Fleet Maintenance - 18

»Organizing wiring throughout a vehicle to
indicate specific voltages per wire may alleviate
issues when implementing new componentry.
Image courtesy of USA Harness

vehicles attempting to prevent idle time and/or
that have sleeper cabs with additional system and
component electrical demands.
"Some of our commercial vehicles, mostly
trucks with living (sleeper) environments, also
provide an inverter that would convert the 12V
DC battery energy to 110V [alternating current]
(AC) for use in the living environment to provide
energy to items like TVs and other conventional
110V power sockets," Makki continues.
The electrical needs of a vehicle vary depending on the integrated components, devices, and
systems present. Lighting and stereos are universally installed on all tractor-trailer combinations.
However, the power needs go beyond the truck,
with added electrical demand from the trailer
when connected to the tractor. The industry has
proven capable of providing adequate electrical
power to these various components and devices
through the use of a 12V electrical system. But as
more technology is introduced to the commercial
vehicle, electrical power demands have increased.
Though most additional technology seems to be
readily integrated into a 12V system, there are
other demands the industry is seeking to obtain
- most commanding of which is improved fuel
efficiency and reduced emissions.

"We've really maximized what we can do
at 12V. As we try to get more and more
efficient [and] reduce emissions, some
of the things the industry is wanting to
do is get rid of engine-driven accessories
because they are a constant drag."
Larry Rambeaux, service application engineer, Purkeys

As the industry seeks to create efficient internal
combustion engines and minimize emissions, an
opportunity presents itself to move select vehicle
systems and components relying on engine-driven
electrical power onto battery-supplied electrical
power. Additionally, the industry will see improvements to the vehicle's electrical system itself. With
the industry seeking optimization and efficiency,
it is through these opportunities that the possibility of higher voltages and multiple voltages integrated into a single vehicle be actualized into the
evolving commercial vehicle's ecosystem.

What would higher
voltages deliver?
There are several reasons to
support integrating higher
»Customized harnessing
can organize wiring in a
multi-volt environment.
Image courtesy of USA Harness

18 Fleet Maintenance | April 2020

voltages into heavy duty vehicles, the primary of
which is supporting increased power demands.
"We've really maximized what we can do at
12V. As we try to get more and more efficient [and]
reduce emissions, some of the things the industry
is wanting to do is get rid of engine-driven accessories because they are a constant drag," says Larry
Rambeaux, service application engineer, Purkeys.
Purkeys, part of Mission Critical Electronics, is a
commercial trucking industry electronics brand.
Rambeaux provides an example through the
power steering system. A shift from hydraulic to
electric power steering pumps would allow the
power steering system to utilize electrical power
to operate the system only when power steering
is needed. This means the electrical system would
deliver power to the power steering system at
lower speeds and during backing the vehicle but
would not use electrical power at highway speeds,
whereas the hydraulic system is a constant draw
on the engine.
"That [would be] a great reduction on the engine
and save fuel," Rambeaux says.
Converting systems such as power steering
pumps or air conditioning compressors, for
example, to electrically powered systems would

Fleet Maintenance

Table of Contents for the Digital Edition of Fleet Maintenance