Technical University of Gdansk, Poland

Rolling Resistance Influence on Fuel

Consumption

[Silka W.: Energochłonność ruchu samochodu, Warszawa, WKŁ 1997]

Decrease of tires Rolling Resistance by 10%

results in approximately 3% reduction of fuel

consumption

Number of vehicles in Poland - 15 000 000, in USA – 250 000 000

Use of tires with 10% less Rolling Resistance would reduce daily

fuel consumption by approximately 1000 tons (USA - 35 000 tons)

Daily savings in CO2 emission would amount to 3000 tons (USA –

100 000 tons)

Resistance forces acting on typical passenger

car

[Silka W.: Energochłonność ruchu samochodu, Warszawa, WKŁ 1997]

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

ECE cycle 90 km/h 120 km/h

Air drag

Rolling resistance

Inertia forces

Rolling Resistance

Rolling Resistance

Rolling Resistance

Road Methods of Rolling Resistance

Evaluation

Towing

(car or trailer)

Coast-down

Torque

measurements

Fuel

consumption

Laboratory Methods of Rolling Resistance

Evaluation

Measurement of:

* Spindle force

* Torque of the power system

* Coast-down time

Laboratory Methods of Rolling Resistance

Evaluation

Errors in Rolling Resistance Estimations

(misalignments / grade)

a

Ry

Rr

W

L F

r

e

01.0

3.0

3800

200

r

ef

mr

NL

NW

WL

Ff

ReRr

LRF

LWR

m

yr

r

y

0)sin(

0)cos(

a

a

0101.0"20

0110.0'04

0187.0'30

0100.0'00

m

m

m

m

f

f

f

f

a

a

a

a

Errors in Rolling Resistance Estimations

(acceleration)

a

Ry

Rr

W

L F

r

e

I

WL

Ff

amI

IRF

LWR

m

r

y

0

0

01.0

28*4.1

20

3.0

3800

200

r

ef

kgmm

kgm

mr

NL

NW

I

0107.0/1.0

0100.0/0.0

2

2

m

m

fsma

fsma

Errors in Rolling Resistance Estimations

(air drag)

Ry

Rr

W

L F

r

e

A

V

01.0

20

200

3.0

3800

200

r

ef

kgm

mmB

mr

NL

NW

WL

Ff

vrBcA

ARF

LWR

m

x

r

y

22

0

0

2

0172.0/20

0100.0/0

m

m

fsma

fsmv

Errors in Rolling Resistance Estimations

(acceleration)

Generally, equipment constructed for

Traction measurements is not appropriate

for Rolling Resistance measurements as

the Traction and Rolling Resistance forces

are of different magnitude.

Usually Rolling Resistance force is at

about 100 times less than maximal

possible Traction force.

Belgian Trailer for Rolling Resistance

Measurements

Principle of Operation

ft = Wt/Z

Pf

Z

Ciężar

Kierunek jazdy

Wt

7

4

3

2

6

1

5 8 9

LOAD

1-frame; 2-loading system; 3-axis of frame and loading device;

4-measuring arm; 5-test wheel; 6-adjustable load; 7-damper and spring

Polish Trailer Mk.1

Polish Trailer Mk.1

rama przyczepy

wahacz pomiarowy

FRAME

ARM

Polish Trailer Mk.2

Polish trailer Mk. 3

Calibration

5 3 4

2

1

6

7

9

8

l x

a

B

C

A’ A

C

α

θ

P

b Wt

Examples of the results

Nawierzchnia odcinka pomiarowego P1 S5 P2 S3 S2 S1 S4

Wartość współczynnika 0,0106 0,0116 0,0117 0,0118 0,0135 0,0140 0,0159

Test section

RR coefficient