When it comes to hybrid cars and trucks, new
technologies don't always mean a drastic change in the metals
used to make them, according to auto industry insiders. While
some analysts and metal industry partisans see a revolution in
the making, the auto industry's response might be not so
Ford Motor Co., Dearborn, Mich., builds both its
Escape and Escape Hybrid sport utility vehicles (SUVs) off the
same platform, Matthew Zaluzec, manager of Ford's Materials and
Nanotechnology Department, said. "As built, there are no
differences in these two vehicles except for the fact that
we've added the electric powertrain (to the hybrid)."
In the future, the company's hybrid electric
vehicles will use the latest lightweight technologies-with
engineers working with both ultra- and advanced high-strength
steels, as well as aluminum and magnesium, he said. "Our
product development design staff is looking at lightweight
steel, aluminum and magnesium for closures .?.?. as lightweight
"Closures" refer to vehicle parts such as doors and
hoods. Because of the heavy batteries required for hybrids,
automakers often look to offset weight elsewhere in the
vehicle-and big parts like trunks and hoods are an obvious
place to start.
Ford also is looking to lightweight vehicles with
cast aluminum alloys for engine blocks and cylinder heads, and
is working with "next-generation" cast iron materials such as
compacted graphite iron. "This class of cast iron takes
advantage of the material's higher strength, excellent
mechanical and fatigue properties and higher operating
temperature capability," Zaluzec said.
Cast iron was the metal of choice for engine blocks
and cylinder heads through the early 1980s. Aluminum cylinder
heads, introduced in the early '80s, are now used in 98 percent
of Ford vehicles, while aluminum blocks, which started to
replace cast iron in the early 1990s, are used in about 65
percent of Ford's engines.
The automaker also is working with lithium-ion and
nickel-metal hydride batteries, as well as fuel cells. Fuel
cells, which are made from bipolar metallic plates and plastic
separator films, will mean a "whole new range of materials
development," Zaluzec said. "These propulsion systems will rely
upon development of metallic plates made from coated steels,
stainless steels and other specialty metals."
"If you talk to someone in the aluminum business,
they would probably say steel is antiquated and on it's way
out," said Jeff Luke, chief engineer of full-size pickups and
SUVs at General Motors Corp., Detroit. "But if you were a steel
person, you would say aluminum prices are escalating and pretty
soon they'll be uncompetitive." The steel industry also would
point out the cost of retooling to switch metals, he said, but
GM likes having the option to use different metals for
But it isn't just through changing metals that
vehicles can save fuel in the powertrain, Luke said. GM's
FlexFuel vehicles can run on gasoline or E85 ethanol, and some
engines sport an active fuel-management system that allows
cylinders to deactivate in order to boost efficiency. A truck
cruising at a steady speed, for example, can run on fewer
cylinders and save fuel.
Even GM's much-touted Chevrolet Volt hybrid
electric plug-in car won't necessarily have a dramatically
different engine, a company spokesman said. "You're not going
to see that drastic of a difference. It's just a typical
engine, except there might be fewer components."
The main difference might be not so much in the
metals used in the engine but instead in the reduced role it
will play in moving the vehicle down the road. "It's going to
run at optimal rpm to recharge the battery to run the
electrical system," he said. "It'll come on by itself only as
The lithium-ion battery, however, does bring
something new to the table-and much is riding on whether GM and
others can perfect the technology. "The ultimate production of
(the Volt) still rests on advances in that battery system," the
spokesman said. "We have thrown lots of resources at developing
it, and we're confident we'll get there."
And what is Japan's Toyota Motor Corp. up to with
its hybrids, especially the iconic Prius? It won't say. "We are
working to reduce the size and weight of the hybrid system so
that we can expand the hybrid application for various types of
cars," a company spokesman said. "However, we can't provide
specific answers about metal mix, weight, materials, etc."
But Toyota's Japanese rival, Honda Motor Co. Ltd.,
thinks it has a better hybrid system than Toyota does. Toyota's
hybrids rely primarily on battery storage, and that makes its
cars a lot heavier, a Honda spokesman said. And while
breakthroughs have been made on battery voltage and output,
advances have been slower in battery storage systems, he
A vehicle like the Honda Civic hybrid instead
features applications such as regenerative braking that assists
the engine, the spokesman said. Regenerative braking allows a
car to capture energy generated during braking. "When you brake
the car, you can produce electricity that is stored in
batteries, and that electricity is used to turn a wheel
(between the engine and transmission) that assists the engine,"
The chief difference between the traditional Civic
and the Civic hybrid instead of a 1.6-liter engine, the hybrid
comes equipped with a 1.3-liter engine, the spokesman said.
"That allows you to get the same performance but with a smaller
engine, so you automatically save gasoline," he said. "But it
doesn't change the basic architecture of the car." One
exception behind the back seat, the Civic hybrid holds a series
of nickel-metal hydride batteries.
The story, however, is somewhat different for the
Civic GX, which runs on compressed natural gas. "That car does
have the standard Civic engine," the spokesman said. "But it
has pistons that are beefed up with special alloys and certain
other parts are made with different aluminum alloys" because
the engine runs 400 degrees hotter than a gasoline engine.
Another different feature of the Civic GX unlike
the plastic gasoline tanks Honda uses in its other vehicles,
the GX sports a tank made from layers of carbon fibers and
other exotic materials that prevent it from leaking or
bursting. And the GX fuel tanks are bigger than plastic tanks
designed to hold gasoline, because the thermal efficiency of
natural gas is about half that of gasoline so you need more of
it to power a vehicle, the spokesman said.
The Honda FCX Clarity, which is powered by fuel
cells, is where the truly revolutionary changes come. Honda is
already producing the vehicles in limited volumes in Japan and
leasing them in California.
Because the Clarity relies on fuel cells for power,
it doesn't even have an engine block, which in effect
eliminates an entire front in the battle for market share.
Honda makes the fuel cell stack using a variety of exotic
metals, but some of the information about the technology is
proprietary, the spokesman said. And while slightly different
from a traditional transmission, the Clarity transmission is
still made with metals.
Many people assume that electric or hydrogen cars
will make heavy use of plastic because limited production
models made in the 1980s and '90s did, the Honda spokesman
said. But that likely won't be the case, especially when
vehicles enter mass production. "It's easier to do a plastic
car in small volumes. But for long production runs, it's easier
to stamp steel," he said. "There are safety standards, and
there is a whole body of knowledge around steel and steel
And heavy isn't necessarily a bad thing for some
hybrids, especially vehicles that employ regenerative braking.
A heavier car means more energy is generated by the brakes, and
therefore is available for the battery to assist the engine.
"So steel isn't necessarily out of the ballgame on a hybrid
car," he said.
And it's not as if one technology will suddenly win
out and drastically remake the landscape of the auto industry,
the Honda spokesman said. "The pace of change will be steady in
the auto industry. It won't be radical and there won't be
overnight triumphs. There is just a lot of experimenting going
But that also means automakers have to keep their
engineers busy working on a wide range of technologies. "Right
now our view is that there is no emerging technology that is
going to trump all of the others as far as fuels of the
future," the spokesman said. "You have to have good engineering
in a variety of areas to remain competitive right now."