Automotive Engineering - December 2022 - 22

FUTURE-TECH
FLAGSHIP
COVER STORY
Veteran program engineering manager Jeremy Loveday worked on the GM EV1's
body structure. His career has come full circle with Celestiq.
focal points is its 3D-printed aluminum steering wheel. " It's a laser
sintering process, " Roma explained. " You break the support structure
off, run a qualifying cut with a five-axis CNC machine, then send it to
the hand polish.
" We looked at doing a die casting, " he continued, " but with the
dipole, you can't get the B-side features that are needed for attachments
and switches and all the other things. So, either you got to
make the thing bigger and bulkier or use additive [manufacturing],
which let us put the material just where we wanted. "
Roma admitted that using AM to make the steering wheel surround
" isn't exactly cheap; you won't see this on a high-volume car
any anytime soon. But this is the literal 'jewelry' that's right in your
face. " Perfect for the client who just spec'd the cabin of their
$100-million yacht.
" We're absolutely going to drive our competitors crazy with
what we're going to easily allow people to customize, " Roma said.
" That would be impossible with other manufacturing methods and
techniques. "
The program also used AM to print the sand cores for the bodycasting
molds. " We 3D-printed those cores before we hard-tooled
anything, " Roma said. " That's incredibly powerful tech and not just
for speed. We sent our rear suspension hollow-cradle design over to
our casting partner and in seven days we had a physical part sitting
on the ground in Milford. "
Cool cabin, DC fast charge and more
The engineers note that Celestiq does share proven, validated componentry
with GM's high-volume programs, in hidden areas of the
vehicle where it made sense. " We partnered with Silverado EV and
Hummer EV wherever possible, " Roma said. " It's no secret that anytime
you partner up with a fullsize-truck program, you're going to
get all the support in the world. "
One example is the HVAC module buried deep under the
22 December 2022
Celestiq chief engineer Tony Roma and his team have broken
new technology ground with this program.
Celestiq's dash. " We wanted a true quad-zone HVAC
with four individual fan zones, modes and temperature, "
Loveday explained. " We came up with a modular
design because not everybody wants a four-zone
system like we're using. It'll be validated and built in
volumes that are two orders-of-magnitude higher
than ours. We get to amortize the investment over
volume, " he said.
Celestiq's 'ClimateSense' microclimate system supplied
by Gentherm features an array of sensors and
controls that allow each occupant to personalize their
desired level of seat heating and cooling.
A comprehensive technical review of Cadillac's upcoming
flagship will require plenty of future reporting
as details are released and discovered. The vehicle's
Ultium-based propulsion system, combining a 111-kWh
lithium-ion structural battery pack and a dual-motor,
AWD driveline, are expected to deliver roughly 600 hp
(447 kW) and 640 lb-ft (868 Nm). An 80% charge will
provide 300 miles (483 km) of range under amenable
thermal conditions, GM engineers promise.
The Celestiq is fitted with a 200-kW DC fast-charging
system capable of adding up to an estimated 78
miles (126 km) of range in 10 minutes.
Front and rear drive ratios (11.59:1 and 11.63:1, respectively)
are unique to Celestiq, with 'smart' control of
each axle. The flagship sedan also features regen-ondemand
braking with a one-pedal function. Ride and
chassis-control systems will break new technical ground
in a GM vehicle, according to engineers.
But as satisfying as these technologies and features
will be for Celestiq's clients, their influence across GM's
vehicle programs will be profound.
AUTOMOTIVE ENGINEERING
BOTH IMAGES: CADILLAC
Automotive Engineering - December 2022

Table of Contents for the Digital Edition of Automotive Engineering - December 2022
