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Committee of Inquiry into Emission Measurements in the Automotive Sector

Additional written questions to AUDI AG

No. Question

1

Audi has agreed, at the request of the KBA, to implement a software update on vehicles in the field in order to address excessive thermal windows as part of a voluntary recall programme. How will the thermal window be extended and by when will the fix be implemented? Audi response: As a result of constant optimisation efforts in the development process and of positive experience in testing, Audi has managed to optimise exhaust gas recirculation even in the lower range of ambient temperatures (below 0° C). This means that the exhaust treatment system can be heated up in a more optimal way. And this, in turn, means that NOx emissions can be reduced even further. A cluster for various different vehicle concepts was put together, together with the KBA, and the applicable time schedule was also agreed here. The fix can only be implemented after the KBA first provides its approval. The first approval for the Porsche Macan V6 TDI EU6 concept was already granted back in September 2016.

2

Audi justifies the modulation of EGR below 17°C on the basis of the exception to the prohibition on defeat devices in Article 5(2)(a) of Regulation (EC) No 715/2007 relating to measures necessary to protect the engine against damage or accident and for the safe operation of the vehicle. Would Audi agree that if the thermal window can be modified by a software update, its initial parameters were not necessary for engine protection? Please answer this question by “yes” or “no” and then justify. Audi response: The version of EGR modulation used up to this point was based on empirical evidence from the field with regard to previous models, an extraordinary number of which experienced incidents of damage due to the accumulation of soot in the EGR cooler when in customer hands. Due to the large number of incidents involving damage, this modulation of EGR quantity was a modification that was absolutely necessary to ensure component protection back at the relevant time. With the benefit of many years of positive experience in the field using more advanced engines, EGR modulation can now be extended to cover lower ambient temperatures.

A 002187 16.02.2017

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3

According to the Commission Notice of 26.1.2017 on the evaluation of Auxiliary Emission Strategies and the presence of Defeat Devices with regard to the application of Regulation (EC) No 715/2007, the justification relating to engine protection is not to be considered available for an AES where a technology or design available on the market that eliminates or reduces that risk is not used to the largest extent technically possible. In answers given to EMIS, several car manufacturers have reported employing EGR modulation at ambient temperatures significantly below 17°C. Taking this into consideration, does Audi consider that it used the available technology or designs for EGR to the largest extent technically possible in order to minimise risks to the engine? Please answer this question by “yes” or “no” and then justify. Audi response: The standard and aspiration that Audi sets for itself is to always use the most modern technology in its vehicles. We are constantly advancing our technology. For this reason, current models do not have a restriction on EGR parameterisation at low temperatures above -10° C.

4

At the time of the legislative procedure, the impact assessment considered LNT technology capable of reducing NOx emissions to a regulatory limit of 150 mg/km and the consistent application of SCR to be able to achieve 75 mg/km. Keeping in mind that the EU law (Regulation (EC) No 715/2007/EC, Article 5(1)) requires manufacturers to equip vehicles so as to enable the vehicle to comply with the emission limit values contained in the Regulation “in normal use”, what was the reason for Audi to increase the share of LNT equipped diesel vehicles between 2012 and 2014 in the EU (from 0% to 49% in the EU as it decreased from 54% to 4% in the US) just as the stricter Euro 6 standard was entering force?

Audi response:

The exhaust after-treatment depends on the model and drive concept. Both the NOx storage catalyst and the SCR system are effective options of exhaust after-treatment. Accordingly, smaller vehicles were equipped with LNT technology and larger vehicles were equipped with SCR systems. Some Audi models also use a combination of both systems.

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5

Can you agree that even when the engine is warmed up there still may be the need to reduce EGR activity for safety reasons?

Audi response: Even when the most up-to-date technology is used, a modulation of the EGR quantity is still necessary at extreme boundary conditions, such as at very high/low temperatures or at great heights, due to the restriction on combustion stability that would be experienced otherwise.

6

Do you think heavy PM generation during certain driving conditions (ie home delivery services, frequent starts and stops) can justify the reduction in EGR efficiency? If yes, how do you think EGR could be modulated only when exhausts contain a certain amount of particles? Is there any particular condition you may think of for which it would be advisable to act on EGR simply after a certain amount of time after it starts?

Audi response: When designing a DPF system, the aim is to have a reliable regeneration mechanism even under extreme driving conditions (home

The parameterisation of the relevant systems ensures that particulate filter regeneration can be performed reliably under all conditions. The regulation of EGR is adjusted depending on engine temperature, amongst other things, in order to ensure combustion stability and to avoid engine misfire.

7

Is it correct that FAP regeneration means high temperature burning of particles trapped in the filter? Can you explain why after FAP regeneration PM cannot be detected anymore? Is it correct that FAP regeneration breaks down particles size by burning larger PMs? Audi response:

1) Experience shows that regeneration takes place at temperatures of approx. 600°C in the particulate filter 2) A full separation of the particulate mass takes place regardless of the loading status of the DPF 3) DPF technology ensures that both the particulate mass and the number of particulates are massively reduced

delivery services, frequent starts and stops), in order to ensure that there is no restriction on the EGR quantity. It is important for the regeneration mechanism that the entire system is operated in an appropriate temperature range in order to ensure that soot is burnt off safely during particulate filter regeneration.

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