| LONDON, March 20
LONDON, March 20 Cutting vehicle weight may be
the next main advance in reducing the financial and
environmental cost of motoring.
Until now carmakers have met a trend towards tougher fuel
economy standards worldwide by reducing engine sizes and
introducing technology for example to cut motors when a car is
In the next step up, choices include electric and hybrid
power technologies but these add thousands of dollars to the
upfront cost of a vehicle.
By contrast, recent U.S. studies have shown that cutting
vehicle weight can improve efficiency while reducing
manufacturing costs, where the higher cost of lighter materials
is offset by less bulk and lower labour costs.
That synergy was summed up by the International Council on
Clean Transportation (ICCT), a research group, in a report it
published in January: "Summary of mass reduction impacts on EU
"Since less energy is required to move a reduced mass, the
vehicle engine can be downsized. Similarly, components such as
the vehicle suspension, brakes, and body can be made smaller or
lighter since they need not support the same mass or dissipate
the same energy."
One hurdle to adoption in Europe has been a policy where
carbon emissions reduction targets are assigned by weight,
applying more ambitious cuts to lighter vehicles, potentially
wiping out the benefit towards meeting targets from shedding
That is changing, slowly.
One alternative is to classify cars by the area they
physically cover, which would allow manufacturers to maintain
their diversity of models while capturing the benefit of lighter
A panel of European Parliament lawmakers on Tuesday approved
a choice of footprint or weight parameters from 2020, giving
manufacturers a choice in how they apply targets. That contrasts
with the European Commission which has proposed a review of a
footprint approach after 2020.
The U.S. Environmental Protection Agency has commissioned
various studies to measure the incremental manufacturing cost of
reducing vehicle weight.
For example, FEV Inc, a designer of conventional and
alternative transportation energy systems, undertook a so-called
teardown analysis of a 2010 Toyota Venza for a study,
"Light-Duty Vehicle Mass Reduction and Cost Analysis - Midsize
Crossover Utility Vehicle", published last August.
The Venza was chosen as an example of a new model which was
typical of the crossover utility type and with the latest safety
The analysis involved tearing apart a vehicle to its
individual components and then estimating the incremental
manufacturing cost of substituting these for lighter
The original weight of the vehicle was 1,711 kilograms (kg)
and the target for mass reduction in the analysis was 20
percent, or 342 kg.
The purchase price of the vehicle was $25,063 and the
estimated direct manufacturing cost was $16,709.
The FEV study concluded that the optimum mass reduction was
312.48 kg, or just under a fifth of the total vehicle weight,
because that could be met with a manufacturing cost saving of
It found that costs turned positive for greater weight
reductions. (Chart 1)
The cost savings were made through offsetting an increase in
material costs with cuts in labour costs and manufacturing
overheads and a mark-up saving.
Weight reductions were met both by downsizing parts and
using different materials, such as aluminium or plastic instead
of iron or steel.
The weight reductions were mostly in the body system, at 4
percent of the total saving; the suspension system (3.91
percent); the interior (2.45 percent); and the braking system
(1.91 percent) (Chart 2)
Chart 1: (page 7) goo.gl/6Wobt
Chart 2: (page 6) goo.gl/6Wobt
Chart 3: (page 25) goo.gl/CTFQa
One common argument against using lighter weight materials
is a feared compromise on vehicle safety.
In a parallel study to that of FEV, the engineering arm of
lightweight vehicle manufacturer Lotus suggested that there was
no such sacrifice, in a report commissioned by the California
Air Resources Board (ARB) and published last August.
The study was titled "Evaluating the Structure and
Crashworthiness of a 2020 Model-Year, Mass-Reduced Crossover
Vehicle Using FEA Modeling".
It performed car crash simulations to measure the effect of
reducing vehicle weight by just over 30 percent, designing a new
model based on the 2009 Toyota Venza according to vehicle
dimensions, utility objectives, and passenger and interior
"The theoretical study indicates that a low-mass body
structure has the potential to meet Federal Motor Vehicle Safety
Standards (FMVSS) for light duty vehicles for front, side, and
rear impacts, roof crush, occupant restraints and several
Insurance Institute for Highway Safety requirements," it
The International Council on Clean Transportation (ICCT) is
an international research firm which supplies technical and
scientific analysis to environmental regulators.
It recently applied such mass reduction studies to analyse
the cost impact of meeting EU carbon emissions targets by
cutting vehicle weight.
ICCT published a study in January which analysed the extra
cost for manufacturers to cut carbon dioxide emissions in line
with the proposed EU 2020 target (95 grams CO2 per kilometre)
compared with a 2010 baseline.
They found that compliance costs under a regulatory system
which credited weight reduction, such as a footprint approach,
were as much as half as an alternative approach which penalised
weight reductions. (Chart 3)
"Compliance costs are much lower under a regulatory
structure that fully credits the CO2 emission reduction benefits
of vehicle mass reduction than under a structure where mass
reduction technologies are not fully creditable," it found in
its January report.
Such findings suggest that the EU might move faster to base
its fuel economy targets on a choice of footprint or weight.
(Reporting by Gerard Wynn)