Automotive Engineering - September 2023 - 8

TECHNOLOGY
REPORT
PROPULSION
Magna's drop-in, off-road electric powertrain
The size of the eBeam
rear axle and motor unit
is at first a bit jarring
when seen from the rear.
But engineers said the
motors have been fully
ruggedized to withstand
typical off-road abuse.
SAE INTERNATIONAL
BOARD OF DIRECTORS
Todd Zarfos
President
Carla Bailo
2024 President
Srinivasa (Sri) Srinath, Ph.D
2022 President
Susan Ying, Ph.D
Vice President - Aerospace
Daniel Nicholson
Vice President - Automotive
Audley Brown
Vice President -
Commercial Vehicle
Andrew Jeffers
Treasurer
David L. Schutt, Ph.D
Chief Executive Officer
If a mid-20th century engineer could time travel
and see Magna's electric off-road powertrains,
they might ask " why is the rear differential so
gigantic? " But that's no differential. It's a powerful
electric motor fully integrated into each front
and rear axle for full 4x4 traction. And Magna
said the system will " very likely " be seen on a
production vehicle within a few years.
At its 2023 tech day presentation, held at a
Michigan offroad park and Magna International
HQ in Troy, Mich., SAE Media had the opportunity
to drive prototype vehicles offroad and
sample Magna's in-cabin safety features.
What Magna calls its Etelligent Terrain dual
motor/solid axle package was installed on the
frame and body of a Jeep Gladiator pickup.
The package consists of the eBeam at the rear,
a coaxial structural axle with on-board inverter.
It has a gross axle weight rating of 5,000
pounds (2,268 kg). The motor is a hairpinwound
permanent-magnet type that generates
238 peak hp (178 kW) and 568 Nm (419 lb-ft).
A locking differential is included. The modular
axle was powered by an 83-kWh battery pack
that brought the weight of the vehicle to 6,360
lb. (2,884 kg), roughly 1,500 lb. (680 kg) more
than the original version. Engineers said that in
a production vehicle, the battery capacity
probably would need to be bigger to meet a
desirable range specification. Up front, what
Magna calls the Steerable eBeam generates 188
kW (252 hp) and 389 Nm (287 lb-ft) in a unit
with a GAWR of 3,500 pounds (1,588 kg). This
8 September 2023
axle's inverter is on the truck's frame, as there
isn't enough room for it on the axle assembly.
Despite all this new packaging, engineers
managed to deliver a vehicle front/rear weight
distribution at 50/50.
Crawling up the rocky " Mount Magna, " as the
highest point at the off-road park is known,
presented little challenge for the eBeam axles.
It was possible to generate considerable wheel
slip, but as soon as the Etelligent system recognized
what was happening, it compensated
the torque apportionment and continued progress
with no jerky motions.
An ICE-powered Gladiator was available for
comparison. And while it had few problems
with the same terrain, there certainly was - as
one might expect, more noise and start/stop
adventure in traversing the steeper and more
challenging obstacles. Descending uneven, rutted
terrain was one of the smoothest experiences
of the kind, thanks to the manner in
which the system adapts the traction motors'
regeneration characteristics on the fly. Brakebased
hill-descent systems can be jarring as
they grab and release multiple times, sometimes
in short succession, during a descent.
Having the inverter packaged on the axle is a
nifty trick that keeps more weight down low,
while also shaving some material costs. The real
engineering prowess, said Magna Chief Engineer
of Electrification Mike Dowsett, was ruggedizing
the inverter, which has to take the punishment
of being on an unsprung part of the truck.
Gregory L. Bradley, Esq.
Secretary
Judy Curran
Mary Lee Gambone
Michael Weinert
Joan Wills
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Automotive Engineering - September 2023

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