HAMON STEWART, IVT INTERNATIONAL
ON THE SURFACE, THEY MIGHT NOT LOOK ANY DIFFERENT
FROM ANY OTHER MHL350 E ON THE MARKET – BUT SOME
OF THOSE BRIGHT BLUE EXTERIORS HIDE A HYBRID HEART.
WHY IS TEREX FUCHS SO CONFIDENT THAT THIS IS THE NEXT
EVOLUTION IN MATERIAL HANDLER DESIGN?
Electric
blue
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Advanced Lift-truck Technology International 2013
CASE STUDY
The display of a hybrid
version of the 33-tonne
to 37.8-tonne Terex Fuchs
MHL350 E material handler at
Bauma in April heralded the OEM’s
BlueEvolution product range, with
claims of up to 30% greater fuel
efficiency in comparison with the
conventional version.
Terex has established the name
BlueEvolution to denote a range of
measures that will further improve
machines in the series, enhancing
their environmentally friendly
credentials with a range of energysaving measures that help preserve
resources and keep operating costs
to a minimum.
Described by Terex as being
“stronger, quieter and cleaner than
ever”, the BlueEvolution machines
combine higher overall output power
with considerable reductions in fuel
consumption and emissions, while
also complying with the Tier 4i/IIIB
standard. Christian Engelhardt, the
head of engineering of Terex Fuchs
material handlers, elaborates: “The
term BlueEvolution is a synonym
for our efforts to make our loading
machines increasingly sustainable
and ‘green’. This begins with the
use of environmentally friendly
materials [including raw, auxiliary
and operational materials] and ends
with our installed engines and
motors that reduce emissions and
fuel consumption to a minimum.”
Value-added tack
The new design is based closely on
that of the conventional machine,
but includes some key developments.
Although the hybrid version of the
MHL350 E shares the same powerful
engine as the conventional model,
in the form of the in-line 160bkW
Deutz TCD 6.1 L6 turbo-diesel, the
plan is to eventually reduce the
power of the hybrid’s engine, due to
the availability of energy elsewhere
in the hybrid system. However, its
engine efficiency has been further
improved via a high-performance
cooling unit to better regulate its
temperature.
The hybrid’s advanced technology
and configuration result in a lower
fuel consumption. However, both
versions provide hydrostatic drive
through an infinitely variable axial
piston motor and an oscillating rear
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axle with selectable oscillation lock.
They both also deliver four-wheel
drive through a two-speed manual
gearshift, and the same travel speeds
of 5km/h (3.1mph) in first gear and
20km/h (12.4mph) in second gear
and a turning radius of 8.7m.
However, the hybrid model has a
lower gradeability (a maximum 39%
in comparison with the conventional
machine’s maximum 45%). It also
incorporates exhaust gas recirculation
and a diesel particulate filter.
Power station
The MHL350 E hybrid replaces
the conventional flywheel with an
integrated motor generator (IMG),
as a means of generating electricity
while the engine is running.
Back in 2012, Terex and Deutz,
with support from the German
Federal Ministry of Economics and
Technology, started work jointly on
the Green Industrial Diesel (GRID)
project to produce a highly effective
hybrid drive for industrial machinery,
combining a highly efficient diesel
engine with an electric generator/
motor for a 20-30% reduction in
fuel consumption and resulting
CO2 emissions.
The result can work as a series
or parallel hybrid system. Electrical
energy generated by the IMG is
stored in a group of capacitors
known as a SuperCap pack. Deutz
explains that this is “comparable in
function to a rechargeable battery
but is based on the principle of
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double-layer capacitors”, which
are in themselves a very powerful
development and are claimed to
generally withstand considerably
more charging and discharging
cycles than batteries.
The electric slewing motor is
powered by a group of capacitors
but doubles as a generator when the
operator slows the upper structure’s
rotation, effectively acting just like
a brake. This braking energy recharges
the capacitors, which are also charged
by the IMG. The OEM is reluctant
to divulge specifics of the capacitors,
although they are clearly extremely
effective in order to meet the
machine’s requirements.
Engelhardt confirms, “Through
the hybridisation of the slew drive,
kinetic energy is fed back into the
hybrid system. For material handling
machines, particularly in applications
such as the loading and unloading
of ships, a large proportion of the
Advanced Lift-truck Technology International 2013
CASE STUDY
“HYBRID VERSIONS WILL COST
MORE, BUT WILL REPAY THAT
PREMIUM MANY TIMES OVER
DURING THEIR WORKING LIFE”
operation consists of slewing
movements where very high levels
of energy recuperation are possible.”
The machine’s output power can
be extended to 190bkW for up to 30
seconds, because when it is working
at full capacity, the IMG can function
as a motor, delivering an additional
30kW and providing the system
with a supplementary boost that is
conveniently in the region of the
maximum load.
As Engelhardt points out, “There
are challenges with the adoption of
integrated motor generators, because
the extra components have to be
incorporated into the machine, so
additional space is required in the
engine area for the SuperCap and
other control items.” However, there
are also clear advantages with this
kind of system, and as he also notes,
“Hybrid versions will cost more, but
will repay that premium many times
over during their working life.”
Additional fuel economy can be
achieved with the Auto Shutdown
feature for when the engine is idling.
The engine is then restarted instantly
using the IMG. A simple start-stop
button for the engine – functional
when the ignition is on – provides
wider control over the machine’s
systems on start-up and shut-down,
and is an advantage in situations
such as when the machine is under
full load. Terex Fuchs emphasises
the machine’s load capacity and
performance efficiency, and describes
the machine’s 380-litre fuel tank as
being sufficient for at least two full
working shifts.
The MHL350 E hybrid also uses
an electric drive to rotate its upper
structure instead of the more
conventional hydraulic slewing
system, and therefore boasts an
infinitely variable slew speed from
0-7rpm with 80kNm swing torque.
This is somewhat greater than the
conventional model’s corresponding
0-6rpm range and 78kNm. One
welcome side-effect is that, as the
slewing system is non-hydraulic, the
hybrid enjoys faster simultaneous
boom/dipper and upper structure
movements even with heavy loads,
which will be welcomed by owners
and operators alike.
Both the conventional and
hybrid MHL350 E machines feature
a new, more powerful and separated
cooling system, enabling operations
in higher ambient temperatures,
with a fan-speed control system for
additional efficiency.
A more robust, resilient machine
will inevitably perform for longer
and provide greater reliability under
tougher conditions, and with this in
mind Engelhardt comments, “The
hybrid system requires additional
cooling, which can be provided
either by the existing cooling
system or by an additional cooler.
The MHL350 E uses an additional
cooler for the hybrid system.”
MAIN IMAGE: A fourpoint stabiliser system and
selectable oscillation lock
ensure the machine is well
grounded
ABOVE: By using an
electric motor for slewing,
hydraulic power can be
concentrated on boom and
dipper movements, making
compound movements
quicker
BELOW LEFT: Doublelayer capacitors capture
the energy from braking
the slewing motion and
quickly make it available
for accelerating the upper
structure
Up for a scrap
Both machine variants weigh
between 33 and 37.8 tonnes. Their
reach of up to 16m makes them
ideally suited to the handling of
scrap materials and offers positive
performance across the various
operating conditions they are likely
to encounter. The hybrid MHL350 E
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CASE STUDY
machine has a dual-circuit hydraulic
system with maximum pump flow
rate of 2x330 l/min at 320/355 bar
maximum operating pressure.
Engelhardt explains, “Twin pumps
are allocated to the boom and dipper,
thereby more quickly supplying the
required quantities of oil for fast
operational movements.”
The material handler’s Linde
mobile hydraulic system features
load-limit control and fuel-saving
power-demand control. Because a
very common issue in conventional
machines with a traditional hydraulic
system is excess hydraulic flow being
generated at potentially considerable
expense, the load-sensing hydraulic
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MAIN IMAGE: Hydraulically
raised cab provides high
visibility levels
TOP: A twin-pump, loadsensing hydraulic system
provides the precise
quantities of oil for fast
operation of boom and
dipper
Advanced Lift-truck Technology International 2013
system on the
MHL350 E works
with the engine to
provide only the
required hydraulic
power, minimising
fuel wastage. This further
highlights the machine’s
BlueEvolution credentials and also
underlines the OEM’s commitment
to adding machine features that will
benefit the owner and the user on
several levels.
In compliance with EU standards
for hydraulic excavators, an overload
warning device is fitted while the
lift and stick cylinders feature hoserupture safety valves for safer loadhandling. Abnormal operating
conditions will automatically be
monitored and recorded.
The Terex Fuchs Quick Connect
System (FQC) enables a variety of
attachments – such as the expected
cactus grab, clamshell grab, magnetic
plate and scrap shears, to be changed
by the operator directly from within
the cabin, quickly and safely. The
system consists of quick couplers,
including the electrical connections
for a magnetic plate, for a notably
faster transition than the manual
alternative. All connections on the
quick couplings are shielded for
protection against damage and dirt.
The FQC system is available as an
option and adds marginally to the
vehicle’s operational weight.
Sound and vision
The cab of the MHL350 E can rise
hydraulically to a maximum 5.6m
sightline height above ground level.
It also benefits from a reduction in
noise levels in the cab, which will
be a welcome feature for operators
working in particularly noisy areas.
The operator is provided with
intuitive machine controls such as
the joystick, and a high-resolution,
high-contrast, multifunctional colour
display screen for all relevant data.
The screen is positioned centrally
and also gives diagnosis of individual
sensors, and is fitted with an antiglare shield as standard.
Careful attention has been paid
to supporting optimum operator
performance through measures such
as the seat design being based on the
latest ergonomic research. Overall
safety has been further improved
through the strengthening of the
protective steel structure through
close co-operation with the Cab
Alliance, while all-round visibility
has also been improved. In addition,
the structure has been refined to give
greater load-carrying capacity, while
increasing stability.
CASE STUDY
Not so secret service
Together with
the optional armoured front
windshield, the operator is given a
considerably safer working
environment with improved allround visibility. A wide-angle rearview camera enables the operator
to see behind the machine with
an improved view, and is fitted as
standard to further enhance the
safety character of the machine’s
layout. This improved view will
undoubtedly prove the camera’s
worth during reversing or carrying
out advanced manoeuvres.
MAIN IMAGE: The Quick
Connect System enables
a range of attachments to
be changed from inside the
cabin
ABOVE: With a more
powerful engine than its
conventional counterpart,
and an integrated motor
generator replacing the
flywheel, up to 190bkW
can be provided for short
periods
The company is keen to point out
that “every Terex Fuchs component
is engineered for a long service life
and for long service intervals”. To
that end, various adjustments have
been made for easier maintenance
and access. All steps and service
platforms have been positioned with
careful attention to functionality
and performance of maintenance
tasks. Other helpful user-friendly
developments include the fuel prefilter now being on top of the fuel
tank and the repositioning of the
windscreen washer filler neck.
A fuse tester is included for the
operator to quickly determine faulty
contacts. The vehicle’s 24V electrical
system can be complemented with
an optional 13kW or 20kW DC
generator featuring controls and
insulation monitoring, driven
directly from the engine.
The launch of a hybrid version
of the MHL350 E emphasises the
adoption of hybrid technology as
an increasingly important factor in
industrial vehicle design, particularly
in demanding, uncompromising
applications where new technologies
usually need to be at least as good as,
if not better than, existing systems
and configurations. Progressive
attitudes to innovative and advanced
technologies that continue to evolve
are taking an increasing hold in
series-production machinery, and
hybrid drives offer very positive
reductions in energy consumption
and emissions. Future developments
in drivetrains and their components
will be closely watched by OEMs
keen to maintain their customer
base, while having to work towards
increasingly stringent emissions
regulations at the same time as
performance requirements. ALT
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