Truck & Off-Highway Engineering - June 2017 - 10

EXECUTIVE VIEWPOINTS

Demand grows for electrified
off-highway machines
Chris Mays,
Commercial
Vehicle -
Senior Technical
Specialist,
Corporate
Advanced
Engineering at
BorgWarner

ydraulic hybrids are very much a part of the alternative drivetrain equation, notes Chris Mays,
Commercial Vehicle - Senior Technical Specialist,
Corporate Advanced Engineering at BorgWarner.
"Machines already have hydraulics on them, so adding a
hydraulic hybrid is somewhat of a logical next step."
Even so, Mays prefers to talk electrification for heavy-duty on-highway and offhighway vehicles because, frankly,
BorgWarner makes a range of electric
products such as motors/generators
with high-voltage hairpin technology,
electrified boosting technologies and
eFans for thermal management in 48-/24-V applications, to name a few. Mays recently spoke with Truck &
Off-Highway Engineering about the drivers for employing hybrid and electric technology in heavy-duty and
off-highway, challenges to implementation, and his
view on waste heat recovery, fuel cells and more.

efficiency and force, so you don't have to rely on your traditional friction brakes. Because you're relying on an electric machine, you also
don't have to service them as often, if at all. And a lot of machines
are very cyclic-using them a lot and then idling a lot. The ability to
shut them down more often helps with that overall noise level as well
as fuel savings.
A couple other points also apply. Emissions for off-highway engines are set in terms of the power rating of the engine. If you hybridize, you can move down a power rating-go from say a 70-kW
engine to a 45-kW engine, and that moves you into different emission bands, which generally have a slightly higher limit, meaning you
don't have to use as much aftertreatment for the emissions control.
That can be a benefit in reducing cost of the machine. One final thing
to think about is some of these machines connect to other accessories-like interchanging tools at the end of the jib. If you're hydraulically connecting, you also need to make a hydraulic interconnection-
remove one and fix another one. If you electrify some of those implements, you can make those connections easier.
What are the best applications in off-highway for electrification?
Anything where it's repeatable and cyclic, where you're doing the same
job all day long-lifting and lowering; boom swinging. Wheel loaders
seem to be one of the first applications in hybridizing-same thing, when
you're driving into a pile of dirt and lifting up, accelerating backwards,
and then slowing down and dropping off-those sort of
cyclic loads can be very good for hybridization.
The other area to look at is when you've got intermittent loads, a vehicle that's operating at full performance
sometimes and then idling or operating at lower load
elsewhere-If you hybridize that, that would be an interesting approach where you can reserve some load capacity from parts of the cycle to use in other parts of the cycle and increase productivity without increasing the engine power.

"Ultimately, it
all comes down
to payback."

Why is demand for hybrid and electric technology
growing in off-highway markets?
It really comes down to the benefits, which can be attractive when you look at certain applications. The OEs
are becoming more cognizant of that and providing
more solutions. Ultimately, it all comes down to payback.
With construction machinery, it's a lot about productivity-how much work can be done within a period of time.
And hybridization allows more to be done within a set
cycle time. It's not so much just about the fuel savings.
The other driver is maintenance requirements. A lot
of the machines-especially larger machines like large
wheel loaders-end up with electric wheel motors,
which improve torque at the wheel. But they also provide a great benefit in terms of improved braking
10 June 2017

How much does technology development from the passenger car
side inform the commercial vehicle technologies?
The usages are very different and the way they operate is very different. Some of the controls logic about how you transfer power can
certainly adapt and apply [across industries] but the actual energy
calculations would be unique for the off-highway machines. When
you think of on-highway, probably the best application where you're
going to see a lot of carryover is in medium-duty and vocational vehicles rather than heavy-duty.
Another area where you might see some carryover between pass car
is going to be 48-V solutions that are coming to play now on mild hybridization. There's a lot of interest in agricultural and off-highway for
some of those 48-V machine solutions. If you've got 48-V that's in
high-volume production on a passenger car, then adapting it and using
it on a construction or agricultural machine is probably an area you'll
see some transfer.
BorgWarner is looking at 48-V solutions and at ConExpo we had some
of that technology on the stand. But we don't necessarily market them as
specifically for one part of the sector or not. If it's a 48-V architecture, as
TRUCK & OFF-HIGHWAY ENGINEERING

Truck & Off-Highway Engineering - June 2017

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