fuel savings potential from low rolling- resistance tires axel friedrich umweltbundesamt (uba)...
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Fuel savings potential from low rolling- resistance tires
Axel FriedrichUmweltbundesamt (UBA)
Germany
Contribution of Tire to Fuel Economy
Historical Trends
ENERGYDERIVEDFROM FUEL
ROLLING LOSSES + VEHICLE LOSSES + STAND-BY LOSSES
AERODYNAMICS: IMPROVING
INERTIA: CAR WEIGHTS AT MAXIMUM ?
TIRE ROLLING RESISTANCE
RELATIVE IMPORTANCE INCREASING
Test Populations (Car Tyres) 12 sets of summer tyres of size category
175/70 R13 82T
• 12 sets of winter tyres of size category
175/70 R13 82Q M&S
• 12 sets of summer tyres of size category
195/65 R15 91V
• 12 sets of winter tyres of size category
195/65 R15 91H M&S
The measurements were carried out in 1997/1998 by the Tyre/Wheel Test Center of TÜV Automotive GmbH
under contract to theUmweltbundesamt.
Test Populations (HDV Tyres)
4 sets of summer tyres of size category (light truck, delivery transport) 225/70 R15C
5 sets of steered-wheel tyres of size category (medium-sized truck,) 215/75 R17,5
5 sets of drive-wheel tyres of size category (medium-sized truck,) 215/75 R17,5
4 sets of steered-wheel tyres of size category (bus, municipal transport) 275/70 R22,5
4 sets of drive-wheel tyres of size category (bus, municipal transport ) 275/70 R22,5
5 sets of steered-wheel tyres of size category (heavy truck,) 315/80 R22,5
5 sets of drive-wheel tyres of size category (heavy truck,) 315/80 R22,5
The measurements were carried out between March and June 2000 by the Tyre/Wheel Test Center of TÜV Automotive under contract to theUmweltbundesamt.
Measurement Procedures
• Tyre/road noise EU Directive 92/23/EEC • Rolling-resistance coefficient cR
ISO 8767 (ISO 9948)
• Wet braking behaviour brake distance on a wet road
size categories 17.5” and 22.5”: braking trailer with anti-lock braking system
size category 15”: commercial vehicles
Cumulative frequency of rolling resistance of 48 tyre types for passenger cars
0
20
40
60
80
100
0,7 0,8 0,9 1 1,1 1,2 1,3 1,4 1,5rolling-resistance coefficient c R in %
cumulative frequency in %
summer tyres 175/70 R13 82T summer tyres 195/65 R15 91V winter tyres 175/70 R13 82Q M+Swinter tyres 195/65 R15 91H M+S
limit ecolabelsummer tyres
limit ecolabelwinter tyres
66 68 70 72 74 760,7
0,8
0,9
1
1,1
1,2
1,3
1,4
1,5 summer tyres
winter tyres
limit ecolabel"Blue Angel"
limit ecolabelsummer tyres
limit ecolabelwinter tyres
Relation between rolling resistance and noise emission 48 car tyre types
(coast-by level measured according to EU Directive 92/23/EEC,
rolling resistance measured according to ISO 8767)
"Blue Angel" Ecolabel for Low-noise and Fuel-saving Tyres (RAL-UZ 89)
Criteria (car tyres)
- coast-by level <= 72 dB(A) (92/23/EEC)
- rolling-resistance coefficient: Summer tyres: <= 1.1% (ISO 8767) Winter tyres: <= 1.2%
- weight: depending on tyre size: 7-9.2 kg
- lifetime: >= 400 (UTQG Test, Standards Testing Laboratories, Inc. (STL),
San Angelo/Texas
- wet braking behaviour at least average properties regarding - aquaplaning behaviour state of the art
wet surface-braking behaviour versus rolling resistance
of 48 tyre types for passenger cars
40
45
50
55
0,8 0,9 1 1,1 1,2 1,3 1,4
rolling-resistance coefficient c R in %
wet-braking distance s
B in msummer tyreswinter tyresLinear (winter tyres)Linear (winter tyres)summer tires
limit ecolabel
winter tyreslimit ecolabel
summer tyres
Relation between aquaplaning behaviour and rolling resistance of 48 tyre types for
passenger cars
80
85
90
95
100
105
110
0,7 0,8 0,9 1 1,1 1,2 1,3 1,4 1,5
rolling-resistance coefficient cR in %
aquaplaning speed v
A in km/h
summer tyres
winter tyres
Linear (summertyres)Linear (wintertyres)
limit ecolabel
winter tyreslimit ecolabel
summer tyres
Influence of Compounds• Ultimate:
• Single compound tire• Low RR compound
==> -52%
• Special low RR compound line-up
- TREAD STANDARDBLACK
SPECIALBLACK
STANDARDSILICA
SPECIALSILICA BASED
RR 100 -17% -22% -30%
- SIDEWALL STANDARD SPECIAL RR 100 -3%
- BELT COMPOUND STANDARD SPECIAL
RR 100 -5%
Balance of Properties
80
90
100
110
120
90 100 110 120 130 140
We
t Pe
rfo
rman
ce
Rolling Resistance RatingRolling Resistance Rating
Silica
Carbon Black
Source: Goodyear
Rolling Resistance of Drive Axle Tires
0,577% 0,562% 0,560%
0,666%0,692%
0,709%0,655%
0,561%0,580%0,587%
0,40%
0,50%
0,60%
0,70%
0,80%
0,90%
1,00%
MichelinXDA 2Energy
GoodYearMarathon
LHD
ContinentalHDL eco-
plus
Dunlop SP451
Toyo M 622
cR [%]
Reifen 1
Reifen 2
315/80 R22,5
Rolling Resistance steering axle tires
0,471%
0,445% 0,447%
0,489%
0,534%
0,504%
0,425%
0,482% 0,477%
0,554%
0,40%0,42%0,44%0,46%0,48%0,50%0,52%0,54%0,56%0,58%0,60%
MichelinXZA 2Energy
GoodYearMarathonLHS
ContinentalHSL eco-plus
Dunlop SP
351 Toyo M111
cR [%]
315/80 R22,5
Exploring the Rolling Resistance Limits
Current Baseline 100
OPTIMIZED FOR RR ONLY
ALLROUND CHAMPION
Next Generation (2002)
150 120-130
Future Generation (2006)
Up to 200 140-150
Source: Goodyear
Potential of Fuel Saving by low rolling Resistance Tires
30% reduction of the rolling resistance reduces the fuel consumption :
city driving: 4- 6%
extra urban driving ( 70 to 89 km/h ) 3- 5%
autobahn driving ( 120 km/h ): 2- 3%
ConclusionThe measuring results obtained show that the EU limit values for tire noise emissions are too high to bring about advances in the state of the art. Steps should be initiated to lower the limit values as soon as possible.
Since no significant conflict of aims was found to exist between tyre/road noise levels or rolling resistance and the wet braking behaviour, binding restrictions throughout the EU should be introduced simultaneously to control the rolling resistance of tyres for heavy-duty vehicles and passenger cars and wet braking behaviour as well.
In case of tires for heavy-duty vehicles, TÜV Automotive GmbH has stated that if, for example, tyres with optimised rolling resistance are used in road haulage, this will lead to a decrease in fuel consumption of between 4% and 12%, depending on route profile, speed, regularity of the speed, and vehicle aerodynamics.
