels wherever we can, and as far as the laws of physics allow. In this context, we will alter parameters that have been mentioned in the media. They are based on new software functionalities, which we will introduce in moving toward RDE. This includes a voluntary service action for cars that are already on the road, starting in June.

- We will use SCR technology as the main emissions control system for our Euro 6 diesels, i.e. all our future diesels will have SCR as of June 2018.

- We will open all our engine management functionalities including algorithms and calibrations to the KBA. Based on the software we already opened to the KBA in October 2015, we have already been working on this for months.

- For the sake of complete transparency for our customers we will in future publish the WLTP fuel consumption and CO2 figures of our cars, in addition to the official NEDC values.

And that’s not all. We are not only optimizing our internal combustion engines.

Next year we are going to bring a pioneering electric car onto the market, the Ampera-e. In addition, we are working on new concepts for mobility in the metropoles of the future. In this context, CarUnity is just the beginning.