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Über dieses Buch

In diesem Tagungsband werden von anerkannten Experten der Automobil- und Nutzfahrzeugbranche eine Fülle neuer technischer Lösungen aufgezeigt.

Die Tagung ist eine unverzichtbare Plattform für den Wissens- und Gedankenaustausch von Forschern und Entwicklern aller Unternehmen und Institutionen.

Der Inhalt

Nachhaltige Mobilität: vollständige LCA.- Gesamtsystem Verbrennungsmotoren und Kraftstoffe: CO2-Reduzierung, Emissionierung, Elektrifizierung.- Klimagerechte Verbrennungsmotoren.- Effizienzsteigerung in Produkten und Prozessen.- Nutzung von Wasserstoff und synthetischen Kraftstoffen.

Die Zielgruppen

Fahrzeug- und Motoreningenieure sowie Studierende, die aktuelles Fachwissen im Zusammenhang mit Fragestellungen ihres Arbeitsfeldes suchen - Professoren und Dozenten an Universitäten und Hochschulen mit Schwerpunkt Kraftfahrzeug- und Motorentechnik - Gutachter, Forscher und Entwicklungsingenieure in der Automobil- und Zulieferindustrie

Die Veranstalter

ATZlive steht für Spitzenqualität, hohes Niveau in Sachen Fachinformation und ist Bestandteil von Springer Nature. Hier wird unter einem Dach das Know-how der renommiertesten Wirtschafts-, Wissenschafts- und Technikverlage Deutschlands vereint. VDI Wissensforum vermittelt als ein führender Weiterbildungsspezialist das Wissen aus praktisch allen Technikdisziplinen und den wichtigsten außerfachlichen Gebieten. Dabei wird großer Wert auf Nachhaltigkeit und Praxisrelevanz gelegt.

Inhaltsverzeichnis

Frontmatter

Why Renewable Fuels should be Considered in the CO2 Standards of New Cars, Vans and Trucks

Within the European Union’s Green Deal, the climate protection strategy for the transport sector is under review in 2021.This paper assesses that the current regulatory scheme of fleet target values is not suitable to reach the new climate goals – regardless of its ambition level. In order to reach the EU Green Deals’ goals, new regulatory options are inevitable. We focus on one of those possible new options, a crediting system for renewable fuels and describe it´s general mode of operation, it´s advantages and possible challenges. Building on previous research, we establish that the cost of CO2 mitigation can be significantly lowered if renewable fuels were allowed to play an additional role in the regulation and that the overall climate protection contribution of the transport sector could be improved. We also touch on secondary effects like cost–benefit for other sectors or the societal advantage that individual mobility would not have to be curbed unnecessarily in the name of climate protection. We end with a recommendation of which political actions would have to be taken in order to stimulate the market to invest in the innovative technology of renewable fuels.

Tobias Block, Manfred Moldaschl, Marc Sens

The Remaining CO2 Budget

In 2018, the IPCC (Intergovernmental Panel on Climate Change) published its report “Global Warming of 1.5 °C.” This special report informed about the impacts of global warming and greenhouse gas emission pathways in the context of strengthening the global response to the threat of climate change and sustainable development.

Thomas Koch, Christian Böhmeke

Customer first! – The key to achieve customers’ acceptance for connected powertrains

The content of this paper describes a user centered development process to evaluate the engine start and stop procedure of electrified powertrains.

Sebastian Barth, Michael Fischer, Pascal Schlatter

Die Verbrennungskraftmaschine im Hybridantrieb – hocheffizient und kostenoptimiert aus modularen Baureihen

Increasing complexity of electrified powertrain architectures and integration as well as their relevant attributes require an overall system approach combining component technology with integration and industrialization requirements when heading for efficiency optimization of the subsystem internal combustion engine.

Wolfgang Schöffmann, M. Howlett, P. Kapus, G. Teuschl, R. Ellinger, C. Sams, I. Barna, K. Weihrauch

Life cycle assessment of an internal combustion engine vehicle using renewable electricity for fuel and vehicle production

The transportation sector is still struggling with very high greenhouse gas (GHG) emissions. One option to significantly reduce the GHG emissions is the utilization of renewable fuels. In this paper, we analyze the GHG emissions, the fossil cumulative energy demand and the electricity demand of an internal combustion engine vehicle (ICEV) using renewable fuels over the entire life cycle (vehicle production, utilization and disposal). We apply renewable electricity in the entire supply chain. This also includes the production of materials from hydrogen produced in an electrolysis. The hydrogen is for example used as reducing agent in steel production as well as converted with CO2 to chemicals and fuels. For this purpose, we conduct an LCA based on the database ecoinvent 3.7 and integrate renewable production processes. Our analysis over the entire life cycle shows that an ICEV can achieve almost zero GHG emissions and almost zero fossil resource consumption. However, the use of renewable electricity for almost all processes will significantly increase the electricity demand. The major share of renewable electricity is required for fuel production that is needed in the utilization phase of the ICEV.

André Sternberg, Christoph Hank, Achim Schaadt

Direct-Injection Hydrogen Combustion Engines - New Requirements for Hardware Development and Simulation Methodology

CO2 emissions from light commercial vehicles and passenger cars have already been regulated by the EU since 2009, yet it was not until 2020 that the limit was tightened from the original 130 g CO2/km to 95 g CO2/km [21]. However, in the heavy-duty sector, especially for trucks and buses, such strict, EU-wide regulation was completely absent until 2019. Nevertheless, in order to achieve the defined climate targets of the EU, it is essential to regulate emissions also or especially in this sector, since heavy-duty vehicles are responsible for about 6% of the total emissions in the EU and for about 25% of the CO2 emissions of road transport in the EU. By 2030, CO2 emissions could even increase by another 40% compared to 2010 [23].

Thomas Ebert, Gidion Maniezki, Gidion Maniezki

Potentials and challenges of hydrogen combustion system development as a sustainable fuel for commercial vehicles

One challenge for commercial vehicle development is reduction of the CO2 greenhouse gas, as a part of the transportation sector is. A trend of strong CO2 reduction is visible for EU, USA which cannot be fulfilled by only vehicle and engine optimization. Hydrogen fuel, which can be produced from biomass or renewable power like solar and wind is regarded as one of the key energy solutions for CO2 reduction in the future transportation.Hydrogen can be used in fuel cells or directly in internal combustion engines. The focus of this paper is the usage of hydrogen for heavy duty commercial vehicle combustion engine. Starting with an emission regulation roadmap and scenarios for future heavy duty engines until 2031, the requirements on combustion system and NOx reduction are defined.The major advantages regarded to hydrogen combustion are due to the wide range of flammability and very high flame speed numbers compared to fossil based fuels. Thus, it can be well used for lean burn combustion with much better fuel efficiency and very low NOx emissions. Potential of lean-burn hydrogen combustion for NOx reduction will be shown using heavy duty 2 L single-cylinder testing at multiple engine speeds and loads.Using numerical simulation, well validated by single cylinder engine measurements the potentials and challenges, as well as requirements on combustion and emissions for HD engines are discussed.The challenges regarding pre-ignition and glow-ignition due to the very low auto ignition delay time of hydrogen at high mixture temperatures and the low ignition energy demand of hydrogen will be discussed and future technologies like direct injection and diffusive combustion are addressed.The effects of a lean hydrogen combustion, i.e. lower exhaust gas temperature and their impact on exhaust gas after-treatment system to fulfill future regulations are discussed. Furthermore, measurements of exhaust gas particulate matter emissions with variation of air-fuel ratio are shown and discussed.Finally, recommendations on hydrogen combustion system for heavy duty commercial vehicle applications are given as an outlook.

Reza Rezaei, Marc Sens, Michael Riess, Christoph Bertram

Combustion system development for hydrogen fueled heavy duty internal combustion engines

Increasingly stringent CO2 emission regulations demand a reorientation of powertrain concepts in the transport sector. CO2 emissions from new vehicles put on the road must be reduced by 15 % by 2025 and by 30 % by 2030 compared to 2019 baseline. Besides increasing the efficiency of existing diesel engines, possible alternatives include the use of low-carbon (e.g. methane) or even zero-carbon fuels (e.g. hydrogen) and the partial or complete electrification of the powertrain. Hydrogen offers the possibility to be used either as a fuel for internal combustion engines or for fuel cells. Fuel cells in combination with a battery electric drive offer the greatest benefit for applications with highly transient driving cycles, e.g. city buses or urban transport of goods. If high constant power and less transient vehicle operation is required, an internal combustion engine fueled with hydrogen represents a cost-effective approach to realize zero CO2 emission long haul transport. To convert a conventional diesel heavy duty engine to hydrogen operation, key components such as thecombustion system, the turbocharging system, the injection and ignition systems, and the exhaust gas aftertreatment system must be redesigned. New software structures for powertrain control are also required. To this end, this paper considers the design of the combustion system regarding piston shape(compression ratio), intake valve timing, charge motion intensity and engine raw emissions. For this purpose, a detailed kinetic reaction based combustion simulation is used to determine the most beneficial layout to achieve high specific power in combination with best engine efficiency and lowest nitrogen oxide raw emissions.

Lukas Virnich, Bernd Lindemann, Martin Müther, Avnish Dhongde, Markus Schönen, José Geiger, Andreas Kremer

LCA – additional requirement for engineers

Academia, general public and policymakers insist on a more sustainable economy. This also affects corporate govervance, which results in additional requirements for engineers, but also creates the need for suitable development tools. In order to holistically improve products, classical development processes have to be complemented by sustainability assessment. In this context, life cycle assessment (LCA) has played an increasingly important role in the past few years, sometimes amended by economic and social consideratons. This work provides insight into several approaches for sustainable development, both from the automotive industry as well as university research. The importance of modular, data-driven software tools is emphasized. In this context, a methodology is presented, which combines vehicle and powertrain simulation with an existing LCA tool-chain. This approach allows to assess new technology cornerstones based on production, usage and disposal. Using the example of lightweight design, the tradeoff between possibly increased manufacturing impact and reduced fuel consumption is shown. Hereby, the sensitivity individual user profiles (i. e. mileage, required driving performance, etc.) is highlighted. To this end, a vehicle simulation, including a map-based 2.0 l diesel engine, is conducted in different driving scenarios. The resulting fuel consumption serves as an input for the LCA calculations, which in turn yield greenhouse gas emissions. Possible effects are exemplified by replacing a steel component of 20 kg with a 5 kg lighter, more energy-intensive magnesium part. To compensate the additional production GHG emissions during the use phase, the simulated vehicle needs to be operated around 124000 / 217000 km in an RDE / WLTC driving scenario. This significant difference underlines the importance of adequate use case modelling.

Olaf Toedter, Philipp Weber, Thomas Koch

Energy carriers for transport: Produced overseas and transported to Germany

The low electricity utilisation efficiency of synthetic fuels (so-called e-fuels) in combustion engines can be partially absorbed economically by producing electricity in parts of the world with particularly favourable meteorological conditions, converting it into liquid e-fuels and supplying those e-fuels to car tanks at low cost using existing transportation infrastructure that is already largely in place.Three different scenarios will be examined in this paper: wind power is used to produce hydrogen, methanol, gasoline and diesel in Chile. Those e-fuels are then brought to Germany. The first scenario considers hydrogen supplied to fuel cell vehicles at newly built filling stations. In the second scenario, gasoline, diesel and methanol are supplied to cars with internal combustion engines at existing filling stations. In the third scenario, electric vehicles are powered by wind or PV power from Germany. These three scenarios will be compared to each other in terms of their respective costs. As evaluation basis, the specific energy costs up to the tank and the energy costs per kilometre driven will be used.Cost calculations based on process simulations show that the specific energy costs of e-fuels from Chile are lower than the specific energy costs of German wind and PV power when the transportation and distribution costs of the electricity are taken into account. However, the costs per kilometre driven are still higher for the e-fuels due to their lower efficiency compared to pure battery vehicles when used in fuel cells or internal combustion engines. That conclusion could alter, though, if the costs, as of yet unknown, of building an electricity grid that only supplies electricity from renewable energy sources were taken into account.

Otto Machhammer

Variable Valve Train systems as contribution to overcome the NOx/CO2 Trade-Off in meeting future emissions legislation - a comparative approach for Diesel PC and CV applications

Schaeffler offers electromechanical, discretely switchable valve lift systems for passenger car applications, e.g. the eRocker system and is inventing a commercial vehicle application solution: the Schaeffler electromechanical switchable rocker arm system. This modular valve train system can be integrated easily in existing engine setups regardless of the camshaft position and number. Both systems support exhaust aftertreatment heat-up and efficient exhaust gas thermal management at extended low load operation. To meet future emission legislations, Schaeffler and IAV investigated various thermodynamic strategies via simulation and experiments on a passenger car, and simulations on a heavy duty diesel engine. Innovative valve lift strategies like early intake valve closure in combination with secondary exhaust valve opening are compared to existing conventional strategies like intake air throttling and combustion late phasing. The results for both passenger car and heavy duty diesel engines show significant potential to increase the exhaust temperature with optimized fuel consumption. This publication summarizes and compares the contribution of innovative valve lift strategies for efficient exhaust gas thermal management for passenger car and commercial vehicle applications.

Michael Elicker, Harald Elendt, Michael Knorr, Andreas Möller, Dimitri Schott, René Pohlke, Maximilian Brauer, Lukas Moslener, David Kovacs

Holistic Hybrid RDE Calibration Methodology for EU7

To calibrate and validate lowest emissions to meet EU6d-FINAL limits, OEMs have set up their own procedures and test matrices. The consequence is often a resource, time and cost intensive process leading to a longer project run time. With the ongoing discussion about EU7 and stricter emission limits, additional restricted emission species, longer catalyst endurance and shorter city drives combined with new hardware solutions like the e-catalysts and subsequently an ever-rising complexity for hybrids, the OEMs will face a severe tightening of the existing efforts.This paper presents a holistic Hybrid RDE calibration methodology to achieve EU7 tackling the upcoming time and cost challenges. An innovative way to create statistical relevant real driving emission cycles from a big data cloud in combination with a Hardware-in-the-Loop (HiL) test bench in an early project phase to reduce effort and increase emission security at the same time is shown. This is combined with a purpose designed and vehicle endurance run derived catalyst aging duration presenting a completely new approach and exceeding the aging severance of existing catalyst aging procedure by far including a pre ashing method on a burner rig.

Michael Görgen, Martin Nijs, Matthias Thewes, Andreas Balazs, Surya Kiran Yadla, Johannes Scharf, Tolga Uhlmann, Johannes Claßen, Frank Dorscheidt, Sascha Krysmon, Stefan Sterlepper, Marc Düzgün

Application of a systematic development methodology for post-EU6 engine calibration under RDE compliance

The recent European exhaust gas emission legislation has extended its homologation processes with real driving scenario tests on public roads utilizing Portable Emission Measurement Systems (PEMS). This shift from a synthetic test environment on a chassis dyno test bench towards the road as a complex, yet unpredictable, testing ground bears many challenges and significantly enlarges the calibration effort for vehicle manufactures. Methodical adaptations to existing development procedures are inevitable to allow early compliance with Real Driving Emission (RDE) legislation and to prevent over-engineering.In this paper, ISUZU Motors Germany and the Institute for Internal Combustion Engines and Powertrain Systems (VKM) of TU Darmstadt, present results from the process-application of a methodical development approach for post-EU6 engine calibration feasibility and robust RDE compliance.In view of increasing system complexity and high time and cost constrains, it is necessary to ensure functionalities and emission conformity at an early stage of the development cycle. This applies in particular to the emission behaviour of vehicle powertrains under RDE boundary conditions. For early identification and optimization of critical real-driving operating ranges, powertrain-specific Most-Relevant-Tests are developed and generated to be used for validation and calibration purposes at RDE-enabled test bench environments for engine-, powertrain- and vehicle applications. Individual Most-Relevant-Tests are applied in a development and calibration feasibility study and allow a process-evaluation regarding future post-EU6 legislation targets. The OEM calibration process is supplemented with a validation and confidence monitoring process enabling an assessment of the testing regarding RDE compliance. By this an objective definition of RDE development targets to reach conformity, especially with future emission limits, is achievable and RDE testing efficiency could be enhanced.

Henning Nies, Christian Beidl, Holger Hüners, Deniz Serifsoy

Jet Ignition as an Enabling Technology for Stable, Highly Dilute Hydrogen Combustion in Off-Road and Heavy Duty Engines

With a trend towards a zero-carbon dioxide (CO2) tailpipe future, driven by legislation and societal factors, engine manufacturers globally are investigating the use of alternative fuels that can minimize or eliminate tailpipe CO2. Hydrogen (H2) has re-emerged as a viable alternative fuel for combustion engines, aided by its relative flexibility to operating condition resulting from a wide flammability range, and the diversity of H2 production sources. An increasing share of H2 production is accomplished through the use of renewable energy, providing improved well-to-tank / cradle to grave and total life-cycle CO2 budgets. H2 as a combustion fuel is exceptionally prone to abnormal combustion, e.g.pre-ignition. The relatively fast laminar burning velocity and wide flammability range enables the use of high levels of dilution, which can partially mitigate the pre-ignition issue as combustion temperatures decrease with increasing levels of dilution. However, the long flame travel distance and asymmetrical flame propagation present in large bore spark ignited engines can limit the effectiveness of this mitigation strategy.Auxiliary-fueled pre-chamber (APC) jet ignition in gaseous-fueled and gasoline engines has proven successful in extending the dilution limit and reducing the likelihood of abnormal combustion. The APC combustor distributes ignition energy throughout the main combustion chamber through high velocity jets containing radical species. These distributed ignition events promote rapid, symmetrical burning of pre-mixed fuel and air. Liebherr and MAHLE are working together on APC jet ignition with H2-fueled engines. The current study details the application of APC to a spark ignited H2-fueled variant of a Liebherr off-road engine. Results are presented that detail APC-enabled stable combustion at dilution ratios significantly extended beyond the limits of the base engine. This dilution limit extension offers the potential for increasing compression ratio. APC jet ignition therefore represents a viable pathway for highly efficient H2 combustion, while achieving a higher power density compared to conventional spark ignited combustion.

Michael Bunce, Nathan Peters, Ulrich Weiss, Bouzid Seba

Cylinder Deactivation as an Effective Means for Exhaust Thermal Management and CO2 Reduction - Test Results on a U.S. 13L HDDE

Cylinder Deactivation (CDA) was evaluated on a 2018 Navistar A26 engine. This is a 13L in-line 6-cylinder engine that was tested with an aftertreatment system comprised of a diesel particulate filter (DPF), urea doser, selective catalyst filter (SCR), and an ammonia catalyst. Several CDA calibrations were evaluated and compared to the baseline engine without CDA. Both Cold and Hot Federal Test Procedure (FTP) were first examined, and then several other test cycles common to the U.S. were measured. Lastly, the new Low Load Cycle test developed for the California Air Resource Board (CARB) and was subsequently adopted in August 2020 as part of its HD Omnibus Low NOx rules, which was tested along with several of its individual constituents. The results of the test show Brake Specific Fuel Consumption (BSFC) and after-treatment temperature improvements in all test cycles while also providing significant NOx reductions, especially in the lowest load and cycle work segments.

Robb Janak, Andrew Matheus, Jasmeet Singh, James Sanchez, James Cigler, DeWitt Evans, Christian Hushion, Justin Baltrucki, Arvind Thiruvengadam

A New Class of AI-based Engine Models

An interesting field of application for neural networks is the mapping of system components in 100 to 1000-fold real-time while maintaining high quality. However, due to the limited extrapolation capability of neural networks, data for all possible operating states must be available during the training phase. Since the necessary amount of data cannot be generated by test bench experiments, fast, predictable and easily parallelizable simulation models must be used for this purpose. For example, the work process calculation in combination with phenomenological models can sufficiently represent the fundamental processes in the combustion chamber.This paper describes how a data set with almost 9.3 million different operating points of a gasoline engine is in the beginning generated using software tools available at the FKFS. Special characteristics of certain motor parameters regarding the network training are shown, as well as the reduction of the data set before the training to increase the network quality. In the following, the layout and training of a neural network is described, which predicts some combustion characteristics(mfb-10 %, mfb-25 %, mfb-50 %, mfb-75 % and mfb-90 % points), pressure characteristics (IMAP, peak pressure and its position as well as the pressure at exhaust opening) and NO emissions according to the data set.This is followed by a presentation of the statistical accuracy of the network and a detailed view of an exemplary map area. Finally, the integration of the network in GT-Suite and the coupling with FKFS RapidCylinder is shown and an exemplary load jump is considered. The paper thus represents a first proof-of-concept of how neural networks can be used in powertrain development.

Valerian Cimniak, Dominik Rether, Sebastian Bodza, Michael Grill, Michael Bargende

"Green" hydrogen for ground-based heavy-duty longdistance transportation – A techno-economic analysis of various supply chains

The overarching goal of this paper is an assessment of different supply chains of “green” hydrogen provided for heavy-duty vehicle hydrogen filling stations. Therefore, for different supply chains the estimated energy efficiency and the hydrogen supply cost are compared from well (hydrogen production) to tank (filling station's nozzle) in Germany for the base year 2030. Compressed gaseous hydrogen, liquefied hydrogen, and a liquefied organic hydrogen carrier, namely dibenzyltoluene (DBT), are considered as long distance transport and filling options. Additionally, a local hydrogen production directly at the filling station is assumed beside centralized hydrogen production scenarios for locations in Northern Germany and Algeria. The hydrogen production is based on a PEMelectrolyzer with a location-specific economic optimized photovoltaic and wind power electricity generation. Storage options are gaseous hydrogen pressure tanks and caverns, cryo tanks for liquefied hydrogen, and conventional mineral oil tanks for dibenzyltoluene. Transportation takes place by truck, pipeline, and/or ship. The centralized production in Northern Germany is for each considered supply chain the lowest-cost hydrogen supply option as long as space constraints do not limit onshore wind power installation. Assuming only offshore wind power as a wind energy supply option for Germany, hydrogen production and import from Algeria is more favorable in terms of cost. In general, gaseous hydrogen shows the highest supply efficiency (52 to 68 %), followed by liquefied hydrogen (44 to 55 %) and gaseous hydrogen dehydrogenated from dibenzyltoluene (38 to 43 %). Also in terms of cost, the gaseous hydrogen supply is favorable since liquefied hydrogen (up to +25 %), and gaseous hydrogen dehydrogenated from dibenzyltoluene supply (+50 %) obtain higher costs. Assuming the technical feasibility of a vehicle on-board dehydrogenation of the filled hydrogenated dibenzyltoluene by using the waste heat of the vehicle's hydrogen combustion engine, hydrogenated dibenzyltoluene supply, and direct filling in the vehicle is identified as the option with the highest efficiency and lowest hydrogen supply cost.

Lucas Sens, Ulf Neuling, Karsten Wilbrand, Martin Kaltschmitt

Der Wasserstoffmotor im Nfz: Brückentechnologie oder langfristige Lösung?

Die Europäische Union schreibt ein verpflichtendes CO2-Reduktionsziel von 30 % am schweren Nutzfahrzeug im Jahr 2030 vor. Auf Basis der Gesetzgebung sind die technischen Wege zur Zielerreichung nicht zwingend vorgeschrieben. Daher werden sich diese, aufgrund von infrastrukturellen und wirtschaftlichen Rahmenbedingungen, aus einer Kombination von Maßnahmen zusammensetzen. Zum einen aus Verbrauchsreduktionen am derzeit dominierenden dieselmotorischen Antrieb, zum anderen aus einer gewissen Durchdringungsrate von alternativen Energiequellen. Diese werden die direkte Nutzung von Elektrizität und Wasserstoff als Energieträger beinhalten. Neben der Möglichkeit, Wasserstoff in einer Brennstoffzelle zu verwenden, bietet ein Wasserstoff-Verbrennungsmotor Vorteile im Hinblick auf den Erhalt der Wertschöpfung sowie Sicherung der Investitionen aus Produktion von Antriebsstrang und Fahrzeug. Das ermöglicht eine schnelle CO2-Reduktion durch rasche Markteinführung in großen Stückzahlen. Damit kann der Wasserstoffmotor zumindest als Brückentechnologie den Weg für die erforderliche Wasserstoffinfrastruktur ebnen und ein Beschleuniger für den CO2-neutralen Transport sein.

Anton Arnberger, Helmut Eichlseder, Peter Grabner, Bernhard Raser

Charge-Air Cooling of High Performance Engines in an Ejector Refrigeration Cycle

Continuous reductions of the CO2 emission targets in Europe demand further efforts to improve fuel consumption. Downsizing of engines proved to be a powerful concept to help achieving current targets. It has though limitations regarding engine knocking and thermal stress of the components. Low temperature charge air cooling can be a solution to overcome these limitations. This study presents a new concept for a stand-alone charge air cooling system in an ejector refrigeration cycle. A high performance engine was measured for different load cases as benchmark for simulations of the new concept. The measured charge air conditions were used as an input in the simulation model. First simulations varied the ejector nozzle diameter and refrigerant filling mass to determine the optimal design for the maximum thermal load condition. Then, a fixed nozzle diameter and filling mass were chosen to simulate other load cases. In comparison to the benchmark, the charge air temperature for knocking sensitive conditions reduces by 5.6 K. Almost no backpressure builds up by the ejector, allowing energy demands to drive the system of less than 50 W. For high thermal stress regions, the charge air temperature is lower by 11.5 K and the energy demand increases up to 460 W. The higher the heat input, the better is the relative cooling performance of the ejector cooling system. Therefore, the system seems a promising approach to enable further downsizing without adding a high system complexity or cost to the engine.

Tobias Beran, Jan Gärtner, Thomas Koch

Spark Ignition System for Alternative Fuels – Robust Ignition, Minimized Spark Plug Wear and Combustion Process Diagnostics

Spark ignited internal combustion engines (SI-ICE) running on alternative and/or renewable fuels are important to reduce the emission of greenhouse gases, motivated by its ability to efficiently make use of renewable fuels with low cetane numbers which are not suitable for diesel-like combustion. Examples of such fuels are natural gas (CNG, LNG), electro-methane, biogas, hydrogen, methanol, ethanol, and ammonia. The property of such fuels may vary significantly, both with respect to heat release rate and ignitability. Also, electro-methane and/or hydrogen can be used as blend-in fuel in bio and natural gas, which may increase the fuel mixture variations. SI-ICE engines can be made flexible, such that they can adapt to the property of the fuel in current use, improving drivability and fuel economy, hereby enhancing the great potential of a renewable fuels suitable for SI-ICE. The paper reviews the challenges and design trade-off’s when designing an ignition system for such SI-ICE, specifically when ion-sense based combustion diagnostics is included. Requirements on the ignition system for different engine designs and fuel properties is discussed with a focus on ignitability, and diagnostics of spark plug wear, and combustion process diagnostics using ion sense. Finally, recent advances in the development of ignitions systems and ion sense at SEM, is presented.

Jakob Ängeby

Dedicated Engine and Exhaust Aftertreatment Concepts for Strongly Electrified Powertrains in the Light Commercial Vehicle Segment

Light commercial vehicles (LCVs) are typically employed for freight and passenger transport within urban areas, but are also used in interurban and/or motorway operation. Future access restrictions for vehicles with internal combustion engines in certain urban areas may require pure or at least strongly electrified hybrid powertrain concepts. Such a strong powertrain electrification offers new degrees of freedom for engine and exhaust after treatment concepts.

Joschka Schaub, Markus Ehrly, Giuseppe Sammito, Paul Muthyala, Theodoros Kossioris

Thermal Management on Demand; the Exhaust Aftertreatment Solution for Future Heavy Duty Application

The currently discussed NOx limits reductions for commercial vehicles in Europe and in the USA for 2024 and 2027 will require a new approach for exhaust gas after treatment in order to keep greenhouse gas and CO2 emissions within the limits. Heating will be required in cold start and low load operation to achieve high NOx-conversion rates for the targeted limits. Placing of catalysts closer to the engine (= passive heating) and insulation seems to be not enough and means at the same time a larger modification of existing configurations. Active heating of existing configurations – with minor changes – shows a big opportunity. Active heating is typically associated with a fuel penalty. Therefore, this measure needs to be very effective. Generating heat by fuel conversion in a catalyst – directly in the exhaust system, close to the SCR system – has the advantage of high thermal efficiency combined with low heat losses.

Rolf Brück, Manuel Presti+, Mathias Keck, Johannes Dengler, Manuel Faiß

Energy Carriers for Future Mobility

The transport sector in Germany relies mainly on oil-based fossil fuels, while industry, households, and businesses derive their energy from a mix of conventional and renewable sources. This exceptional position of the transport sector has technical reasons, such as the high energy density and easy handling of liquid fuels. Taking into consideration the intended energy transition process (Energiewende), there is a growing demand for ways to utilize non-fossil energy in vehicles – that is, mainly, wind- and solar power.

Martin Härtl, Sebastian Blochum, Christoph Kraus, Georg Wachtmeister

Refining the Vision for a 2035 Heavy-Duty Engines Portfolio

There is need for development and change in the vehicle powertrain technologies of the road transport freight industry, in order to mitigate the effects of climate change. This need is reflected in the regulated emissions levels for such new vehicles within Europe up until 2030 and the recent, aspirational targets for net zero emissions in many aspects of societal activity by 2050. Achieving such targets is a significant challenge, which will need changes in the energy carriers (vectors), powertrains, vehicles, operational and infrastructure aspects of road freight transport should it be achieved. Furthermore, the potential routes to such change and their rate indicate that the available powertrain portfolio in 2035 will be pivotal to success or not in meeting this challenge. Following from earlier considerations, in this paper the current understanding of these routes will be reviewed, the necessary, immediate next steps highlighted.

Simon Edwards, Andrew Skipton-Carter, Andrew Auld, Nikolas Hill

Zero Impact – Objective and Significance for Vehicle Powertrains and Air Quality

In the recent past, the term ’zero impact’ has been used quite frequently when articulating the environmental compatibility of future drive systems in the field of mobility. Often, no distinction is made between climate and air quality relevance and only one of the two categories is addressed.

Helmut Eichlseder, Stefan Hausberger, Christian Beidl, Tim Steinhaus

Model Based xEV Test and Calibration – Benefits and Limitations

The regulatory requirements tightening with regards to fleet CO2, Emission and xEV technology shares push for significantly increasing shares of electrified and electric vehicles. Since more than 2 decades, hybrid powertrains are a major solution increasing fuel economy hence reduce CO2 in an affordable way. Tightening of global CO2 and emissions regulations are pushing hybrid technology into an even wider range of applications, resulting in a significant higher number of derivatives and variants puts a huge challenge to the industry.

Gerald Teuschl, Christian Jung, Raimund Ellinger, Peter Ebner, Arno Huss, Reinhard Merl

AI-Driven Gasoline Direct Injection Development: A Knowledge-Discovery Framework for Comprehensible Evaluations of Complex Physical Phenomena

The complementary analysis through simulations and measurements led to a huge success in the development and the improvement of Gasoline Direct Injection (GDI) systems. The complexity of the physical interactions involved increases dramatically starting from the single component, e.g. the highpressure injector, going to the system level, including spray patterns, engine combustion and emissions. This implies strong non-linear and high multidimensional domains, requiring a significant effort in the generation and the evaluation of the necessary data. Furthermore, new emission regulations and the demand of high power output, as well as high efficiency, require deeper analysis and understanding in the field of GDI engines.In this paper a modular interdisciplinary AI-Based Knowledge-Discovery framework is presented and applied in the analysis of in-cylinder Computational Fluid Dynamics simulations, based on the variation of spray targeting coordinates and injection strategies. In particular, with a limited number of evaluations, the AI is able to explore and exploit the investigated domains, discovering connections and correlations among non-linear and complex phenomena. The framework is based on a novel explainable AI algorithm, able not only to provide robust models but also to allow the understanding of its decisions from a human point-of-view, stepping beyond the concept of black-box AI.After the introduction of the investigated dataset, the main structure and characteristics of the Knowledge-Discovery framework are presented. The nonlinear dependencies among spray targeting and injection strategies are then modeled through the AI algorithm. Beside the high prediction capabilities on engine results achieved by the models, the potential of their interpretability is used to gain a deeper understanding of complex physical phenomena, opening new frontiers for improvement and optimization.

Massimiliano Botticelli, Robin Hellmann, Paul Jochmann, Karl Georg Stapf, Erik Schünemann

Heavy-Duty Combustion Engine 2030: Which Concepts can Contribute to Achieving the CO2 Targets for Commercial Vehicles?

The transportation industry has to face major challenges, because of global efforts towards a reduction of greenhouse gases and a general tendency towards decarbonisation. The EU reduction targets for example stipulate an OEM specific fleet CO2 decrease of 30% by 2030. Furthermore, future emission legislation will potentially require measures for ultra-low NOx. In this context, multiple technology scenarios ranging from cabin & vehicle design, efficient conventional combustion engines to hydrogen combustion engines and electric powertrain concepts can be expected in the future. From total cost of ownership and representative fleet composition calculations, IAV has derived possible scenarios for a future heavy-duty powertrain configuration: a high efficiency diesel powertrain using mechanical, thermodynamic and thermal management measures in a mid-term, and an advanced engine design for hydrogen combustion and eFuels in a long-term scenario.

Hubertus Ulmer, Tom George, Reza Rezaei, Jan Böhme, Jörn Seebode

50% Efficiency on a Combustion Engine - Status and Measurement Results

Due to the work carried out by AVL, possible concepts for achieving a brake thermal efficiency of 50% on a 13-liter class Diesel engine for a Heavy-Duty on-road commercial vehicle can be presented in this paper. Based on the latest developments of exhaust aftertreatment systems, higher engine raw NOx emission concepts appear to be a feasible approach for maintaining a relatively simple engine layout. Following such an approach, two possible engine concepts are presented as result of AVLs investigation:Concept 1 is essentially a currently available EGR engine layout with cooled, highpressure EGR and reed valves. Due to the limitation of EGR, "moderate” engine out NOx levels can be achieved with this concept.In Concept 2, with "high” engine out NOx, no EGR is applied in a wide engine map zone. The turbocharger selection is conducted independently of EGR path requirements. Hence, additional fuel economy benefits can be achieved and a more moderate peak cylinder pressure level than for Concept 1 is required. Due to the lack of EGR at full load, all necessary and further NOx reduction needs to be achieved by the EAS system. For all operation points, where EGR delivery is possible (e.g. low engine load, high engine speed), cooled high pressure EGR can still be applied and consequently the urea consumption can be improved under real driving conditions.Engine tests have been conducted and prove that highest BTE can be achieved, if highest turbocharger efficiencies, an optimized combustion system and low engine friction concepts are applied.

Rolf Heinreich Dreisbach, Daniele Corsini, Patrick Egarter, Klaus Hadl, Julian Schäffer, Hans Felix Seitz, Helmut Theißl, Martin Wieser, Bernhard Raser

Operation of OME in a single cylinder research engine and a series engine - An Analysis of efficiency and ultralow emissions by an OME-specific application

In this paper, various investigations are carried out with the synthetic diesel fuel oxymethylene ether (OME). OME belongs to the group of C1 oxygenates, which are characterized by low-soot combustion and thus have enormous potential for reducing emissions. A series engine for industrial applications and a single-cylinder research engine are used in the described investigations. The aim is to demonstrate the potential in terms of efficiency and emissions compared to diesel. The investigations show that a significant reduction in the number of particles can be achieved when operating with OME, while at the same time achieving lowest nitrogen oxide emissions. Because of favorable combustion properties, the efficiency can be maintained at the same level as for diesel, even though the installed series components of the injection system are not optimized for OME. If the components are adapted, an increase in efficiency can be assumed. In a final test, the potential of OME is demonstrated. The results show that it is possible to operate a series engine with OME by adapting the engine control system with regard to the power requirement. In addition to lowering nitrogen oxide and particulate emissions, all regulated exhaust gas components can be reduced. The findings show that OME as an energy carrier is a promising approach to con-tribute to future sustainable mobility.

Philipp Demel, Friedemar Knost, Alexander Mokros, Christian Beidl

The road to a low CO2 mobility - New perspectives on the transport and energy transition in Germany

The reduction of CO2 emissions in the transport sector is highly relevant and the subject of intense debate. However, from our point of view, an objective comparison of e-mobility and its alternatives is still outstanding. In this study, we establish a holistic perspective on e-mobility in Germany and examine CO2 effects of electric vehicles. We conclude that electric vehicles are not the optimal contribution to CO2 reduction in the foreseeable future. Depending on the scenario, electric vehicles cause more emissions or save only a relatively small amount of CO2 at prohibitively high abatement costs. Under realistic assumptions (base scenario), e-mobility increases German net CO2 emissions by 40 mn tons until 2030. If best case assumptions for e-mobility are taken (extreme scenario), 95 mn tons of CO2 emissions can be saved (2020- 2030). However, the costs of e-mobility will amount to EUR 47-75 bn until 2030, depending on whether EVs will reach price parity with ICE. Hence, even in the extreme scenario the CO2 abatement costs of EVs are prohibitively high with 400-700 EUR/t CO2 and therefore e-mobility can be questioned as a CO2 saving measure. Hydrogen and synthetic fuels are compared as alternatives based on the assumption that the cost of e-mobility could be used to subsidize hydrogen vehicles, infrastructure, and fuels as well as synthetic fuels. In the case of hydrogen, ~200 mn tons of CO2 emission can be saved until 2030. Synthetic fuels provide an even bigger saving impact and can abate ~600 mn tons of CO2 emissions until 2030. Implementation risks for synthetic fuels are mainly limited to the development of the production infrastructure in sunny regions and the achievement of economies of scale.

Martin Stahl, Markus Seeberger, José Miguel Escobar Coto

Application of Life Cycle Analyses to assess the Efficency of Car Drive Systems

Life cycle analyses (LCA) are the accepted method to determine the overall impact of a product. Usually, they are quantified by all material flows in the production and consumption chain. With the result, emissions and ressources consumptions can be quantified. One interesting number is the total energy input, the "gray energy". Related to the mechanical energy output of a car drive system results in a good measure of the overall efficiency. While this measure is common for the efficiency of power plants, it seems to be not well known to assess the efficiency of car drive systems. The methodology for the application of car drive systems will be presented here.

Daniel Weißbach, Stephan Gottlieb, Götz Ruprecht, Armin Huke, Marcel Schäufele

Potential Analysis of a DMC/MeFo Mixture in a 4-Cylinder Light Vehicle Gasoline Engine

Parallel to investigations with a fuel mixture of dimethyl carbonate (DMC and methyl formate (MeFo) on a single-cylinder-research-engine, a 4-cylinder light vehicle gasoline engine was operated with the same synthetic substitute for gasoline. When produced with renewable energy the fuel is CO2-neutral and offers the potential to reduce emissions. The results of the 4-cylinder engine operation confirmed the expectations. With minor adjustments to the engine control unit (ECU), a brake thermal efficiency gain of 16 % was achieved at the lowend-torque operating point while the particulate emissions were reduced by 99 % during static operation. The physical properties of DMC/MeFo help to lower the cylinder charge temperature, enabling a stoichiometric operation over the entire engine map. Investigations in homologation relevant driving cycles result in a particulate number reduction of up to 90 %, while CH4 and CO are reduced by 46 % and 84 %. The results gained from this study show the potential of oxygenated, CO2-neutral fuels when used as a substitute for fossil fuel for modern gasoline engines in order to reach the climate targets with lowest local pollutant emissions.

Bartosch Gadomski, Mario Retzlaff, Fabian Thamm

reFuels – rethinking fuels: Performance of regenerative fuels

The future of mobility presents various challenges. For the future CO2 targets, savings in the existing fleet are necessary. In this paper and the accompanying poster, the project reFuels- Rethinking Fuels is introduced and results of the developed gasoline and diesel fuels are presented. The aim of the project is to enable the use of fuels from renewable sources via BtL and PtL pathways as drop-in components to fossil fuels for use in the existing vehicle fleet. For this purpose, it is shown how the gasoline fuel blend G40 with regenerative fuel components produced from biomass has advantages in particle behavior in RDE tests compared to conventional fossil gasoline. In single-cylinder tests, a significantly reduces proportion of aromatics larger than or equal to C9 in the optimized bioliq ® fuel leads to improved particle emissions. Tests with diesel and components from regenerative sources (PtL and BtL), which mixture was within EN 590, show no adverse thermodynamic behavior but advantages from a raw emission point of view. On production engine at cold start conditions at -7 °C, paraffinic diesel shows improved particulate emissions under transient driving maneuvers, especially in idling phases, compared to fossil diesel.

Thomas Weyhing, Mitra Zabihigivi, Mohammad Moradi, Tobias Michler, Jonathan Ziegler, Uwe Wagner, Olaf Toedter, Thomas Koch

Fluorination of Methanol Catalysts to improve Productivity and Selectivity

In this work the oxidative fluorination of methanol catalysts is examined. A systematic variation of the compositions of the investigated oxidic ternary CZFe (copper, zinc, iron) catalyst systems led to a total of nine different catalyst systems. A subsequent oxidative fluorination of all systems showed a significant improvement in the methanol productivity and selectivity of almost all systems tested. Low-iron systems benefited most from oxidative fluorination. Furthermore, BET, TGA, IR, pXRD and SEM measurements showed that the properties of the CZFe systems (crystallinity, surface-area, high-temperature carbonate content) are very well tuneable. As shown in preliminary investigations, fluorination leads to an increase in the number of active centres for methanol synthesis and at the same time increases the activation energy for the rWGS reaction.

Lukas D. Ernst, Ingo Krossing

Fridays For Future demands climate neutral mobility and a complete mobility revolution

Fridays For Future is a worldwide movement which is protesting against the lack of action on the climate crisis. Climate change has already and will have even more severe consequences (like sea level rises, increased poverty, food insecurity, social crises, economic crises, water availability and climate refugees), if we don’t reach the target of staying below 1.5°C global warming. There are tipping points which are at some point self-enforcing and irreversible.Transport accounts for 20% of global carbon dioxide (CO2) emissions, so we are demanding a climate neutral mobility and the phase-out of fossil fuels by 2035. No more subsidies for fossil fuels, would be a first step in the right direction, as well as an eco-social tax reform. But most importantly not every car of the existing fleet should be replaced, traffic has to be reduced. Good urban planning and urban-rural connections, good public transport and car sharing services will be key to this transformation.

Gregor Petrowitsch, Anna Pribil
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