JEC COMPOSITES MAGAZINE - Issue #102 - January/February 2016 - 19

- Decreasing rolling resistance through
the use of efficient tyres.
- Making traffic smoother:
reducing, through regulations, the
maximum speed on roads, developing
vehicles adapted to the maximum speed,
better regulating the traffic and develo-ping carsharing.
- Using materials efficiently:
in particular with an objective of weight
reduction.

CO2 and weight

The CO2 reduction (g/km) that results
from a vehicle weight reduction of
100 kg is not easy to estimate precisely.
Several approaches can be considered:
Fig. 1: Manufacturers' positioning in 2013 in relation to 2021 targets (new passenger cars)

By 2015, the law requires that the new
cars regis¬tered in the EU do not emit
more than an average of 130 grams CO2
per kilometre (g CO2/km). This means
a fuel consumption of around 5.6 litres
per 100 km (l/100 km) of petrol or 4.9
l/100 km of diesel.
The average emissions level of a new
car sold in 2014 is estimated at 123.4 g
CO2/km, well below the 2015 target.
Since 2010, emissions have decreased
by 17 g CO2/km (12%).

value curve.
- The curve is set in such a way that the
targets for new car fleet average emis-sions are achieved.
- The limit value curve means that hea-vier cars are allowed higher emissions
than lighter cars.
- Only the fleet average is regulated, so
manufacturers can still produce vehicles
with emissions above the curve, provi-ded these are balanced by vehicles
below the curve.

By 2021, phased in from 2020, the fleet
average to be achieved by all new cars
is 95 grams of CO2 per kilometre. This
means a fuel consumption of around
4.1 l/100 km of petrol or 3.6 l/100 km
of diesel.
The 2015 and 2021 targets represent
reductions of 18% and 40%, respectively, compared with the 2007 fleet
average of 158.7 g/km.

Not all carmakers have the same
positioning versus these targets. While
generalists tend to get easily close to the
targets, premium carmakers will have to
deploy more efforts (see Figure 1).

Each carmaker has its individual annual
target calculated on the basis of the
"mass in running order" of the registered passenger cars and light commercial
vehicles. The calculations are made as
follows:
- The emission limits are set according
to the mass of the vehicle, using a limit

Ways of reducing CO2 emissions

CO2 emissions can be reduced in multiple
ways:
- Acting on the powertrain: better combus-tion, downsizing, more power for the
same cylinder capacity, and electrification.
- Keeping motorizations with low CO2
emissions at a high level of use: diesel
and electrified motorizations (battery
electric vehicles and hybrid vehicles).
- Decreasing the drag coefficient (CX):
by styling the vehicle or by replacing
external mirrors with video cameras.

First, comparing two vehicles of subsequent generations. This consists in
comparing a generation "n" model with
the same model of generation "n+1",
with closer characteristics (power,
dimensions, ...).
This methodology has several drawbacks. First, it is very difficult to
differentiate the contribution of weight
reduction from the contribution of
other factors. Secondly, the measurements can only be performed on a
limited number of models.
Second, adding a complementary
weight of 100kg into a given vehicle.
The vehicle's CO2 emissions are measured before and after adding the weight,
using the current NEDC cycle test.
The drawbacks of this methodology are
that the CO2 increase when loading the
car is underestimated as the properties
of the loaded car are inferior to the properties of the unloaded car (for instance
the power). Moreover, it is necessary
to take into account that more weight
needs to be added (secondary weight)
to return to the properties of unloaded
vehicles. Finally, the measurements can
only be performed on a limited number
of models.
Third, thinking statiscally. This is
Inovev's approach (see Figure 2). A
graph (CO2/mass) showing all the

No102 January - February 2016 /

jec composites magazine 19

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #102 - January/February 2016