Truck & Off-Highway Engineering - December 2021 - 21

LUBRICANTS FEATURE
Dr. Michael
Gahagan,
technology
manager of
driveline at
Lubrizol.
The e-motor can be integrated into the DCT box and cooled
by the transmission lubricant. This approach allows for lower
development complexity and higher production volumes.
copper corrosion test, in which a bare copper piece
was placed in a conventional fluid as well as an e-fluid.
The two samples were heated to 80°C (176°F) over a
period of 168 hours, and the results were striking.
The copper portion above the conventional oil demonstrated
significant vapor corrosion damage, whereas the
specifically-formulated e-fluid provided robust protection
against the same phenomenon. This has implications for
the protection of sensitive copper-based components.
Lubrizol also developed an in-house test to measure a
fluid's ability to prevent conductive deposits and corrosion.
In this more sophisticated test, a team immersed
printed copper circuit boards in a fluid heated to 150°C
(302°F) for a period of 1,000 hours with or without voltage
applied and monitored the process. The conventional
fluid used as reference showed high levels of corrosion
and deposit formation, whereas the e-fluid demonstrated
outstanding protection. These tests clearly demonstrate
the importance of a dedicated fluid that has been formulated
to interact with and protect copper electronic elements
that are essential to the functionality of EVs.
Additionally, e-fluids increasingly come into contact
with different plastics in newer EVs. For example,
some OEMs have replaced traditional metal bearing
parts with high-performance polymer in thrust bearings.
A traditional fluid may have the tendency to
compromise the strength of these polymers. For example,
Lubrizol tested a polyamide (PA66 GF-35)
sample submerged in conventional fluid at 150°C for
1,000 hours and found the sample had lost nearly 45%
of its strength. A dedicated e-fluid subjected to the
same test provided robust protection. E-fluids must be
formulated with this type of performance in mind.
TRUCK & OFF-HIGHWAY ENGINEERING
A copper corrosion test shows the " robust protection " provided by the
customized e-fluid.
Dedicated fluids formulated to interact with and protect copper electronic
elements are essential to the functionality of EVs.
Thermal, NVH considerations
Lubricants and fluids for use within EVs also must have increasingly
effective thermal-management properties to handle some severe
operating conditions. Unlike traditional internal-combustion engines,
the temperature differentials in EV engines often spike at high temperatures
and are generally less consistent. For these and other reasons,
lubricant manufacturers must pay closer attention to the e-fluid's
heat transfer and thermal stability characteristics.
December 2021 21
CLOCKWISE FROM TOP LEFT: LUBRIZOL; SAE TECHNICAL PAPER, 2017-01-2358; LUBRIZOL; LUBRIZOL

Truck & Off-Highway Engineering - December 2021

Table of Contents for the Digital Edition of Truck & Off-Highway Engineering - December 2021

Truck & Off-Highway Engineering - December 2021 - CVR4
Truck & Off-Highway Engineering - December 2021 - CVRA
Truck & Off-Highway Engineering - December 2021 - CVRB
Truck & Off-Highway Engineering - December 2021 - CVR1
Truck & Off-Highway Engineering - December 2021 - CVR2
Truck & Off-Highway Engineering - December 2021 - 1
Truck & Off-Highway Engineering - December 2021 - 2
Truck & Off-Highway Engineering - December 2021 - 3
Truck & Off-Highway Engineering - December 2021 - 4
Truck & Off-Highway Engineering - December 2021 - 5
Truck & Off-Highway Engineering - December 2021 - 6
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Truck & Off-Highway Engineering - December 2021 - 11
Truck & Off-Highway Engineering - December 2021 - 12
Truck & Off-Highway Engineering - December 2021 - 13
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Truck & Off-Highway Engineering - December 2021 - 25
Truck & Off-Highway Engineering - December 2021 - 26
Truck & Off-Highway Engineering - December 2021 - CVR3
Truck & Off-Highway Engineering - December 2021 - CVR4
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