German automotive supplier Mahle has developed a new breed of electromotor with an integrated oil cooling that can run almost endlessly at 90% of its peak power as long as the battery can hold. That’s quite unique as today’s e-motors on the market generally can deliver their peak power only for 50-60 seconds because of thermal restrictions.
Mahle says its SCT e-motor – which stands for ‘Superior Continuous Torque’ – can power an electric class-8 semi-truck of 40 tons or more to swiftly climb the Brenner Pass in the Alps without ever falling back. Or have a battery-electric car perform multiple ‘racing’ sprints.
The very compact and lighter design makes the SCT motor suitable for every kind of vehicle and can be delivered as a magnet-free motor without rare earth metals used. It will be presented at the IAA Transportation 2022 in Hanover in September.
Peak power versus continuous
When talking about EVs, it’s often the maximum or peak power that’s mentioned, which means the peak power reached by the motor (and supported by the battery) for a short period. Continuous power is generally the maximum power an engine can deliver over 30 minutes, being much lower on average.
That’s why electric cars today perform poorly in race track conditions with continuous high accelerations, contrary to race cars with combustion engines. A Porsche Taycan 4S advertizes a peak performance of 390 kW, but the continuous power it can deliver is 140 kW (according to ECE-R 85 standard).
Unrestricted for everyday use
“Building large electric motors that deliver short-term high performance is easy. What was still lacking on the market until now were durable yet compact drives to make electric vehicles unrestricted for everyday use,” said Martin Berger, Director of Corporate Research and Advanced Engineering at Mahle, in a press release. “Our new SCT E-motor is the solution.”
“A new cooling concept makes this technological leap possible. The new electric motor is surpassingly clean, light, and efficient and can be assembled without using rare earth materials by customer request.”
In May last year, Mahle introduced a new magnet-free electric motor for passenger cars that does not require rare earth elements. It generates the magnetic field using excitation copper coils inside the rotor that replace conventionally used permanent magnets.
The new electric motor provides a high degree of durability because the necessary transmission of electrical currents between the rotating and stationary parts inside the motor takes place without contact and is therefore wear-free. This makes the engine maintenance-free, and because it’s scalable, suitable for a wide range of applications, Mahle says.
Other electric motor developers are evolving in the same direction, avoiding using expensive rare earth materials. At the 35th (EVS) Electric Vehicle Symposium in Oslo, German Vitesco Technologies, a spin-off from Continental, presented its new generation of electric motors. These also no longer use a permanent magnet but a second (controlled) electromagnetic field to bring the engine in motion.
Mahle now leapfrogs the competition by combining the wear-free motor with the SCT technology. If it comes from the Stuttgart-based automotive supplier giant, one can expect that this can be a real game-changer.
The company is one of the three largest systems suppliers worldwide for ICE and electric engine systems, filtration, mechatronics, and thermal management. It currently employs 71 298 people worldwide with 160 production facilities and 12 R&D centers.
Although components for the internal combustion engine were a large part of their business for years, today’s turnover comes from more than 60% of non-ICE-related components. It offers electric powertrains from 1 to 250 kW for two-wheelers like e-scooters and e-bikes, passenger cars, commercial vehicles, golf carts, utility vehicles, non-road mobile machinery, or material handling vehicles.