Automotive Engineering - March 2025 - 12

TECHNOLOGY REPORT
Abuelsamid, vice president for market
research at Telemetry. " On the plus
side, it's a drop-in replacement for fossil
fuels, which means it can use existing
distribution infrastructure. And existing
vehicles, especially classic cars, can
keep running. It has all of the technical
advantages of liquid fuels, such as high
energy density and the ability to avoid
the cost of batteries. For low-volume
brands like Aston Martin, Ferrari and
even Porsche, it allows them to avoid a
huge investment in electrification. "
The downside? A high cost in both
dollars and power. " Producing eFuel
requires the production of hydrogen as
an intermediate feedstock, " Abuelsamid
said. " While this can certainly be done
with renewables, it remains unclear if
the total net energy use and emissions
are a positive rather than just using the
electricity directly to charge a battery.
There's also the question of whether
burning any sort of hydrocarbon, even
if it is produced as an eFuel from direct
air extraction, will actually reduce the
amount of greenhouse gases we put
into the atmosphere. "
In the interim period, eFuel has seen
some limited use in European racing.
Porsche's Mobil 1 Supercup, with up to
32 cars in 2024, used eFuels exclusively.
" We are currently the exclusive off-taker
of the e-fuel from the pilot plant,
which is used in lighthouse projects
such as the Mobil 1 Supercup and test
drives with classic cars at highlight
events (including the Goodwood
Festival of Speed) to demonstrate that
the use of e-fuels require no changes in
existing combustion engines and the
existing infrastructure, " Porsche said.
There's a practical side to eFuels for
classic car owners, who see a way to
keep their vehicles on the road. Rob
Sass, the editor of the Porsche Club of
America's Panorama magazine, said he
envisions a $10- to $12-a-gallon fuel
that the owner of a 1967 Porsche 911S
can use on weekend jaunts in, say,
2040. " It will be a boutique fuel to continue
operating our cars, " he said.
" Without that, they'll be behind velvet
ropes in a museum. "
Jim Motavalli
12 March 2025
FUEL STORAGE
Hydrogen storage: Not everything need look
like a sausage
Linamar said its Flexform conformable
hydrogen storage system can use less
material in the same storage volume while
delivering anywhere from 5-25% more
volumetric efficiency than conventional
cylindrical tanks.
Since the 1860 Hippomobile, hydrogen
has been a part of powered mobility.
Today, most hydrogen storage applications
use cylindrical tanks, but other
solutions are available. At a recent
Bosch-sponsored event, SAE Media
noted Linamar's Flexform conformable
storage, which the company says uses
the same or less material for a given
storage volume while delivering anywhere
from 5-25% more volumetric efficiency
than conventional cylindrical
tanks within that volume.
" We see space as a regular bounding
box where all you're losing is this area
around the corners, closer to five to 10%
[loss]. Where Flexform really shines and
where the value proposition really is, is
irregular spaces, such as between frame
rails, " said representatives from the
Linamar engineering team.
Linamar's packaging study for an
unnamed hydrogen-powered van with
storage between, under and around the
crossmember, " achieved 55% more hydrogen
storage than they could store
with cylindrical tanks, " the Linamar engineers
said. " Where Flexform really
shines is being able to fit into multiple
irregular storage spaces. "
Current Flexform configurations vary
from 40-80 mm (1.6-3.2 in) in diameter
and use a liner covered by a carbon
fiber braid. " We then fold it into the
desired shape, add fittings, apply the
resin and cure it in an oven, " the engineers
said. " If desired by the customer,
Linamar can install the assembly into
an existing enclosure. " R&D, testing
and validation are performed at
Detroit-based McLaren Engineering
with production facilities in Guelph,
Ontario. GTR-13 phase 2 certification is
expected to be completed in the first
quarter of 2025. Others, including
Forvia, have also researched non-cylindrical
H2 tanks.
There are five main types of hydrogen
storage options:
* Type I all-metal cylinders.
* Type II load-bearing metal-lined cylinders
(typically steel or aluminum
alloys) with glass fiber composite
overwrap and partial fiber reinforcement
of the metallic cylinder.
* Type III non-load-bearing metal-lined
cylinders (aluminum) with a full carbon
fiber composite overwrap.
* Type IV non-load-bearing plastic/
composite cylinders with composite
AUTOMOTIVE ENGINEERING
LINAMAR
Automotive Engineering - March 2025

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