Automotive Engineering - May 2022 - 11

ROAD READY
2022 Grand Cherokee plugs in
Water's no worry for the
first-ever hybrid variant of
Jeep's Grand Cherokee.
Plug-in hybrids are a controversial subject in engineering and
product-planning circles. With a modicum of electric-only capability
and superior driving range but retaining the tailpipe emissions
and cost/complexity burden of two powertrains, PHEVs are
a polarizing yet ideal product for certain applications.
Clawing confidently across Texas slickrock, with only its
batteries providing drive torque to all four wheels, the all-new
2022 Jeep Grand Cherokee 4xe makes a strong case for PHEV
in the SUV segment. Off road operation is as quiet as a mountain
bike to other trail users, and in moderate thermal conditions
the " 4-by-e " Grand Cherokee can travel up to 25 miles
(40 km) before the long-stroke 2.0-L turbocharged Ottocycle
engine (part of Stellantis' GMET family, made in Italy)
engages. When it does, as SAE Media experienced during the
4xe's recent launch event, the transition is smooth and nearly
seamless. And in very cold ambient temperatures, the hybrid
system defaults to combustion-engine power, based on coolant
temperature, a feature that customers in four-season markets
will appreciate. With 470 lb-ft (637 Nm) of total system
torque on tap, there is a lot to like about the fifth-generation
Grand Cherokee configured for plug-in duty.
Jeep planners and many customers agree. The Wrangler
4xe, with essentially the same hybrid-electric system as the
Grand Cherokee, is the top-selling PHEV in North America.
Jeep brand CEO Christian Meunier says " 4-by-e is the new
4-by-4, " whether serving as a pathway to battery-electric
Jeeps in 2025 or filling a longer role in the Jeep portfolio. The
plug-in powertrain is available on the standard Grand
Cherokee as well as Trailhawk, Overland, and Summit trims.
Simulation sped development
" We knew electrification was a requirement " for the 2022
model, explained Grand Cherokee vehicle line executive Tom
AUTOMOTIVE ENGINEERING
Naked display chassis shows packaging for the Grand Cherokee 4xe's
twin battery packs, hybrid transmission, electronic power control
modules and ZF rear diff module.
May 2022 11
Seel, " but it was also a requirement to not
compromise the customer package or comfort. "
The development team packaged the
twin lithium-ion NMC battery packs as low as
possible in the unibody structure, ahead of
the second-row seat crossmember, to maintain
a center of gravity conducive to good
vehicle dynamics. Each of the batteries, supplied
by Stellantis partner Samsung SDI, contain
48 nickel manganese cobalt (NMC) cells,
same as the Jeep Wrangler 4xe. The 400-volt
system incorporates a dedicated thermal
management system with coolant heater. It
delivers a total of 17 kWh without reducing
the non-hybrid model's rear occupant leg
room (38.2 in./971 mm) and knee room 4.1
in./103 mm).
Seel described engineering the vehicle's
high-voltage cable routing as a balancing act
between product and process. " All the routings
had to be engineered for the [in-plant
assembly] process, " he explained. " We completed, with manufacturing
engineering, numerous virtual simulations of the
process of connecting all the high-voltage cables prior to any
hardware being built. This ensured that we'd have quality connections
to support the electrified vehicle. "
FROM TOP: STELLANTIS; LINDSAY BROOKE
Automotive Engineering - May 2022

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