Alternative powertrain tech for CO2 reduction a focus at ICPC 2017

  • 14-Mar-2017 01:03 EDT
Dr Marko Dekena.jpg

“The amount of CO2 reduction by [connectivity/ADAS] technologies cannot yet be estimated, but certainly it will be higher than technical measures on the powertrain alone will enable,” said AVL’s Dr. Marko Dekena.

Focusing on technologies and strategies impacting truck and bus, agricultural tractors, and construction machinery, the biennial AVL International Commercial Powertrain Conference (ICPC) organized in cooperation with SAE International will be held in Graz, Austria from May 10-11, 2017. Experts from each of these sectors will share their insights related to the 2017 event's overarching theme: CO2 reduction and innovations to improve operating efficiency. Dr.-Ing. Marko Dekena, Executive Vice President, Global Business Development, Sales and International Operations Powertrain Systems, AVL List GmbH, recently spoke with Editor-in-Chief Ryan Gehm about some of the strategic and technical issues to be discussed at this year’s event.

Electrification is a major topic of the event across all three segments. What is the outlook for electrification in each of them?

Let’s first define “electrification” because it is spread over a huge field of technologies: hybridization (mild, full, plug-in), battery electric vehicles (BEVs), and fuel cell electric vehicles (FCEVs). Most likely this is also the introduction sequence for the eventual application of these technologies. The extent to which these technologies will be applied depends on the kind of vehicle, application and the main operating conditions—so, you see, quite complicated.

Secondly we need to be clear how “CO2 emissions” is defined: tank-to-wheel, well-to-wheel or cradle-to-grave. The results are completely different. Personally, I would prefer the holistic view from cradle-to-grave, because it is the only correct way to reduce CO2 emissions. However, it is the most difficult approach due to lack of data in the various areas at present. To make it a little easier, let’s take tank-to-wheel—this is also the way most publications are dealing with this matter.

Light-duty and partially also medium-duty trucks, operating in urban traffic, are suitable both for hybridization and BEV operation, maybe long term also for fuel-cell operation. The CO2 saving potential with city hybrids is in the range of up to 20%. But there seems to be a new trend towards BEVs. And here the amount of CO2 reduction (tank-to-wheel) is much higher, but the reduction when you regard well-to-wheel depends very much on the electric power source—where does the power come from? If you take, for instance, today’s power mix of China there could be no well-to-wheel reduction at all. If all electric power comes from renewable energy sources, the well-to-wheel CO2 reduction will be much higher. Very much the same can be said for city buses.

Heavy-duty long-haul trucks are different. They run typically 150,000 to 200,000 km per year and therefore every %-point of fuel / CO2 savings makes a big difference. Hybridization in combination with downsized diesel engines makes a lot of sense and can achieve 8 to 10% of savings depending on the topography. Waste heat recovery can save another 3 to 5%. I can hardly imagine HD trucks as BEVs. Batteries are still—even in a theoretically very advanced status—by far too heavy and costly. Trucks have to earn money and so every kilogram of dead weight / lost payload reduces efficiency and profitability. If at all, I could imagine longer term a fuel-cell-powered long-haul truck.

Let’s come to agricultural tractors—I mean real farming tractors not derivates such as street sweepers, utility tractors for communities, etc. For the hard and extremely diverse tractor work, electrification can save a lot of CO2 and consumables when applied to the various implements. The diesel drives a generator which supplies power to the PTO and/or to the implements which have now no mechanical connection anymore to the engine but are driven by electric motors. This makes a lot of sense—the whole system is much more efficient and flexible for different applications.

Finally, construction equipment. BEVs may be suitable for very small equipment for shorter operations, very much depending on the operation purpose. Hybridization is the choice for all vehicles operating under heavily changing load cycles and braking. Here the electric motors can assist transient behavior by boosting acceleration and acting as generators during braking, thus feeding back power to the battery, which then can be used for the next acceleration. Simulations we made in AVL, for example, for wheel loaders proved fuel / CO2 savings in the order of 10-15%.

How much is shared technology?

I think quite a lot, both in hardware and control software. However, the huge amount of different vehicles, applications and operation conditions makes it very difficult to find the best solution in every case. To find the “right” combination of diesel engine, transmission, electric devices, storage system and control system is an enormous challenge in all discussed application areas, even if the individual components are known or even the same. Here, full system simulation comes into the game, an area where AVL collected significant experience in the last 10 years. All tools and procedures to simulate even very complex systems in any real operating condition are developed, proven and ready for use.

Likewise for operator efficiency, connectivity and ADAS appear to be major trends that cross the segments. What specific technologies will most influence each segment?

Basically there is a huge potential to increase efficiency of all kinds of commercial vehicles by applying connectivity, Big Data and autonomous driving. Although there seems to be a hype at present in all areas, it will take many years to make use of these technologies on a large scale. Too many issues are still open like standardization, legal issues, national and international rulemaking, safety and technical issues, insurance and liability questions and many more. You may know that for years larger agricultural tractors already operate autonomously or at least partially autonomously, enabling precision farming. The vehicle or several vehicles at once are controlled by GPS not only for precise tracking but also for soil detection and optimized fertilizer output control.

Trucks and buses will be the next category of vehicles to apply this technology rather soon on enclosed areas and later also on highways, in the simplest form of platooning. Also, logistics control will enable a major improvement of vehicle and operator efficiency by avoiding ‘empty drives’ to a high extent. The ongoing intensive activities in the passenger car area will definitely pave the way also for commercial vehicles. But it is clear that every vehicle needs specific adaptations according to their operating conditions. I can hardly imagine driverless vehicles but surely the tasks of the driver or operator will change and result in higher efficiency.

Big advantages I see in the operation of construction machines, especially when it comes to larger construction sites with many different machines and vehicles involved—the so-called site management. By optimizing and linking the various and manifold operations, waiting times and inefficient travels can be avoided. Intelligent condition monitoring and preventive maintenance and service of the vehicles will help to further reduce unplanned downtime to a high extent.

The amount of CO2 reduction by these technologies cannot yet be estimated, but certainly it will be higher than technical measures on the powertrain alone will enable. The challenges mentioned initially have to be solved across all applications, but everyone will have their very specific solution. Thrilling times ahead of us!

Which upcoming emissions regulations are top of mind and pose the greatest challenges to your (and industry’s) engineering efforts?

It’s still the well-known emission of NOx, hydrocarbons, and particulates. We have to envisage even tighter limitations beyond EU6 and Stage V together with changes of the measurement procedures—keyword Real Driving Emissions and In-Use Compliance. The real future challenge is the combination of tough CO2 / fuel consumption limitations in nearly every part of the industrialized world with further drastically reduced NOx limits. Whatever we do to reduce the toxic emissions will basically contradict CO2 and fuel consumption reduction. How to reduce emissions in general is well known in the meantime—the technologies to be applied are available and proven. They need to be refined for the various applications. It’s a tremendous amount of work but the road map is rather clear. This applies for all vehicle segments from passenger cars to construction equipment within different time frames.

However, at the time being the recent new proposals or intentions of the U.S. Environmental Protection Agency (EPA) and the California Air Resources Board (CARB) give us engineers a lot of headaches. Fuel consumption of HD truck engines has to be reduced until 2027 by further 4% compared to model year 2017, according to EPA. CARB wants to cut fuel consumption figures by even 8% within the same time frame combined with a further NOx reduction of 90% compared to MY 2017! In addition, the new EPA proposal calls for a 20% reduction of fuel consumption of the complete truck—this is a quite new and extremely challenging situation. And it is very likely that similar restrictions will be transferred to the non-road sector. AVL is currently successfully working on solutions—how modern powertrain technologies can be combined in a cost-effective way to meet those tough regulations.

Besides electrification, what other alternative powertrain technologies can make a big impact in this regard?

Certainly there is still improvement and refining potential in conventional powertrains including transmissions. This is ongoing and business ‘as usual.’ Fuel cells are back again after the hype in the late ’90s. As I said already I do see a good chance longer term for application in long-haul trucks. When it comes to fuel cells it is mandatory to make the view from cradle to grave. Although the fuel cell itself offers a rather high efficiency, there are significant losses to be taken into account which happen during production and transport of hydrogen—at the end there might not be an efficiency advantage for many applications. Of course, infrastructure issues will be a major hurdle, especially when it comes to ag tractors and/or construction machines. I cannot imagine a hydrogen filling station somewhere on a construction site in the middle of nowhere. And of course the price question has to be answered.

I do see much more potential in alternative fuels, but not those discussed in the past. I see a thrilling potential in synthetic fuels or so-called e-fuels generated from renewable CO2-neutral power, and hydrogen synthesis making use of CO2 from power plants and other CO2-generating factories—or even taken out from ambient air. The basic technologies and processes are known and according to recent publications even the costs could be reduced significantly. I do hope that all involved industries take this pathway seriously into account as it opens a much more effective way by which conventional diesel (and also gasoline) engines could be used further on. It would be a great achievement, because these kind of alternative fuels would also have an immediate effect on the whole existing engine population.

What’s your view of waste heat recovery? Many say it’s not cost-effective and becomes less important as engine efficiency is optimized.

I do not agree at all! Even if engine efficiency is increased there still will be a waste of 20% of the fuel energy, so it is worth to exploit that potential. AVL and others proved a fuel consumption reduction by WHR in the order of 3-5% in real long-haul trucking. These trucks run about 150,000 km/year and consume about 40,000-50,000 L of diesel. Depending on the actual fuel price, savings in the order of 2000-3000 €/year are realistic. This means that the payback period could be less than 2 years. Of course, it depends very much on the application, the topography the vehicle is driving and the fuel price. WHR is still under development and I expect further efficiency improvements to come. WHR makes a lot of sense for applications like long-haul trucks, coaches or marine applications in which no extra energy is needed for cooling fans to get rid of the heat during WHR operation.

Can you speak to “predictive controls” and software’s role in the powertrain and CO2 reduction moving forward?

This is a very important point and partially answered above. The general trend is to transfer more and more functionality from hardware to software in order to be more flexible, to use the same hardware platforms for multiple applications and to optimize the operation of all powertrain elements to increase efficiency, productivity and to reduce emissions. Therefore, the importance of software has gotten higher over the years but also the effort for software creation and calibration increased dramatically.

To implement predictive functions into the control software is the consequential next step. The prediction of the next minutes of vehicle operation enables us to take decisions as shifting to another gear, controlling the vehicle speed in certain limits and in dependence of the topology, delaying the regeneration of a DPF to the next uphill drive, etc., in order to reduce overall fuel consumption. For this purpose, real-time simulation models of complete vehicles or only of subsystems like an SCR system are implemented into the control software to apply the most efficient operating strategy. AVL is leading in real-time simulation and now we use this capability to create advanced control software solutions.

So, you see, predictive controls will be a very cost-effective key element in future vehicles.

Outside of powertrain, what other major trends / technologies are most impacting future on- and off-highway?

For trucks, reduction of air and rolling resistance immediately come to my mind. There is a potential of up to 20% fuel reduction. Weight is an issue and new or other materials will be applied like more aluminum, plastic material, carbon fibers, etc. But also new joining processes and methods for structural parts and sheet metal will enable weight reductions.

Regarding manufacturing, I would like to mention as just one example the more and more applied modularization of components and even whole vehicles. Even the production of so-called ‘world engines’—engines used all over the world in the same design, a dream of engineers for a long time—came true in the last years, as can be seen at Daimler with the new HD and MD engine platform.

What do each of these segments look like 10-15 years from now?

10-15 years is a reasonable horizon. During this time I do not see drastically different solutions than today. In the commercial vehicle business, it is all about (total) efficiency. There will be an evolutionary development by improving the existing solutions, adding hybridization where it makes sense, and starting to go into ADAS. BEVs will show up in the cities and near city operation. The vast majority of commercial vehicles on- and off-road will still be diesel-powered. And I do hope that synthetic, CO2-neutral fuels will gain more attention.

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