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A U t o M o t I v E
Aluminium in innovative light-weight car design
J. Hirsch, Bonn 1
This paper presents principal
aspects and recent trends in average
and specific use of aluminium
in passenger cars. Aspects of
material selection and innovative
concepts of car construction using
light-weight materials that help to
meet economical and environmental
requirements are discussed
as well as special aluminium
alloys developed for the increasing
demands in higher strength
and better formability for light
weighting and crash worthiness
aspects and the specific advances
of aluminium semi products as
castings, extrusions and sheet.
Examples are presented for successful
aluminium solutions in the
most advanced SLC ’SuperLIGHT-
Car’ concept, which reaches 34%
weight reduction within a cost
increment of 7.8 €/kg saved.
The European automotive industry is
known world wide as the technically
most advanced and innovative. Based
on economical and political pressure
to reduce fuel consumption and CO 2
emission the efforts for light weighting
in automobile design and constructions
have increased significantly and
specific solutions based on the inten-
1 This paper was presented at the Volkswagen
Conference ’Innovative Developments for Lightweight
Vehile Structures’ on 26/27 May 2009.
Fig. 1: State-of-the-art ’body in white’ multimaterial concept
sive use of aluminium as modified or
new alloys have been developed in
the last decades [1-5]. The European
automotive industry has more than
doubled the average amount of aluminium
used in passenger cars during
the last decade and will do even more
so in the coming years.
The European automotive industry’,
in close co-operation with the
European aluminium industry, has
developed and introduced numerous
innovative light-weighting solutions
based on established and improved
aluminium alloys [2-9] and optimized
aluminium oriented car design. Synergic
effect together with a multimaterial
exploitation can guarantee
an optimum design solution. One of
the main advances of aluminium is its
availability in a large variety of semifinished
forms, such as shape castings,
extrusions and sheet, all suitable for
mass production and innovative solutions.
Compact and highly integrated
parts meet the high demands for high
performance, quality and cost efficient
manufacturability. Challenges
involved here are mainly joining and
surface treatment issues for which
many suitable solutions have been
developed. Aluminium semis are applied
as castings, extrusions and sheet
increases, e. g. in engine blocks and
power train parts, space frames (e. g.
Audi A8, BMW Z8, Lotus Elise), sheet
structures (Honda NSX, Jaguar) or as
closures and hang-on parts (e.g. Daimler
E-class, Renault, Peugeot) and other
structural components [1-3].
The average total aluminium content
per European car was 132 kg in
2005 [9]. It has been analysed systematically
as:
• Power-train (engine, fuel system,
liquid lines): 69 kg (25 compo-
nents analysed) in engine block
and cylinder head, transmission
housings and radiators
• Chassis and suspension (cradle,
axle): 37 kg (17 components
analysed) in wheels, suspension
arms and steering systems
• Car body (body-in-white (BIW),
hoods, doors, wings, bumpers and
interiors): 26 kg (20 components
analysed) in bonnets and doors,
front structure and bumper beams.
This shows that for the body the most
potential exists. Seen as one component
the BIW is the heaviest part of
a conventional car with a share between
25 and 30% of the complete
car’s weight, depending mainly on
options installed, engine size, and integrated
safety features.
State-of-the-art
for the body in white (bIW)
As state-of-the-art for a BIW ’extrusion
intensive design’ the Aston Martin
Vanquish, model year 2001, is
mentioned with a volume of 350 cars
28 ALUMINIUM · 9/2009
Images: Hydro