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About this book

Every year, the international transmission and drive community meets up at the International CTI SYMPOSIA – automotive drivetrains, intelligent, electrified – in Germany, China and USA to discuss the best strategies and technologies for tomorrow’s cars, busses and trucks. From efficiency, comfort or costs to electrification, energy storage and connectivity, these premier industry meetings cover all the key issues in depth.

Table of Contents


48 V Hybrid Manual Transmission

The automotive industry faces significant changes. Main driver for those changes are legal requirements, new technology trends, new customer preferences and their mobility behaviour. Propulsion electrification could be part of solution to solve new challenges. While combustion engine technology will be part of this future propulsion architecture e.g. in hybrids, manual transmissions are frequently claimed to become obsolete.But, Opel as well as other car manufacturers still have a high penetration of manual transmissions in their current portfolio for good reasons like high efficiency, low cost, low weight, its proven technology and lower complexity compared to automatic transmissions. Combination of those attributes with a propulsion electrification technology leads to a hybrid version of a manual transmission that could be the successor of the conventional version.

Konstantin Baron, Matthias Werra, Arno Ringleb, F. Küçükay

Torque Sensors for High Volume Production Applications

Magnetoelastic sensors are the first solution that allows measuring torque and other forces economically so they can be integrated into high volume applications. The current status quo for force measurements - strain gauge type sensors - require extensive manual labor during application, fault susceptible telemetries and recalibration due to aging effects. This makes them suitable for use in test benches and prototype vehicles, rather than high volume production applications. Magnetoelastic sensors have many advantages that make them ideal for high volume production applications. The sensors have small space requirements, the sensing object (e.g. a driveshaft) does not need to be modified and there is no telemetry, making the technology truly non-contact. Magnetoelastic sensors have excellent performance characteristics, exceptional long-term stability and have been proven in many high volume applications for more than 10 years, including automotive (e.g. electronic power steering, anti-roll stabilization), consumer products (e.g. eBikes), and agricultural equipment (e.g. power take-off shaft).The magnetoelastic effect states that a ferromagnetic material will change its magnetic properties when subjected to mechanical stress (e.g. due to an applied torque). A standard magnetoelastic sensor consists of two circumferential magnetization bands that are encoded into the shaft during production. Sensing coils placed around the shaft pick up changes in the magnetic field when torque is applied to the shaft, which is the sensor electronics converts into the output signal.An almost completely automated production process and multiple large-scale manufacturing facilities around the world allow Methode Electronics to produce over three million sensor units per year, satisfying even the highest volume orders.

Julius Beck

Quick Start with AI for Diagnostics and Calibration

AI offers great new opportunities. To become a successful player in AI driven business, companies need to find the right balance between investments for AI and benefits in their product strategy. The paper gives a short introduction to AI, especially Deep Learning Neural Networks (DLNN) and provides long-term experiences on the successful application to real-world applications. A scenario for the application of DLNN to drivetrain calibration and diagnostics as a very promising field of application with a beneficial balance of investment and benefits is described.Who will be the right companies to drive AI in drivetrain calibration and diagnostics? These applications are “too special purpose” for AI giants like Google, Apple or Amazon and will therefore very likely not be a suitable field of application for them. This is a great opportunity for the automotive industry: With the application of AI, drivetrain calibration and diagnostics can provide very valuable benefits for the automotive industry by reducing the growing effort for calibration on the one hand, and on the other hand enhancing availability and reducing quality cost by predictive maintenance.The paper concludes with an extract of experiences from 25 years of successful AI commercialization like speech recognition that will support a quick start with AI for automotive applications besides autonomous driving.

Ulrich Bodenhausen

Thermal Management System for High Performance Battery Based on an Innovative Dielectric Fluid

Fast and ultra-fast charging can create tremendous thermal stresses on a battery pack and may cause battery failure or a reduction in its service life. To tackle this issue a new and efficient battery thermal system is proposed. The originality of this system lies in the use of a highly advanced fluid that allows excellent thermal performance by direct contact with the electrochemical cells. A bench test was designed to measure the cooling properties of this system at the cell level and then demonstrate its efficiency. Numerical show an excellent agreement with the experimental data. These results allow the simulation at the battery pack level to be scaled up. An ultra-fast charging scenario (350 kW) was simulated for a 60 kWh battery pack: temperature inhomogeneity or maximal temperature appears to be under control. Lastly, to assess the performance of this battery thermal management system a holistic approach is made by considering parameters for the pumps required for this system (weight and consumption), but also parameters concerning the types and sizes of heat exchangers. Ultimately this enables a global view of the system (performance, weight, power consumption) in order to compare it easily with current solutions.

Nicolas Champagne

PUNCH Powerglide’s Dedicated Hybrid Transmission (DHT)

The Automotive industry is currently looking for efficient hybrid transmission concepts for use with a single electric machine. The aim is to find a cost effective alternative to current parallel and power-split hybrid concepts.To meet this challenge, PUNCH Powerglide is introducing a novel hybrid concept that delivers electric and mechanical states using less number of gears and dog clutches to maximize efficiency.The proposed DHT concept contains a unique patented gears and shafts arrangement, in a very compact environment to achieve very stringent package space of new OEM platform. This DHT offers a full-integrated high-voltage solution, with its own electric machine and electronic power.The transmission operation requires a very precise and reliable operation of the dog clutches chosen to support the highest efficiency of the overall powerflow.The synchronization of the dog clutch during the gear change is managed with the introduction of the EVT mode, which makes this DHT concept a powershift transmission.The base variant has been developed to propose four mechanical speeds, which allow a good compromise between functionality and system cost. By applying slight changes within the modular design, the proposed concept can also evolve to a 2-gear transmission with EVT mode or even a single gear transmission to support lowest possible transmission cost while still being able to manufacture all the variants on the same manufacturing line.

Philippe Ramet, Wolfgang de Loth

Development and Prototyping of Lithium-Ion Cells for Demonstrator Drivetrains

The progressive drive train electrification of vehicles also leads to a technological and technical development of battery cells and systems.Developments on the cell, module and system level have various objectives. The most common are: cost reduction, increase of energy density, high power charging (HPC).The corresponding adaptations at cell level are naturally subject to physical limitations, but can achieve the desired cell performance by optimizing all cell components from the electrode active material combination to the tab design.The development process starts with a basic cell design and selection of materials. During the subsequent development process, the electrochemically active components in particular are optimized. Recurring prototyping enables the verification on pack level and even in the actual application, which in turn leads to an efficient overall product development. Even radical system designs become testable in this way.

Jan Diekmann, Sebastian Kraas

Spring Loaded Rotor Shafts as New Flexible Shaft Hub Joint for E-Rotors

To improve the performance and range of electrified cars, the power density of the electric machines has to be increased, which is possible by increasing the rotational speed. However, the maximum rotational speed is limited by the radial expansion of the lamination stack due to centrifugal forces and radial temperature gradients. Improper centrifugal expansions may cause a loss of contact between shaft and lamination stack as well as a loss of radial centering of the lamination stack on the rotor shaft.Hence, Mubea developed and presents a revolutionary spring loaded tubular rotor shaft, whose innovation is a defined radial spring stiffness. This radial spring-like behavior results in a significantly reduced sensitivity of the transmitted torque with regard to the rotational speed, since the spring loaded shaft compensates the centrifugal deformations of the stack. This ability is new in the state of the art including interlocking connections. In addition, the spring behavior results in lower sensitivities regarding tolerances, the needlessness of fine machining the press fit surfaces and the avoidance of thermal joining. Also, the mechanical load on the stack is on average reduced by approximately 50%, which results in better electromagnetic properties. Tests and simulations show the high robustness with respect to transmitted torque and radial centering of the stack, also beyond 25.000 rotations per minute. Inner cooling of the shaft is easily applicable due to a relatively large contact surface.

Benjamin Dönges, Maximilian Rolfes, Stefan Buchkremer

BEV Range Increase by Optimal Combination of 800 V E-Machine and Multispeed Transmission

To cope with increasing customer demands on vehicle range and efficiency, Valeo and Valeo Siemens eAutomotive Germany develop electrical drives from the beginning as a fully integrated system. This work presents the newest seamless multispeed and 800 V eAxle designed for SUV premium class vehicles. The paper depicts the architecture and technical advantages of the 250 kW eAxle system combining a multispeed transmission with an 800 V electrical permanent magnet machine and a SiC Inverter. Advantages in efficiency and resulting range increase on the WLTC cycle are highlighted. Throughout the work, a comparison with a single speed transmission and a 400 V round wire machine illustrates decisive factors and key enablers of the newly developed eAxle.

Boris Dotz, Camelia Jivan, Sebastian Waider, Norberto Termenon

A Comprehensive Approach of the Lubrication for the Electric Powertrain Based on an Innovative Multi-purpose Fluid

Because of the increasing power density of electric motors, it is anticipated that the oil would not only lubricate the gearbox, but it will also be used as a coolant for the electric motor. TOTAL Quartz EV-Drive MP Technology has been designed as an innovative multi-purpose fluid which meets the new requirements of the combination of electric motor cooling and transmission lubrication. A comprehensive approach which identifies all the new constraints was followed in order to design such a multi-purpose fluid. Oil needs to maximize the heat transfer. Numerical simulations of an electric motor coupled with the data generated on a Stator Cooling Test enable us to identify the electric motor hot spots and to determine the fluid cooling power. As oil will be in direct contact with electrical components, it needs to be electrically insulating to avoid any current leakage. A direct oil cooling system also implies that oil should be inert towards electric motor insulation materials and bare copper. Test rigs were used to assess the oil compatibility with copper and polymer coated wires. Another critical aspect of electric vehicles is the high-speed lubrication properties. Ball bearings could experience lubricant starvation when the electric motor runs at high speed. A High-Speed Ball Bearing Test was designed to assess our fluids in this regard. Transmission components are also running at high speed, which increases oil aeration and churning losses. A specific test rig has also been designed to characterize churning losses at high speed.

Hakim El Bahi

Assessing the Relative Endurance Capacity of Hybrid Drivetrain Components in an Early Development Stage with an Indicator Based on Preceding Drivetrain Generations

In this paper an approach is shown to estimate the load on a component in a hybrid drivetrain. Therefore, the already existing method for conventional drivetrains is modified and expanded to fulfill the new requirements of hybrid drivetrains. The interaction between combustion and electric engine is considered to calculate a load-equivalent constant torque that is used as an input to determine a drivetrain specific, load proportional standardized value. With the help of drivetrain simulations, it is shown that the new approach leads to better estimation results in the case of hybrid drivetrains. Additionally, it is displayed that the new method is valid not only for hybrid drivetrains but also for conventional drivetrains, as it is a more general method. Furthermore, an example is given, how the knowledge about a component’s usable load range and the estimated load of a new drivetrain can be used to predict roughly the necessary activities during the development of the new drivetrain.

Jannick Fischer, Simon Rapp, Katharina Bause, Albert Albers

Drivemode – High Speed Electric Drivetrain

The paper investigates and suggests a high-speed electric drivetrain combining a SiC inverter, a PMSM electric machine (EM) and a 3-stage parallel axis gearbox. To reduce cost, a modular structure is applied allowing for installing several drive units into the vehicle according to power demand. The developed modular drivetrain concept is suitable for low and high-performance vehicles. To downsize the EM, i.e. decreasing the torque, the gear ratio and the rotor speed is increased, allowing the same power but from smaller packaging. Increasing the gear ratio gives a reduced mass and size, which primarily decreases the cost of the EM. To meet both increased speed and modular installation, different transmission concepts have been rated which is more likely to fulfill the requirements. To address cooling and rotor stresses and keep efficiency at maximum, the permanent magnet synchronous motor with buried magnets and dry rotor is developed. The peak efficiency goes above 96% with specific torque density of 4.9 Nm/kg. To supply the high-speed motor high frequency switching silicon carbide (SiC) power electronics is adopted. The converter can deliver 140 A continuous AC with a semiconductor switching frequency of 20 kHz.

Mattias Flink, Michael Burghardt, Roland Bittner

Advances in Drivetrain Lubricating Fluid Technology for Hybrid Electric Vehicles

The automotive transmission market has seen an increase in the number of hybrid electric vehicles (HEV), and forecasts predict additional growth. As the design of HEV drivetrain hardware evolves; so must the lubrication technology to anticipate this pace. The reason is that in HEVs the hybrid drivetrain hardware may increasingly combine electric motor, friction devices, gearbox, electro-hydraulics and the control unit all of which will be expected to be lubricated by a suitable drivetrain fluid. There is an extra challenge posed by incorporating an e-motor within the transmission housing while being constrained to ever smaller packaging dimensions, since the e-motor provides an extra source of heat which would be expected to be managed by the lubricating fluid. This leads to the need for an understanding and optimization of corrosion protection and thermal management characteristics of the fluid, and the development of new high-performing lubricating fluids suitable to the challenges is therefore paramount. There are further new challenges to lubricants. In addition to ensuring the lubricant will be durable in the harsher thermal environment, it must also be compatible with new plastics and able to protect them from degradation. There are ramifications that the hotter transmission design and environment has had on shaping the latest lubricant technology for electrified transmissions. The heat transfer characteristics of lubricants and the fundamental factors that impact them and fluid and transmission design are reviewed. The critical factors of protection against corrosion, including the ability of the fluid to allow both fluid and vapour-phase corrosion protection of copper-based componentry is addressed by the fluid technology. A secondary impact on the design of other fluid attributes, such as minimizing noise vibration and harshness (NVH), is addressed and the new fluid technology formulation approach to deal with such challenges is highlighted.

Michael Gahagan

AVL High Performance 48 V Integrated Electric Axle

Compared to conventional 48 V drive systems, the AVL P4 e-axle layout enables the customer to use the vehicle in pure electric drive modes, with much higher performance compared to currently available systems on the market.A set of use cases is defined to calculate the torque and power requirements for the e-axle. Based on this, the required torque-speed characteristic of the e-axle can be determined. To be competitive on the market, the target package space is defined by the available package of a conventional 4WD rear axle to minimize vehicle modifications. Mechanical interfaces such as e-axle bearing support and half shafts to the wheels of the 4WD system shall be reusable. Additionally, a co-axial design is used to minimize the package space.The definition of the e-motor torque and the transmission ratio is a compromise between available package for the e-machine, maximum rotational speed of the e-machine, 10500 rpm, and the fixed value of required e-axle torque, 1280 Nm. The overall gear ratio of 9,45 is divided in two steps, equipped with a disconnect element placed on the intermediate shaft. This e-axle shall be able to support the powertrain up to 130 kph as well as to be disconnected from the wheels above 130 kph to improve the overall efficiency.For achieving best-in-class power density with low torque ripple, the e-machine is designed with 6 phases and distributed winding. The 6-phase technology shifts the 48 V system to the next higher level of electrification and allows pure electric drive capability. The inverter consists of 2 modules, each controlling 3 phases of the e-machine and is fully integrated into the e-axle, having all connections routed internally. The cooling system of inverter and e-machine is connected in series.Within this paper the 48 V e-axle system will be outlined, and the technical solution and its features will be explained.

Inigo Garcia de Madinabeitia Merino, Christian Schmidt, Julian Pohn, Mohamed Essam Ahmed, Klaus Kronfeldner

48 V High Power: Electric Drive for Excellent CO2 Emissions and Electric Driving Features

Future motor vehicles regulatory requirements for CO2 emission reduction require a significant increase in hybrid vehicles in the fleet mix of manufacturers.The use of the internal combustion engine is increasingly replaced by the electric drive in hybrid vehicles and the challenges for exhaust aftertreatment increase, as the thermal supply of the internal combustion engine for thermal management decreases. The electric machine must have sufficient performance to enable corresponding driving patterns not only in the test cycle but also in real-life operation.Results from Vitesco Technologies 48 V Eco-Drive System have shown that for P2 compared to a P0 hybrid, the challenge for emissions is significantly exacerbated by an increase in pure electric driving capability, especially for plug-in hybrid vehicles. At the same time, technological advances allow 48 V drives to penetrate areas of application that were previously reserved for high-voltage solutions.This paper presents a compact design 48 V 30 kW electric machine solution, suitable for a P2/P4 configuration intended for full hybrid applications or even a plug-in hybrid and characterized by compact design with a very high-power density. At the same time, the system approach of exhaust aftertreatment is illustrated. A 48 V 30 kW “electric” means not only less CO2, but also increased electric driving and more total driving performance with significantly less effort and complexity due to 48 V as compared to a high-voltage solution.With the help of simulations and vehicle measurements, CO2 potentials as well as various emission-relevant driving conditions of a 48 V 30 kW high-performance hybrid are examined. At the same time challenging environmental conditions and the potential for improvement is determined by the advanced Emicat® exhaust aftertreatment system.CO2 performance is also the result of intelligent operating strategies. In the future, they will have to make their contribution robustly to the lowest CO2 in every driving cycle. For this purpose, connectivity and optimization algorithms in real time are enablers [6].

Friedrich Graf, Martin Beiderbeck, Thomas Knorr, Dietmar Ellmer, Mattia Perugini

Efficient CFD Simulation Method for Calculation of Drag Torque in Wet Multi-plate Clutches in Comparison to Test Rig Results

Wet multi-plate clutches and brakes are important components of modern powershift transmissions and industrial drive trains. In the open state, drag losses occur due to fluid shear as load-independent losses. Determination of drag losses can be done by experiment or by CFD simulation. CFD simulation has many advantages over the experiment process, but often has the strong disadvantage of high computational times and in consequence, strongly simplified models. Therefore, the target is to develop an efficient and validated model to compute drag losses for any clutch design in a short computational time.This work presents an innovative and validated CFD model to calculate drag losses of wet clutches. To ensure a convenient implementation of the model with high computational efficiency and quality at the same time, the commercial Software Simerics MP+ is used. Because of efficient modeling and solvers, the CFD model considers the geometry of a complete clearance between a steel and friction plate. This enables the model to calculate the drag losses for any possible groove design, which is a tremendous advantage in comparison to state of the art models, which often use circumferential symmetry. Furthermore, the model development is focused on a short calculation time: computational time is very short, which enables the overnight calculation of a whole drag-torque-differential speed curve. This allows variational calculations and at the same time, detailed investigations that are important both in early and advanced stages of development.Extensive measurements on a component test rig using automobile series production parts allow a thorough validation of the model. The influences of changes in operating conditions, groove design, differential speed, oil injection temperature and volumetric flow rate are shown both in the measurements and in the simulation results.

Daniel Groetsch, Rudi Niedenthal, Katharina Voelkel, Hermann Pflaum, Karsten Stahl

Significant Drag Torque Reduction and Improved Clutch Dynamics by Innovative, Very Compact Separating Springs for Wet Clutches

Due to the CO2 limits, which are becoming even harsher, losses in automatic transmissions must be drastically reduced. Furthermore, electrification of the drivetrain requires better controllability in order to improve interaction between combustion engine and electric motor. Mubea separating springs offer a good solution to achieve these goals. In order to minimize clutch losses, separating springs are accepted as an innovative component of current transmission programs in which discs in the clutch system are actively separated from each other. Extensive investigations have shown that drag torque losses can be reduced by 40% and more and that CO2 savings of 0.5 g/km (in WLTP) can be achieved. First of all, this lecture presents the validation of earlier simulation results regarding a positive effect of separating springs on shifting comfort through measurement of real starting-up with a dual clutch transmission. Here shift comfort and NVH behaviour could be greatly improved by the use of separating springs. In addition to well-known wave-shaped separating springs, a new type of so-called “torsional separating spring” is presented for the first time, which offers the same technological advantages by improving the installation space requirement. Furthermore, excerpt from test results will be presented with the new torsional separating spring. In addition to already known advantages in reducing drag torque, it offer further important advantages with regard to clutch dynamics. Tests were carried out at the IPEK and IAE on a clutch test bench with near-series hardware. All results show a better controllability and a more stable control behaviour with separating springs, when engaging the clutch due to a better linearity of the torque/pressure curve. When clutch is disengaged, a higher dynamic is achieved by a faster separation of the discs.

Hüseyin Gürbüz, Jörgen Schulz, Ferit Kücükay, Fatim Scheikh Elard, Sascha Ott

48 V AWD Demonstrator with P0 + P4 Close to Wheel Concept

This paper presents a 48 V Hybrid demonstrator with an electric rear axle which is setup by SEG Automotive Germany GmbH in cooperation with the Institute of Automotive Engineering of the Technical University Braunschweig.First, the concept of the 48 V Hybrid demonstrator is presented. It consists of a P0 electric machine which replaces the alternator of the conventional vehicle. The conventional front wheel driven vehicle is extended to an all wheel driven vehicle. Two identical new 48 V electric machines - developed by SEG Automotive Germany GmbH - are integrated into the rear axle. Therefore, a rear axle with a new gear box is developed. For this reason, the dimensioning of the gear box ratio is analysed. Afterwards, the design and construction of the gear box and all necessary changes in the vehicle to realise the electric rear axle are shown. Finally, the concept of the operating strategy is presented.

Matthias Werra, Matthias Ristau, Arno Ringleb, Sven Oliver Hartmann, Julian Kumle, Daniele Rosato

Industry 4.0 Applications for Improved Efficiency in EOL Testing

There are significant more and new data generated during EOL testing of hybrid and e-Drive components. In addition new products and new requirements in testing appear. Due to that there is a strong request to optimize production and testing processes like reducing cycle times, predictive operations, lean production and an efficient high volume production. This is why modern EOL-testing needs flexible and performant data analysis. This article gives three data based Industry 4.0 applications for improved efficiency in EOL testing.

Ralph Heckmann

Triple Wet Clutch e-Module for P2 Hybridization

Architecture and Technical Description of a Triple Wet Clutch Unit and the Related Active and Passive Clutch and Shift Actuation System

Bei P2-Hybridarchitekturen haben integrierte Lösungen von Triple Wet Clutches mit effizienten Aktuierungssystemen bei mehreren OEM-Projekten einen hohen Stellenwert. Insbesondere bei DHT- oder Hybrid-FWD-Architekturen, bei denen es um die Abmessungen in axialer Richtung geht, bietet die Integration der Trennkupplung zwischen ICE und Getriebe (C0) in ein Triple Wet Clutch Modul (TWC) eine intelligente Designlösung.Das Papier beschreibt verschiedene Architekturen von TWC mit Zentraleinrückern (CSC) und integrierten Betätigungskolben mit Schwerpunkt auf P2-Offline-Hybridarchitekturen und den damit verbundenen Vor- und Nachteilen.Der Beitrag beschreibt auch ein innovatives Betätigungssystem des TWC Moduls, das auch weitere Getriebefunktionen wie Parksperre und Schaltzylinder betätigt. Das Betätigungssystem ist eine Innovation von Valeo, die auf die Bedürfnisse der DHTs zugeschnitten wurde. Es kann drei Kupplungen betätigen und die Schaltung der Gänge und Ansteuerung des Parksperrzylinders durchführen.Moderne DCTs und DHTs verwenden so genannte “On-Demand”-Aktuierungsysteme, um die ständigen Verluste der zentralen Powerpacks zu vermeiden, die durch ihr konstant hohes Druckniveau und den Leckagen in den Steuerventilen entstehen.Die hydraulische Betätigung der Kupplungen und Zylinder bringt eine hohe Leistungsdichte und damit Vorteile im gesamten Aufbau des Getriebes. Der Schwerpunkt der Entwicklungsarbeit liegt auf niedrigem Stromverbrauch, geringem Gewicht, kleinen Einbauräumen, die frei positioniert werden können, und attraktiven Preisen. Ein geschlossener Ölkreislauf mit eigenem Ölbehälter ermöglicht eine lebenslange Befüllung und freie Wahl des Schmieröls.Am Ende des Papiers steht die Beschreibung der Systemarchitektur einschließlich der Software.In case of P2 hybrid architectures, integrated solutions of Triple Wet Clutches with efficient actuation systems are having a big attention on several OEM projects. Efficient ways for hybridization can be achieved either using existing dual clutches gearboxes, either using dedicated hybrid transmissions (DHT). In those cases the packaging constraints in axial direction are at stake, particularly on FWD applications. The integration of the disconnecting clutch between ICE and gearbox (C0) inside a the Triple Wet Clutch (TWC) is providing smart design solution. The paper will describe different architectures of TWC with Clutch Slave Cylinders (CSC) and piston type actuation technologies focusing on P2 Off-line hybrid architectures, and their associated advantages and drawbacks.The paper will also describe an innovative actuation system of the TWC, managing also some gearbox functions as park lock and gear shift cylinders. The actuation system is a Valeo innovation which considers the needs of DHTs. It can actuate three clutches and operate the shifting of the gears and park lock cylinders. Modern DCTs and DHTs use so called “on-demand” actuation systems to avoid the constant losses of central power packs, which are generated by their constant high pressure level and leakages in the spool valves. The hydraulically actuation of the clutches and shifters brings a high power density and therefore advantages in the gearbox packaging. The focus of the development work is on low power consumption, low weight, small packaging free in positioning, and attractive pricing. A closed oil circle with an own oil reservoir allows lifetime filling and free choice of the lubrication oil. A description of global system architecture including software will be described at the end of the paper.

Olivier Simon, Wilhelm Heubner

Method for Thermal Modeling of Electric Traction Machines for Hybrid Vehicle-Applications

The method aims for maximum simulation quality on the one side and on the other side minimal effort in creating thermal models by combining test bench and vehicle tests as well as the use of thermal networks and 3D CFD- /CHT-simulation.A self developed concept for semi-automatic creation of thermal networks for electric machines is presented and applied to the electric traction motor of the current Porsche Panamera Turbo S PHEV in parallel hybrid configuration. With the use of an automatic optimization process for the data of the thermal network, the behavior of the model can be fitted to realistic measurements. The basis is the so called calibration-cycle that was measured with a prototype car and was transferred to a test bench. The configuration of the test procedure was improved to have a maximum accordance between the two measurement methods and consequently also compared to the two simulation methods. A noticeable high improvement of the simulation quality is presented. A relevant influence of the dynamic variable thermic environment on the monitored temperature in rotor and stator is shown. The resulting models are used to predict the component behavior in the vehicle environment and to evaluate sensitivities in optimizing the durational performance of the machine for dynamic load cycles. The method can be extended to modelling machines in a wide variety of electric machines, also for purely electric vehicles.

Holger Hinrich

System Cost Reduction by Electric Powertrain Design Optimization

The presented optimization method supports early system design of electric axle drives (eDrives) for battery and hybrid electric vehicles. The multi-criteria design problem of finding the best suitable solutions regarding performance, efficiency, package and costs is addressed with a sophisticated multi-objective optimization method. The overall system costs are reduced by including common-part considerations for purchased parts, demonstrated on the example of bearings. Two approaches are compared: the implicit approach relies on an extended cost model that covers a quantity-dependent cost reduction effect. The explicit approach directly minimizes the number of unique parts in the system. Both approaches are compared and the effect on the optimal system solution is discussed for a case study, which shows significant cost reduction potential.

Martin Hofstetter, Dominik Lechleitner, Mario Hirz

The Ideal Future Hybrid Powertrain

How to Conduct a Comprehensive Simulation and Design Analysis, Identifying Ideal Hybrid Powertrain Architectures and Operating Strategies

Studies in the automotive area agree that the number of electric vehicles has increased over the past years and will increase further in the future. The high number of electric vehicles will not be high enough to fully replace the conventional powertrains utilizing and internal combustion engine (ICE). Instead, conventional and electric powertrains are expected to co-exist in the future [1]. The closest co-existence of these two powertrain systems is the hybrid powertrain. Hybrid vehicles use two different sources of power, most frequently petrol and electricity. There are several ways to arrange these power sources in the powertrain. Solutions range from both sources providing propulsion in parallel to one feeding energy into the other in a serial setup.None of the hybrid systems proofed to be the most favourable one so far. Car manufacturers prefer certain setups to others while competitors have contrary preferences. One setup is becoming more and more popular: The so-called dedicated hybrid transmission (DHT). The DHT attaches the electric motor (or multiple) to a central point in the transmission while common hybrids tend to connect their electric machine either before or after the transmission. The DHT is flexible in its attachments and also concerning drive modes as well as e-motor and battery size. It can thus cover a wide range of applications. Is the DHT therefore the ideal future hybrid powertrain?This paper investigates hofer powertrain’s approach to hybrid transmission development from the empty sheet to the final hardware product. The focus lies on the first steps to find the concept most suitable for the respective application. Mechanical components are considered rather than other key components like e-motors, software or system integration. The concept development follows automated analytic approaches looking at all hybrid layouts imaginable and narrowing down the solution pool step by step. Each step dismisses hybrid layouts from the pool when violating key parameters. The key parameters originate from various engineering fields e.g. manufacturing, NVH or efficiency.hofer powertrain’s development process shows that most evaluation criteria are tied to the respective application. Every application has different key parameters that automatically lead to a different ideal solution. Hybrid transmissions, common ones as well as DHTs, only live to their full potential whenever tailored to their respective application. There is – so far – no hybrid transmission setup that proofs to be the best for all hybrid applications and thus no overall ideal future hybrid powertrain.

Y. Jokmin, F. Holldorf, E. Montefrancesco, K. Loock, N. Moeller

E-FDU: An Innovative Double Motor, Disconnectable Front Electric Drive Unit for Ferrari Sport Car Application

Hybrid technology offers key opportunities for fuel economy and performance enhancement also in the sport cars application. The main driver of the technology is the vehicle requirements definition and the development of the components focused on efficiency, performances and weight reduction.Ferrari and Dana Graziano, together with sister company Vocis and an electric motor partner, has developed and taken into production in less than 24 months a novel P4 hybrid powertrain in the form of a dual motor front torque vectoring axle. The unit is capable to drive the front wheels of the vehicle independently, enhancing traction and improving vehicle dynamics, providing at the same time full electric drive capabilities and fuel consumption reduction. The system comprises a twin independent disconnectable transmissions driven by two high revolution (25000 rpm) and high-power density electric motors (up to 162 kW in total).The front axle is also responsible for EV mode and electric reverse.Both left and right transmissions integrate an innovative electromagnetic disconnecting device with integrated electronic HW and advanced controls developed by Vocis and Dana Graziano. Advanced control techniques enable transmission disengagement\engagement in 100 ms and replace entirely traditional actuation systems reducing overall weight, cost and vehicle integration complexity.Ferrari developed an optimized system control in terms of e-motors torque and transmission disconnecting strategies to achieve overall best vehicle performances.E-AWD and torque vectoring capability improve acceleration performances, vehicle dynamics, and fuel optimization.

Fabio Irato, Carlo Cavallino, Gianluca Quattromani, Giulio Lapini, Giuseppe Manici

Effective Battery Design and Integration of Cylindrical Cells for High Power Applications

To fulfill the far-reaching requirements of an effective battery design for high power applications, every single component, including their interactions with the battery module, have to be optimized. Without making compromises on battery safety, designing a compact battery module for Lithium-Ion cells is the main development target. To address customer demands and enable fast adoption of the technology in the markets, tough cost targets have to be met. Even though no design aspect can be ignored, a sufficient battery thermal management system (BTMS) is key to increase safety, fast charging capability and lifetime. Kreisel Electric’s battery design based on cylindrical cells and immersion cooling, answers all these questions and proposes new solutions on the design and material side.

Helmut Kastler, Kilian Menzl

Compact E-drive for Trucks—Efficient Utilisation of the E-motor Through Multi-speed Transmission

The Battery Electric Vehicle (BEV) shows great promise for the future evolution of our transportation system by significantly improving efficiency while reducing cost of operation and harmful emissions. This is still an emerging technology that is gaining broad market acceptance.

John W. Kimes

Representative AWD System Evaluation by High-Function Dyno—New Simulation Model of Sand Road

Previously, AWD system evaluations have taken place using actual vehicles on real roads. However, there have always been concerns regarding inaccuracies from test to test due to seasonal differences in road conditions and weather. This problem is especially prevalent on sand road tests, these tests are particularly affected due to the sinking behavior of tires in soft sand. Therefore, when a comparative evaluation is implemented on a vehicle with changes made to the AWD control logics and specification, it is difficult to identify whether any phenomenon observed between tests is a result of the adjustment made to the AWD specification or a change in the road conditions. To solve this problem a new simulation model replicating a sand road has been developed. The model is able to simulate driving a car on sand using Dynamos with low inertia and high response motors. To create this simulation model, 4 characteristics of sand, which are “the running resistance”, “the static and dynamic sinkage characteristic of the tires” and “the traction coefficient” were identified and calculated by carrying out full-scale test with an actual vehicle running on sand.

Wataru Kobayashi, Satoru Okubo

Environmental Benefits of Used Batteries from E-Vehicles as Stationary Energy Storage

The batteries aged during the life of an electric vehicle can be reused for a variety of stationary applications. In combination with photovoltaics, higher private consumption rates can be reached at a module level. At the level of complete vehicle high-voltage batteries, DC quick charge stations with low power connections or load management (peak shaving) represent an example for industrial clients. In the megawatt area, used electric vehicle batteries can provided grid support or they can be used to stabilize the energy from wind parks. The environmental benefits of an electric vehicle face repeated criticism. Along with the use of CO2-intensive, coal-based electricity for vehicle operation, the ecological rucksack of the battery is the primary focus. When the battery is reused at the end of the vehicle’s service life, the environmental benefits far exceed those of just regular recycling. The paper will show two already realized battery plants on a megawatt scale and report the experience in planning and construction. Both systems are used for grid control and can support a smart grid in the future.

Juergen Koelch

Finite Element Modeling (FEM) and Fatigue Analysis of Hypoid Gears and Laser Welding Joints Installed in a Power Take-off Unit (PTU)

Effective analysis modeling of power take-off unit by using finite element method is developed in order to investigate gear root bending fatigue and welding fatigue. The hypoid gear plays an important role in the PTU system. Without proper information of system stiffness it is impossible to exactly predict fatigue failure life in finite element (FE) analysis. In this study, a simulation model is developed with the focus of affecting gear mesh misalignment, such as gear body flexibility, shafts, bearing stiffness and gearbox stiffness. To validate results this paper presents a correlation study of fatigue failure life between physical test results and fatigue life analysis results. The proposed integrated FE model for predicting the fatigue life of hypoid gear root and welds based on the full-system agreed well with the result of physical durability test.

Kibok Lee, Myeongeui, Jongho Seo

Highly Efficient Drivetrains for the Mobility of the Future

World population is increasing, urbanization progressing at a constant rate, and by 2030 we will have 10 more megacities in the world. As our megacities continue to expand at a steady rate so would our CO2 if not counteracted; this is the key driver for the advancement of the electrification agenda. A clear path from zero to 100% electrification has been developed: efficiency increases on traditional drivetrains as well as disconnect architectures have been analyzed and their potential has been assessed. 48 V technology represents a further step on the path of reducing CO2. PHEV solutions as well as DHT architectures represent technologies for even higher CO2 reductions, culminating in “zero” CO2 BEV-powertrains. The potential of all these technologies has been studied in detail. A specific analysis on 2-speed eDrive transmission has been performed and results are presented as well as CO2 related aspects of the Twinster® technology.

Andreas Mair

The 8G-DCT Plug-in Hybrid Transmission for the Mercedes-Benz Compact Car Family

With the new 8G-DCT plug-in hybrid transmission, Mercedes-Benz has electrified the modular 8G-DCT transmission family with a powerful and efficient plug-in hybrid powerhead. The plug-in hybrid transmission is launched as part of the new generation of the Mercedes-Benz compact car platform. Therefore, additional requirements concerning fuel consumption, pure electric driving possibility, torque capacity, minimal space, modularity and shifting performance are considered. This allows to fulfill increasing customer requirements in hybrid powertrains. The main elements of the highly compact and modular plug-in hybrid powerhead are an integrated dual clutch, an additional low-loss disconnect clutch and a new powerful 75 kW electric motor. The powerhead is characterized by its high functionality and extremely high efficiency in combination with the high torque of the electric motor. It provides all hybrid functionalities, such as boost, energy recuperation and pure electric driving. Special emphasis was placed on optimized efficiency of the powerhead by reducing the drag torque of the disconnect clutch as well as by means of on-demand cooling and lubrication. The actuation and cooling of the hybrid powerhead required only minimal adaptations to the basic transmission. The hybrid powerhead also allows starting the combustion engine in a very smooth manner, almost imperceptible for the driver. Within the transmission family the 8G-DCT plug-in hybrid transmission is therefore available for future use in electrified front-wheel drive compact car series.

Matthias Maisch, Martin Hörz, Daniel Jesser

Solutions for Increased Power Density at Shifting Clutches

Modern vehicle and drivetrain concepts face many integration problems due to the various functions within the system. Hybrid and Electric vehicles present new challenges, especially in terms of weight reduction and installation space. BorgWarner has developed special solutions to increase the power density of shifting clutches. New friction materials with increased static and dynamic coefficient of friction have been developed to allow a compact clutch design. BorgWarner has also developed new high performance friction materials which can handle higher interface temperatures without sacrificing robustness against hot spotting. Thanks to these advantages, the power and energy limits of clutches can be increased. A new friction plate design has been developed using plastic core plates and a new manufacturing concept. The design advantage is getting the same performance in a smaller packaging space with lower weight. BorgWarner has also developed a new clutch concept that allows high torque transmission in an extremely compact installation space. The new clutch design combines a friction plate clutch with a mechanical lock device.

Harald Merkel

A Brief Evaluation of Freewheeling Motor at P4 Position: Retrofit Approach to Electrification

Several approaches are taken towards the electrification of the future’s automotive fleet. This Paper explores a possibility for electrification of existing on-road vehicles with high residual value. Notion of this paper is that electrification of certain sectors of the vehicle fleet is economically feasible when existing vehicles are retrofitted with electric parts rather than being replaced with pure electric vehicles. Retrofit refers to addition of components which was not there during the time of manufacturing. The paper presents the benefits of retrofitting a “P0 hybrid” vehicle with a freewheeling motor at the P4 position. This Config is evaluated by a detailed simulation on CO2 savings and performance using MATLAB and AMESim. We try to contemplate the amount of modifications needed on the vehicle for retrofitting and summaries the benefits.

Jérôme Mortal, Ashwin Charles

Laser Joining of Copper-Copper and Copper-Aluminum Application in the E-Mobility

The rise of e-mobility has particularly increased the use of copper and aluminum in the series production of vehicles. The production of electric motors in particular focuses on copper-copper connections in hairpins. Due to the late position of hairpin welding in the stator’s value chain, defective welds lead to irreparable damage to the stator and thus to increased scrap costs. In addition, the focus is also on copper-aluminum connections, particularly in the area of battery contacting with high demands on the connection cross-section. The presentation will highlight the possibilities of using precise beam guidance, high deflection speeds and beam shaping to safely and robustly design automated welding processes in series production. Different welding strategies will be discussed using the example of the copper hairpin welding process and the welding of aluminum and copper contacts in battery production. Furthermore, the possibility of using beam forming technology in the beam source and the welding optics to make the processes safe and robust and to additionally improve the appearance of the welds on copper and aluminum will be discussed. Furthermore an outlook is been given which technical trends for welding especially copper in the laser branch, as well as the possibilities to use intelligent optics to ensure robust joining processes in series production.

Stefan Mücke

ELIKA Automotive

Marzocchi Pompe was established in 1961 by Guglielmo and Stefano Marzocchi, in Casalecchio di Reno, in the outskirts of Bologna. Today the Company is the head of an industrial group that employs more than 400 people. This group, owned and led by Paolo Marzocchi, is specialized in designing and producting of hydraulic external gear pumps and motors. As of 16th July 2019 Marzocchi, is listed on the Milan Stock Exchange (: MARP). Over the years, Marzocchi Pompe has expanded the Company and increased its product range to reach its present position as one of the most important Italian players in the hydraulic pump market. Marzocchi Pompe is the manufacturer with the broadest range of displacement reaching as low as 0,12 cc/rev and up to 200 cc/rev. The product includes micropumps (families 0,25, 0,5, 1P; displacements range 0,12–8 cc/rev), pumps and motors (families 1, 2, 3 4; displacement range up to 200 cc/rev) that could be also supplied in multiple pumps, with integrated valve, with special codesigned interfaces tailored on Customer needs, in low noise solutions. The families 0,25–0,5–1P–1–2–3–4 identifies different, increasing, specific displacement (in simple terms, “the size of the gear”). Among this wide variety of products, there are 2 main areas where Marzocchi is targeting, pulled by the market: special micro-pumps conceived for automotive applications and low-noise pumps for all the markets where noise reduction is a requirement (automotive market included).

Danilo Persici, Michelangelo Musiani

Park by Wire System for Current Electric Drive Units

Park lock systems are safety critical units. Due to intellectual property rights and different transmission configurations, a large variety of park lock design exists in the market. Furthermore, many park lock designs are still manually actuated. A new mechanical park lock system will be presented which is actuated by wire. The system has been optimized for rotary actuators and is extraordinarily compact. In addition, it minimizes the contact stresses due to optimized geometries. Furthermore, the functional safety and diagnostic concept for park-by-wire park lock systems, exemplarily for this system, will be presented. This will be done in accordance to current multi speed power-shift EDU concepts, including FMEA, legal, requirements summary, safety goal definition and error detection mechanism. The following chapters are divided according to the park lock development steps shown in Fig. 1.

Jan Nowack, Gereon Hellenbroich, Arnab Ghosh, Valerij Shapovalov, Ralph Fleuren

Innovative and Highly Efficient Clutch System for Multispeed BEV with Highspeed Powertrains

Tackling the Efficiency and Drag Loss Challenges Through a Novel Latching and Actuation System

According to the state of the art in research and technology, previous clutch systems based on multidisc design are not suitable for shiftable BEVs with highspeed transmissions up to 30,000 rpm in order to meet the higher requirements with regard to controllability at high clutch input speeds, efficiency and freedom from drag torque. The consortium project “Highspeed Clutch” was started with the IPEK—Institute of Product Engineering and transmission suppliers Mubea Tellerfedern GmbH, Miba Frictec GmbH and Kaco GmbH + Co. KG with the aim of developing and prototyping friction clutch concepts for electric vehicles with a multi speed transmission. The focus is on electric drives with high speeds of up to 30,000 rpm. This article presents the clutch concept for multispeed electric drives that was developed in the project. Two designs of friction system for high sliding speeds and combination and arrangement of the subsystems shift piston, separating spring and sealing system are presented in order to improve the system behaviour in the synchronization phase as well as in the open phase. To increase efficiency, the clutch concept is equipped with an innovative latching system that is based on the ballpoint pen mechanism and requires no energy when closed. This paper presents the first results of the functional verification. Furthermore, a novel release bearing in the form of a plain bearing was developed in order to realize actuation by a non-rotating shift piston at high clutch input speeds. In this lecture the test bench concept and the test specimen variants, test parameters and lubrication concepts are described also.

Sascha Ott, Hüseyin Gürbüz, Falk Nickel, Andreas Genesius

Multipurpose Oil Filter Systems for Innovative Drivetrains and e-Axles

Changing drivetrain architectures and designs such as highly integrated e-Axles and hybrid transmissions require different filtration solutions. Not only the requirements towards oil cleanliness and differential pressure of the lubrication and cooling circuit become more challenging, but also the dielectric and electric oil properties and the insulating function, for instance, come more and more into focus. To protect all system components starting from the oil pump MANN+HUMMEL developed a new generation of filters using their depth filter media MULTIGRADE eM-CO. The new concept increases the degrees of freedom for the development of the lubrication circuit significantly. Offering an ultra-compact and flexible installation space, lowest differential pressure or highest filtration efficiencies for system reliability. The new MANN+HUMMEL filter media portfolio MULTIGRADE eM-CO offers filter media with excellent properties and a gradient structure that provides a high dust holding capacity at a low differential pressure. Customized numerical development tools are supporting the media development by analyzing and optimizing the structure and the filtration performance. To multiply these advantages and to add further benefits for the customers a new generation of pleated suction-side filters has been developed. With up to 60% higher filter area the new concept uses the given installation space to the maximum. A 3D structured drainage grid keeps the media performance at a maximum level over the whole filter life. The latest computational fluid dynamics (CFD) analysis tools are used to optimize the differential pressure of the housing even in challenging installation spaces. Special oil drying units are applied to minimize water induced increase of conductivity. This allows the dielectric properties of the oils to be kept constant and even water sensitive oils can be used for the applications. With this knowledge and expertise, MANN+HUMMEL developed a sensor-supported oil management system with intelligent cooling function and integrated oil drying for highest oil quality over the entire life of the system.

Marius Panzer, Claudia Wagner, Anna-Lena Winkler, Alexander Wöll, Richard Bernewitz

The Propulsion, Energy Storage and Charging System of the New Opel Corsa-e

Various forms of electric mobility contribute to the target of decarbonizing the traffic sector. Depending on the energy source for charging of Electric Vehicles (EVs), the CO2 reduction contribution for Battery-EV (BEV) and Plugin-Hybrid EV (PHEV) cars differ, same as the emissions for electricity production differ by country. Once BEV and PHEV cars are stronger represented in the passenger car fleets, societies will take further benefit from progress in de-carbonization of the energy sector through this growing, coupled lever in the traffic sector. The new Corsa-e marks another milestone of EVs in the Opel product lineup. Other than the well-known, roomier Ampera-e, the Corsa-e is more clearly placed in the B-segment. It will make electric mobility more affordable for a wider customer range. Besides an enthusing exterior and interior design, great drivability and class-leading charging capability were key development targets. This paper describes how EV Functionality was maintained and improved subsequent to the Ampera-e. High Voltage (HV) architecture design simplifications were brought in place. Commonality leverage with the “Corsa” sister model as well as manufacturing insourcing within the corporation were employed to widen the affordability of this car to a broader customer area. With approx. 330 km in WLTP (preliminary figure), further optimized roadload for motorway driving and DCFC charging up to 100 kW peak, the car provides a perfect balance of Battery size even for longer distance usage. Details on the major HV Powertrain components are compared to the Ampera-e as reference. Key functions related to electrical driving and charging are explained, supplemented by performance data. The paper also compares charging options and delivers charge recommendations for different types of EVs, including the BEV vehicles, like the Corsa-e.

Peter Ramminger, Hans-Georg Schade

Fast and Accurate Road Interference Compensation for Objective Drivetrain Evaluation

In cooperation with the Institute of Automotive Engineering of the Technische Universität Braunschweig and AVL List GmbH, a system to compensate the influence of the road surface on the objective driveability assessment is developed. Based on an existing simple function in AVL-DRIVETM (The Objective Tool for Driveability Assessment and Development) a system with two vertical-longitudinal axis wheel sensors is created. By this, road surface interferences on the left and right side as well as on the front and rear axle of the vehicle are considered, and the influence on the longitudinal acceleration signal, which is the main input for driveability evaluation, can be effectively compensated. In this work the influence of different road interferences on the longitudinal acceleration is measured and investigated in different driveability maneuvers like accelerator pedal tip-in or gearshifts. The principle of the road interference compensation based on multiple wheel acceleration input signals is shown, and a performance optimized algorithm is developed. While four sensors would be required to acquire the inputs of all four wheels a way to effectively compensate all wheels with only two sensors is integrated in a real time capable environment. The aim of this cooperation was to take a further step towards public road driveability assessment. Usually, this is done on test tracks with consistently good road surface conditions and exactly reproduced driving maneuvers. In contrast, during public road driving, all kinds of road surface conditions are found, significantly complicating the objective driveability assessment. With the road interference compensation, the influence of the road surface is decisively reduced.

Johann Rutz, Thomas Ebner, Ferit Küçükay

BEV AWD EDU Gear Ratio Selection for Efficiency

The single speed gearbox is a largely preferred solution for electric drive units (EDU) in hybrid vehicle P4 and Battery Electric Vehicles (BEV). A proper gear ratio selection is required to meet the power and speed performance requirements, and also to minimize the parasitic losses over the life of the vehicle. Conventional wisdom holds that a higher ratio power dense gear box design for an EDU is lighter, more packaging friendly, and more efficient. This study examines the validity of this assumption for an auxiliary EDU installed in the rear of a BEV CUV providing AWD functionality. This paper outlines the power loss analysis for a single speed EDU propelled by an induction electric machine, and provides a useful approach for gear ratio selection at the concept phase of a design. Specifically, this paper determines the range, mass and cost tradeoffs for two auxiliary EDU design options without disconnect function, with gear ratios of 7 and 10 for a given duty cycle, and for two different induction motor material choices (aluminum and copper). We show that the lower gear ratio design option with aluminum rotor saves approximately 450 kWh energy compared to the higher gear ratio over the life of the vehicle. For an assumed battery miles/kWh, this saving translates into approximately $30 lower overall cost (battery+EDU). Alternately, for a given battery pack capacity, the ratio 7 design with aluminum rotor is expected have a longer range (+2.13 miles) for an estimated $31 cost and 6.5 kg mass increase.

Yogesh Mehta, Cong Liao, Michael Schulte

An Efficient and Automated Design Strategy for Multiphysics E-Motor Development

Standard design processes for e-motors foresee siloed development of different attributes depending on nature and type of requirements. Thus, electromagnetic, thermal, mechanical and NVH attributes are developed individually which leads to unfavorable compromises and/or late costly firefighting. Mercedes-AMG GmbH are developing high-performance e-motors that deliver maximum performance under severe driving conditions. This requires high attention to durability and thermal effects and although serving high-performance cars, the motors must fulfill highest NVH standards. Altair Engineering has introduced Simulation-Driven Design (SDD) to support holistic, multiphysics development of e-motors. SDD processes are introduced to enhance classical development by accounting for essential development requirements simultaneously using optimization and by continuously providing a maximum of information to support the design process. This paper introduces a pilot application of a unique, highly automatic, multiphysics design process for e-motors, based on a current e-motor program at AMG. The process is developed to consider essential development requirements including electromagnetics and thermal requirements, NVH, stress and durability. It accommodates for DOE, multi-objective optimization and design exploration methods to be used to explore and find feasible motor designs. The paper will show how the strategy adds efficiency to the e-motor development process and how it can impact the total costs of development. The uniqueness of this development lies in the automation of the multiphysics design process and the creation of an environment to democratize multiphysics design optimization within the e-motor design departments.

Torben Schulze, Jean-Baptiste Mouillet, Thomas Lehmann, Lars Fredriksson

How to Ensure Safety of EV or FCV Without Reliable, Helpful Saving Functions Made by ICE

The power train electrification has been remarkably evolving and HEVs or EVs are increasing in world-wide markets. Especially recently, pure electric driving system such as EVs or FCVs without any ICEs are highly desired as better solutions for environmental protection. However, we have to recognize the important role of engine for conventional ICE vehicle. Engine has reliable, helpful saving function on long and steep downhill road. It provides everlasting reliable engine brake. On the contrary, EVs and FCVs do not have engine. Instead of engine brake, regenerative brake is usually utilized for EVs and FCVs. However there remains emergent situation where battery SOC is full on long and steep downhill road driving. Thus, we have to develop emergency brake for those pure electric driving systems. In this paper, the background of this issue is explained in detail and several effective solutions to fix this issue are proposed.

Takashi Shibayama

P2i, a Family of Modular, Scalable, and Integrated Hybrid Drive Modules

Among the many hybrid architectures, the P2 layout is a cost-effective solution that provides one of the best combinations to achieve CO2 reductions especially within a given ICE vehicle architecture. The P2 layout allows the engine to be disconnected from the driveline, and the electric motor leverages the ratios of the gearbox to drive the wheels. However, packaging the motor and disconnect clutch without increasing the overall length of the powertrain is very challenging and needs detailed knowledge in electric motor and inverter development and integration. By combining a unique method for winding the stator of the electric motor, a scalable stack length and years of experience designing compact clutch systems, BorgWarner has developed a family of new drive modules including a scalable and modular custom engineered hydraulic actuation systems suitable for MHEV up to PHEV applications. P2 On-Axis modules for Dual Clutch Transmissions (DCT) and Automatic Transmissions are in various stages of development. For the DCT, the disconnect clutch and dual launch clutches are integrated inside the electrical machine rotor. Currently in pre-production phase at multiple customers, this P2 and P2i (with integrated inverter) Triple Clutch Module has a very compact design that minimizes the impact to overall powertrain length. For planetary automatic transmissions and CVTs, modules are being developed that are compatible with both torque converter and launch clutch configurations. Various rotor and stator lengths are available to match vehicle torque and power requirements, and these motors are compatible with both high voltage and 48-voltage architectures. A common lamination stack is used along with a unique winding pattern to realize a motor for the desired voltage. In addition, the three-phase inverter interface is standardized to have a modular P2i concept for both 48 V and high voltage. The P2i family also includes a matching inverter that can be integrated in the housing of the module. This inverter integration leads to significant benefits in overall system efficiency and EMC behavior. A custom engineered hydraulic module is also integrated into the housing to actuate the disconnect clutch and provide cooling flow to the clutch and motor. This presentation will describe the technical innovations that were necessary for successfully developing this family of P2i Hybrid Drive Modules.

Heiko Jausel, Wolfgang Wenzel

Innovative Sensor Technology Revolutionizes Lubrication System Analysis in Transmissions

With increasing requirements for transmissions in terms of rotational speed and geometrical constraints, the topic of lubrication gains in importance. In the future, more accurate and sophisticated lubrication system analysis methods will be needed to ensure functionality in series applications. Therefore, it is necessary to reconsider current testing methods like tilt tests based on visual inspections with transparent housings and pursue new and innovative approaches for test and verification as well as for condition monitoring. One of those approaches was developed at the Graz University of Technology and comes in the form of a unique fluid sensor. The innovative sensor was designed for the quantification of multiphase flows and is ideal for analyzing the lubrication in transmissions. By integrating several measurement principles into one miniaturized sensor, the flow and the temperature of the oil are measured. Furthermore, the sensor is able to detect gas bubbles and oil splashes. The combination of the obtained measurement data from several of these innovative sensors at different positions is used to determine the exact lubrication condition dependent on rotational speed, tilt angle and oil temperature. Different sensor designs like a sensor probe or an adhesive sensor foil allow measurements at individual test points inside of the transmission. Together with the objective of implementing a wireless data transfer, this sensor application provides a new way of analyzing lubrication conditions.

Mario Theissl, Hannes Hick, Peter Neger-Loibner

Proposal of Application of Magnetostrictive Torque Sensor in EV—Seamless 2-Speed Shifting with Torque Feedback Control

This paper shows the high potential of magnetostrictive Torque Sensor applied in electric vehicles (EVs). Although most of the current EVs are equipped with fixed-ratio gearboxes, the demand for 2-speed transmission will be increased in the near future for improving cruising range and driving performance. The torque feedback control of clutches and an e-motor with Torque Sensor can realize seamless shifting even with large gear step ratio which causes uncomfortable shifting shock. In order to evaluate the advantages of Torque Sensor applied in 2-speed EV, preliminary evaluation in the powertrain system of an ICE vehicle was conducted. Moreover, seamless 2-speed eAxle concept is proposed for long cruising range and comfortable ride.

Seigo Urakami, Kota Fukuda, Junji Ono, Tomoyuki Miyazaki, Shinji Okada

Compact Pushbelt Variator Module to Improve Energy Economy in Electrified Powertrains

A lot has happened since the introduction of the Variomatic with its rubber belts based continuously variable transmission (CVT) in the DAF passenger cars in 1958. The rubber belt evolved into a compact steel belt with a far higher torque capacity, and the transmission is now built into the vehicle instead of a vehicle built around the transmission. Since then, the CVT is known as an excellent system regarding fuel economy and offers outstanding NVH qualities. It is these qualities that EV developers look for, when designing electrified powertrains and reducing the ecological footprint of mobility. CVT is ready for its next evolutionary step. Previously, studies have been published which show that CVT—just as it did for internal combustion engines (ICE) based powertrains—offers the potential to reach better energy economy in electrified powertrains. In this paper these results will be further explained. The CVT will look different from what we know from ICE applications; it is smaller and has a better energy efficiency. The solution consists of a small variator combined with an energy optimal actuation system as the core elements for an electrified powertrain.

Gert-Jan van Spijk, Ingmar Hupkes, Mattijs Tweehuysen, Arno Klaassen, Jordi Meegdes, Rokus van Iperen

Supply Chain Implications of Increasingly Integrated EV Drivelines

IHS Markit undertakes component-level research in the automotive industry through a combination of peer-level interviews and discussions with contacts and thought leaders. This is underpinned by their industry leading vehicle and powertrain-level forecasts. The approach generates a unique level of varied and comprehensive insight, which helps drive the business lines and investment decisions of our clients. With the move to electrified powertrain technology, the automotive supply chain is undergoing a transformational shift towards more compact configurations that will liberate interior space in the vehicle. Whilst this ‘end state’ might appear somewhat simplistic and uninspiring, the interim period will generate a huge number of creative technical evolutions. IHS Markit has undertaken component-level research focusing on the extent to which power electronics, transmission and e-motor technology as well as the thermal management will become increasingly integrated, analyzing the approaches of OEMs and interpolating the supply chain dynamics to understand how solutions will evolve with time.

Claudio Vittori, Wen Gao, Graham Evans

Fuel-Saving Potential of Hybrid Electric Vehicles Using Surroundings Sensor System Information

Operation strategies used in hybrid electric vehicles need a traffic speed profile for an initial operation strategy planning, which can be obtained from real-time traffic information services. However, microscopic traffic flow is unrepresentable in this initial planning which leads to deviations in the batteries’ state of charge. Therefore, the presented method plans partially automated micro maneuvers to correct the deviations during the drive using local prediction based on the surroundings sensor system, which is assumed to offer exact data of the future speed profile within its visual range. The method is applied to various driving cycles such as the WLTP and to real speed profiles in cities and on highways. Comparing driving cycle runs with and without the use of local prediction shows a fuel-saving potential of up to 11% in emission test cycles. Moreover, validation with real data confirms the results and indicates a higher potential in urban areas.

Dominic Waldenmayer, Johannes Buyer, Katharina Bause, Nikolas Andriessen, Hermann Koch-Gröber

Quality Assurance of Composite Materials for Powertrain Applications

Unidirectional carbon fibre reinforced plastic (CFRP) composite materials can be used in gas storage systems, lightweight housings for powertrain components (e.g. battery casing, transmission casing), and also for light-weighting of the vehicle body to reduce load on the powertrain. In each case, we would like to optimize costs and minimize the amount of composite required. Due to the complex interaction of many factors, it is often difficult to interpret the performance of composite prototype parts, and implement countermeasures regarding the materials, material synthesis route, and part production methods. One challenge we face is a lack of detailed real information on the incoming material feedstock. In particular, to obtain fibre content and fibre distribution it is necessary to cut the material and inspect it under a microscope. A single material spool may contain hundreds of meters of material, and therefore the extracted and inspected material may not be representative of the entire length of material. In this paper, we present a novel non-destructive and non-contact method for measuring the fibre content and fibre distribution of unidirectional carbon fibre composite materials based on terahertz time domain spectroscopy.

Andrew Willett

The Rolling Bearing in the Electrified Power Train—Requirements and Solutions

Climate change and global regulations for CO2 emission reduction are nowadays the drivers for the megatrend to E-mobility. Initiated with the hybridization of the power train the industry arrived today at the battery driven electric vehicle. Here one of the most important sub-assemblies is the E-axle, which consists of an electric machine and a reduction gearbox. Market requirements like rising power density, energy efficiency, maintenance free operation and cost efficiency require adequate technical solutions on component level. Especially the rolling bearing is subjected to high demanding operating conditions. High dynamics, poor lubrication, elevated temperature levels, risk of current leakage and others more need to be considered and call for a customized bearing design. For bearing dimensioning and development work on component level an SKF proprietary simulation software toolkit is available. By that it is possible to model the entire E-axle, to analyze the bearing reactions and to optimize the bearing components in terms of service life and efficiency. The simulation of cage deformation at high rotor speed is crucial to develop a high-speed cage design. The potential risk of electrical continuity which damages balls and raceways and reduce grease life, is another issue which asks for a technical solution. With the focus on bearing technology an E-axle and its specific operating conditions will be described, simulation tools and calculation results presented and the current SKF bearing portfolio for E-mobility applications introduced.

Thomas M. Wolf


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