Why we still need a mix of drive technologies in the future, the role the modern diesel engine has to play and why we rely on innovation instead of bans.
With the judgment by the German Federal Administrative Court on 27 February 2018, it seemed the death knell had been sounded for the diesel engine as a drive variant: an allegedly outmoded technology and the main cause of excessive levels of pollution in cities and metro areas. This, at least, must be the impression of many consumers if they gave credence to the headlines and commentary in the media in recent weeks.
First and foremost: As an automotive manufacturer we are not seeking to dodge the issues or make things seem better than they are. We are clear that we bear responsibility for reconciling the demands for individual mobility, climate protection and clean air.
And that is precisely why we fully back the diesel engines of today as a part of the drive mix of tomorrow:
• First, diesel engines enjoy an undisputed advantage in respect to CO2 over comparable gas engines.
• Second, as a result of our experience over the last few years we can improve the NOx emissions of many vehicles on the road -- both effectively and relatively swiftly -- through software updates.
• And, third, the market penetration of vehicles with the new generation of engines, as well as vehicles with Euro 6d-Temp certification, is really picking up speed. These record emissions that are in many cases under - and in some cases significantly under - the laboratory threshold value of 80 mg/km in normal driving operation.
To put it succinctly: To do away with the diesel at this point in time would be a big mistake, for both environmental and economic reasons.
And the most recent German Federal Administration Court's judgment on the possibility of banning driving cars in particularly polluted cities changes nothing in that respect. As a company that, for more than 130 years now, has demonstrated its total commitment to helping people be mobile we reject driving bans, which are a forced restriction on mobility. We are convinced that it is possible to bring the violation of threshold limits under control in cities, too – without driving bans and with the diesel. The objective reasons and technical facts supporting our position are provided below:
1. NOx emissions are continuously decreasing thanks to new engine technologies
The differences between laboratory and road-test measurements of the pollutants emitted from diesel vehicles have, understandably, led to many questions. In the current debate, however, the impression is often given that nitrogen oxide (NOx) pollution in Germany has never been so high. But, in fact, the opposite is true. According to the German Federal Environmental Agency, the pollution caused by traffic has fallen by around 70 percent since 1990. And this despite traffic volumes rising significantly in the same period. This even applies to the city that is currently particularly in the public eye in Germany: Stuttgart, where NOx pollution declined again in 2017.
It's clear that the NOx threshold limits at measuring stations close to traffic are still exceeded often. But it is also a fact that, as early as 2016, in Germany there were no violations of threshold limits at the monitoring stations in urban areas more removed from heavy traffic.
A study, backed by the Federal Environment Ministry, Federal Environmental Agency and the German Association of the Automotive Industry amongst others, demonstrates that just by renewing the base the number of measuring stations close to traffic exceeding the NOx threshold values would reduce by 70 percent by 2020. And five years later the reduction would be over 90 percent.
In the current debate, particulate matter and NOx are mixed up time and again. The fact of the matter is that the problem of particulate matter emissions from engines could be solved with the introduction of diesel particulate filters.
Mercedes-Benz already equipped a diesel car with a filter back in 1985. The lessons learned from this program formed the basis for the development of innovative and effective filter technologies – which have rendered the diesel nearly soot-free. Filters have been standard equipment for Mercedes diesel vehicles since 2005. Of course, there are still older vehicles on the road. Nevertheless, overall particulate matter emissions from engines are low. According to the German Federal Environmental Agency, engines are only responsible for 7 percent of particulate matter emissions on the Neckartor road in Stuttgart. As far as PM10 particulate matter pollution in Germany is concerned, in 2017 the threshold limit was only exceeded at the measuring station close to traffic on the Neckartor road in Stuttgart, with 45 days of violations recorded.
Chances are not bad that the limit can be met this year which would mean that in 2018 the annual limit value for particulate matter pollution would not be exceeded in any German city.
The positive trend especially in NOx emissions levels will further intensify in the next couple of years. Three developments in particular will play a critical role in this: First, vehicles with the latest-generation diesel engines are coming to the market in ever greater numbers. Second, more and more vehicles are being offered that are certified to the latest and therefore most stringent emissions standard to date - namely the Euro 6d-Temp. And, third, the measures adopted at the "diesel summit" on August 2, 2017 are beginning to take effect.
a. The latest generation of engines
Mercedes-Benz has already had the crucial innovations in the further development of diesel technology in series-produced cars for two years now. The four-cylinder diesel engine OM 654 with a combination of exhaust-gas aftertreatment close to the engine, stepped combustion bowls and further developed multiple exhaust gas recirculation was already introduced in the Mercedes-Benz E-Class in April 2016. Since then, Mercedes-Benz has systematically adapted its product portfolio to the new generation of diesel engines. For that purpose, the company has invested approximately three billion euros in research and production.
Following the launch of the new generation of diesel engines in the E-Class (four-cylinder OM 654) and the S-Class (six-cylinder OM 656), the four-cylinder OM 608 is being introduced in May in the new A-Class A 180 d (fuel consumption combined: 4,5-4,1 l/100 km combined CO2 emissions: 118-108 g/km). The new diesel engines from Mercedes-Benz are therefore now available from the compact class to the large, luxury class.
Vehicles fitted with these engines have low NOx emissions also on the road: Indeed, on many trips using the Real Driving Emissions (RDE) measuring process, they record values significantly lower than the current laboratory threshold limit of 80 milligrams. For example, in a test conducted by the magazine Auto Motor und Sport (issue 18/2017) the Mercedes E 220 d (fuel consumption combined: 4.4-3.9 l/100 km; CO2 emissions (combined): 112-102 g/km) recorded 41 milligrams of nitrogen oxide per kilometer. Other organizations like for example Dekra, the German Technical Inspection Authority TÜV, or automotive newspapers have confirmed very good values in road tests as well. We also achieve average emission results of 40 to 60 milligrams in our internal test measurements for continuous operation, covering many thousands of kilometers in both urban and long-distance driving.
Current Mercedes-Benz vehicles equipped with the latest diesel technology can achieve NOx emissions in a very low double-digit and sometimes even single-digit range in some RDE-measurements on the road. For instance, the technical inspection company TÜV Hessen tested a wagon version of the new C-Class with a new 1.6-liter four-cylinder OM 654 engine according to the currently applicable RDE regulations, and measured nitrogen-oxide emissions below 10 milligrams per kilometer in the overall cycle, both with and without cold starts. When a sedan version of the new C-Class with the same engine was tested in accordance with the RDE method, NOx emissions of approximately 10 milligrams per kilometer were measured. However, average emissions over many thousands of kilometers as described above are much more meaningful than individual measurements.
At low levels of engine load, for example while driving slowly, the effectiveness of exhaust-gas aftertreatment can be substantially enhanced due to the close proximity of the system to the engine and further developed exhaust-gas temperature management, thus significantly increasing the system’s effectiveness in the city. Also the temperature range at which exhaust treatment works particularly effectively can be extended significantly with the new engines, without any of the components being damaged. Average NOx values that are well below the laboratory value of 80 mg/km are therefore achieved in normal driving operation at low temperatures, too.
The new engines have yet more potential for future improvement, so we can assume we will be able to reduce NOx emissions further still. Ola Källenius, Member of the Board of Management of Daimler AG, responsible for Group Research and Mercedes-Benz Cars Development: “Our goal is to arrive at average NOx emissions of around 30 milligrams per kilometer in RDE Stage 2 tests by 2020. And we are determined to achieve averages approaching 20 milligrams in the following years. We are targeting these figures in particular for our vehicles on RDE driving tests in cities.”
One of the levers is the continuous improvement of the interaction of the various components in the overall system – which includes the highly complex engine-management system. On the other hand, further developed technology will also be applied in the coming years.
Figure 1: German Technical Inspection Authority and DEKRA PEMS measurements at differing temperatures of the OM 656 and OM 654 diesel engines in Mercedes Benz vehicles. The values are also significantly below the laboratory threshold limit of 80 mg/km and the RDE threshold limit for EU6d-Temp (level 1) of 168 mg/km at low temperatures.
b. EURO 6d-Temp certification
The rapid replacement of the base with vehicles certified to Euro 6d-Temp is a very effective way of further reducing NOx emissions in road traffic. Many models with this certification will be launched over the coming months. We ourselves plan to have converted over 30 currently available models and over 200 variants to the Euro 6d-Temp standard (RDE level 1) by September 2018. And all this a year before it becomes mandatory for all vehicles. Our customers will therefore have an ever-wider range of such vehicles to choose from over the coming months. Examples are the CLS, the new A-Class and C-Class, as well as the G-Class and also new engines following in succession in existing model.
To gain Euro 6d-Temp registration, these vehicles must also initially pass an RDE test. The threshold limit for this is 168 mg/km. Vehicles must, of course, stay under this limit in every imaginable type of RDE trip that complies with the statutory provisions. If the vehicle exceeds the threshold limit just once, certification might not be possible. The vehicles certified to EU 6d-Temp have therefore been developed so that a suitable margin from the 168 mg/km threshold can be maintained. So, for the vast majority of trips in normal driving operation, emissions are significantly lower than 168 mg/km (see Figure 2). On average, most vehicles record values significantly under the 80 mg/km limit in normal driving. This explains why the rapid penetration of the existing base of vehicles by vehicles with the new certificate will significantly improve air quality. And this is also why we have extended the trade-in premium on old diesel cars in Germany and other European markets until the end of June 2018.
Figure 2: Example of the frequency distribution of RDE measurements in two Mercedes-Benz vehicles. To achieve certification, the Euro 6d-Temp RDE threshold limit of 168 mg/km may not be exceeded. In the vast majority of journeys, however, emissions are significantly lower. This explains why rapid penetration of the existing base of vehicles by vehicles with the new certificate will significantly improve air quality.
Meanwhile, engineers at Mercedes-Benz are also using the lessons learned from field testing and the development of the new family of diesel engines to improve emissions on vehicles that are not yet certified to Euro 6d-Temp, too. A bundle of measures has been feeding into series production since the end of 2016.
2. The measures adopted at the "diesel summit" are just starting to take effect
In order to rapidly improve emissions from EU5 and EU6 vehicles in Europe, we had already decided to extend our ongoing servicing measures to over 3 million vehicles even before the "diesel summit" in August 2017.
a. Software updates
This involves the deployment of software updates. Across all vehicles, NOx emissions will reduce on average by 25 to 30 percent in normal driving operation as a result. For example, in a test conducted by "Auto Motor und Sport"on a Mercedes-Benz V-Class, NOx emissions were reduced by more than 80 percent following the software update. This reduction is just one example; it will surely not be possible to achieve the same result on average and in all model series. Nevertheless, with software updates NOx emissions can be rapidly and effectively reduced in many model series.
And our experience with the ongoing service measures indicate that the updates are being taken up in very large numbers by our customers: As an example, since March 2017 we have been able to implement a software update for some 85 percent (as at May 2018) of our diesel entry-level compact class models (Mercedes-Benz A-Class, B-Class, GLA and CLA) in Germany already. For Mercedes-Benz V-Class customers the company has been voluntarily carrying out a service measure as well - some 90 percent of all vehicles in Germany (as at May 2018) have benefited from this as well.
Keeping in mind the complexity of the engine control system not only the development but also this approval process with regards to effectiveness and reliability of the software updates naturally takes some time. For this reason we’re also prioritizing our model series in terms of their volumes and their potential for improving air quality as quickly and effectively as possible. We are confident that we will have finished developing all the main software variants by the end of the year.
Many may be asking themselves why we are able to improve the emissions of vehicles out in the field now and not before; and why so clearly with the aid of software updates alone.
There is an explanation for this: Our developers are continuously working on making the various components and functions work better together. The same is true for the highly complex engine controls. We have made great progress in this area in recent years: Our engineers have used the lessons learned from the development of our new diesel engine family and experience from the field, as well as from ongoing measures still in progress for updates. This has allowed us to take many vehicles closer to their system limits without significantly increasing the risk to the quality of the vehicles.
Our position on hardware retrofit solutions
We are, of course, looking very intensively at hardware solutions. Our assessment, however, has not changed: We consider comprehensive retrofits of vehicles in the field with SCR systems in Germany and Europe as impractical: they would have to be developed individually for each model. A hardware conversion nearly always means a far-reaching intervention into the control system and vehicle architecture. In particular, we must also ensure that converted systems are capable of delivering their full functionality and meeting our quality and safety standards over the long term. An article in the Frankfurter Allgemeine Sunday paper describes these challenges.
The development of hardware solutions with retrofitted SCR-systems that meet the high safety and quality standards of both the OEM and regulatory authorities would, under the current development and certification processes in Europe, take at least 2 to 3 years -- and a lot longer for many models. In our estimation, the resources needed to offer comprehensive hardware solutions in Germany and Europe would be out of proportion to their benefits. As in previous years, NOx levels in cities such as Stuttgart, Mainz, Ludwigshafen and Koblenz continued to fall in 2017. This shows that measures introduced by municipalities and industry, and stock renewal in particular, can improve urban air quality faster and effectively.
b. Local measures
Since the end of last year, the German Association of the Automotive Industry (VDA) has been supporting cities and municipalities throughout Germany with measures to improve air quality. Daimler is taking part in these discussions, as are the other automotive manufacturers. They are particularly aimed at implementing measures to optimize the flow of traffic, to check on the expansion of an e-charging infrastructure and to continue the networking and digitalization of transport.
With local measures Daimler is focusing in particular on Stuttgart. Thus, for example, we are subsidizing our employees to use public transport such as the local tram and train network or buses to get to work. Since January 2018, on days in which a particulate matter alarm is issued, employees of the Group have been able to use the Stuttgart regional transport network to travel between their homes and their place of work simply by showing their work ID. Daimler then pays the costs of these trips. On days with high particulate matter readings Daimler does not conduct any test drives in Stuttgart.
The company continually informs the public in and around Stuttgart about the fact that they can win free VVS (the public transport operator) tickets on days with high particulate matter readings by accessing the moovel app. The probability that moovel customers will, as a result, be able to use buses, trains and trams for free is set at 50 percent. When booking their tickets, a random generator decides whether moovel will pay the cost for the trip. Car2go offers discounted prices on using an all-electric smart fortwo on days with high particulate matter warnings.
A new Group initiative, entitled F.L.O.W., bundles all these measures together and is also developing additional planned or already piloted projects into new mobility concepts for Daimler employees. F.L.O.W. stands for "Fortbewegung, Lebensweise, Ökologie und Wirtschaft" (mobility, lifestyle, ecology and business). It includes, for example, a future ride-sharing offer for Daimler commuters, using the Flinc app. Flinc is a subsidiary of Daimler Mobility Services. In future, Daimler employees will also have the opportunity, using the "Flex Location" app, to reserve a workplace in a Daimler location nearer to their home, to help relieve congestion within the Stuttgart urban area. The aim is to get other companies, cities and municipalities to join the F.L.O.W. initiative in the future.
The company will also be making available around 50 smart electric drives for use in the city center by community/voluntary services.
3. Electric mobility and mobility services are making inroads
We aim to further improve the combustion engine and, in parallel, are championing hybrid technology. However, it is also clear that even better than low emissions are no local emissions at all. That is why we are going full speed ahead with electric mobility, and the technical and commercial opportunities now exist for us to do so:
The energy density of batteries is increasing. At the same time, production costs are decreasing. By 2025 an e-drive system could cost roughly the same as combustion drive. And we want to drive this forward, with e-vehicles that customers don't have to buy, but choose to buy because they are attractive. To this end we will be investing more than ten-billion euros over the next few years in extending and developing our electric fleet.
We will be offering at least one all-electric option in every Mercedes model series. And by 2020 in both Europe and the U.S., we will make smart the first car brand to have moved its entire model range over to electric drive. E-mobility is a big issue for our commercial vehicles, too: Mercedes-Benz Vans is working on the electrification of all its commercial model series. The first of these will be the eVito in 2018; followed by the Sprinter in 2019. The first vehicles from our Mercedes-Benz Citaro fully-electric bus line will be delivered at the end of the year as part of our so-called near-launch road trials.
Innovation was, is and will continue to be what drives us forward. Even if it has been claimed that the German automotive industry wishes to hold on to the status quo rather than drive change - the reality at Daimler is very different: Worldwide, no other automotive manufacturer registered as many patents in 2016 as Daimler: 2,175 in total, of which 761 addressed the topics of the future such as connectivity, automated driving and mobility services like car-sharing and e-mobility (so-called CASE topics). In the passenger car area we have more than doubled our investment in research and development since 2010, while investment into the above-mentioned "future fields" has increased fourfold.
There are many more measures that can be taken to further reduce nitrogen oxide in the short and medium term that make significantly more sense than introducing driving bans: Taking the development of state-of-the-art combustion engines even further, while, at the same time, pushing electric mobility and new forms of mobility; providing software updates for diesel vehicles in the field; improving traffic flow in cities; closer collaboration between municipalities, suppliers and automotive manufacturers; and the electrification of local public transport and local delivery.
As a car and commercial vehicle manufacturer, we are also working to keep people mobile and to deliver them the goods they need on a daily basis.
Note: This article was last updated in May, 2018.