At Plant Landshut, the place a number of the BMW’s most superior electrical parts are developed, we attended a workshop that supplied an inside take a look at the Neue Klasse’s electrical drivetrain. Recent off discussions about BMW’s sixth-generation (Gen6) battery expertise, our consideration turned to the second half of the equation: the electrical motors answerable for placing energy to the pavement.
Whereas battery developments typically dominate EV discussions, motors and energy electronics are simply as essential in defining how an electrical automobile performs, how effectively it makes use of vitality, and—most significantly for BMW—the way it drives. And never surprisingly, the corporate isn’t following the business playbook.
Extra Energy, Extra Flexibility
In contrast to many automakers relying solely on everlasting magnet synchronous motors (PSM)—which use uncommon earth supplies—BMW is taking a special strategy, combining externally excited synchronous motors (EESM) on the rear axle and asynchronous motors (ASM) on the entrance.
BMW’s Gen5 electrical drive system, utilized in fashions just like the iX and i4, has matured since its introduction in 2018. However Gen6 improves in practically each means. One of many greatest adjustments? Extra motors, extra energy, and a extra adaptable platform.
As a substitute of the dual-motor setups utilized in most of at present’s efficiency EVs, the Neue Klasse platform can accommodate as much as 4 electrical motors. That’s a significant leap in flexibility. These motors are lighter, extra environment friendly, and cheaper to provide, due to refinements of their design and supplies.
BMW engineer Michael Salmansberger gave us a better take a look at the brand new motors, explaining that 4 variants of the EESM items are deliberate, every weighing round 125 kg (276 lbs) and producing between 268 hp (200 kW) and 402 hp (300 kW). The ASM will include two variants within the entrance axle, with 120 and 180 kilowatt on the rear axle.
The ability potential is apparent—BMW may scale from a single-motor Neue Klasse sedan to a quad-motor, high-performance M automobile with over 1 megawatt (1341 hp) utilizing the identical base expertise. We’ve already seen what the BMW Imaginative and prescient Driving Expertise prototype can do.
There’s additionally a change in how that energy reaches the wheels. As a substitute of a standard two-speed gearbox, BMW is utilizing a single-speed transmission, but it surely operates as a two-stage gearbox due to an intermediate shaft that adjusts the gear ratio as wanted. It’s primarily a high-performance single-gear system designed for each motors.
Why BMW is Shifting Away from Everlasting Magnets
Most premium EVs at present, together with these from Tesla, Lucid, and Mercedes-Benz, depend on everlasting magnet motors for his or her excessive effectivity and compact dimension. The catch? They require uncommon earth supplies, that are costly, environmentally problematic to mine, and topic to geopolitical provide chain points.
BMW’s externally excited synchronous motor (EESM) eliminates that dependency by producing its personal magnetic subject utilizing an electrically excited rotor as a substitute of a everlasting magnet. This has some key benefits:
- No reliance on uncommon earth supplies, making sourcing and manufacturing extra sustainable.
- Extra exact management over torque supply, for the reason that magnetic subject might be adjusted dynamically.
- Lowered vitality losses at decrease hundreds, enhancing total effectivity.
Nevertheless, there’s a motive EESM motors aren’t frequent—they require electrical enter to generate the magnetic subject, which might barely scale back effectivity underneath fixed high-load circumstances. BMW acknowledges this however argues that in real-world driving, the flexibility to optimize energy output dynamically outweighs the downsides. By adjusting the excitation ranges on the fly, BMW’s Gen6 motors can fine-tune effectivity based mostly on driving circumstances, one thing everlasting magnet motors can’t do as successfully.
A Smarter Entrance Motor for Effectivity
BMW’s selection to make use of an asynchronous motor (ASM) on the entrance axle is simply as strategic. In contrast to synchronous motors, an ASM doesn’t require steady electrical enter, which means it will probably stay inactive when front-wheel traction isn’t wanted. Which means much less vitality consumption throughout regular driving whereas nonetheless permitting prompt engagement when additional grip or energy is required.
Whereas ASMs are typically barely much less environment friendly when engaged in comparison with everlasting magnet motors, the important thing benefit right here is their potential to function with zero drag when not in use. This setup permits BMW to steadiness effectivity and xDrive efficiency dynamically, reasonably than forcing all 4 wheels to be powered always.
The end result? A system that maximizes vary in regular driving whereas conserving AWD functionality on standby for when it’s wanted.
Silicon Carbide: The Secret Effectivity Booster
Even with higher motors, energy electronics make or break an EV drivetrain. That’s why BMW is transitioning to silicon carbide (SiC) semiconductors (seen already within the facelifted BMW iX), which scale back vitality losses in energy conversion, permitting for:
- Extra environment friendly operation at 800V
- Decrease warmth technology, which means smaller cooling techniques and improved sturdiness
- Quicker and extra exact energy administration, enhancing each effectivity and responsiveness
BMW claims these adjustments contribute to a 20% effectivity acquire throughout the whole powertrain, although real-world outcomes will in the end decide how a lot of that interprets into improved vary and efficiency.
Scalability: From Effectivity to M Efficiency
One of many greatest takeaways from the Landshut workshop was how modular and scalable BMW’s new electrical drive system is.
A single-motor rear-drive Neue Klasse would be the best setup, however for high-performance fashions, BMW can add extra EESM motors for extra energy and AWD functionality. Future M vehicles may use a quad-motor setup, enabling superior torque vectoring, rear-biased AWD dealing with, and excessive energy outputs.
The system has been designed from the outset to permit for exact energy distribution between axles and particular person wheels.
A Completely different Method from the Competitors
BMW’s technique differs from opponents in a couple of key methods.
- Tesla and Lucid proceed refining everlasting magnet motor tech, prioritizing outright effectivity and energy density.
- Porsche and Audi take a hybrid strategy, combining PSM and ASM motors for efficiency optimization.
- Mercedes-Benz stays dedicated to uncommon earth-based PSM setups for his or her excessive effectivity and predictable energy output.
BMW is betting that its rare-earth-free strategy will repay in price, effectivity, and long-term sustainability, even when it requires extra subtle energy administration.
Engineering Over Hype?
Attending BMW’s Landshut workshop highlighted one factor: the corporate isn’t dashing into EVs simply to satisfy laws or comply with traits. It needs to use the identical engineering-led strategy that has outlined its combustion powertrains for many years. Will they rise to the highest? We are going to quickly discover out, however for now, the speculation sounds nice.
