Axial Flux Motor Powers Supercars to New Heights

Tesla was the first to patent a primitive electric motor with an axial magnetic flux.Nikola Tesla, that is, back in 1889. It took 126 years before the concept found its way into a car, the US$1.9 million, 1,500 horsepower (1,103 kW) Koenigsegg Regera hybrid in 2015. Even today, almost all the world's cars electric cars and hybrids rely on relatively inefficient and easy to produce radial– flow engines.

However, the latest electrified revolution is already in full swing. under the leadership of YSA. Founded in UK Tim Woolmer in 2009, as a result of his Oxford doctoral project, the company's pioneering development of axial flow. motors use hybrid supercars from many manufacturers: Ferrari, Lamborghini, McLaren and Koenigsegg. These include Ferrari 296 Special and the Lamborghini Temerario I recently drove Italy.

Powered by these powerful electric machines, these colorful Italians cut up the roads of Emilia-Romagna like pieces of Parma prosciutto. The Temerario's V-8 gasoline engine revs to the limit. stratospheric 10000 rpmhigher than any production supercar. Still not enough: the Temerario is also equipped with three YASA engines. The pair on the front axle provides all-wheel drive traction and peak power of 294 horsepower (216 kilowatts). A total of 907 hybrid horsepower (667 kilowatts) allows the Temerario to reach a top speed of 343 km/h (213 mph). electric motors will cleverly fill any gaps in petrol acceleration and improve handling with torque vectoring, while the electrified front wheels help the Lamborghini catapult out of corners with incredible ease.

With their compact design and excellent power-to-weight ratio, these engines set records on land, sea and air. world's fastest electric planeRolls-Royce Spirit of Innovation integrated three YASA engines into its propeller, allowing it to achieve a record top speed of 559.9 km/h (345.4 mph). Using technologies from our Formula E racing program, Jaguar used YASA engines for installation marine electric speed a speed record of 142.6 km/h (88 mph) in England's Lake District in 2018 (this record has since been broken).

Stated Power Density three times the best according to Tesla

In August, YASA engines helped assemble the Mercedes-AMG GT XX prototype. dozens of electric vehicle endurance records. Traveling around Italy's Nardo circuit at a constant speed of 186 mph (300 km/h), the Mercedes EV, with about 1,000 kilowatts (1,360 horsepower), covered about 5,300 kilometers per day. In 7.5 days, he covered 40,075 kilometers (24,902 miles), which corresponds to the circumference of the Earth. This time, charging stops were included at 850 kilowatts.

Mercedes F1 driver George Russell stands next to a Mercedes AMG GT XX during the record-breaking endurance race in August this year. The electric concept vehicle, powered by three YASA axial flux motors, traveled the equivalent of the circumference of the Earth in 7.5 days at a nearly constant speed of 300 km/h. The production version of the car may become a competitor Porsche Taycan. Mercedes-Benz

Mercedes bought YASA outright in 2021. Daimlerparent company Mercedes, modernization of the plant in Berlin producing up to 100,000 YASA engines per year would be the next logical step: these engines would be used in production electric cars for the first time, especially from AMG, Mercedes' formidable high-performance division.

The company recently unveiled its latest engine, and its stats are eye-opening: The axial-flow prototype generates a peak power of 750 kilowatts, or 1,005 horsepower, according to dyno testing. The engine can produce a continuous power of 350–400 kilowatts (469–536 horsepower). However, the device weighs only 12.7 kg (27.9 lb). Woolmer says the resulting power density of 59 kilowatts per kilogram is an unofficial world record for electric motorand approximately three times greater than leading radial flow designs, including Tesla's design.

“And it’s not a concept on screen—it’s running on the dynos right now,” Woolmer says. “We have created an electric motor that is significantly more energy efficient than any previous model, all using scalable materials and processes.”

Simon Cultivationhead of the new technologies department at YASA, introduces me to the technology. Conventional radial flux motors are shaped like a sausage roll. The rotating rotor is located inside a stationary stator. The magnetic flux lines are oriented radially, perpendicular to the central motor shaft. These flow lines represent interacting magnetic fields belonging permanent magnets in the rotor and electromagnets in the stator. It is this interaction that provides torque.

An axial flow calculation more like a pancake. In the YASA configuration, a pair of much larger rotors are located on either side of the stator, and, remarkably, all three have approximately the same diameter. The magnetic flux is oriented axially, parallel to the shaft. Since torque is proportional to the square of the rotor diameter, axial flow The design can generate significantly more torque than a comparable radial flux unit. Dual permanent magnet rotors double the key torque-generating components and provide a short magnetic path, increasing efficiency by reducing magnetic field losses.

YASA R&D engineer Eddie Martin holds a 12.7 kg, 750 kilowatt/1,005 horsepower axial flux motor.WHY

Odling says the company's engines are about one-third the weight and length of a comparable radial flow machine, which offers intriguing advantages for vehicle packaging and weight reduction. “The motor fits very conveniently between the engine and gearbox in a hybrid, or provides a very compact drive in an electric vehicle,” says Odling. The configuration is also ideal for motor-wheelsbecause the flat shape easily fits into the width of the car and even motorbike wheels.

YASA also promotes weight loss. Cascading advances in vehicle architecture could reduce the weight of today's electric vehicles by at least 200 kilograms, about half from the engines themselves and the rest from smaller engines, the company says. batteriesbrakes and lightweight support structures.

YASA's secret sauce is the soft magnetic composite.

The company's name provides another clue to its technical advantage: YASA stands for “pitless and segmented architecture.” The motors lack the heavy iron or steel yoke, the structural and magnetic backbone of the copper coils of a conventional stator. Instead they use Soft magnetic composite (SMC) is a material with very high magnetic permeability. This characteristic means that the material is a very efficient conductor of magnetic flux, so it can be used to concentrate and direct the field in a motor. In a typical application, the stator coils are wound on SMC structures.

Woolmer began studying SMC in the mid-2000s, before there were potential customers paying for his nascent engine designs: the first Tesla Roadster didn't go on sale until 2008, and suppliers and tooling for those engines didn't yet exist. Woolmer's early axial flow designs finally found their way into the Jaguar C-X75 in 2010, and the concept was canceled before production began. By 2019, Ferrari had integrated one of Woolmer's engines into its first hybrid, the SF90.

SMC became a key innovationbecause axial flux engines could not be made from the laminated steel plates of radial flux machines. Woolmer divided the stator into individual SMC “pole pieces” that can be pressed into a huge variety of three-dimensional shapes. What flexibility significantly reduces weight and eddy current losses, and reduces cooling loads. While a conventional engine might have 30 kilograms of iron, a comparable YASA design would only need 5 kilograms to produce the same power and torque.

YASA stators also have direct oil-cooled flat copper windings, says Odling, with no “hidden copper” that oil can't reach. This significantly improves thermal performance and recovery under stress conditions, a potential boon for high-performance electric vehicles.

YASA designs and develops its engines at its Oxford Innovation Centre. A new axial engine “super plant” opened in nearby Yarnton in May, with a capacity of more than 25,000 engines per year. The company also lends British Advanced Propulsion Center (APC) as the core of its expansion. Collaboration between the UK government, industry and academia aims to accelerate domestic development of zero-emission technologies.transport to achieve Net Zero goals.

YASA expects to release more details about its latest engine prototype in December. But company executives say the engine is ready for customers and does not require exotic materials or manufacturing techniques.