Truck & Off-Highway Engineering - August 2024 - 5

TECHNICAL INNOVATIONS
MODELING & SIMULATION
In pursuit of a dedicated hydrogen ICE for
heavy-duty vehicles
Heavy-duty vehicle regulations from the
European Union specify a 43% carbon
emissions reduction by 2030. The EU's
carbon emissions reduction mandate
climbs to 64% by 2035 before soaring
to 90% by 2040. " The hydrogen combustion
engine has a role to play to reduce
CO2
emissions, " said Vincent
Hexagon Agility announced a collaboration
with Norwegian EV transmission supplier
Brudeli Green Mobility at the 2024 ACT Expo in
Las Vegas.
awareness of the need to cut emissions
from medium- and heavy-duty trucks,
which make up more than 20% of overall
CO2
emissions in the U.S. transport
sector, " said Brudeli CEO Lasse
Bjørkhaug, " Our partnership with
Hexagon enables fleets in hard-to-electrify
market segments to achieve zeroemission
operation in sensitive areas,
while eliminating range anxiety for longer
trips with RNG. Additionally, fleet
operators will benefit from trucks that
offer superior electric-like performance
without the same payload restrictions. "
The PowerHybrid plug-in battery system
is capable of Level 2 charging. The
system offers 75 miles (120 km) of electric-only
range. Brudeli claims that this
is intended to be the first NZEVcompliant
(Near Zero Emission Vehicle)
technology commercially available in
the U.S. market. Once NZEV certified,
the Class 7 and 8 trucks outfitted with
Brudeli's system would comply with the
Advanced Clean Truck (ACT) rule,
which has been adopted by California
and 10 other states.
Brudeli announced in December 2023
that it had partnered with Emoss
Mobile Systems to outfit a prototype
truck with the Brudeli PowerHybrid
module. Brudeli and Hexagon Agility
plan to introduce the first pilot trucks
with this technology in 2026, with serial
production slated for 2028.
Matt Wolfe
TRUCK & OFF-HIGHWAY ENGINEERING
Giuffrida, CFD engineer for IFP Energies
novellas (IFPEN), a Rueil-Malmaison,
France-headquartered public research
and innovation organization.
Giuffrida and IFPEN colleague and
research engineer Olivier Colin were
the presenters for a webinar addressing
the " Development of a Dedicated
Hydrogen Combustion System for
Heavy-Duty Applications " in July. The
webinar was hosted by Madison,
Wisconsin-headquartered Convergent
Science, whose CONVERGE CFD software
simulates three-dimensional fluid
flows. Features of the CFD software
include autonomous meshing, complex
moving geometries, a detailed chemical
kinetics solver, advanced physical
models, conjugate heat transfer model,
fluid structure interaction/FSI (including
rigid and non-rigid body FSI), and
a volume of fluid (VOF) tool to model
multi-phase flows.
CONVERGE CFD tools played a major
role in the development, simulation and
optimization of IFPEN's experimental
heavy-duty hydrogen combustion engine.
Specific software models developed
in collaboration with IFPEN were
used to simulate combustion in a hydrogen
engine that underwent experimental
testing. Those tools include:
ISSIM (Imposed Stretch Spark Ignition
Model) for ignition, TKI (Tabulated
Kinetic Ignition) for auto-ignition and
knock prediction, as well as ECFM
(Extended Coherent Flame Model) for
premixed flame propagation.
A new turbulent stretch model, LPF
(Low Pass Filter), showed very good
agreement with DNS (Direct Numerical
Simulation) results for both Le>1 and
Le<1 mixtures - " Le " stands for Lewis
number - in the flamelet as well as in
the Thickened Reaction Zone (TRZ)
regimes, according to IFPEN's Colin. In
addition, the multi-fuel capability of
ECFM, implemented in CONVERGE,
makes hydrogen or ammonia simulations
possible with this model.
The design and optimization process
with the CONVERGE CFD software
showed that a high turbulence level is
required for better hydrogen/air gaseous
mixing, which is achievable via a
Tumble aerodynamic motion approach.
CFD simulations also showed that the
hydrogen injector definition (location
A priori tests against Direct Numerical Simulation (DNS) of the new turbulent stretch model LPF
(Low Pass Filter) for the CFM turbulent premixed flame model. X-axis: variation of turbulence
intensity from the flamelet regime (lowest Ka) to the Thickened Reaction Zone (TRZ) regime (two
other Ka). Left: stoichiometry iso-octane/air flame. Right: lean hydrogen/air flame (phi=0.4).
August 2024 5
FROM TOP: SAE/MATT WOLFE; IFPEN

Truck & Off-Highway Engineering - August 2024

Table of Contents for the Digital Edition of Truck & Off-Highway Engineering - August 2024