Truck & Off-Highway Engineering - February 2021 - 18

A TESTING POWERHOUSE

Engineering veterans Brad Stamper and Jeanne
Rues in the VET's cold-test chamber.

Following strict health and safety guidelines during SAE's visit in
December 2020, Proctor and the author walked from the building's
control- and meeting-rooms area into the voluminous high-ceilinged
ambient-soak area, where two customer step vans were the objects of
engineers' attention. The entire space is maintained at 72°F (22°C)
year-round. Vehicles that arrive for emissions testing in the dead of
winter are parked here until their engine-sump temperatures come up
18 February 2021

to the 72°F ambient before they're submitted for testing. It's also an area where fabrication is done, such as
adding thermocouples, transducers and sensors.
Prototype and pre-production vehicles not yet approved for the public's eyes enter directly from their transport trailers through secure doors. Some get covered or
dedicated partitions, according to the owner's instructions.
The hot and cold soak chambers are enormous -
each is large enough to accommodate two articulated
city buses, or up to nine smaller vehicles. " We were
able to test multiple vehicles at -40°F [-40°C] and
reduce overall test time by one-third, compared to
past practice, by rapidly returning the [engine] sump
temperature to -40°F after a test. This allowed a second test to be performed within an 8-hour shift, "
Proctor noted. Attention to thermal control enables
temperatures in the huge chambers to hold within ±2.5
deg. Humidity in the hot-soak chamber can be varied
from 5% up to 95% if required.
Throughout our tour, Allison Transmissions' speedand-efficiency mantra was evident in workplace organization. All hand tools and equipment needed for vehicle and subsystems hook-ups are stationed on carts
for mobility and easy access. The concept is similar to
that used for quick tooling changes in plants.
" We want to be as efficient as we can in all aspects of
this facility, because our customers' time is money, "
Proctor said. " We have about a seven-minute window to
move vehicles from the soak areas into our test dynos to
TRUCK & OFF-HIGHWAY ENGINEERING

FROM TOP: ALLISON TRANSMISSION; SAE/LINDSAY BROOKE

With tighter emissions standards for
combustion engines looming through
model year 2027, the Allison VET team
is preparing for steady business in
emissions testing this decade.

Truck & Off-Highway Engineering - February 2021

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