News

Prof. Küçükay passes the baton to Prof. Jaensch

Posted on 19th May 2023

After more than 20 successful years, the chair and co-founder of CTI SYMPOSIUM GERMANY, Prof. Dr. Ferit Küçükay, is passing the baton to Prof. Dr. Malte Jaensch.

Prof. Küçükay began working with CTI back in 1999, when he chaired the first specialist conference on vehicle transmissions. Two years earlier, he had been appointed professor and Director of the Institute for Vehicle Technology at the TU Braunschweig from his managerial role at BMW.

The new cooperation with CTI soon paid dividends: by 2001, the specialist conference had become an international symposium for innovators, decision-makers and specialists from all over the world.

Prof. Küçükay is a respected scientist, author and co-author of numerous publications and specialist books (his latest is the comprehensive work “Fundamentals of Vehicle Technology”). He is also a strategic and technical expert with a deep grasp of the topics, trends and technologies that matter in the vehicle and drive industry. As CTI chair, these abilities enabled him to attract high-profile speakers from international companies. Under his leadership, an advisory board comprising international experts from the industry and universities was set up.

The CTI Symposium grew to become Europe’s foremost industry get-together, covering all relevant fields connected to vehicle drives. One example of the importance of the CTI Symposium among specialists is the term DHT, or Dedicated Hybrid Transmission. This was first defined and introduced by the Advisory Board, and is now used internationally. Building on its successful track record, the CTI Symposium later expanded to the USA and to China.

As the topics of importance in the industry changed, so did the topic portfolio at the symposia. In the early days, transmissions for conventional drives and their components played the main role; these were later joined by transmissions for hybrid and electric drives. Today, the main focus rests on electrified and electric drives for cars and commercial vehicles.

An extensive trade exhibition also evolved alongside the wide-ranging lecture program. This exhibition, together with the seminars Prof. Küçükay has held on all three continents over the years and his commitment to giving attendees a hands-on experience of the latest technologies at the numerous Test Drives, have fueled the growth of the CTI Symposium into a unique industry event.

After over twenty years of outstanding work as chair, and as Chairman of the Advisory Board, Prof. Küçükay will pass on his role as chair to Prof. Malte Jaensch, Head of the Chair for Sustainable Mobile Drive Systems at the Technical University of Munich, during the CTI SYMPOSIUM GERMANY 2023.

Malte Jaensch studied mechanical engineering at the TU Braunschweig, followed by a doctorate in mechatronics at Imperial College London. His doctoral thesis was recognized as the best in mechanical engineering. Next, he founded a startup for high-performance electric motors and drives in the UK; six years later, the company was taken over by GKN. From 2013 to 2021, Prof. Jaensch was Head of Electric Drivetrain at Porsche Engineering.

With his long years of experience in the industry, his engineering expertise and his understanding of the challenges the industry faces, Prof. Jaensch is ideally equipped to help the CTI Symposium evolve further. Under his leadership, the different electrified and electric drives and their most important components will remain in focus, and related issues will continue to be addressed and discussed.

CTI wishes to thank Prof. Dr. Ferit Küçükay for over two decades of successful cooperation, and we welcome his ongoing support in his future role as Founding Chairman. At the same time, we look forward to moving the CTI SYMPOSIUM forward with Prof. Malte Jaensch at the wheel, and to growing this international industry get-together for sustainable automotive drives further still.

Development if a multi-Speed Two-Drive-Powertrain

Posted on 17th March 2023

Aaron Kappes , Steffen Frei , Sebastian Luz , Prof. Stephan Rinderknecht, Institute for Mechatronic Systems, TU Darmstadt; Institute for power electronics and control of drives, TU Darmstadt

An electric Two-Drive-Powertrain using two electric machines is presented, which allows a highly efficient over all usage. The multi-motor approach achieves a downsizing effect, when one motor is deactivated during moderate driving. The novel features of the powertrain are its electric synchronized dog clutches and its two highly overloadable electric machines, each connected to a two-speed sub transmission providing a total of four different electric speeds. This arrangement enables full torque support during shifting processes. In addition, the waste heat from the inverters and the electric machines is used for heating the transmission oil under cold environmental conditions, thus increasing efficiency. Furthermore, the possibility and advantages of adding an internal combustion engine mechanically linked to both sub transmissions and its realization in a public founded project is addressed.

Introduction

Increasing efficiency is a major target in the development of electric drivetrains. In parallel to established BEVs with one electric motor and a fixed transmission ratio, multi-speed [1, 2] and multi-motor [3, 4, 5] con-cepts are gaining importance. At the IMS of the TU Darmstadt, research is focused on multi-motor and multi-speed drives called TDT („Two-Drive-Transmission“). These electric drives combine high efficiency and performance by using a downsizing effect, according to which a highly utilized electric drive can be operated more efficiently than a large one in its corresponding partial load.

The conceptual benefits of an all-electric concept with two small electric machines with two speeds each, called TDT22, have al-ready been outlined in [6]. Efficiency advantages of up to 8.3% were identified for urban use compared to a benchmark fixed speed BEV. For short and slow driving, there is almost no alternative to a BEV from an ecological point of view. When it comes to long range, [7] stated that it is currently not reasonable to realize high ranges by using larger and heavier batteries. The battery capacity of BEVs ca-pable of reliably reaching distances greater than 500 km increases to more than 100 kWh. A current P2 hybrid concept with optimized energy storage sizes and propulsion machines shows poten-tial to reduce the CO2 footprint from cradle to grave because of its smaller battery. To achieve this, however, it must be charged regularly and driven mainly electrical. In addition, there are user benefits such as rapid refueling e.g., using renewable fuels in the future if an even longer distance is to be covered.

With these potentials in perspective, this paper will focus on the de-velopment of a hybrid version of a TDT22 already mentioned in [8]; a TDT4LR („Two-Drive-Transmission for Long Range“). This concept is based on a DRT (Dedicated Range-Extender Transmission) and is cur-rently being developed and built in the public funded Project DE4LoRa for a dedicated use case.

1. Development

The vehicle being developed in DE4LoRa is designed for a typical German average user and leaves a minimal environmental footprint. According to the “Kraftfahrt-Bundesamt” [9] the 101-110 kW power class contained in 2020 by far the most new-registrations in one of the dis-crete subdivisions. This number was only topped by the open-ended category of more than 151 kW. At the same time, the most frequently registered class was the rather unspecific one of SUVs, closely followed by the C-segment [10]. As the former is not suited for an ecological vehicle, the focus is on the latter. According to a study from the Federal Ministry for Digital and Transport called “Mobility in Germany” sur-veyed in 2017 [11], approx. 80% of passenger car trips covered less than 20 km, with only approx. 30% of the total mileage of a vehicle reached on short distances of less than 20 km in total. Therefore, the develop-ment of the drivetrain was focused on this use case (e.g., daily commute to work and twice a year a long trip on vacation).

A BEV designed for this user profile needs a large and heavy battery, barely using its full capacity. In contrast, the DE4LoRa concept was de-veloped to cover ranges of up to 100 km electric combined with the high efficiency benefits of a TDT22. To reduce complexity, two iden-tical electric machines have been designed, each realizing a continu-ous power of at least 40 kW to enable highly efficient driving with one EM during moderate cycles like the WLTC. Furthermore, they can jointly provide 120 kW peak power for short sporty driving. To enable shifting without interrupting traction even at high accelerations, both electric motors are able to provide 120 kW each for the very short duration of a shifting process. The development of these permanent magnet syn-chronous machine is further described in [12].

Assuming constant transmission efficiencies, as well as a constant bat-tery voltage and temperatures, a simple heuristic operating strategy for electric modes can be created. The resulting shifting map for this TDT22 is shown in Figure 1. The advantages of four different electric gears com-pared to a non-shiftable transmission are described in more detail in [6].

In an overall assessment of the electric consumption, the relatively low transmission losses cause a significant proportion of the total loss-es due to the high efficiency of power electronics, electric machines, and batteries. Therefore, electrically synchronized dog clutches were chosen to avoid friction losses which would occur in mechanical syn-chronization units. Furthermore, the losses of a transmission increase with higher viscosity of the transmission oil e.g., at low temperatures. To keep the efficiency as high as possible after a frequently expected cold start in winter, it can be beneficial to use the waste heat from the electrical components for conditioning the transmission oil. To further increase electrical efficiency, DE4LoRa also uses a rather high voltage level up to 820 V. Since the efficiency drops with the voltage over the state of charge of a battery, the latter should be kept as high as possible. In this concept, the electrical consumption in the WLTC increases by ap-prox. 5% if started at an SOC of 25% compared to 90%.

For the use case described above, highly efficient short-range electric driving alone is insufficient. To improve the concept for occasional long-distance, a monovalent methane gas engine is added. This engine can be connected to both sub-transmissions with different gear ratios, as shown in Figure 2, enabling multiple parallel and serial hybrid modes. This integration combined with the high dynamics and performance of the electric drive allowes the gas motor to be operated in a phlegma-tized manner, thus minimizing emissions and maximizing its efficiency.

In addition, methane provides a high energy density per carbon atom, can be produced synthetically more efficiently than liquid synthetic fuels, and, unlike hydrogen, is easy to store and benefits from an existing infrastruc-ture. Optimizing the gear ratios of this transmission involves a compro-mise between highly efficient electric and SOC-neutral hybrid modes, with SOC-neutral consumption being more sensitive to changes. It has been shown that an electric overdrive provides efficiency benefits, re-sulting in a top speed of 180 km/h in SOC-neutral operation in the third, not fourth gear.

2. Oil-Conditioning

During optimization constant transmission efficiencies were assumed between 96.9 and 97.8% for each mode-dependent combination of two spur gears. In real applications, these effi-ciencies depend not only on the acting speeds and torques but also on the viscosity of the gear oil and thus its temperature. With lower temperatures, the transmission losses increase disproportionately. The inverter and electric machine generate usually unused waste heat. If the lubrication concept of the transmis-sion already uses an oil pump, the heat can be used for conditioning the oil by adding a heat exchanger.

The potential depends on several parameters like the current efficien-cies, the water flow rate, and the oil used. To investigate the possibili-ties for this project, an analytical transmission loss model was created, which includes the viscosity of the gear oil in its calculations of churning losses, meshing losses, sealing losses, and bearing losses. Not only the load-carrying elements but also all co-rotating parts for every mode are considered. This model is supplemented by a lumped-element thermal model of all transmission components. All loss effected transmission parts as well as a water-oil heat exchanger and 30% of the losses of the electric machine at the input shafts are implemented as heat sources. Thus, both the self-heating of the gearbox and the heat transfer from an external water circuit is represented.

Two different transmission oils and two different scenarios were consid-ered, using only modes with one EM for simplification. First, a common rather more viscous transmission oil was modeled corresponding to a SAE 80W90. Figures 3 and 4 show the simulation results for a cold start in the Artemis Urban cycle with 0°C ambient temperature.

The efficiency changes of the transmission are shown in Figure 4; in blue without using the heat exchanger, in red with a water flow rate of 1 l/min. In addition, the efficiency with an oil temperature of 60°C at the beginning is shown as a benchmark in gray. Figure 5 shows the most relevant results of the simulations. The heat exchanger in this configuration enables an efficiency advantage of 1.3% which is no-ticeable, but significantly lower than the efficiency with already warm oil. If the gear layout and the acting surface pressures allow the use of an oil with (very) low viscosity, much higher total savings are pos-sible. On the other hand, the benefits of conditioning are hardly notice-able with this lubricant. Finally, the potential in a WLTC at 20°C ambi-ent temperature is evaluated, whereby the heat exchanger leads to an 0.6% lower energy consumption. Prospectively, the usage of additional waste heat by other consumers, such as an internal combustion engine, could achieve greater improvements. Furthermore, the effect could be improved by further optimizing the flow rates and quantity of water and oil.

Conclusion

The concept idea for a hybrid TDT22, the development process as well as the results achieved in the DE4LoRa project so far were stated. It is tailored to fulfill the requirements of an average Ger-man driver with minimized ecological footprint. It covers short distances in highly efficient elec-tric driving due to the advantages of four speeds, uses a comparatively small and thus light battery, a high voltage level, and supplementary oil conditioning. To maximize efficiency, it is rec-ommended to keep the SOC as high as possible. In addition, the effect of transmission oil con-ditioning was examined in more detail, and in summary, the loss reduction potential depends primarily on the oil used. If a conventional trans-mission oil is used, there can be considerable efficiency benefits for short trips and cold am-bient temperatures – 1.3% in this example. How-ever, if the design or maintenance strategy al-lows using a low-viscosity oil, the effect if an oil conditioning decreases significantly and com-bined with longer driving distances and higher ambient temperatures, becomes unnoticeable small.

Gratification We want to thank Max Clauer, Zhihong Liu, and Arved Eßer for theirhelpful feedback and advice.References[1] Biermann, T, “The Innovative Schaeffler Modular E-Axle“, April 2018, Schaeffler Symposium[2] Schmidt, C., Dhejne H., Vallant, W.,

„AVL Two-speed e-Axle – High Efficient and Shiftable Under Load”, November 2021, CTI Symposium, Berlin[3] Xu X., Liang J., Hao Q., Dong, P, et al., “A Novel Electric Dual Motor Transmission for Heavy Commercial Vehicles”, Januar 2021, Automotive Innovation, Springer[4] Hirano, K., Hara, T., “Development of dual motor multi-mode e-axle”, November 2021, CTI Symposium, Berlin[5] Brückner, U., Strop, M., Zimmer, D., „Mehrmotorenantriebssys-teme – intelligente Betriebsstrategie“, May 2017, Antriebstechnik[6] Eßer, A., Mölleney, J., Rinderknecht, S., „Potentials to reduce the Energy Consumption of Electric Vehicles in Urban Traffic”, Juli 2022, VDI Dritev, Baden-Baden[7] Eßer, A., “Realfahrtbasierte Bewertung des ökologischen Potentials von Fahrzugantriebskonzepten“, 2021, Shaker[8] Langhammer, F., Kappes, A., Viehmann, A., Rinderknecht, S., „Novel “Two-Drive-Transmission for Long-Range” Powertrain: Ecology and Efficiency meet Driving Comfort”, October 2021, VDI Dritev, Bonn[9] Kraftfahrt-Bundesamt, „Fahrzeugzulassungen (FZ) Neuzulassungen von Personenkraftwagen und Krafträdern nach Motorisierung Jahr 2020“ – FZ 22; https://www.kba.de/SharedDocs/Downloads/DE/Statistik/Fahrzeuge/FZ22/fz22_2020.pdf?__blob=publicationFile&v=5 last checked: 11-10-2022[10] Kraftfahrt-Bundesamt, „Neuzulassungen von Personenkraftwagen nach Segmenten und Modellreihen“ – FZ 11; https://www.kba.de/DE/Statistik/Fahrzeuge/Neuzulassungen/Segmente/n_segmente_node.html?yearFilter=2020 last checked: 11-10-2022[11] infas, DLR, IVT und infas 360, “Mobilität in Deutschland – MiD: Ergebnisbericht,” Im Auftrag des BMVi, 2017;http://www.mobilitaet-in-deutschland.de/pdf/MiD2017_Ergebnis-bericht.pdf last checked: 11-10-2022[12] Clauer, M., Binder, A., “Automated Fast Semi-Analytical Calculation Approach for the Holistic Design of a PMSM in a Novel Two-Drive Transmission”, September 2022, ICEM, Valencia

Ruiping Wang, Geely Auto Senior VP, Plenary Speech at CTI SYMPOSIUM Germany 2022

Posted on 16th March 2023

Ruiping Wang, Geely Auto Senior Vice President, joined CTI SYMPOSIUM GERMANY 2022 as plenary speaker via video from China. See her contribution “Geely’s strategy and practice in powertrain electrification” as video and hear about BEV growth rates, the regulatory context, and Geely´s drive solutions and outlook on HEV, PHEV and BEV in the Chinese market.

JJE Advances Electromagnetic ClutchTechnology to a New Level

Posted on 8th March 2023

JJE DirectFluxTM Mono-stable and Bi-stable Electromagnetic Clutches for Disconnect and Differential Locker Applications

Jing-Jin Electric (JJE) has been developing electromagnetic clutches for various electric drive applications over a decade. Instead of using “reluctance” magnetic force, JJE electromagnetic clutches utilize direct magnetic force – flux in the same direction as the magnetic force – which is named “DirectFluxTM”. A mono-stable clutch is engaged by actuation current, and disengaged by spring force when the current is off. A bi-stable clutch will only change its state when there’s an affirmative pulse of command current; otherwise, it will hold its state. Earlier this year, JJE launched industry’s first bi-stable electromagnetic clutch for automotive applications.

The technology roadmap for developing an electromagnetic dog clutch (EMDC) plays a key role in the product’s developing stage. Back to 2009, JJE started to develop the electromagnetic clutch in “DirectFluxTM” concept. The first generation (Gen 1) EMDC product is a circle configuration, mainly applied on hybrid systems as a hybrid mode clutch, which was very successful in China’s commercial market.

In 2017, the 2nd generation (Gen 2) EMDC product was launched, and expanded its application to transmission shifting after optimization over mechanical design. The “crescent” configuration was developed and added in the JJE’s EMDC family.

In early 2019, JJE began the development of 3rd generation (Gen 3) EMDC. The third generation (Gen 3) EMDC features further innovations. It has both mono-stable and bi-stable options. It overcame some limitations of the existing design. Coils evolved to smaller solenoids, and magnetic circuit are further optimized to reduce flux leakage. The Gen 3 EMDC is more capable, faster, functionally safer, and more energy efficient.

DirectFluxTM Electromagnetic Clutch

JJE’s DirectFluxTM mono-stable electromagnetic clutch has several advantages because of its unique magnetic circuit design and mechanical structure. Compared to the more conventional reluctance flux magnetic circuit design, the DirectFluxTM design greatly reduces flux leakage, therefore it utilizes the magnetic flux to generate force more effectively. The reluctance flux design cannot avoid magnetization of parts near flux circuit, or “flux leakage”, which cause less effective utilization of the magnetic flux.

Because of the more effective flux utilization, the DirectFluxTM clutch has much higher electromagnetic force than reluctance flux clutch, therefore it acts 2-3 times faster, as shown in the charts.

Bi-stable Electromagnetic Clutch

The bi-stable electromagnetic clutch – still based on JJE’s DirectFluxTM electromagnetics – is an innovation beyond JJE’s mono-stable electromagnetic clutch. It uses permanent magnets to hold the clutch in its en-gaged position, while still allowing the electromagnetic coil to “push” the clutch plate away while disengaging. As the clutch can self-hold at both engaged and disengaged positions, there is no need for holding current as the mono-stable clutch does. The operation current curve exactly illustrates the difference between the mono-stable and bi-stable. For bi-stable clutch, the operation only needs to provide a current pulse to switch the clutch’s state (see Fig.).

The bi-stable clutch is inherently fail-safe as it won’t change state in the event of loss of holding current. This feature brings the bi-stable clutch a higher safety level than mono-stable clutch for disconnect, differential lock-er, and transmission shift applications. As far as energy consumption, the bi-stable clutch’s feature of “zero hold-ing current” achieves the zero consumption.

Figure 4: Operation Comparison Between Mono-stable and Bi-stable Clutch

Disconnect

JJE’s mono-stable clutch has already been successfully applied on electric drive disconnect. In an offset, layshaft reduction gearbox, the disconnect clutch is on the output and is integrated with differential. Compared with disconnect on the input shaft or on the layshaft, the output shaft discon-nect cuts out most mechanical losses. JJE is also introducing bi-stable electromagnetic clutch to disconnect application. There is no holding current or power consumption when the clutch is engaged. It is mechanically fail-safe in the event of critical electrical or control fault. When the vehicle is in AWD state, all-wheel power will be maintained for consistency; when the vehicle is in the 2WD state – or secondary axle disconnected – the secondary axle won’t be suddenly engaged, which would cause big jerk, or even wheel lockup at low traction. DirectFluxTM bi-stable clutch has a great performance on the action time. The differential locker and disconnect driven by DirectFluxTM bi-stable EMDC have been tested on JJE’s Dynamometer. The average action time is less than 70ms, and only current pulses are needed for engagement and disengagement. With JJE’s disconnect clutch, the drag loss reduction is remarkable. In a typical 200kW electric drive unit with permanent magnet motor, at 150km/h vehicle speed, the drag loss reduction is greater than 90%, or from nearly 8kW to less than 500W.

Differential Locker

JJE debuted industry’s first electromagnetic bi-stable differential locker at 2022 CTI US. Bi-stable’s greatest advantage is still fail-safe – in the event of critical electrical or control fault, this bi-stable feature can prevent sudden locker release and dangerous loss of tractionThis bi-stable DirectFluxTM differential locker will be used in high capability pick-up trucks, SUVs and off-road vehicles in independent electric drive module (EDM) or eBeam axles. It will be launched into production in 2023 in JJE’s newest 6000Nm, 300kW Silicon Carbide EDM for a high-end 4×4 SUV by a leading OEM, which features over 100% gradeability.“JJE has been developing and producing electromagnetic clutch for over a decade”, says Ping Yu, JJE’s Chairman and Chief Engineer, “we have pioneered electromagnetic dog clutch’s application in many areas and generated multiple global patents. The introduction of the bi-stable clutch technology is more exciting – it brings security like a mechani-cal sleeve clutch while maintaining or even improving all other great aspects of an electromagnetic clutch. It will further reinforce our leadership in electric drive technology”.

Development of “JTEKT Ultra Compact Diff.” for eDrive system

Posted on 10th February 2023

Contribution to further eAxle compactness and higher power density

Makoto NISHIJI, Senior General Manager / Chief Engineer, Driveline CE Department, Automotive Business Unit, JTEKT Corporation

In response to the strong expansion of the battery electric vehicle (BEV) market, JTEKT has developed and just announced “Ultra Compact” product series, JTEKT Ultra Compact BearingTM, JTEKT Ultra Compact SealTM and JTEKT Ultra Compact Diff.TM aiming for e-axle size and weight reduction. (Fig. 1)

“JTEKT Ultra Compact Diff.TM (hereafter referred to as JUCDTM)”, is new differential proposal for BEV e-axle using very unique/patented differential gearing. JUCDTM is extremely small compared with traditional  two pinion – one piece housing bevel gear type differential for the same strength.*JTEKT Ultra Compact Diff. and JUCD are registered trademarks of JTEKT.

Needs for eAxle compactness
Following with automotive electrification growth trend and also high ratio of 4 Wheel Drive BEV trend, development and production of eAxle is growing rapidly worldwide. e-axle is the heart of the eDrive system, and integrated inverter, motor, and reducer including differential. In order to develop a better BEV keeping enough battery capacity installation space, the e-axle is required to be smaller and should have much higher  lower density (power/weight ratio) in future. In response to this market need, demand of very compact differential for e-axle is expected to grow, and will replace the typical bevel gear type differential widely used for traditional vehicles.

JUCD Background
JTEKT has developed a very compact size and highly durable differential as “JTEKT Ultra Compact Diff.”, which is suitable for BEV e-axle. A differential is a device that absorbs the rotational speed difference between the left and right wheels that occurs in cornering, and transfer the torque between the drive power source to both wheels.

We have further evolved our “No.1 & Only One” product, the Torsen LSD technology, which is a high-performance differential suitable for high power 4WD/sports vehicles, by adding new knowledge of gear design and machining technologies. Introducing smaller gear module geometry into the unique composite planet gear set, we have made it smaller in radial and axial directions, and reborn as “JUCD” general-purpose differential for wide range of eAxles. * LSD: Limited Slip Differential

JUCD Features and Advantages

• High torque density and durability.
• Wide range of torque capacity.

Compared to the bevel gear type differential, JUCD has an increased mesh quantity and wider mesh width at larger diameter between planet gear and side gear. This is possible by using smaller diameter parallel axis planet gears which are directly supported by the housing bore similar with journal bearing structure. (Fig. 3) As a result, for the same differential gearing functional volume, the ultimate strength is more than doubled. Consequently, for the same ultimate strength, the required volume is less than half for JUCD. (Fig. 2)

In addition, high durability is ensured by reducing each load of the sliding surfaces between planet gears outside diameter to housing bore, compared with the bevel gear type differential pinion gear hole to drive pin. (Fig. 4)

JUCD can support wide range of torque capacity requirement, by selecting the number of side gear teeth and the size of differential outer diameter and/or additional planet gear set, while keeping the common planet gear sets and differential width. (Fig. 5) With these, JTEKT can now propose the optimum ultra compact differential for various eAxle reducer structures and torque requirements. JUCD contributes to the further eAxle compactness and higher power density, and also improves flexibility of the eAxle mountability to the vehicle.

Improve electricity power consumption and safety performance
JUCD also has mild and stable torque biasing LSD characteristics derived from its unique structure, mainly by planet gears outside diameter to housing bore friction as journal bearing structure. This feature contributes to reducing the vehicle wheel friction brake load that intervenes when the tire slips at vehicle start on slippery road surface or climbing a hill. It also contributes to expand the range of regenerative braking situations by stabilizing vehicle behavior during deceleration. These effects are expected to improve electricity power consumption. In addition, these characteristics also contribute to improve straight-line stability, which will reduce continuous steering wheel angle adjustment during steady straight-line driving, contributing to reduce driver’s fatigue and improve ride comfort. (Fig. 6)

For more detail
JTEKT Ultra Compact Diff.TM: www.jtekt.co.jp/e/news/2022/220831.html
JTEKT Ultra Compact BearingTM: www.jtekt.co.jp/e/news/2022/221018.html
JTEKT Ultra Compact SealTM: www.jtekt.co.jp/e/news/2022/221024_3.html

 

Magna’s eBeam™ Family for Truck and LCV Electrification

Posted on 3rd February 2023

Although light trucks and light commercial vehicles are used for different purposes, the requirements are similar in terms of robustness, performance, package compatibility, etc. The Magna eBeam™ family offers a flexible electrification solution that covers class 1 to 6 trucks as well as LCVs up to 7,5 tons.

Introduction:

The electrification of pickup trucks has recently become a major topic, especially in North America. Solutions are needed that do not compromise on robustness, payload, or towing capacity. In Europe, these trucks have been playing a comparatively minor role so far. However, there is a big market for electrified light commercial vehicles (LCV) and small commercial trucks. These may not have major require-ments regarding off-road capability, but the expectations for payload capacity are similar.

The Magna eBeam™ product family, is compatible with class 1 to 6 trucks, which compares to a gross vehicle weight of up to 11.793 kg or 26.000 lbs respectively. Regarding LCV and truck classes in Europe, classes are typically differentiated into 4,25 tons and up to 7,5 tons, the latter requiring a special driver’s license. Like in American trucks, there are many different requirements as to robustness, power, package, and weight. The new Magna eBeam™ product family addresses these through several variants, which can be seamlessly integrated into existing vehicle platforms.

Rear axle requirements for trucks and LCVs

Pickups are used for work and transport. They should be able to carry large loads and serve as towing vehicles, for example for boat or equipment trailers. At the same time, they are being used in daily traffic situations, requiring high comfort in terms of suspension, NVH, etc.

LCVs, although their purpose is quite different, have similar requirements. Typical applications are delivery services, logistic companies, vehicles being used by craftsmen, installation services, etc. Especially in terms of the load on the driven axle, requirements are similar to light trucks, sometimes even higher.

Based on customer surveys, Magna developed the new eBeam™ product for all these kinds of private and commercial use. There were several objectives: Firstly, an electric rear axle must not have any disadvantages compared with ICE-based powertrains and drivetrains. Secondly, a cost-effective solution was crucial. Thirdly, the new technology should enable full electrification within the typical ladder frame of existing vehicle platforms.

Suspension architectures for heavy-duty applications

Traditionally, light trucks and some LCVs have often been designed with a beam axle, which has proven to be particularly robust in practice. One main characteristic of the beam axle is its continuous lateral structure for high rigidity. Starting its development project, Magna also investigated De Dion axles and independent suspensions, which are common in passenger cars and SUVs, (Fig. 1). The following characteristics were compared: cost, weight, shaft angle, packaging, towing, and payload capacity.

Figure 1

In comparison, the independent suspension is disadvantageous in terms of cost and weight, but also regarding payload and towing capacity. The De Dion axle showed disadvantages in terms of towing, cost, weight, and payload. Moreover, it is significantly inferior regarding packaging and half-shaft angles, the latter being crucial in off-road driving. In all the areas mentioned, the beam axle proved to be superior for the target applications mentioned.

One potential disadvantage of the beam axle is that it has a higher unsprung mass compared to an independent suspension. The independent suspension, on the other hand, would require a sub-frame system, increasing the sprung mass, and compromising payload as well as towing capacity. Investigations and simulations of typical use cases have proven that the unsprung masses do not result in any noticeable ride comfort disadvantages. The decision was therefore taken to develop a whole family of structure-oriented electric beam axles with different application-dependent design options.

Variants for different applications

The two critical performance factors for the vehicle classes we are looking at are continu-ous power and peak torque. They are primarily influenced by the GVWR, which by definition stands for the gross vehicle weight rating over both axles.

Figure 2

Besides these, there are two more essential requirements defining the drive and beam archi-tecture. One is the package: For example, possible obtrusion of the e-motor into z-direction can be an issue, especially for LCVs with the target to keep a low loading height. Another as-pect is rigidity: It can be said that from 3500 to 4500 kg GVWR (~ 8000-10.000 lbs) upwards, the rigidity of the horizontal eBeam™ structure must meet higher demands, (Fig. 2).

The eBeam™ family includes both coaxial architecture for lighter applications and an offset architecture for Class 3 and above, (Fig. 3). In the coaxial architecture, the eDrive is part of the weight-bearing structure, whereas the offset architecture is mounted to a solid beam structure. The e-motor is installed coaxially, with the gearbox close to the center. All mounting points to the frame correspond to those of conventional suspensions, complying with OEM specifications. The coaxial architecture ensures a similarly compact package as a conventional beam axle. As a result, practically no vehicle-side modifications must be made in terms of package, spring mounting, wheel end, etc.

Figure 3

For applications above – 3250 kg gross axle weight rating (GAWR) an offset architecture of the eBeam™ is available. The offset mounting of the e-motor enables a higher structural rigidity for applications with very high payload and towing requirements. Whereas GVWR defines continuous power and peak torque, GAWR is the defining factor for the axle structure. This is why, depending on the application, the Magna eBeam™ flexible family approach includes both coaxial and offset solutions. For example, depending on the OEMs model alignment, class 3 truck architectures may be based on either coax or offset architectures.

Apart from these two basic design variants, there are some further options: a one-speed version with two e-motors and a two-speed product with one e-motor, as well as an electric locking differential, disconnect system, and a park lock. Especially for certain off-road applications, there is also a steerable eBeam™ for front use available.

Electrification opportunities

The trend towards truck electrification in North America is evident and being pursued by all major OEMs in the US. There are especially two approaches that set the Magna solution from others: One is the modularity and scalability of torque, power, and architecture, which cov-ers all classes of trucks and light commercial vehicles. Secondly, Magna offers the in-house expertise to provide advanced traction and driving dynamics add-on value. For example, this includes dedicated trailer-tow, off-road, rain/snow, and city/highway modes, which dis-tribute the e-motor torque between the front and rear axle for best efficiency, traction, and driving safety under any driving conditions.

As to LCVs, the eBeam™ offers similar benefits. LCV applications may have another purpose, but the requirements regarding power, torque, rigidity, package, etc. are very similar. The eBeam™ family offers the capability to tailor these while relying on standard products of the Magna eDrive family. This makes it a promising and versatile product for the growing field of emission-free delivery traffic.

The Automotive Industry Drives Sustainability

Posted on 31st January 2023

The days of viewing the powertrain as a system on its own are gone. As the 21st CTI Symposium in Berlin showed, the challenges even extend well beyond the vehicle itself. Software and networking play an increasingly central role; circular economy and social responsibility are extending the responsibilities of OEMs and suppliers; and competition for the best drive technology is ongoing. Download the Event Report and read more about CTI Symposium Germany 2022.

 

European Electrification Outlook to 2035

Posted on 18th January 2023

The fragmented situation around the world

A. Saboor Imran and Romain Gillet, S&P Global Mobility (formerly IHS Markit | Automotive)

The regional propulsion mix is a subject of multi-dimensional, complex, and interrelatedness with various sensitivities. It is based on factors such as compliance, regulations, policies, industry perspective, consumer behaviour, and technology developments.

Propulsion strategies are now governed by an increasingly complex set of interactions and influences whose impacts vary across the regions. The aim is to speed up the transition to electric cars and fight climate change. To that end, three regions (EU28, Mainland China, USA) have adopted some stringent regulations for the years to come, leading to more rapid changes within the local powertrain trends. In order to comply, carmakers competing in these markets, have to roll out specific product strategies relying essentially on electrification.

The deviation of BEV across these regions is immensely different based on each local factor. By the end of this decade, the EU BEV rate is projected to reach more than 60%, whereas Greater China would be close to 50%. North America is also catching up with the pace of the EU and Greater China in electrification adoption. So far, the expected production share is around 40%. However, at the global level, we will likely observe a 2-speed electrification development, with those three regions being far ahead of the others due to the lack of stringent regulation elsewhere.

As a consequence, the latest volume projection anticipates more than half of the Global light vehicle production to be Electric cars as soon as the early years of the next decade

Source: S&P Global Powertrain production forecast September 2022
*ICE Based PWT = Internal Combustion Engine + Mild Hybrids + Full Hybrids

Focus on EU – The projected impact of the revised regulation outlook

In Europe, the predominant factor behind this massive shift is the regulatory framework. The European convergence towards electrified powertrains is the result of two types of legislation:

• CO2 reduction, trajectory to mitigate climate change
• Pollutant Emission standards, to tackle the local pollution matters

Following the CAFE (Corporate Average Fuel Economy) CO2 framework revision with the introduction of more stringent targets in 2020, each Carmaker will further see their specific targets being revised downwards again for 2025 and 2030 with -15% and -55%, respectively. Consequently, the powertrain strategies favor BEV adoption as it would not be possible for carmakers to comply without a high level of electric cars within their fleets. Furthermore, with the recent decision by the European Union that carmakers should achieve a 100% cut in their CO2 emissions by 2035, there is no other way for the OEMs but to scaling-up on electric vehicles.

Source: S&P Global Mobility Powertrain Production September 2022

Zero-emission technologies to decarbonize mobility

From the projected production outlook, around one in four cars produced in 2025 will be electric before  accelerating strongly in the second half of the decade to reach almost two in three by 2030 to provide enough BEVs to the relevant markets to comply with the CAFE targets. This massive volume growth will also be supported by a substantial ramp-up of dedicated BEV platforms to underpin these new vehicles. Therefore, this complete shift in the regional propulsion mix will materialize by a tipping point in 2029, where BEV will become the leading technology against all the other ICE-based configurations.

In order to reach zero-emission fleets by 2035, Fuel Cells (FCEV) could also be a viable alternative to BEVs, featuring tailpipe zero-emission as well. However, projected volumes are still minimal within the forecast horizon as certain challenges remain to scale the hydrogen powertrain properly. The critical drawback here is certainly the lack of existing infrastructure, and it would prove to be an immense challenge to have widespread H2 availability for passenger cars. Also, to contribute to the industry decarbonization path, mobility would need to get access to a low-carbon Hydrogen ecosystem that did not reach the required scale so far. That being said, it should not prevent some pilot programs from being launched (fueled by hydrogen produced by natural gas reforming), particularly in the light commercial vehicle area, which probably offers the best business case for FCEV at the moment in Europe.

As for eFuels, even if focusing a lot of attention recently, the current EU regulatory framework does not offer a clear route as it is not considered a zero-emission technology within the existing EU mandate. On top of that, other industries (aviation, MHCV, off-highway) will likely rely on these developments as part of their decarbonization roadmaps, eventually creating a certain form of competition leading to limited car availability. E-Fuels could anyway have a potential market in motorsport and accelerate the Vehicles-in-operation decarbonization in some markets.

On the other hand, some remaining conventional powertrain shares would remain almost flat from 2029 onwards, primarily driven by some Eastern European production activities (Russia, Uzbekistan, Turkey) and not being destined for EU markets. Indeed, as clear roadmaps for electrification do not exist yet in these markets and in light of the latest geopolitical developments, CIS operations will become more isolated, following its path, with foreseeable very limited electrified volumes within the next 15 years.

Hybridized powertrains as bridging technologies alongside BEVs

While electric cars will represent most of the volumes in the future, the transition period will definitely require alternative options. In waiting for the EV era to reach its full maturity in becoming the mainstream technology, hybrid powertrains (from mild hybrid to plug-In hybrid) must spread heavily across all segments to bring some form of electrification to almost all vehicles.

The hybrid powertrain portfolio will essentially consist of three different technologies – plug-In hybrid vehicles (PHEVs), full-hybrid vehicles (HEVs), and mild hybrid vehicles (MHEVs) – with various associated levels of cost and efficiency.

Once perceived as offering the best of both worlds, plug-in hybrids (PHEV) are now facing different headwinds that should eventually even question their availability on many nameplates. Indeed, while playing an essential short-term role as transition technology to bridge customers to the electric era, based on the latest developments, it appears that plug-in hybrids (PHEV) will eventually fall down quite shortly from 2025 onwards. The technology is expected to peak in the mid-decade before strongly ramping down. One of the reasons behind this quick demise is to remain competitive and comply with future regulations. Battery capacities must increase to achieve longer zero-emission ranges, driving additional costs.

Moreover, from the regulation point of view, the utility factor currently used for the homologation process must be revised around 2025 to reflect the real driving emission level better. Consequently, the certified CO2 figure will undoubtedly be adjusted upwards, jeopardizing the current PHEV benefit within OEM portfolios. Volumes should then reduce, still focusing almost exclusively on higher segments.

Source: S&P Global Powertrain Production forecast August 2022

In parallel, full-hybrid vehicles (HEV) will still represent an attractive technology for OEMs to reduce their average CO2, especially in mainstream segments. While it was initially mainly developed by very few Asian OEMs, more carmakers now rely on this technology for the remaining markets,  not transitioning to BEVs at the same cadence. There is also a potential for this technology in other markets (such as Asia and the U.S.A), offering some attractive product development synergies to better leverage the associated cost.

Last but not least, mild hybrid technologies provide a certain efficiency level with lower costs to ICEs. Therefore, it does offer opportunities for carmakers, suppliers, and customers before the complete death of ICE. While this technology alone would certainly not bring enough savings to comply with the new CO2 targets, in covering different features thanks to the 48V electric machine, it helps anyway to reduce emissions slightly. It will progressively become almost standard in Europe. Furthermore, to deal with the extended boundary conditions of the RDE (Real Driving Emission) procedure as part of the EU7 pollutant standard, cold starts compliance might require EHC (Electric Heated Catalyst) device for some powertrains. Hence, 48V systems are likely to be installed to fulfill the power demand, simultaneously creating opportunities for mild hybrid architectures.

Different architectures coexist, but volumes will still be driven by P0 systems in the future. Most of the EU7-compliant engine families should feature such systems as standard. However, some OEMs like Stellantis or Volkswagen will adopt different technology routes with, respectively, P2 and P0+P3a rollover for some of their upcoming platforms and vehicles. Another significant development is the eAWD 48V systems. Installing a 48V drive module on the rear axle, it brings an attractive opportunity to offer an all-wheel drive option also on platforms that were initially not designed for mechanical AWD. Typically Renault and Stellantis are the two groups exploring this technology with their CMF and CMP platforms, with P0+P4 and P2+P4 layouts, respectively.

Source: S&P Global Powertrain Production forecast August 2022

A tremendous challenge to the battery ecosystem

Source: S&P Global Powertrain Production forecast August 2022

Batteries are a key technology to successfully achieving the targets for decarbonization. As manufacturers rapidly move towards the growing electrified industry, more resources are put in place to make batteries more affordable, efficient, and available. Collaborations play a vital role between carmakers, battery cell manufacturers, start-ups, the auto industry, and mobility providers to strengthen Europe‘s fully electric future further.

As there will be associated risks due to the raw material availability, the right battery pack sizing approach must be adopted to mitigate the shortage threat. As greater efficiencies are achieved (thanks to improvements to energy density, thermal management, optimized cell chemistries, and advanced battery management systems to extend battery lifetime or also with the vehicle platform design), the average battery capacity trendline will tend to stabilize.

However, in parallel, in order to cover all areas of the market and to maintain a certain level of affordability for some vehicles, the range of combinations offered will be extended to both the higher and lower end. Other improvements, such as high voltage architectures, would improve charging time, peak power, copper usage, and the vehicle‘s overall weight.

At the global level, this will lead to a battery demand exceeding 3TWh in 2030. Carmakers are therefore striking deals with battery suppliers to ensure they can fulfill their targets. Battery cell production must increase, and this scale-up has resulted in a number of new facilities being built or existing ones repurposed as ‘Gigafactories’.

There are aspects of lithium-Ion batteries that must be considered and accounted for in the regulatory framework. As we move away from tailpipe emission monitoring towards a broader scope, it will be imperative that BEVs are adequately scrutinized. Concerns around mining emissions, lifetime energy usage and recyclability will likely be included in the new scope. These steps could help mitigate the geopolitical risks associated with the battery ecosystem.

Conclusions

For light vehicles, BEV will be the mainstream option to switch the EU market to zero-emission by 2035. Decarbonization roadmaps from various sectors require different solutions to fulfill each market constraints.

The transition period in Europe will be relatively short, a decade or thereabouts, this might take much longer in more cost-sensitive markets and where regulation is less severe. Although ICE-based powertrains will be phased-out rapidly in Europe, there is a potential to continue production for a considerable time, serving slower transitioning markets.

Europe aims to lead the transition towards net-zero mobility. Achieving these targets will be challenging for car manufacturers as this will require an optimized global carbon footprint based on a sustainable supply  chain in operating markets. The fight against climate change is only possible with widespread renewable electricity to produce the components required for BEV proliferation and be circular on material utilization and waste.

Policy and associated financial risks have served as key market drivers for a low-carbon economy. They will continue to propel the automotive industry‘s decarbonization progress with additional sustainability frameworks.

Now available: CTI magazine 2022 edition

Posted on 14th December 2022

After a two-year break, we are again providing you with content beyond our annual events. The technical papers in this issue cover developments such as bi-stable electromagnetic clutches from JJE
and ultra-compact differentials for edrives from JTEKT European Operations. Magna International reports on the versatile eBeam drive for electrictrucks and light commercialvehicles, while the Technische Universität Darmstadt has developed a twodrive electric powertrain that promises outstanding efficiency in both electric and dedicated range extender operation. Marelli introduces an eaxle family that is intended to cover 90 % of the market.

We also report on last May’s CTI Symposium USA, where one much-discussed question was: “What are our electrification strategies during the transition phase until 2030?” On the same topic, we interviewed Michael Maten to hear his company’s viewpoint. General Motors, he says, has uncompromising electrification plans: “We don’t want to make what we call half a vehicle.”

Another game changer is the field of tomorrow’s sensor technology and E/E architectures in electrified vehicles, plus the growing importance of in-vehicle smart devices. So to round off this issue, we held a short interview on the subject with our advisory board member Sven Beiker from Stanford University, California.

Our special thanks to everyone who helped make this issue of CTI Mag happen. We hope you enjoy it!

Get your CTI magazine here

We need to harmonize the worlds of battery pack and cell

Posted on 2nd December 2022

At the CTI symposium in Berlin from 6-7 December, Mareike Schmalz, Team Leader Battery Pre-Development, Automobil-Prüftechnik Landau GmbH, Germany, will speak about “Range vs. fast charging capability – new development tools for solving the optimisation conflict of HV-batteries”.

We had the opportunity to interview Ms. Schmalz beforehand.

At the upcoming CTI event in Berlin, you will talk about optimization conflicts of high-voltage batteries. What are these conflicts?

We see major advancements at all system levels of a battery. The cell is continuously evolving in its chemical composition, stoichiometry, and morphology. The conflict is to combine high energy densities with fast charging capability and safety. In system design, the trend points clearly toward compact cell-to-pack or cell-to-car concepts. As a result, problems and challenges associated with the cell and its integration – electrical, thermal, and mechanical – must now be solved at a system level. The battery becomes a structural element and its development process is increasingly interlinked with that of the overall vehicle.

Another issue you deal with in your work is thermal energy dissipation. What are the challenges in this area?

The battery releases heat during operation, especially under high electrical loads such as fast charging. To ensure safe operation and avoid derating due to overheating, the heat must be dissipated in a targeted manner. The concept of immersed cooling is now gaining ground. In contrast to the established indirect cooling, the cooling fluid flows directly around the battery cell. This offers a highly efficient heat dissipation but challenges lie in the system design, sealing concept, and formulation of a suitable dielectric fluid. Issues of material compatibility are likewise a key challenge.

From your view, which will be the most important development fields for traction batteries in the coming years?

At the system level, cell-to-pack development will be a major task. At the cell level, work will continue on improvements to cell chemistry. Great expectations are placed on solid-state batteries. Key development work lies in harmonizing the two worlds of the battery pack and cell and achieving a clean understanding of their interdependency. As an engineering service provider, APL is well acquainted with the diverse developments in the market as we work from cell chemistry up to the whole pack on fast charging, thermal management, safety, and operating strategies, to name a few.

Thank you for these insights, we are looking forward to your speech in Berlin.

Questions: Gernot Goppelt