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Future of Automotive Powertrains Trends and Developments in engine and transmission technology

Authors

Martin van Besouw Senior Consultant ATC Stijn Huijbers Consultant ATC


TABLE OF CONTENTS

1. THE REGIONAL AUTOMOTIVE INDUSTRY ___________________________________________________ 3

2. CURRENT SITUATION ___________________________________________________________________ 4

2.1 Introduction _______________________________________________________________________ 4

2.2 Legislation _________________________________________________________________________ 4

2.3 Current Technologies ________________________________________________________________ 6 2.3.1 Gasoline engine technology ________________________________________________________ 6 2.3.2 Diesel engine technology __________________________________________________________ 8 2.3.3 Hybrid and EV technology _________________________________________________________ 9 2.3.4 Transmission technology __________________________________________________________ 9

3. FUTURE PERSPECTIVE ___________________________________________________________________ 9

3.1 Introduction _______________________________________________________________________ 9

3.2 Passenger cars _____________________________________________________________________ 10

3.3 Transmission development __________________________________________________________ 12

3.4 Truck and Bus _____________________________________________________________________ 13

4. IMPACT ON REGION ___________________________________________________________________ 14


1. THE REGIONAL AUTOMOTIVE INDUSTRY The Automotive industry in the EU region Maas Rhine (EMR) is a significant Hot spot within the European Automotive Sector (figure 1). In this region alone over 22.400 people are active within R&D and production. Within this group of engineers and companies a large number is involved in the development and production of engines, transmissions or subsystems in the field of automotive powertrains. Companies like Ford Research Aachen, Bosch Transmission Technology (formerly VDT) and DAF Trucks are key players in their segment of the global market place. In addition a group of companies and institutes are working on innovative powertrain solutions for the future being mechanical or electro mechanical of nature with a strong link to controls (e.g. FEV, DTI, TNO, GIF, Flanders Drive).

Figure 1: EMR Region All this is supported by educational institutes and academic research on both Aachen, the Netherlands, Flanders and Wallonia. The automotive industry changed during the past 10 years in the EMR. The truck industry flourished while the car industry had to cope with deteriorating market conditions. With the disappearance of the by Daimler-Chrysler introduced model, Smart ForFour at NedCar the total volume of cars produced in the Netherlands dropped significantly. In addition the volume of cars produced in the Flanders region (Ford, Volvo, Opel, Audi) also decreased. The truck industry with companies such as Volvo, Scania, Terberg, Ginaf and DAF Trucks experienced a volume growth in production unlike any other period in the past. Direct related subcontractors to these Truck- and Car-companies went through nearly the same tendencies.


Next to the OEMs, the subcontractor companies with a more European or even global approach, could also profit from the economical growth of the European and global automotive industry. In 2008 however all things changed: due to the economic downturn both car and truck manufactures suffered and some annual turnover losses of over 50% are reported. 2011 Seems to become a better year but economies are still fragile. If we focus more on the content of powertrains inside these companies, we see a different scenario: DAF Trucks became center of excellence with regard to engine technology for the entire PACCAR Group leading to the development of engines for the US market by the company in Eindhoven. This could only be achieved with significant investments and increase in resources. In Aachen FEV created growth by becoming one of the leading engineering companies in the world in the field of powertrains expanding their portfolio from only engines to complete powertrains including hybrids, EVs and their control. Research and education has picked up as well: driven by an increase in required technology research programs such as High Tech Automotive Systems (HTAS) new industrial partnerships have been formed and educational institutes created new bachelor and master tracks to cope with the industries demand for highly educated engineers in the field of mechanical, electrical and control engineering. 2. CURRENT SITUATION

2.1 Introduction

The current engine and transmission line up is changing rapidly: hybridization, electrification, downsizing, down speeding are just a couple of technology paths being introduced in the last decade. This leads to parallel development of used technologies. The problem with this multiple engineering tracks is that it is straining resources at the OEMs and suppliers. The economic crisis that struck the world in 2008 and from which we are slowly recovering, did not help the financial situation in the automotive industry either. It is expected that this differentiation will continue for the next decade which is further discussed in chapter 3 future perspective. One primary driver for the increase in development and differentiation in the powertrain area is legislation.

2.2 Legislation

Both in the truck industry and the passenger car industry technical challenges are driven by legislation: legislation in emissions of hydrocarbons (THC), Carbon monoxide (CO), Carbon dioxide (CO2 = linked to fuel consumption) and Nitro oxides (NOx) and Particular Mass (Pm) being either voluntary or enforced are pushing the technology envelop. Graph 1 shows the global emissions levels for diesel engines. Graph 2 shows the answer to these requirements from Mercedes Benz. Like other OEMs Mercedes shows that although the emission levels and fuel consumption targets are tough to reach, OEMs have increased the power density and improved the efficiency of all its passenger cars with increased safety and comfort.


Graph 1: Diesel Emission Standards worldwide Graph 2: Power density versus fuel

consumption improvements overtime With regard to the challenges ahead of us: for diesel engines (both truck and passenger car) it is clear that meeting the emission standards will be a big challenge especially without a negative trade off on fuel consumption. An increase in system cost seems unavoidable. For gasoline engines the biggest challenge lies in the CO2 (=fuel consumption) targets set by the EU. Graph 3 shows the gasoline engines current CO2 emission level compared to its inertia weight class as homologated. It is clear that we are far from the fleet proposal for 2019 and even for premium manufactures of bigger cars the 2012 fleet average can only be achieved with proper technology measures that are underway.

Graph 3: Gasoline powered vehicle CO2 emission vs Inertia weight class


2.3 Current Technologies 2.3.1 Gasoline engine technology As stated before there is a general drive for emission reduction. Technology paths chosen are downsizing (mainly gasoline engines), advanced aftertreatment systems (mainly diesel engines), hybridization and the full electric vehicle. Looking at the technologies with gasoline engines the twin air engine developed and produced by Fiat Powertrain Technologies (FPT) can be highlighted as a state of the art example of modern engine technology and the drive for CO2 reduction on gasoline engines. The 0.9l displacement PFI engine uses downsizing and advanced valvetrain control to reduce pumping losses and at the same time uses turbocharger technology and advanced engine block design to reach power levels above normally aspirated engines of 50% larger displacement and at the same time create a fuel consumption and CO2 reduction of 25% compared to that same NA engine. When selecting the number of cylinders an analysis is made of efficiency versus displacement (Graph 4). It shows that FPT has chosen a 2-cylinder engine as a basis due to the defined small displacement of only 0.9l.

Graph 4: Thermodynamic efficiency vs engine architecture


Other manufactures make similar choices on their slightly bigger engines so the graph seems to be a good indication. FPT also used the MultiAir technology on their engines. These variable valve actuation systems are not new (e.g BMW valvetronic has been in production for many years), but the amount of flexibility this system provides and the modular structure of the system that allows it to be a added on current production engines is unique. Graph 5 provides a short explanation of the system.

Graph 5: FPT MultiAir

The 2-cylinder high boost concept brought up a number of problems that are new to the powertrain developers. Due to the pulsation effect of the 2-cylinder engine normal development benches for the turbocharger could not be used: the compressor map that was defined in the common procedure did not match the real world application results on the dyno. It showed that surge was encountered much sooner than anticipated. Another issue dealt with was NVH: the vibration levels and general noise pattern of a highly boosted small 2-cylinder is very different to a common 4-cylinder engine. FTP was able to counter act on some of the negative aspects by using their multiair technology and especially during idle the vibration of the engine could be reduced significantly. Still the NVH properties of the smaller 2- and 3-cylinder engines are different to the current lineup. During interviews with premium car manufactures they stated that 2- or 3-cylinder engines, although they might be the best solution for CO2 reduction, might not meet the requirements set out by these premium manufactures when it comes down to NVH. The last problem which is mentioned by the majority of gasoline engine developers that work on downsized boosted engines are abnormal combustion phenomena. This combustion behavior that leads to emission peaks and engine damage due to uncontrolled pressure fluctuation, occurs at higher specific load and low engine speeds an area that was never examined in the past. This uncontrolled combustion cannot be detected by current knock systems and ignition retard does not solve this problem in all cases. Ford noted that multiple design chases to the combustion chamber, software calibration and internal cooling had to be made to reach the desired torque levels without the abnormal combustion occurring in the real world. These design changes are incorporated in their new EcoBoost engines.


2.3.2 Diesel engine technology Another area of interest to all engine developers (being diesel or gasoline) is internal friction reduction, basically insight in reduction of friction in part load (passenger car) or all loads (trucks) is increasing and the newer engines are showing a reduction of 40% on wall to piston ring friction by introducing new honing processes allowing the piston ring pre-tension to be reduced by up to 50%. These actions lead to a reduction of fuel consumption and CO2 of roughly 1% in the European driving cycle (NEDC). Losses in the drive of auxiliary systems are tackled by introducing variable waters and oil pumps that allow the precise balance between pump volume/pressure and engine condition to be controlled and thus not waste energy on driving them. This control of the water pump also allows more advanced heat management: during cold start up of the engine the water pump is disconnected altogether and the coolant is only circulating in the block by thermo siphon process this allows the engine to warm up quicker and this leads to a CO2 reduction. In addition the water pump does not need to be driven anymore reducing the auxiliary drive losses in the NEDC since the test starts at 20 C. As mentioned before both gasoline and diesel car engine development is driven by meeting emission legislation while at the same time maintaining or even improving the excellent efficiency of the diesel engine. System cost is a key issue: if you look at the aftertreatment system of a modern diesel engine it is clear that there is almost a chemical factory on board and that comes at a price. On the other hand performance levels of diesel engines have increased signifactly allowing smaller diesel engines to be fitted reducing for instance frictional losses and improving fuel consumption. Next to advances in the combustion system (e.g. increase of injection pressure, improved control of the injection system and improvement to the thermodynamic system) there are 3 methods being used to reduce emissions on diesel engines: EGR (exhaust gas recirculation), SCR (selective catalytic reduction) and DPF (diesel particle Filters) often the systems are used in combination to find the optimum solution. Generally speaking the SCR, DPF system has become mainstream in the truck industry (combined with low EGR rates). Engines that only use EGR (like Navistar in the US) have the disadvantages that they require more cooling area (to cool the high amounts of EGR) and that the internal contamination is causing durability issues. We also see new methods being introduced like low pressure EGR. Here the exhaust gas is fed back into the intake system before the turbo compressor. Advantage is that the amount of EGR can be better controlled with lower pumping losses (often in conventional EGR set ups a throttle valve is required to make sure that the exhaust gas is entering the intake manifold at higher boost pressures that exceed the exhaust gas pressure) in addition mixing of exhaust gas with fresh air is no longer a problem due to the turbo compressor being a mixing device and last but not least the exhaust gas fresh air mixture is cooled by the intercooler allowing smaller EGR cooler to be fitted. Renault has introduced this system on their new 1.6DCI engine but had to make numerous changes to the material spec of the intercooler and ducting to overcome contamination and component failure due to the acids present in the exhaust gas.

Graph 6: RSA 1.6 DCI EGR system lay out


2.3.3 Hybrid and EV technology Toyota stunned the automotive industry with their introduction of the Prius in 1997. With the introduction of new Prius models and the application of the torque split hybrid technology to other models, Toyota became market leader when it comes to hybrid technology. The Toyota system has been explained numerous times so it will not be discussed in this trend analysis. It is however interesting to see that new hybrid systems are under development to enhance performance or to reduce fuel consumption. Many of these systems are developed in such a way that they can be added to existing powertrains (e.g the BMW and PSA 4wd hybrid systems). Both PSA and BMW foresee further development of these systems using both diesel and gasoline engines. The last couple of years we have seen an increase in the development of EVs with the introduction of lithium ion cells for automotive applications the first mass produced models (Nissan LEAF, Mitsubishi i-MiEV) are entering the market in 2011. 2.3.4 Transmission technology In the field of transmission technology a lot of development has taken place all driven by emission reduction and fuel consumption improvements. The first new product to be introduced in the late 90s was the automated manual transmission: a manual transmission automated by the use of clutch and transmission actuators. The cost price of these transmission was lower that ATs and fuel consumption in the NEDC cycle outperformed the MT variants due to optimized shifting points. Lately we see a reduction of this transmission type and this is caused by severe drivability issues on especially the lower cost variants. Another transmission that entered the market and also caused a reduction on the amount of AMT sold was the DSG (or DCT) transmission developed by Volkswagen, this transmission combined the performance of the MT with the drivability of a premium AT. Multiple OEMs have since developed a variant of this transmission and it seems likely that this transmission type is here to stay. If we look at the CVT transmission we see the typical markets where this type of transmission is doing well: Japan. This is CVT market number 1 with a lot of transient traffic and a large volume of smaller cars. Furthermore the NVH behavior of a CVT powertrain seems to fit the Japanese customer better (higher frequencies, no booming noise). If we take a look at ATs we have seen the mass introduction of 6 speed ATs that enable down speeding of the engine and thus reducing emission levels. This is combined with flex lock up to reduce booming noise and further control emissions. In addition we have seen advanced Diesel/AT combinations especially on premium European cars. 3. FUTURE PERSPECTIVE 3.1 Introduction As mentioned before the primary driver for the future are emissions (being CO2 (fuel consumption) or the other components). Graph 7 shows a scenario for CO2 emission reduction levels for mobility as a whole for the long term. A combination of individual transportation and an increase in public transportation is foreseen. With the current growth of the global megacities this seems to be a valid scenario.


Graph 7: CO2 emission reduction

The possible used technology from the powertrain side to achieve this is highlighted in the next chapter. 3.2 Passenger cars If we want to analyze potential future trends it is best to have a look at the roadmaps of some of the OEMs and TR1 suppliers. For example Graph 8 shows the social economic drivers and technology roadmap of Daimler.

Graph 8: Daimler technology path

The current multiple development paths are likely to continue. Hybridization, EVs and also new fuels will make an increasing contribution to meet the targets set.


The gasoline engine will still have a large role to play; due to the increased emission limits for NOx and PM the diesel system costs will further increase. It is also likely that both engine types will come closer to each other with HCCI concepts being under development. If we look at gasoline engines it is likely that further downsizing will take place (already proposed via downsize concept by Mahle /Bosch, FEV and AVL with swept volumes of less than 1 liter for midsized sedans and specific output levels of over 100kW/liter). Increased development will take place in the area of turbo/supercharging with new boosting concepts being under development and the amount of turbocharger manufactures increasing. In addition the further development of direct injection systems is taking place according to some German OEMs and TR1s stratified mode is unlikely to become the main combustion strategy: the gain in pumping losses reduction (especially in downsized engines) is not big enough and does not compensate for the increase in system costs due to the required NOx treatment system and complex control for drivability and system aging. Injection pressure increases new air and spray guided systems will be introduced and better control of swirl and tumble air movement is under constant development. If we look at diesel engines the main challenge lies in reducing NOx and PM and keeping system costs under control. Denso and others are showing that closed loop combustion may be the way forward: a better control of the combustion process itself will lead to a strong reduction of emissions and at the same time help to keep system cost under control. Interesting to see that also in The Netherlands development in this area takes place within the HTAS program. Hybrids and EV technology Both the hybrid and EV track will benefit greatly from a decrease in battery cost and the development of battery systems that can increase the range of the vehicle. Graph 9 provides an overview of expected battery performance as seen by a battery supplier.

Graph 9: Lithium Ion expected battery performance


In addition one of the challenges facing EVs is unreliable prediction of market size, this slows down the development of new systems especially in Germany due to uncertainty of the business case. A German OEM predicted a sales market share of between 5 and 15% of EVs (BEV and PHEV) in 2020, this is a rough indication and with a far bigger uncertainty than ever before. However premium manufactures can use their EVs to reduce fleet average and at the same time keep on selling the profitable premium cars the produce. Therefore most German OEMs are developing some sort of EV. An example is the MegaCity vehicle by BMW and Audis E-tron. It also seems that the major OEMs and TRs are taking development into their own hands: the production of batteries (Daimlers stake in Tesla) and the development of E-powertrains (BMWs new development department) showcases that OEMs are taking EVs seriously and building up competence so it will become a part of their core knowledge. Interesting company in this respect is Renault-Nissan, EVs are part of their strategy and they will produce a full line up of EVs before 2012. The combined knowledge of Nissan, Renault and their supplier base, especially their Japanese supplier base, allows them to move quickly. 3.3 Transmission development Transmission development is focusing on a few main subjects. Graph 10 shows the proposed steps to be taken and the anticipated technology path.

Graph 10: Transmission improvement potential

Further electrification and consequently better control combined with an increase ratio coverage/number of gears are the main topics. CO2 reduction potential from the transmission of up to 9% in the future is mentioned by both transmission suppliers and OEMs. Expected global market share for automatic transmissions is displayed in graph 11. It shows the before mentioned trends translated into market share.


Graph 11: Market share automatic transmission

3.4 Truck and Bus The truck and bus industry is facing similar challenges as the passenger car industry however due to usage the diesel engine is likely to remain the prime mover. Hybridization and electrification is taking place for distribution (in city usage) purposes with both DAF and Mercedes introducing hybrid vehicles. If we look at the diesel engine we can see that the power race has calmed down a bit and according to several OEMs it is unlikely that the requested power output from the market will continue to grow. On the other hand some manufactures are producing premium larger engines that are capable of producing over 500kW. In the 12 liter range the 6-cylinder engine is mainstream and multiple turbo charging to increase power density and to compensate for the full load EGR power losses are under development. A big difference with passenger cars is however that even under full load condition stringent emission levels need to be attained. In addition like passenger cars closed loop combustion processes are under development with the main concern being controllability and durability of the pressure sensors with a field demand of 1 million kilometers this is not easy to achieve. Drive train efficiency in combination with an increase in driver comfort causes an increase of automated gearbox usage in the truck industry. It is anticipated that this rate will increase further along with the further development and introduction of hybrid and EV solutions.


4. IMPACT ON REGION Powertrain development is undergoing changes for the region. This means that we need to cope with a wider spread of themes: further electrification of the powertrain is without a doubt taking place. Furthermore it shows that the region needs to make sure that we bundle our knowledge, make sure we have a feed of well educated young engineers with skills in both the mechanical and electronics field and provide the infrastructure to deal with the challenges in front of us. With increased regional cooperation and a strong backing of the industry the EMR region is and will remain one of the key areas for powertrain development.


REFERENCES

19th Aachener Colloquium 4 to 6 October 2010 Aachen Germany

6th CVT World Congress 17 to 19 November 2010 Maastricht the Netherlands

eCarTec conference 19 to 20 October 2010 Munchen Germany

Workshop Powertrain Control ATC, DAF Trucks 2010

7th International Automotive Congress.NL 2010

Interviews during ATC Innovation Visit, South-Germany and Austria 2009

8th International CTI Symposium 2009

IMAGES

DAF Trucks NV

Daimler AG

Bosch Transmission Technology

Renault S.A

Jatco co

Siemens AG

Fiat Powertrain Technologies

This study has been made possible by the AC EMR 2012 project. This project is a cooperation of: ATC, the Regional Development Agency in the province of North-Brabant, Interreg and foreign partners of the regions: Flanders, Aachen and Wallonia. In this project the aim is to enforce the position, opportunities and attractiveness of the EMR region in the field of automotive industry.

Authors

Martin van Besouw Senior Consultant Stijn Huijbers Consultant

1. THE REGIONAL AUTOMOTIVE INDUSTRY2. CURRENT SITUATIONU2.1 IntroductionU2.2 Legislation2.3 Current Technologies2.3.1 Gasoline engine technology2.3.2 Diesel engine technology2.3.3 Hybrid and EV technology2.3.4 Transmission technology

3. FUTURE PERSPECTIVE3.1 Introduction3.2 Passenger cars3.3 Transmission development3.4 Truck and Bus

4. IMPACT ON REGION

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Future of Automotive Powertrains - acemr.euacemr.eu/uploads/media/Trendstudy_ACEMR_PowerTrains.pdf · Future of Automotive Powertrains . ... of engines, transmissions or subsystems