Truck & Off-Highway Engineering - October 2022 - 19

ORIGINAL EQUIPMENT
The Toyota-developed powertrain was
being demonstrated on a two-mile highway
loop at the American Center for
Mobility in Ypsilanti, Michigan. The
truck's acceleration was impressively
quick, while light on noise and vibration,
and moderate rattle and squeak - essentially
a byproduct of not having the
diesel engine masking in-cabin noises.
At the start of the closed-track drive,
Chris Rovik, Toyota's executive program
manager for the heavy-duty hydrogen
fuel cell, steadily depressed the accelerator
- and the whirl-sound of electric
motors increased. " A traditional diesel
truck uses pulley-driven systems for the
brake air compressor, A/C compressor
and power steering pump. But in this
former diesel-engine truck, the engine
compartment's pulley-driven systems
have been replaced with electric motors
to run the ancillaries, " Rovik noted.
In roughly 15 seconds, the tractor accelerated
to more than 55 mph (88
km/h). " We've gone from zero mph to
highway speeds in 30 seconds with truck
and trailer " during previous testing, Rovik
said. The vehicle's four-speed automatic
transmission - part of the eDrivetrain
module that also includes two electric
motors to provide up to 450 kW of peak
power and 2400 Nm (1,770 lb-ft) of peak
torque - quickly completed its tasks. The
first-gear shift occurred around 25 mph
(40 km/h), followed by another upshift at
40 mph (64 km/h) and a final upshift at
60 mph (97 km/h). " If we had a trailer
with a load on it, the ride would feel even
smoother because the load would help
damp out some of the shifting, " Rovik
said, referring to the slight vehicle sway
felt during the automatic gearshifts.
Under the Kenworth's tilting hood
are two second-generation fuel-cell
stacks based on the stack used in the
Toyota Mirai sedan. The overall package
dimensions of the fuel-cell module,
which includes the stacks, air compressors,
pumps and fans, are essentially
the same size as a diesel engine,
Rovik pointed out. Toyota's fuel-cell
powertrain kit will enable buyers to
replace their diesel engines with hydrogen-fueled
electrification. In the
prototype vehicle, hydrogen storage
TRUCK & OFF-HIGHWAY ENGINEERING
October 2022 19
The advanced prototype
Kenworth T680 uses
Toyota's hydrogen fuelcell
electric powertrain,
which combines hydrogen
gas and air to produce
electricity.
tanks and related components are
housed in a cabinet behind the cab.
The 60 kg (132 lb) of onboard hydrogen
provides approximately 1,800 kWh
of usable energy. That represents more
than three times the 565-kWh battery
capacity of the Volvo VNR Electric
Class 8 truck.
The advanced prototype's 200-kWh
lithium-ion battery pack is located below
SAE/KAMI BUCHHOLZ
http://info.hotims.com/82346-710
Truck & Off-Highway Engineering - October 2022

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