After more than a century, in-wheel technology is ready to help transform mobility as we know it
For more than a hundred years, the internal combustion engine (ICE) – in all its shapes and forms – has been propelling us across land, sea and air. Now, its long-term future appears bleak given the ever-growing concerns of fossil fuels affecting the environment, more so given their supply is finite. Enter e-Mobility – a simple term until you scratch the surface deep enough to reveal a multitude of new or different technologies that all need to come together to keep future generations on the move.
The playing field of the automotive industry has significantly changed with the arrival of electric vehicles in the mainstream market. Today, electric vehicle design and production is not limited to only traditional players, but has become an open playing field. There is a vast number of competing powertrain architectures and technologies, some being simple adaptations of the traditional 100-year-old ICE concept, and others more advanced, which bring more radical changes to the vehicle as we know it. Since a lot of different technologies are possible and the development of mass-production compatible electric powertrains is practically in its infancy, vehicle makers are scrambling to find the right formula for the future user.
Currently, electric vehicles are competing on acceleration performance and range. In the future, the discussion will be less about cars and more about mobility. Vehicle makers will bring cars to the streets that are connected, have autonomous driving capabilities, and are made to be shared between multiple users. Needless to say, these vehicles will mostly be built on electrified platforms. As battery technology, cost, and production capacity improve, the priorities for the powertrain are shifting. Some of the traditionally most important development drivers will become less important.
As an example, one could postulate that the electric powertrain reached a level of efficiency where additional investments will bring only limited overall benefit compared to other possible improvements. And since some electric city cars currently exceed the performance of many ICE sports cars, there is not much need for performance improvement either. This thinking translates into the conclusion that the mechanical actuation of the next generation of vehicles will be much less in the spotlight, while function, safety and comfort, along with a high-level of autonomy and connectivity will become main drivers for vehicle design.
E-Mobility activists and electric vehicle technology companies like Elaphe Propulsion Technologies, are creating innovative solutions for designers of current and future vehicles. They lend a much-needed helping hand to EV developers to meet passenger comfort, safety and road security objectives: advancing state of the art on batteries, fuel-cells, motors, drive trains (or lack of drive trains), electro-mechanical control, on-board electronics, sensors, mechanics, thermal- and power management, all packaged in lightweight but durable, minimal maintenance structures.
For example, in-wheel electric propulsion can eliminate the entire conventional drivetrain, drastically simplifying and shortening the whole vehicle engineering process from concept to series production. Transmissions, gearboxes, drive shafts, and the associated space constraints are now becoming obsolete.
Figure 1 – An in-wheel motor has only a single rotating part – the wheel bearing. The assembly fits in existing design space within the wheel, and is built around the (still, for now) required friction brake, making all the transmission and gearing found in traditional cars, unnecessary.
Although the idea of an in-wheel motor platform was already proposed by Ferdinand Porsche at the turn of the 19th century, the underlying technology and the whole ecosystem at that time was in its infancy. A development of in-wheel propulsion over the past two decades has brought the technology to a mature, production-ready state where it now enables a fundamental shift in design for mobility. In-wheel motor platforms now have the potential to reshape the EV industry and support the shift away from performance focus, making way for innovation in packaging, user-experience, driving automation, new safety features, and optimization of the electric vehicle supply chain.
The in-wheel concept plays a significant role in the development of compact, transmission-free drive systems. Increased safety, improved handling and unparalleled traction control are just some of the benefits of the decentralized in-wheel architecture. Having a lower overall powertrain weight, a lower center of gravity and optimized balance, the dynamic behavior of the vehicle changes dramatically. The drive architecture, with its weight distribution and contact pressure at precisely the point of traction, allows greater control over the vehicle’s behavior in comparison to standard drives. More so when we consider the possibilities for integration of advanced systems, such as:
i) brake blending, which can greatly improve safety on different-adhesion surfaces,
ii) active traction control that is constantly optimizing the grip between the wheel and the road and
iii) torque vectoring, improving vehicle stability and keeping control over the vehicle’s dynamic behavior in unstable, critical situations, just to name a few.
In the late 1980s Elaphe’s co-founder imagined his ultimate powertrain concept by drawing inspiration from nature, in particular, the anatomy and mechanical energy generation of animals. He had good technical reasons to believe his research could be applied to cars and other vehicles in the future. The availability of more robust, new materials not available in the past and the advent of computer simulation methods, combined with a strong belief in the need for a simple, clean and highly efficient powertrain architecture with very few moving parts, drove further innovations.
Most importantly, the envisioned potential to change how a vehicle looks like, how it is used and how to lower its environmental impact, spurred Elaphe’s commitment to technological innovation. The initial designs proved the conceptual feasibility, so the team set up a company to support the development of this great technology for the benefit of our green planet.
Challenges along the way included how to deal with the influence of temperature and temperature variation. People rarely realize the effort that goes into designing a car component that works in conditions from -40°C to +85°C.
Figure 2 – Housed entirely within the hub, or in close proximity, Elaphe’s in-wheel drive systems comprise not only electric motors, but also integrated standard OE braking systems and functions performed in conventional engines by the clutch, transmission, differential and other related parts, making them redundant in the overall EV architecture and lay-out of in-wheel-driven vehicles.
Today’s vehicles are essentially built around parts that are needed for propulsion. The central engine, a big multi-speed gearbox and a transmission to the wheels leave little room for designing the vehicle with user mobility needs in mind. In order to build and design a vehicle around the user rather than the powertrain, this logic should be reversed.
Already today, a major trend is to reduce the footprint of underlying technology, freeing up space to enhance the user experience. With the growing importance of mobility services over individual vehicle ownership, the requirements towards user experience are leading to even more dramatic change.
The vehicle transformation through different levels of driving autonomy and digitalization requires a transformation of the underlying technology that moves the vehicle. In order for car designers to build vehicles around user’s needs, Elaphe believes the powertrain should become virtually invisible to the user, so the focus can be put on the »front-end« functionality. As in-wheel motors share space with existing components in the wheel, they become »invisible«.
But more importantly, the use of this architecture provides additional design space for a safety- and user-focused chassis. Unparalleled agility in all conditions is achieved thanks to independent multiple-wheel control, the full potential of which is realized with increasing autonomous driving functions.
Figure 3 – Integration of Elaphe’s in-wheel direct drive to an electric SUV, holding the the highest-performance record for in-wheel vehicle in history. The performance these motors can achieve without the need to transfer mechanical power from a central source to a wheel is astonishing – achieved without using any gears, transmissions or a differential.
The disruptive nature of the technology that can provide a sportscar performance while increasing driving range, is facilitated by a lighter built vehicle with less efficiency losses. Performance and efficiency are only two of the major benefits that the technology brings to the field of future mobility solutions.
Designing around the user
The more enjoyable the end-user experience is, the better the chances for success of a given vehicle application. Elaphe in-wheel technology delivers one of the smartest packaging solutions on the market and enables vehicle designers, for example, to lower outer vehicle dimensions for the same interior spaciousness. Having unified, modular, symmetric platform solutions can significantly reduce the manufacturing and development costs of multiple vehicle designs. Manufacturers can exploit a reduction in the total number of components, and save drastically on vehicle development costs.
In-wheel technology comes with multiple advantages thanks to packaging-space availability, overall vehicle weight reduction, and the implementation of advanced vehicle functions. It represents an essential part of the needed future advance of the electric vehicle – removing many parts in the drive assembly, enabling design freedom and advanced solutions in the conception of new, energy efficient, more spacious, lighter and safer mobility solutions.
The high versatility of in-wheel technology can power anything from small city EVs, to performance cars, from delivery vehicles to people movers and large public transportation. Enabling all these different solutions opens the door to new business models by unlocking potential through advanced functions. The propulsion solution can be fully interchangeable and fully upgradeable with new features and new user value while on the vehicle.
Where does this all lead to?
The industry is currently undergoing significant changes by transitioning from automotive to a mobility industry. Over the next years, it is very likely we will see a lot of work being done on light-weighting and minimizing volume footprint of vehicles in the cities, consolidation of powertrain components across models and brands, increased modularity and completely new concepts of multimodal transport.
While SUVs and similar vehicle sizes will likely continue to grow in numbers in the next years, we should begin to see increasing vehicle utilization rates and the gradual disappearance of diesel cars. Data and connectivity will become the backbone of the EV industry and smart cities. Safety of vehicles will set a completely new benchmark, and the line between a smartphone and the vehicle will become blurred.
Although the vehicle architecture has not changed much in past years, we see that more can be done in respect to smart packaging and development of new functions to support these trends. It is like using the internet – we did not know (we still do not know) everything it was capable of transforming, until we actually started using it. In-wheel technology is following a similar path. We are looking forward to experience and help shape the innovations for the needs that future mobility will bring.
Luka Ambrozic Elaphe