Truck & Off-Highway Engineering - April 2023 - 25

CONEXPO 2023 FEATURE
JCB's prototype H2 engines currently are powering a backhoe loader and Loadall telescopic handler machines.
JCB states that a hydrogen fuel-cell machine could
cost as much as triple its diesel counterpart. Because
of these findings, the company decided to begin development
on its hydrogen combustion engine as a
zero-emissions fuel solution.
" If employed in an affordable and practical way, hydrogen
is a perfect solution for our industry, " said
Burnhope. " Our customers are demanding a carbonfree
mobile fuel which delivers maximum uptime. We
believe hydrogen is that fuel. "
Back to basics
During its presentation, JCB stressed that the engineering
team had gone back to first principles in designing
its hydrogen combustion engine. The team
reportedly studied 76 different technical papers on the
subject and identified four key technical challenges:
achieving a perfect mix of air and hydrogen, increasing
the volume of air, achieving a clean spark ignition,
and managing steam output.
Ryan Ballard, JCB powertrain engineering director,
explained some of the challenges the team encountered.
" When most hydrogen engines were developed
in the early 2000s, they were large-capacity naturally
aspirated engines, " he said. " Today, engines work on
lower capacities with powerful turbochargers. "
Ballard also explained the operating principles behind
JCB's engine based on their research into past
designs. " What we noticed in earlier [H2
] engines is
most people ran them in a way that produced a lot of
NOx. That's really different to what we're doing. We
run the engines at a much lower temperature and
pressure, which essentially does not create NOx emissions.
It's not a problem anymore. "
" We discovered that there's a certain temperature
you can burn air at where it's incredibly clean, " said
Burnhope. " However, if you go over that temperature,
it's awful. In the past, people tried H2
combustion using
a gasoline engine with hydrogen fuel. So they were
TRUCK & OFF-HIGHWAY ENGINEERING
JCB designed a mobile refueler that can deliver hydrogen directly to the jobsite in
which the machines are working.
working at the wrong temperatures and pressures, and the result was
awful outputs in terms of emissions and efficiency. "
New ground
Something that was completely new to JCB for this engine design
was spark ignition. The company reportedly drew on expertise from
the auto industry to integrate sparkplugs into their engine and provide
the right amount of spark for H2
combustion.
According to Ballard, the first generation of JCB's 448 ABH2 engine
features a port fuel injection (PFI) system for speed to market
and because PFI systems are very robust. There is also no aftertreatment
system required. The 4.8-liter inline-four engine features a single
turbocharger with a variable-vane design due to the high airflow
requirements of H2
engines.
In addition to powering its own machines, JCB stated that it's open
to selling the engine to external suppliers in the future. The company
also plans to address the infrastructure concerns of H2
refueling in
innovations such as its mobile refueler that can deliver hydrogen directly
to the jobsite on which the machines are working.
Matt Wolfe
April 2023 25
BOTH IMAGES: JCB

Truck & Off-Highway Engineering - April 2023

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