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04/09/2018
Automotive components: new pieces for mobility's puzzle

Electric car

 

The automotive industry is changing. But how and by how much? There is an easy way to figure it out: just look at how vehicle parts are changing

Nicodemo Angì

As they say, "the best is yet to come" in the automotive sector and as a consequence in the aftermarket too. In the next few years we will witness several epoch-making changes, such as a widespread popularity of electric and hybrid vehicles, autonomous cars and car sharing schemes.

The latter development appears to be potentially the most disruptive for a very simple reason: what would happen if companies like Uber or Lyft decide to take over a car manufacturer? Cars would be considered as mere "tools" and therefore fleet managers/manufacturers would produce reliable, spacious and versatile vehicles with little difference between them, in terms of aesthetic appeal  or equipment range.

This trend would apply to any car, whether electric/hybrid, conventional or autonomous, without changing its basic essence.

Conversely, radical changes are expected to affect autonomous and electric cars alike.

 

Fulfilling stringent rules

However these changes will be, in a sense, ushered in by the auto parts industry and manufacturers such as Schaeffler which recently released a full-bodied publication entitled Symposium 2018, providing a fairly accurate idea of the expected changes. To contextualize the situation we must talk about the new Wltc approval procedures, based also on Rde road tests, leading to more realistic emission and consumption measurements.

These new procedures, quickly adopted following the Dieselgate scandal, should provide more realistic data compared to the previous NEDC cycle.

Another key to understanding how the current scenario is changing is a forecast, by Schaeffler, on vehicle sales by 2030. Even assuming an aggressive market penetration of alternative cars, these will not completely disrupt the market.

30% of new registrations in 2030 will be totally electric, while an impressive 70% will still rely on traditional engines. Of these, 40% will consist of hybrid vehicles, while the remaining 30% will continue to use fossil fuels.

But wait, there’s more! Cars sold in 2030, despite the growing electrification, will hardly change the very essence of the traffic we are so accustomed to seeing, in fact in 12 years from now, 90 percent of the cars around the world will still have a traditional combustion engine on board!

 

Relying on heat engines

Combining these elements we understand that the newly introduced (and stringent) anti-pollution regulations will require a reduction in emissions that will largely fall on hybrid and petrol powered cars, since EVs, though rapidly growing, still make up an insignificant share of the market.

Therefore, the focus will fall on improving exhaust treatment devices and other strategies aimed at reducing emissions directly from the engine even before treating exhaust gasses.

Schaeffler’s experts mentioned hybrid vehicles, optimized combustion - for example by deactivating one or more cylinders when not needed, a strategy applied on the new (and award-winning) 3-cylinder Ford Ecoboost engine - and mechanical improvements for the reduction of internal friction.

As already stated, Schaeffler assigns a key role to hybrid systems, regardless of the voltage (both 48 volt and high voltage), and therefore more components, like its new P2 module, are bound to be used. This compact engine/generator fits between engine and transmission and can reduce consumption by 15 percent during the Wltp cycle.

This efficient high-torque module takes a lot of the “pressure” off the internal combustion engine, allowing it to coast along while recovering energy in the deceleration phase and to be driven in totally electric mode in plug-in hybrids. This solution is modular and can be used on series-parallel hybrids and power-split hybrids (the system Toyota uses in its Prius / Auris / Yaris hybrids) and is available in a 48 volt or high voltage version.

We mentioned the 48 volt system so we are going to look at the possible applications of this interesting solution. Pneurama has already written about it and therefore we will simply confirm that multiplying by 4 the voltage allows to reduce the intensity of the current to one quarter with the same power or to multiply by 4 the power with the same current. Hence, as a result, EVs are able to start the engine, recover energy and provide about 15 kW of extra power reducing consumption at the same time.

 

Meticulous improvements

Far from being futuristic, these technologies are already here, for example Renault has already used them on its Scenic and Grand Scenic Hybrid Assist, where new components have been introduced. If the transmission in an EV takes place through a “V” belt, its related tensioner requires 2 rollers since torque can come from the engine but, unlike what happens with a simple alternator, it can also go towards the engine.

Improvements on combustion engines certainly do not end here: variable timing plays an important role and Schaeffler has a number of variations in its portfolio, including the Multiair system developed alongside FCA.

In addition, maximum efficiency requires replacing the classic crankshaft bushing with a rolling bearing, a solution particularly indicated to strengthen the area near the “V” belt pulley. Here, in fact, important transversal loads increase friction which can be minimized involving transmission and timing.

Nevertheless, electric motors, notoriously very efficient, pose new difficulties to the bearings supporting the rotor. The first is high speed: these engines reach 15/18 thousand rpm and provide high torque immediately; in addition these bearings must also be silent since electric motors are known for generating little noise. Their working "environment" also exposes them to a large temperature difference between the inner and outer ring and the presence of variable magnetic fields that generate parasitic currents able to wear out the bearings. To solve this predicament, Schaeffler has developed a conductive ring which allows the potential difference between the bearing rings to be grounded.

 

Electric motors, hybrids and more

The German auto parts maker plans to improve power trains, whatever they are. So they have solutions for manual, robotised, double-clutch and torque converter transmissions. These are both mechanical, designed to maximize efficiency and comfort, as well as reduce emissions, optimizing efficiency.

Thus we find CVT transmissions with an integrated electric motor able to sustain high torques  allowing a vehicle to move in electric mode.

Currently studies are being carried out around a robotized gearbox that incorporates an electric motor: torque interruptions are eliminated and the auxiliary gears for reverse are done away with as their task is  taken over by the electric unit.

Finally, we would also like to mention the fact that Schaeffler is currently involved in developing a totally electric drive system. It is interesting to know that in electric motors also the type of winding has an effect on performance, a bit like the compression ratio in internal combustion engines. Schaeffler has tested a few of them finding that Distributed winding has a slightly higher yield than Airpinwinding and can also be used to build different types of power units.

Particularly noteworthy are the E-Axle modular units, which integrate in a single unit, engine, diff and possibly a 2-speed transmission which translates into great acceleration and high maximum speed. These can also be used to create 4 x 4 vehicles without the need for a transmission shaft.

And now a special component: the Wheel Module, a unit that integrates suspension, steering, engine and brakes. Conceived for autonomous urban transport vehicles, this compact module has an adaptable design that allows to assemble a 4-wheel drive and steering systems to different vehicle bodies, the action of which is controlled by a software developed by Scheffler itself. Sophisticated algorithms can automatically stop the vehicle even if all systems (note that even steering is done by-wire) are out of order, an essential feature in an autonomous vehicle.

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