Contents

By

Niteesh K Shukla

Asst. Dir. Head- South Center

IRMRA

Importance of rolling resistance of tyres in the fuel economy of the vehicles

Contents

• About IRMRA

• Tyre Testing Facilities

• Global and Indian scenario on RR

• Methods of measurement and factors affecting RR

• Challenges towards the Tyre Materials to meet the desired RR.

• Case Study

• Conclusion

Contents

About IRMRA

Established in 1959, as a small scale R& D Institute, is now an

internationally well known Centre of Excellence both for non-tyre & tyre

sectors .

At present, IRMRA is under jurisdiction of Dept. of Industrial Policy &

Promotion, Ministry of Commerce & Industry, Govt. of India, New Delhi.

In the last 50 years, with the help of state-of-the-art facilities created with

the financial assistance granted by Ministry of Commerce & Industry,

Govt. of India and expertise developed by the scientists of IRMRA, it has

rendered remarkable service to rubber Industries .

Accreditations and Recognitions Accreditation and Recognition

• ISO/IEC 17025:2005: NABL Accredited

• ISO: 9001:2015 Certified

• BIS Recognized

• DGMS Accredited

• CEMILAC Approved

• DSIR Recognized / CEMILAC Approved

• BMO Accredited with ‘’Diamond Grade’’

• NABET Accreditation for LMS training

• RSDC approved training center

Certificates

Centre of Excellence for Tyre Research, Testing & Certification

Centre of Excellence for Tyre Research, Testing and Certification is

engaged in Testing and Certification of Automotive Tyres received

from the various national and international tyre manufacturers,

automotive OEMs, Customs, BIS, SRTUs, Industrial sectors.

Apart from testing, the centre is also equipped with facilities for

pursuing the research on tyre technology, tyre materials and Failure

Investigation of Automobile and Military Aircraft Tyres.

The Rolling Resistance test facility available with this centre is being

utilized by major automotive OEMs and leading tyre manufacturers in

order to demonstrate the fuel efficiency of their tyres used in

automotive vehicles.

About

Tyre Testing Standards

I. BIS standards :

IS15627 : 2005 : For 2 & 3 Wheeler tires

IS 15633: 2005 :For passenger car tires

IS 15636 : 2012 :For commercial vehicle tires

II. ECE.

III. FMVSS (U.S.).

IV. GSO (Gulf Countries).

V. SNI(Indonesia).

VI. IN Metro (Brazil).

VII.CCC (China).

VIII.ISO .

IX. SAE

X. OE specific standards

Passenger /Light truck tyre

Endurance Machine:

2 Station Type

Max. Load : 2500 kg

Max. Speed : 350 km/hr

Deflected radius .

Dynamic loaded radius checking facility

Facilities available

Facilities available

Rolling Resistance Machine:

Torque method

Test Standard- ISO 28580, ISO 18164

2 Station Type

Capacity:-Two/three wheeler/Passenger

car/Commercial vehicle tyres

Max. Load : 10000 kg

Max. Speed : 350 km/hr

Deflected radius .

Dynamic loaded radius checking facility

Tyre Testing and Research Centre has got the status of Candidate Laboratory Alignment for

the measurement of tire rolling resistance of C1, C2 and C3 tyre in accordance with

Regulation (EC) 1235/2011 and 1222/2009 following the test procedure described in ECE

Regulation No 117,

Facilities available

Tyre Shearography Machine

Advanced computerized non destructive

inspection Technology.

Capable of finding defects such as faulty

repair, inner liner separations, broken cords,

porosity and voids, foreign material.

Capable of giving scans of different regions

like crown, sidewall, shoulder, bead, inner

liner.

Facilities available

Universal testing machine.

Plunger Test: Carcass strength is checked against the

min. specification. Plunger rods

(8, 19, 32, 38 mm Dia.) are used.

Bead Unseat Test: For tubeless passenger car tires, bead

unseat force is checked against the min. specification

with standard fixture.

Static Loaded Radius: Min. distance from centre of tyre

rim assly. to the ground under specified load & inflation

conditions.

Radial Stiffness: Stiffness in radial direction.

Lateral Stiffness: Stiffness in lateral direction.

Tangential Stiffness: Stiffness in tangential direction.

Cornering Stiffness: Stiffness in cornering angle.

Foot print test: Digital Footprint with Land & sea

calculations as well as pressure distribution in contact

path.

Facilities available

Tyre Uniformity Machine :

Radial force and radial force variation

Lateral force and lateral force variation

Conicity, Ply steer

Radial and lateral runout.

Tyre Profilometer

Computerized dynamic growth profile facility.

Max. Speed : 300 km/hr

To check maximum growth of tyre at

maximum speed due to effect of centrifugal

force against theoretical envelop curve

Global Scenario on RR

TYRE LABELLING &

PERFORMANCE REGULATIONS

15

•Mandatory EU+TR as from NOV2012 for stage 1, Nov 2016 for stage 2 •Scope: passenger, light and heavy CVs tyres •RR,wet grip and external rolling noise •Self certification •Member States responsible for surveillance •Minimum requirements for RR, wet grip, rolling noise

EC Regulation 1222/2009 - labelling

Rolling Resistance

C1-tyres C2-tyres C3-tyres

RRC in kg/t

Energy

efficiency

class

RRC in kg/t

Energy

efficiency

class

RRC in kg/t

Energy

efficien

cy

class

RRC≤6,5 A RRC≤5,5 A RRC≤4,0 A

6,6≤RRC≤7,7 B 5,6≤RRC≤6,7 B 4,1≤RRC≤5,0 B

7,8≤RRC≤9,0 C 6,8≤RRC≤8,0 C 5,1≤RRC≤6,0 C

Empty D Empty D 6,1≤RRC≤7,0 D

9,1≤RRC≤10,5 E 8,1≤RRC≤9,2 E 7,1≤RRC≤8,0 E

10,6≤RRC≤12,0 F 9,3≤RRC≤10,5 F RRC≥8,1 F

RRC≥12,1 G RRC≥10,6 G Empty G For "snow tyre for use in severe

snow conditions", the limits shall

be increased by 1 N/kN.

17

Stage 2- Nov 2016

Stage 1- Nov 2012

Tyre Class Max value in (N/kN)

C1 12.5

C2 10.5

C3 8.0

For "snow tyre for use in severe snow

conditions", the limits shall be increased by 1

N/kN.

Tyre Class Max value in (N/kN)

C1 10.5

C2 9.0

C3 6.5

LABELLING AROUND THE WORLD

18

Japan Voluntary since 2010

Only Summer replacement car tyres RR and wet grip

(future) minimum requirements for wet grip

19

The tyres with a grading of A and above for rolling resistance performance and grading a to d for wet

grip performance are defined as "Fuel Efficient Tyres", and uniform mark (right) is marked to promote

use.

Unit(N/kN)

RRC Grade RRC≦6.5 AAA 6.6≦RRC≦7.7 AA 7.8≦RRC≦9.0 A 9.1≦RRC≦10.5 B 10.6≦RRC≦12.0 C

Wet Grip performance (G) Grade

155≦G a

140≦G≦154 b

125≦G≦139 c

110≦G≦124 d

LABELLING AROUND THE WORLD

20

South Korea Voluntari 2011

Mandatory as of November 2012 Applies to PC/LT tyres

RR and wet grip Registration of all products required

Minimum requirements for RR and wet grip

LABELLING AROUND THE WORLD

21

BRAZIL •Mandatory from 2015 •Applies to passenger,Light and Heavy CVs tyres •RR,Wet grip and rolling noise •Certification by Lab accredted by INMETRO •Minimum requirements for RR, wet grip and rolling noise

LABELLING AROUND THE WORLD

22

USA Final decision pending NHTSA Tire Fuel Efficiency Consumer information RR, wet grip and durability

23

Indian Scenario on RR

The prepared Automotive Industry Standard AIS-142 for tyre

rolling resistance, tyre wet grip and tyre rolling sound properties

for C1, C2 and C3 tyre which has been adopted by CMVR-TSC

Tyre rolling resistance , Tyre wet grip and

Tyre Noise properties by April 2020

The proposed date

of implementation

Why rolling resistance is

important ?

The payoff can be quite significant , How much

??

20 to 25 percent reduction in rolling

resistance can increase fuel economy by 3-5%

percent.

1.Force Method 2. Power Method:

Test Methods for Rolling Resistance

Measurement

• Measures the torque input to test machine & converts it to rolling

resistance . We measure the torque input to test machine &

converts it to rolling resistance .

Torque Method

Rr = T / R

Where Rr : Rolling Resistance

T : Net input torque

R : Test wheel

Radius

Cr = Rr /FL

Where Cr : Rolling Resistance

coefficient

Rr : Rolling Resistance

FL : Tyre Load

International Standards for Rolling

Resistance measurements of Tyres

ISO 18164

ISO 28580

SAE J 1269

SAE J 2452

Test Observations :

Speed (km/hr)

Load (kg)

Inflation Pressure (kPa)

Loaded radius (mm)

Dyn. Rolling radius (mm)

Room temp.(°C)

Rolling resistance (N) at room temp.

Rolling resistance (N) at 1.707 m drum & 25°C

Cr (N/kN) at 1.707 m drum & 25°C

Rolling resistance (N) at 2 m drum & 25°C.

Cr (N/kN) at 2 m drum & 25°C

Test observations of RR as per

ISO : 28580

Speed (km/hr)

Load (kg)

Inflation Pressure (kPa)

Loaded radius (mm)

Dyn. Rolling radius (mm)

Room temp.(°C)

Rolling resistance (N) at room temp.

Rolling resistance (N) at 1.707 m drum & 25°C =+RR amb*(1+(K*(T amb-25)))

Cr (N/kN) at 1.707 m drum & 25°C =+RR 25/1.7m

/(load*9.81)*1000

Rolling resistance (N) at 2 m drum & 25°C. =+RR25/1.7m * 0.98

Cr (N/kN) at 2 m drum & 25°C =+RR25/2m

/(load*9.81)*1000

Test calculations of RR as per

ISO : 28580 for PCR tire

• Inflation Pressure

• Load

• Speed

• Temperature

Parameters affecting Rolling

Resistance

To get the real benefit of low resistant tyre ,one should inflate the tyre to correct value .Why?? Size : 155/65R13 of 4 different makes.

Standard : ISO 28580. Pressure type : Regulated.

Rolling Resistance (N) vs Pressure (kPa)

Standard : ISO 28580

Sr. No. Pressure kPa

155 /65R13 Make A 155 /65R13 Make B 155 /65R13 Make C 155 /65R13 D

RR in N CRR

(N/KN) %

Change RR in N

CRR (N/KN)

% Change

RR in N CRR

(N/KN) %

Change RR in N

CRR (N/KN)

% Change

1 210 38.53 10.76 35.03 9.78 35.77 9.99 32 8.94

2 180 41.63 11.63 8.05 38.25 10.68 9.19 39.72 11.09 11.04 34.81 9.72 8.78

3 150 45.83 12.80 18.95 42.25 11.80 20.61 45.7 12.76 27.76 39.32 10.98 22.88

0

10

20

30

40

50

210 180 150

155 /65R13 Tyre A

155 /65R13 Tyre B

155 /65R13 Tyre C

155 /65R13 Tyre D

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

210 180 150

155 /65R13 Tyre A

155 /65R13 Tyre B

155 /65R13 Tyre C

155 /65R13 Tyre D

Pressure (kPa) Vs RR (N) Pressure (kPa) Vs CRR (N/ kN)

If tyre is underinflated 30 kPa ,then there is increase of RR to 8-11% If tyre is underinflated 60 kPa ,then there is increase of RR to 19-23%.

Effect of Inflation Pressure on rolling resistance

Size : 235 /65R17 104H

Standard : ISO 18164

Pressure : regulated type

Sr.no . Speed Load Inflation Pressure

Room Temp.

Rolling Resistance

Rolling Resistance

Crr Rolling

Resistance Crr

at room Temp.

at 25°C at 25°C at 25°C at 25°C

& 1.707 m

Drum & 1.707 m

Drum & 2 m Drum

& 2 m Drum

Km/hr Kg kPa °C N N N/KN N N/KN

1 30 720 220 21 68.89 66.69 9.44 65.35 9.25

2 50 719.9 220 21.1 70.42 68.22 9.66 66.86 9.47

3 90 720.1 220 21.6 72.76 70.78 10.02 69.37 9.82

4 120 720 220 22.4 75.92 74.34 10.53 72.85 10.31

60

62

64

66

68

70

72

74

30 50 90 120

Speed (kmph) Vs RR (N)

8.5

9

9.5

10

10.5

30 50 90 120

Speed (kmph) Vs CRR (N/kN)

Effect of speed on rolling resistance.

If speed is increased from 30 to 120 km /hr then ,there is increase of rolling resistance by

11%.

Size : 185/65R15 88S

Pressure : regulated type

if load is increased from 400 to 475 kg then ,there is increase of rolling resistance by 21

%.

0.00

10.00

20.00

30.00

40.00

50.00

400 475

Load (kg) Vs RR (N)

9.60

9.65

9.70

9.75

9.80

9.85

9.90

400 475

Load (kg) Vs CRR (N/kN)

Effect of load on rolling resistance

35

Challenges towards tyre materials to achieve the desired RR

Rolling resistance, wet grip and wear resistance form the so-

called Magic Triangle of tyre performance.

36

Tyre materials plays key role

towards the magical triangle of tyre

performance

37

This work is being carried out with modified special compound, in tyre

construction aspect to reduce rolling resistance thus gaining in fuel consumption.

• This is latest development in passenger radial tyre

• These tyres have low rolling resistance than normal tyres

• These tyres have a high proportion of non petroleum based material and are

called environment friendly or GREEN TYRE

Fuel economy / low rolling resistance

tyre - special compound

Green tyre ---Environment Friendly

The following are requirements for the tyre technology for

its sustainable growth

• Production of green tyres with the use of eco friendly rubber

ingredients

• Production of fuel efficient tyres to save the economy and

excessive emission of CO2

• To meet the Global tyre performance regulation

• To meet the Fuels and Vehicle norms (BS-V, BS-VI/Low

carbon vehicles/ Electric vehicles (EVs)

Conclusion:-

Thank You