{"id":29696,"date":"2022-08-20T12:03:41","date_gmt":"2022-08-20T16:03:41","guid":{"rendered":"https:\/\/autosector.com\/?p=29696"},"modified":"2022-08-20T12:03:41","modified_gmt":"2022-08-20T16:03:41","slug":"axial-flux-electric-car-motors","status":"publish","type":"post","link":"http:\/\/autosector.com\/?p=29696","title":{"rendered":"Axial flux motors: Mercedes and Ferrari\u2019s edge in electric car performance | Autoblog"},"content":{"rendered":"

When drivers of future Mercedes AMG<\/a> models stomp the accelerator of their electric performance cars, they\u2019ll get extra oomph out of the batteries<\/a> from something that sounds straight out of “Back to the Future<\/em>.”<\/p>\n

No, not\u00a0flux capacitors<\/a>, but axial flux motors.<\/p>\n

Mercedes-Benz AG<\/a>\u00a0and\u00a0Ferrari NV<\/a>\u00a0are turning to this type\u00a0of electric motor\u00a0to generate headrest-hitting torque. Axial flux motors are much smaller than predominantly used radial motors, yet pack a more powerful punch.<\/p>\n

High-end motors like these\u00a0will be crucial to brands like AMG<\/a> and Ferrari<\/a>\u00a0as they\u00a0race to electrify the high-performance vehicles that earn prestige and bumper profits. All EVs offer the sensation of\u00a0instant acceleration,\u00a0from Nissan<\/a>\u2019s Leaf to Tesla<\/a>\u2019s\u00a0\u00a0Model S Plaid<\/a>. Whereas in the combustion age, quicker times off the line and higher top speeds were achieved with more engine cylinders, manufacturers will differentiate performance EVs by\u00a0getting the most out of batteries with lighter and more efficient motors.<\/p>\n

\u201cThe power-to-weight ratio is really a record number, and much better than conventional motors,\u201d\u00a0Markus Schaefer,\u00a0Mercedes<\/a>\u2019s chief technology officer, said of the automaker\u2019s upcoming AMG electric vehicle<\/a> platform. \u201cIt will make use of the small size of the motor.\u201d<\/p>\n

With each press of the accelerator, EV drivers push hundreds \u2014\u00a0and in some cases thousands \u2014\u00a0of amps of electric current to copper coils. When these coils are energized, they become electromagnets with attractive and repulsive forces. The magnetic force created by\u00a0a stationary stator surrounding a rotating rotor produces the torque that turns the wheels of the vehicle.<\/p>\n

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In axial motors, rather than have\u00a0a rotor spin\u00a0inside a stator, disc-shaped rotors spin alongside a central stator. This leads\u00a0the flow of current \u2014\u00a0the flux \u2014\u00a0to travel\u00a0axially through the machine, rather than radially out from the center. Since\u00a0the motor generates torque at a bigger diameter, less material is needed. Yasa, an Oxford, England-based manufacturer of motors used in Ferrari\u2019s\u00a0SF90<\/a>\u00a0and\u00a0296\u00a0GTB<\/a>\u00a0plug-in hybrids<\/a>, uses just a few kilograms of iron for its stators, reducing the mass of the machines by as much as 85%.<\/p>\n

Yasa\u2019s motors are the brainchild of\u00a0Tim Woolmer<\/a>, whose work on them were the focus of his\u00a0electrical engineering PhD at the University of Oxford. Within a few years of earning his doctorate, Jaguar Land Rover<\/a> made plans to use\u00a0Yasa\u2019s motors in the\u00a0C-X75<\/a>, a hybrid-electric two-seater with enough horsepower to rival\u00a0the Porsche 918 Spyder<\/a>, McLaren<\/a> P1\u00a0and Ferrari LaFerrari<\/a>. While JLR ended up canceling the project due to financial constraints, Yasa\u2019s motors found their way into the\u00a0Koenigsegg Regera<\/a>\u00a0hybrid hypercar<\/a>, followed by the\u00a0Ferrari SF90.<\/p>\n

In July of last year, Mercedes announced it had\u00a0acquired Yasa<\/a>\u00a0for an undisclosed sum and would put its motors in AMG models slated to launch starting\u00a0in\u00a02025.<\/p>\n

\u201cIf you look at the history of automotive generally, the auto companies have wanted to have the engine,\u00a0their core technology,\u00a0in-house,\u201d Woolmer said in an interview.\u00a0\u201cThe batteries, the motors, this is their core technology now. They recognize the importance of having long-term differentiation in these spaces, so they have to bring it in-house.\u201d<\/p>\n

The most important aspect of axial motors is form-factor potential, according to\u00a0Malte Jaensch, professor of sustainable mobile drivetrains at the TUM School of Engineering and Design in Munich. Their\u00a0smaller size could allow carmakers to put one motor on each wheel, which isn\u2019t feasible with radial motors.<\/p>\n

Putting a motor on each wheel \u2014\u00a0or at least one on each axle\u00a0\u2014\u00a0could translate into hair-raising EV driving performance. The innovation allows for torque vectoring that better controls\u00a0how much power the motors send to each individual wheel\u00a0for improved\u00a0agility. High-speed cornering may help AMG and Ferrari drivers get over the lost\u00a0roar of their\u00a0eight-, 10- or 12-cylinder engines.<\/p>\n

Yasa\u2019s motors also could completely remove the need for a powertrain on the so-called skateboard underneath the middle of an EV,\u00a0Woolmer said. That would open up more space for engineers to package batteries, make more room for bigger front and rear trunk\u00a0spaces,\u00a0or allow\u00a0designers to experiment with new aerodynamic ideas.<\/p>\n

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The small size and light weight of axial motors won\u2019t just benefit high-performance cars. They\u2019re also finding a home in aerospace, leading Yasa to spin\u00a0out its electric aviation division\u00a0Evolito last year.\u00a0The world\u2019s fastest electric vehicle, Rolls-Royce<\/a> Plc\u2019s electric aircraft called the Spirit of Innovation, uses\u00a0three axial flux motors to drive its propeller. The aircraft can travel around 380 miles (612 kilometers) per hour, making it faster than the Spitfire fighter aircraft that was powered by a Rolls-Royce V12 engine.<\/p>\n

\u201cThe critical thing is their efficiency,\u201d said Matheu Parr, the Spirit of Innovation project leader at Rolls-Royce. \u201cThis allows you to keep the weight of the aircraft low.\u201d<\/p>\n

Axial motors won\u2019t necessarily be the death knell of radial motors, which deliver higher top speeds. This\u00a0led\u00a0Ferrari to use two radial motors on the front axle of the SF90, along with an axial motor on the rear axle. For the 296 GTB<\/a>, handling was deemed more important, so only a lighter axial motor was used between the engine and transmission.<\/p>\n

\u201cIt\u2019s just a matter of what kind of driving experience you want to design for your customers with a specific engine,\u201d said Davide Ferrara, Ferrari\u2019s electric motors manager. \u201cDifferent voices make sweet notes.\u201d<\/p>\n

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