Truck & Off-Highway Engineering - June 2022 - 21

EXECUTIVE VIEWPOINTS
driven equipment implements also can be fine-tuned
with variable-speed electric motors driving the hydraulic
pumps.
Environmental/regulatory concerns: In many major
markets, evolving emissions and air-quality regulations
continue to affect construction OEMs. In certain urban
environments, noise and emissions regulations have
led to OEMs launching all-electric, small skid loaders,
wheel loaders and other equipment capable of working
in restricted sites.
Managing the demand for power
Battery storage and power-management technology,
and the efficiency with which electric drivetrains use
that power, continues to make rapid progress. In the
700-volt segment, OEMs have swiftly moved from
prototypes to successful machine designs, building on
a new generation of batteries, motors, inverters, gear
units and advanced software platforms for traction
and implement control.
Nevertheless, for construction, agricultural and other
off-highway applications, creating and consistently delivering
the power needed to move the machine and/or
its load lies at the heart of mobile-machine engineering.
Applications and operating environments matter.
For example, a combine harvester working in a rural
location moves constantly over acres of distance, with
some implements being hydraulically powered and
others with less-demanding requirements (such as
steering control) using electromechanical devices. For
a fully electric combine, the availability of high-kilowatt
(kW) recharging stations or other power sources
to recharge in remote locations could remain limited.
One interim solution already being implemented by
some OEMs is to have replaceable battery packs for
machines operating under these conditions. It would
be a standard service established and managed remotely,
enabling battery-electric machines to continue
making inroads in these particularly challenging offhighway
applications.
Modular approach to powering
drivetrains
With current electric motor technology, most heavyduty
mobile machines can use electric motors for their
drivetrains as a direct replacement. The greater challenge
is how that electricity is generated and supplied
to the electric drives. Multiple methods exist, and
some are more unique than others - hydrogen fuel
cells or combustion engines that run on natural gas
and other fuels, for example.
The power source for the drivetrain and implements
will continue to be driven by what the machine needs
TRUCK & OFF-HIGHWAY ENGINEERING
Bosch Rexroth's eLION portfolio, comprising motors, inverters, cables, power
distribution units, DC to DC converters and on-board chargers, offers mobilemachine
OEMs a new platform to accelerate electrification.
The newest version of electronic load sensing combines electric-powered hydraulic
pumps with pre-compensated valve platforms, such as RM mobile control valves
(shown), and integrates advanced recuperation to maximize machine efficiency.
to do in its duty cycle, as well as its operating environment. So, a
modular, application-driven approach will include:
Conventional combustion engines: The standard diesel engine still
delivers optimum performance in applications where the machines
operate constantly (as in remote locations) and make heavy demands
on travel-distance and implements, such as mulching equipment.
Diesel-electric: In this configuration, the drivetrain motors and hydraulics
power are provided by a combination of a combustion engine
and electrics drawing from batteries. This configuration is similar
to hybrid passenger cars and trucks. For some construction vehicles,
this can be a plug-in vehicle; the battery can be charged from a fixed
June 2022 21
Truck & Off-Highway Engineering - June 2022

Table of Contents for the Digital Edition of Truck & Off-Highway Engineering - June 2022
