1

Open Points: Annex 4 Road and Dynamometer Load

Running number (not com-

ment num-ber)

Para-graph, table #

Subject Action to be taken/action taken

1. 2. Terms and definitions Definitions will eventually be incorporated into B.3. Definitions.

----- 2.3. Road load 10.12.2012: Proposed text from DC and I.R.

----- 2.9. On-board anemometry 10.12.2012: could be deleted if on-board anemometry is not used in the GTR.

----- 2.11. Aerodynamic stagnation point 10.12.2012: could be deleted if on-board anemometry is not used in the GTR.

2. 2.19. TMH 07.10.2012: Definition shortened and the method of calculating TMH placed in §4.2.1.1.5.1.10.12.2012: “higher” or “highest” TMH?

3. 2.20. TML 07.10.2012: Definition shortened and the method of calculating TMH placed in §4.2.1.1.7.5.1.10.12.2012: “lower” or “lowest” TML?

4 4.1.1.1. 31.10.2012: The table will be modified should the on-board anemometry method not be included in the final GTR.21.11.2012 web/telecon: The on-board an-emometric method is apparently used in the US. A. Müsche will investigate.10.12.2012: What is meant by “average wind speed” (direction in relation to the track)? How does this relate to the table be-low? What is a recognised meteorological instrument? Should the location and height be defined? What is a representative wind condition?10.12.2012: Should on-board anemometry disappear, we could have:Coastdowns may not be performed if the absolute wind speed exceeds 5 m/s and the crosswind component exceeds 3 m/s.

5 4.1.1.2. Atmospheric temperature German RLD experts: range changed to avoid non-linear behaviour of correction factors.22.09.2012: JAMA asks why the upper limit is proposed to be raised from 35 to 40°C.Furthermore: at least one JAMA manufac-turer performs the road test below 10°C. Therefore they strongly want gtr to keep ISO tolerance for lower limit, which is 0°C.19.10.2012: This remains an open point.07.11.2012 (Japanese position): 5 to 35°C. As Mfrs option, between 1 and 5 °C is OK to run test.21.11.2012 web/telecon: 5 to 35°C to be kept, to remain an open point but must be discussed with India.10.12.2012: The atmospheric temperature

WLTP-2013-010 Draft Annex 4, Road and Dynamometer Load 04.01.2013

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should be within the range of 278 to 308 K inclusive.

6 4.1.2. Road slope 31.10.2012: Text accepted but 0.1% re-mains; information from JAMA to be sup-plied.07.11.2012 (Japanese position): The cur-rent design of oval track has been investig-ated (data from 4 Mfrs)The sum of the longitudinal slope of oval track, all data are [zero].21.11.2012 web/telecon: This issue to re-main open.18.12.2012 DC and I.R.: editorial change regarding slope and inclination (see text in blue)

4.2.1. Test vehicle preparation 18.12.2012 DC and I.R.: (see text in blue)7 4.2.1.1. Test vehicle selection 07.11.2012 (Japanese position): Support

the Audi proposal from Audi.Reason: it should be more appropriate to run test TML condition with [best aerody-namics].

8 4.2.1.1.1. Test vehicle selection 07.11.2012 (Japanese position): All of factory options. Reason: determination of [permanently installed] could make flexibil-ity.21.11.2012 web/telecon: Rewritten by DC to include permanently installed factory op-tions to be used under normal conditions.The section is currently being rewritten by I. Riemersma.02.12.2012: Proposed paragraph from I. Riemersma.18.12.2012 DC and I.R.: should “for which approval is sought” be deleted?

9 4.2.1.1.2. ----- 19.10.2012: Paragraph to be deleted, para-graphs below it will be renumbered once the section is finished.

10 4.2.1.1.3. Moveable body parts I. Riemersma asks if worst case should be tested for TMH and best case for TML.05.10.2012: Moveable body parts could lead to discontinuity of the coast down curve.Manufacturers are requested to submit data on the influence of moveable parts on coastdown curves.18.10.2012: Proposal that moveable aero-dynamic body parts shall operate as inten-ded under normal driving conditions.“normal driving conditions” means: a vehicle with TMH driven through a WLTC cycle at temperatures between [274 and 308] K19.10.2012: M. Bergmann to redo Power-Point slides on CO2, vehicle mass and aero-dynamic parts.19.10.2012: Aoyama-san to discuss this in Japan.31.10.2012: To be discussed at LabProcICE in November 2012.07.11.2012 (Japanese position): Worst case condition + negotiation with authorit-

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ies. If moveable control by vehicle speed only, it is OK to run as-is.Because CO2 impact by the moveable parts is depending on the control. Even in the condition of WLTP cycle running under 1-35degC, it could have flexibility.

11 4.2.1.1.5. Minimum vehicle weight 19.10.2012: Subject to be discussed at the LabProcICE meeting in November in Brus-sels.07.11.2012 (Japanese position): We sup-port the proposal of T&E, which are;- Higher than the objected weight (TMH or TML) during coast down testing.- Road load is calculated by the averaged weight of the highest and lowest during coast down testing.20.11.2012: New text agreed upon at the LabProcICE meeting November 2012.02.12.2012: Proposed text from I. Riemersma.

12 4.2.1.1.5.1. Calculation of TMH To remain an open point; percentages re-main in square brackets.02.12.2012: Proposed §4.2.1.1.5.1. from I. Riemersma.

13 4.2.1.1.7. Best case 05.10.2012: To be discussed separately and remains an open point.19.10.2012: If §4.2.1.1.3. is changed, §4.2.1.1.7.3. must be modified accordingly.

4.2.1.1.7.5.1. 02.12.2012: Proposed text from I. Riemersma.

14 4.2.1.2.1. Test vehicle run-in mileage German RLD experts: value changed from 3,000 to 10,000 kilometres5.10.2012: Objections should be submitted before Friday, October 19.07.11.2012 (Japanese position): Vehicle run-in.Min. 3,000km, Max. 10,000km. For certi-fication test. (ISC is separated discussion.)21.11.2012 web/telecon: To remain an open point.

4.2.1.2.2. Test vehicle condition 18.12.2012 DC and I.R.: proposed text in blue.

4.2.1.2.3. Test vehicle condition: alignment parameters

18.12.2012 DC and I.R.: proposal to re-place test vehicle with production vehicle.

4.2.1.2.4. Test vehicle condition: items to be closed

18.12.2012 DC and I.R.: manually-oper-ated moveable panels

15 4.2.1.2.5. Coastdown mode Proposed text from I. Riemersma.07.10.2012: Also found in §6.3.2.

16 4.2.1.2.6. Presence of a coastdown mode Text changes from German RLD experts.07.10.2012. Moved to §6.3.2.1.

17 4.2.2.1. Tyre selection 14.10.2012: Text provided by I. Riemersma.07.11.2012 (Japanese position): We sup-port the proposal from EU commission, which is: the widest tyre shall be selected.21.11.2012 web/telecon: Rewritten by DC to eliminate specific reference to ECE-R 117.

18 4.2.2.2. Tyre condition 4.9.2012: Proposal from André Rijnders.07.11.2012 (Japanese position): 80% of original tread depth or more, over the full

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width of the tire.Mechanical shaving is OK, but at least 300km driving on the road after shaving is required.5% proposal from EU commission seems too stringent comparing with vehicle run-in condition.

19 4.2.2.3. Tyre pressures Comments from JAMA.See §6.3.1.

20 4.2.4. Vehicle warm up 20.11.2012: The time span of 5 to 10 seconds was agreed during the LabProcICE meeting, November 2012.21.11.2012 web/telecon: Clutch shall be disengaged. Added during web/telecom and agreed by all.

21 ----- ----- -----

22 4.2.5. Vehicle warm up W. Coleman to define the warming up pro-cedure (possibly based on repeatability)German RLD experts: 10 km/h proposed as this is required to trigger the measurement system (ISO?)Should there be a minimum speed?19.10.2012: is it necessary to describe how to warm up the vehicle?31.10.2012: remains an open point until the results of validation 3 are received.

23 4.3. Measurement of total resistance by the coastdown method

21.11.2012 web/telecon: K. Kolesa pro-poses a non-drafting meeting on this sec-tion.

24 4.3. Measurement of total resistance by the coastdown method

31.10.2012: It is not known if any manufac-turer uses the on-board anemometer-based coastdown method to determine the total resistance curve.This will be discussed at the LabProcICE meeting in November.

25 4.3.1. Multi-segment calculation method 19.11.2012 from TÜV Nord:General suggestion for 4.3.1 to 4.3.3: give just one way of calculation (4.3.1) in detail and allow all other methods that provide the same values.

26 4.3.1.3.1. Vehicle warm up 28.10.2012: Reference to vehicle warm up will be removed if it is decided not to have any warm up before starting a set of coastdowns.

27 4.3.1.3.3. Coastdown procedure 28.10.2012: DC: addition of “under the same”.

28 4.3.1.4.1. Coast down delta V’s 19.11.2012 from TÜV Nord:V = 10km/h delivers more accurate time values but little less overall accuracy (cal-culated with actual data of several different vehicles);suggestion: standard V = 5km/h; V = 10km/h as an option

WEB/TELEPHONE CONFERENCE WEDNESDAY, NOVEMBER 21 STOPS AT §4.3.1.4.1.

29 4.3.1.4.2. Statistical accuracy Equation comes from ECE-R 101.German RLD experts: 3 % brings in line with EV (ECE-R 101: +/- 4%).19.11.2012 from TÜV Nord: Equations are OK.

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30 4.3.1.4.2. Statistical accuracy Standard deviation symbol is normally rho, not s

31 4.3.1.4.4. Total resistance: test mass German RLD experts: test mass is meas-ured at the beginning of the test.4.9.2012: proposal not accepted.31.10.2012: Point to be discussed at next LabProcICE.19.11.2012 from TÜV Nord:Calculation formulas are correct; using av-erage mass is okay; (change of mass about 1 kg per coast down on consecutive runs, dependent on vehicle)

32 4.3.1.4.5. Total resistance curve Comments, questions from I. Riemersma.German RLD experts: text struck through. Three coefficients are accepted in the WLTP process.19.11.2012 from TÜV Nord:Both ways of calculation are correct; US directive takes the average of Fa and Fb and derives f out of Favg

33 4.3.1.4.5.1. Alternative calculation 19.11.2012 from TÜV Nord:Calculation formulas are correct; also aver-aging of the times in this case is correct be-cause it is done by using the reciprocal val-ues

34 4.3.2. Average deceleration method 19.11.2012 from TÜV Nord:General suggestion for 4.3.1 to 4.3.3: give just one way of calculation (4.3.1) in detail and allow all other methods that provide the same values.

35 4.3.2.4.1. Determination of total resistance 19.11.2012 from TÜV Nord:Should be: …. (Vj + V) to (Vj - V)…;..,where V is more than 10km/h (limit for maximum V?) compare to 4.3.1.4.1.

36 4.3.2.4.2. and 4.3.2.4.3.

Determination of deceleration How are A1 , A2 and A3 derived from A1a, A1b,…..,A3b?19.11.2012 from TÜV Nord:How to derive A1 to A3 from A1a, A1b… is not clear.

37 4.3.2.4.3. to 4.3.2.4.6.

Total resistance equations 19.11.2012 from TÜV Nord:Calculation equations are correct.

38 4.3.3. Direct regression calculation method

19.11.2012 from TÜV Nord:General suggestion for 4.3.1 to 4.3.3: give just one way of calculation (4.3.1) in detail and allow all other methods that provide the same values.

39 4.3.3.1. Road load curve determination General comment from I. Riemersma.

40 4.3.3.4.4. Equation 28.10.2012: If this is arctan, then Atan is not correct. Can also be written tan-1.

41 4.4. Anemometer-based coastdown method

German RLD experts: German RLD ex-perts: on-board anemometer method not supported by these experts. Table 1 must be changed accordingly.28.10.2012: This is also a coastdown method and should become §4.3.4.19.11.2012 from TÜV Nord:Method not supported by TÜV Nord.20.11.2012: The method is struck through for the time being.

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42 4.4.3. Anemometer calibration procedure Missing reference.

43 4.4.4. Determination of coefficients Inconsistent symbols.

44 4.5.1. Installation of torque meters German RLD experts: text struck through (the word “driven”).

45 4.5.2.1. Anemometer coastdown method 28.10.2012: Will warming up be required with this method?

46 4.5.3.1. Equations JAMA requests clarification of the use of upper or lower case for certain symbols.

47 4.5.3.1. Equation DC requests clarification of “over a time period”.31.10.2012: Ford AG will clarify.

48 4.5.4. Resistance curve determination I. Riemersma concern regarding averaging coefficients.

49 4.6. Correction to standard atmospheric reference conditions

28.10.2012: DC change

50 4.6. Correction to standard conditions 19.11.2012 from TÜV Nord:Separate correction for each run in each dir-ection, averaging afterwards. Valid also es-pecially for §4.6.1.3.2.

51 4.6.1.2. Correction factor for rolling resist-ance

31.10.2012: JAMA to provide comments.

52 4.6.1.3.2. Wind correction 19.11.2012 from TÜV Nord:Separate correction for each run in each dir-ection, averaging afterwards.

53 5.2.1.2. Moving belt 26.07.2012: M. Bergmann comments that input from VW is outstanding. Surface to be defined? Audi: 100 grit06.08.2012: K. Behlau: VW uses 300 grit. For the measurement of rolling resistance at constant speed, it’s not so important which grit is used.31.10.2012: Surface to be defined? Is there a need? To be discussed at same time as the three methods of calculations.

54 5.2.2.2. Test room temperature German RLD experts: the temperature range comes from ISO 10521 §6.2.2.2.

55 4.6.1.2. Correction factor for rolling resist-ance

31.10.2012: JAMA to provide comments.

WEB/TELEPHONE CONFERENCE WEDNESDAY, OCTOBER 31 STOPS AT §5.2.2.3.

56 5.2.2.3. and 5.2.2.4.

Driving and non-driving wheels German RLD experts ask if §5.2.2.3. and 5.2.2.4. should not be combined.DC to check.

57 5.2.2.4.(k) Load scatter at reference speeds Is 4 per cent tolerance too large?German RLD experts ask if absolute values in newtons should be introduced?

58 5.5. Total rolling resistance correction 28.10.2012: Is this a recommended practice or must it be done?

59 6. Transferring road load to a dyno Proposed text from German RLD experts.

60 6.1.1.1. Tyre slip on dynamometer JAMA concern and proposal.

61 6.1.1.1. Additional weight on driving axle German RLD experts: additional weight has to be included in documentation. No objec-tions from industry.

62 6.1.1.2. Room temperature German RLD experts: is a deviation from the ISO standard acceptable?

63 6.2.1. Inertia mass setting (vehicle mass category)

TML, TMH to be edited

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64 6.2.1. Inertia mass setting Comment on rotating mass from Japan.02.12.2012: Proposed text from I. Riemersma.

65 6.3.1. Tyre pressure adjustment DC text proposal.

66 6.3.2. Vehicle setting German RLD experts: comment from GA.

67 6.3.2. Vehicle setting Text from I. Riemersma

68 6.3.3. Vehicle warm-up Text added by the German RLD experts.

69 6.3.4. Vehicle warm-up Certain Japanese concerns to be taken into consideration.

70 7. Dyno setting proposal Fixed-run method (refer to SAE J2263) has been added by Japan.

71 7.1.1. Initial load setting 23.09.2012: Comments received from Ja-pan.

72 7.1.3. and 7.2.3.2.

Coastdown error criteria German RLD experts: Percentage error to be determined in validation.4.9.2012: More data are needed to form a position on this issue.

73 7.3. Running resistance table German RLD experts: the complete section on running resistance table to be reviewed by B. Mercier.

74 7.3. Running resistance table German RLD experts: should the number of specified speeds be increased?

75 7.3.2. Chassis dynamometer setting error 4.9.2012: More data are needed to form a position on this issue.

76 Appendix I, 1.1

Rotating mass for calculation Determination of m’r is edited by Japan.

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1. Scope2. Terms and definition3. Required accuracy4. Road load measurement on road 4.1. Requirements 4.1.1. Atmospheric 4.1.1.1. Wind

4.1.1.2. Temperature4.1.2. Test road

4.2. Preparation for road test 4.2.1. Test vehicle 4.2.1.1. Test vehicle selection4.2.1.2. Test vehicle condition

4.2.2. Tyres 4.2.2.1. Tyre selection4.2.2.2. Tyre condition4.2.2.3. Tyre pressure

4.2.3. Instrumentation4.2.4. Vehicle warm-up

4.3. Measurement of total resist-ance via C/D method

4.3.1. Multi-segment mode 4.3.1.1. Selection of speed points4.3.1.2. Data collection4.3.1.3. Coastdown procedure4.3.1.4. Resistance using coastdown time measurement

4.3.2. Average deceleration method

4.3.2.1. Selection of speed points4.3.2.2. Data collection (as 4.3.1.2.)4.3.2.3. Vehicle coastdown (as 4.3.1.3.)4.3.2.4. Determination of total resistance

4.3.3. Direct regression method 4.3.3.1. Selection of speed range4.3.3.2. Data collection (as in 4.3.1.2.)4.3.3.3. Vehicle coastdown (as 4.3.1.3.)4.3.3.4. Determination of total resistance by coastdown meas-urement

4.4. Onboard anemometer-based C/D method

4.4.1. Selection of speed range

4.4.2. Data collection4.4.3. Vehicle coastdown4.4.4. Determination of coeffi-cients4.4.5. Determination of total res-istance

4.5. Measurement of running resistance by the torque meter method

4.5.1. Installation of torque meter

4.5.2. Vehicle running and data sampling4.5.3. Calculation of mean speed and mean torque4.5.4. Running resistance curve determination

4.6. Correction to standard at-mospheric conditions

4.6.1. Correction factors 4.6.1.1. Determination of cor-rection factor for air resistance4.6.1.2. Determination of cor-rection factor for rolling resist-ance4.6.1.3. Wind correction

4.6.2. Road load curve correc-tion

5. Road load measurement by wind tunnel/chassis dynamometer

5.1. Aero drag in wind tunnel 5.1.1. Requirement for wind tunnel

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5.1.2. Testing procedure5.1.3. Test result

5.2. Rolling resistance determin-ation with chassis dynamometer/moving belt

5.2.1. Testing device 5.2.1.1. Chassis dynamometer

5.2.1.2. Moving belt5.2.2. Testing procedure5.2.3. Test results

5.3. Total resistance calculation5.4. Total resistance curve de-termination5.5. Correcting total rolling res-istance using a chassis dyno.

6. Transferring road load to a chassis dynamometer

6.1. Preparation for chassis dyno test

6.1.1. Laboratory condition 6.1.1.1. Chassis dynamometer roller6.1.1.2. Room temperature

6.2. Preparation of chassis dyno 6.2.1. Inertia mass setting6.2.2. Precon. of chassis dy-namometer

6.3. Vehicle preparation 6.3.1. Tyre press. Adjustment6.3.2. Vehicle settings6.3.3. Vehicle warm up

7. Load setting on chassis dyno. 7.1. Chassis dyno. setting by coastdown method

7.1.1. Dyno. load setting 7.1.1.1. Initial load setting

7.1.1.2. Coastdown7.1.1.3. Verification7.1.1.4. Adjustment

7.2. Chassis dyno. adjustment using torque meter method

7.2.1. Load setting 7.2.1.1. Initial load setting

7.2.1.2. Wheel torque measure-ment7.2.1.3. Verification7.2.1.4. Adjustment

7.3. Chassis dyno. setting based on tabular values

7.3.1. Specified dyno. speed

7.3.2. Verification of dynamo-meter7.3.3. Table

Appendix 1 Calculation of road load for dyno. test

1. Calculation of road load using the coastdown method

1.1. Calculation of measured road load1.2. Determining A, B and C1.3. Calculating road load for each speed

2. Calculation of road load using the torque meter method

2.1 Calculating mean speed and mean torque for each reference speed2.2. Determining A, B and C2.3. Calculating road load for each speed

Appendix 2 Adjustment of chassis dynamometer load setting

1. Adjustment of chassis dyno. load setting using the coastdown method2. Adjustment of chassis dyno. load setting using the torque meter method

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ANNEX 4

ROAD AND DYNAMOMETER LOAD

1. ScopeThis Annex describes the determination of the road load of a test vehicle and the transfer of that road load to a chassis dynamometer. Road load can be determined us-ing coastdown, torque meter or wind tunnel/chassis dynamometer methods.

2. Terms and definitions For the purpose of this document, the terms and definitions given in ISO 3833 and the following apply.

2.1. Total resistanceTotal force-resisting movement of a vehicle, measured either by the coastdown method or by the wind tunnel/ chassis dynamometer method, including the friction forces in the drivetrain.

2.2. Running resistance Torque-resisting movement of a vehicle, measured by the torque-meter installed in the drivetrain of a vehicle, including the friction torque in the drivetrain downstream of the torque-meter.

2.3. Road load General meaning of the force or torque which opposes the movement of a vehicle, in-

cluding total resistance and/or running resistance.2.3. Road load

The force which opposes the movement of a vehicle which is the total resistance if using the coastdown method or running resistance if using the torque meter method.

2.4. Aerodynamic dragAir resistance to the motion of a vehicle.

2.5. Rolling resistanceOpposing force in the drivetrain, axles and tyres to the motion of a vehicle.

2.6. Reference speed A vehicle speed at which a chassis dynamometer load is verified. Reference speeds may be continuous speed points covering the complete cycle speed range.

2.7. Reference atmospheric conditions means atmospheric conditions (pressure, temperat-ure, density and speed) to which road load measurements are corrected.

2.8. Stationary anemometryMeasurement of wind speed and direction with an anemometer at a location and height above road level alongside the test road where the most representative wind conditions will be experienced.

2.9. On-board anemometry Measurement of wind speed and direction with an anemometer appropriately in-stalled to the test vehicle.

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2.10. Wind correction Correction of the effect of wind on road load, which is achieved either by stationary

or by on-board anemometry.2.10. Wind correction

Correction of the effect of wind on road load based on input of the stationary or on-board anemometry.

2.11. Aerodynamic stagnation point Point on the surface of a vehicle where the wind velocity is equal to zero.

2.12. Target road loadThe road load to be reproduced on the chassis dynamometer.

2.13. Chassis dynamometer load settingThe load to be set on the chassis dynamometer’s power absorption unit.

2.14. Simulated road loadRoad load to be calculated from measured coastdown data.

2.15. Speed rangeRange of speed of chassis dynamometer roller between the maximum speed of the WLTC cycle corresponding to the test vehicle class plus 10 km/h and minimum ref-erence speed of 20 km/h minus 5 km/h, over which the coastdown test is conducted.

2.16. Chassis dynamometer using coefficient control Chassis dynamometer whose absorption characteristics are determined by coefficients of a road load approximation polynomial.

2.17. Chassis dynamometer using polygonal control Chassis dynamometer whose absorption characteristics are determined by giving loadvalues at several speed points.

2.18. Vehicle coastdown modeA vehicle coastdown mode means a special mode of operation, for example by de-coupling drivetrain components from the wheels mechanically and/or electrically, enabling an accurate and repeatable road load determination and an accurate dy-namometer setting;

2.19. “Test mass high (TMH)” means the higher mass of a test vehicle for road load and

emissions determination;

2.20. “Test mass low (TML)” means the lower mass of a test vehicle for road load and emissions determination;

3. Required overall measurement accuracyThe required overall measurement accuracy shall be as follows:a) vehicle speed: 0.5 km/h or 1 per cent, whichever is greater;b) time accuracy: min. 1ms; time resolution: min. 0.01 s

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c) wheel torque: 3 Nm or 0.5 per cent, whichever is greater;d) wind speed: 0.3 m/s e) wind direction: 3°;f) atmospheric temperature: 1 K;g) atmospheric pressure: 0.3 kPa;h) vehicle mass: 10 kg; ( 20 kg for vehicles > 4000 kg)i) tyre pressure: 5 kPa;j) product of aerodynamic drag coefficient and frontal projected area (S * Cd):

2 per cent;k) chassis dynamometer roller speed: 0.5 km/h or 1 per cent, whichever is

greater;l) chassis dynamometer force: 10 N or 0.1 per cent of full scale, whichever is greater.

4. Road load measurement on road

4.1. Requirements for road test

4.1.1. Atmospheric conditions for road test

4.1.1.1. WindThe average wind speed over the test road shall not exceed 10 m/s. Wind gusts shall not exceed 14 m/s. The wind correction shall be conducted according to the applic-able type of anemometry specified in Table 1. In order to decide the applicability of each anemometry type, the average wind speed shall be determined by continuous wind speed measurement, using a recognised meteorological instrument, at a location and height above the road level alongside the test road where the most representative wind conditions will be experienced. Wind correction may be waived when the aver-age wind speed is 3 m/s or less.

Table 1 — Applicable anemometry depending on average wind speed and cross-wind com-ponent

Wind speed in metres per second (m/s)

Type ofanemometry

Average wind speed, m/sAbsolute wind speed v 5 Absolute wind

speed5 < v ≤ 10

Crosswind component

(vc)vc ≤ 3

Crosswind com-ponent (vc) 3 <

vc ≤ 5

Stationary anemo-metry

Applicable Not applicable Not applicable

Onboard anemo-metry

Applicable Applicable Applicable

NOTE : Stationary anemometry is recommended when the absolute wind speed is less than 1 m/s.

4.1.1.2. Atmospheric temperatureThe atmospheric temperature should be within the range of 278 to 308 K inclusive .At its option, a manufacturer may choose to perform coastdowns between 274 and 278 K.

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4.1.2. Test road The road surface shall be flat, clean, dry and free of obstacles or wind barriers that might impede the measurement of the running resistance and its texture and compos-ition shall be representative of current urban and highway road surfaces. The test-road longitudinal slope shall not exceed 1 per cent. The local inclination between any points 3 m apart shall not deviate more than 0.5 per cent from this longitudinal slope. The maximum cross-sectional camber of the test road shall be 1.5 per cent.

4.1.2. Test road The road surface shall be flat, clean, dry and free of obstacles or wind barriers that might impede the measurement of the running resistance, and its texture and compo-sition shall be representative of current urban and highway road surfaces. The test-road longitudinal slope shall not exceed 1 per cent. The local slope inclination between any points 3 m apart shall not deviate more than 0.5 per cent from this longitudinal slope. If tests in opposite directions cannot be performed at the same part of the test track (e.g. on an oval test track with an obligatory driving direction), the sum of the longitudinal slopes of the parallel test track segments shall be not more than [ 0.1] per cent. The maximum cross-sectional camber of the test road shall be 1.5 per cent.

4.2. Preparation for road test4.2.1. Test vehicle

The test vehicle shall conform in all its components with the production series, or, if the vehicle is different from the production series, a full description shall be given in the test re-port.

4.2.1.1. Test vehicle selection

4.2.1.1.1. The vehicle selected for road load determination shall be fitted with the worst case combination of permanently installed factory options, i.e. having the highest air res-istance of the vehicles for which approval is sought.

4.2.1.1.1. The vehicle selected for road load determination for which approval is sought shall be fitted with the worst case combination of permanently installed factory options leading to the highest vehicle air resistance. Permanently installed factory options are those which would be expected to be used under normal driving conditions.

4.2.1.1.1. The vehicle selected for road load determination shall be fitted with the worst case combination of permanently installed factory options, i.e. having the highest air resistance of the vehicle family for which approval is sought . Options that are in-tended to increase the carrying capacity and/or use the towing capacity of the vehicle must not be fitted if they are not permanently installed during normal driving condi-tions. The options excluded from the road load determination shall be listed in the test report.

4.2.1.1.2.: no such paragraph; paragraphs to be numbered once the complete section is fin-ished.

4.2.1.1.3. Moveable aerodynamic body parts shall be fixed in the most unfavourable position

for the duration of the road load test unless it is obvious that the favourable position is representative for normal driving conditions.

14

4.2.1.1.3. Moveable aerodynamic body parts shall be operated as representative under normal driving conditions.

4.2.1.1.3. Moveable aerodynamic body parts shall operate as intended under normal driving conditions.

– “normal driving conditions” means: a vehicle with TMH driven through a WLTC cycle at temperatures between [274 and 308] K

4.2.1.1.4. For the selected tyre, the wheel rims with the highest expected air drag shall be used.

4.2.1.1.5. The minimum weight of the selected vehicle including the test driver and equipment shall be equal to or higher than the TMH as calculated according to §4.2.1.1.5.1. at the start of the road load determination procedure.

4.2.1.1.5. Before and after the road load determination procedure, the selected vehicle shall be weighed, including the test driver and equipment, to determine the average weight m (see §4.3.1.4.4). The minimum weight of the vehicle shall be equal to or higher than the target test mass (TMH or TML, calculated according to §4.2.1.1.5.1 and §4.2.1.1.7.5.1 ) upon completion of the road load determination procedure. If the test vehicle needs refueling to avoid under-shooting falling short of the test mass, it shall be weighed before being refueled. This shall be used as the end weight of the preceding road load determination sequence. After refueling, the vehicle shall be weighed again. This weight shall be used as the starting weight of the next road load determination sequence.

4.2.1.1.5. Before and after the road load determination procedure, the selected vehicle shall be weighed, including the test driver and equipment, to determine the average weight m (see §4.3.1.4.4). The minimum weight of the vehicle shall be equal to or higher than the target test mass (TMH or TML, calculated according to §4.2.1.1.5.1 and §4.2.1.1.7.5.1 ) at the beginning of the road load determination procedure. For all further calculations, the average weight m shall be used.

4.2.1.1.5. Before and after the road load determination procedure, the selected vehicle shall be weighed, including the test driver and equipment, to determine the average mass m (see §4.3.1.4.4). The minimum mass of the vehicle shall be equal to or higher than the target test mass (TMH or TML, calculated according to §4.2.1.1.5.1 and §4.2.1.1.7.5.1 ) upon completion at the start of the road load determination procedure. If the test vehicle needs refueling to avoid undershooting falling short of the test mass, it shall be weighed before being refueled. This shall be used as the end weight of the preceding road load determination sequence. After refueling, the vehicle shall be weighed again. This weight shall be used as the starting weight of the next road load determination sequence.For the calculation of the CO2 emissions at additional test masses regression in Annex 7, the actual test masses TMH, actual and TML, actual will be applied, i.e. the average mass m for the re-spective test masses.

4.2.1.1.5.1. TMH shall be calculated by adding (a) the unladen mass of the vehicle, (b) the mass of all optional equipment, (c) 100 kilograms and (d) a variable mass represent-ing additional luggage and passengers. The mass in (d) for M1 vehicles shall be [15] per cent of the difference between the maximum laden mass and the sum of (a), (b) and (c). For N1 vehicles, the variable mass shall use a factor of [35] per cent.

4.2.1.1.5.1. TMH shall be calculated by adding (a) the unladen mass of the vehicle family UM, (b) the mass of all optional equipment available for the vehicle family OMH, (c)

15

100 kilograms and (d) a variable mass representing additional luggage and passen-gers. The mass in (d) shall be [15] per cent of the difference between the maximum laden mass LM and the sum of (a), (b) and (c). In some regions For N1 vehicles, it may be required for particular vehicle classes to the variable mass shall use a factor of [35] per cent in an additional test.

4.2.1.1.6. The test vehicle configuration shall be recorded in the approval test report and shall be used for any subsequent testing.

4.2.1.1.7. Where a manufacturer chooses to use the regression method as outlined in 4.3.3. 3.2.3. of Annex 7, a ‘best case’ vehicle may be selected for road load determination.

4.2.1.1.7. At the request of the manufacturer, the vehicle may be tested again at a test mass TML [and at different road load settings (RLHH, RLHL and RLLH)] to determine the CO2 emis-sion value for individual vehicles in the vehicle family according to the CO2 regression method in §3.2.3. Annex 7. These additional tests are allowed if OMH for the vehicle family is 100 kg or higher. If OMH is lower than 100 kg, additional testing is allowed if OMH is set to 100 kg. The vehicle shall fulfil the following criteria: .

4.2.1.1.7.1. The vehicle shall have none of the available factory options for production vehicles installed which negatively influence air resistance.

4.2.1.1.7.2. Options that are designed to positively influence air resistance shall be installed.

4.2.1.1.7.3. Moveable aerodynamic body parts shall be fixed in their most favourable position for the duration of the road load test unless it is obvious that the favourable position is representative for normal driving conditions.

4.2.1.1.7.3. Moveable aerodynamic body parts shall be operated as representative under nor-mal driving conditions.

4.2.1.1.7.3. Moveable aerodynamic body parts shall operate as intended under normal driving conditions.

4.2.1.1.7.4. For the selected tyre, the wheel rims with the expected lowest air drag shall be

used.

4.2.1.1.7.5. The minimum weight of the selected vehicle including the test driver and equip-ment shall be equal to or higher than the TML as calculated according to §4.2.1.1.7.5.1. at the start of the road load determination procedure.

4.2.1.1.7.5.1. TML shall be calculated by adding (a) the unladen mass of an empty vehicle in-cluding its standard equipment, (b) 100 kilograms representing the mass of the driver, some luggage and non-OEM optional equipment and (c) a variable mass based on the heaviest vehicle.

4.2.1.1.7.5.1. TML shall be calculated by subtracting the mass of all optional equipment avail-able for the vehicle family OMH from TMH. 4.2.1.1.7.6. The test vehicle configuration shall be recorded in the approval test report and

shall be used for any subsequent testing.

4.2.1.2. Test vehicle condition

16

4.2.1.2.1. The test vehicle shall be suitably run-in for the purpose of the subsequent test for at least 3000 10,000 km.

4.2.1.2.2. Unless otherwise intended, the vehicle shall be in normal condition, as specified by the manufacturer regarding tyre pressures (see 4.2.2.3.), wheel alignment, vehicle height, drivetrain and wheel bearing lubricants, and brake adjustment to avoid unrep-resentative parasitic drag.

4.2.1.2.2. The vehicle shall conform to the manufacturer’s intended production vehicle spe-cifications regarding tyre pressures (see 4.2.2.3.), wheel alignment, vehicle height, drivetrain and wheel bearing lubricants, and brake adjustment to avoid unrepresentat-ive parasitic drag.

4.2.1.2.3. If an alignment parameter is adjustable (tracking, camber, caster), it shall be set to the nominal value for the tested vehicle manufacturer’s intended production vehicle . In absence of a nominal value, it shall be set to the mean of the values recommended by the manufacturer.Such adjustable parameter(s) and set value shall be recorded in the test report.

4.2.1.2.4. During the road test, the engine bonnet, manually-operated moveable panels and all windows shall be closed.

4.2.1.2.5. The vehicle coastdown mode is mandatory if the determination of dyno settings cannot meet the criteria described in chapters 7.1.1.3. and 7.2.1.3. due to non-repro-ducible parasitic losses, except if the torque metering method is used for road load determination [reference to specific GTR paragraph]. To be discussed in a meeting with the EV group KW 36/2011

4.2.1.2.5. If the determination of dynamometer settings cannot meet the criteria described in paragraphs 7.1.3. or 7.2.3. due to non-reproducible forces, the vehicle shall be equipped with a vehicle coastdown mode. The coast down mode shall be approved and recorded by the re-sponsible authority.

4.2.1.2.6. If a vehicle is equipped with a vehicle coastdown mode, it shall be engaged both during road load determination and on the chassis dynamometer.

4.2.2. Tyres4.2.2.1. Tyre selection The selection of tyres shall be based on their rolling resistances, measured according to ECE-R 117 and categorised according to the rolling resistance classes in the table below. The selec-tion of tyres shall be based on their rolling resistances as measured using the appropriate tech-nical procedure of the contracting party., measured according to ECE-R 117 and categorised according to the rolling resistance classes in the table below. From the range of tyres that will be offered on the production vehicle, a tyre shall be selected from the highest rolling res-istance class. If multiple tyre types are offered in the highest rolling resistance class, the widest tyre shall be selected. The same tyre type will be used for road load determination at test masses TML and TMH.

Class Rolling Resistance (RR) - kg/tonne1 RR ≤ 6.52 6.5 < RR ≤ 7.73 7.7 < RR ≤ 9.0

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4 9.0 < RR ≤ 10.55 10.5 < RR ≤ 12.06 RR > 12.0

4.2.2.2. Tyre condition The tyres shall be suitably run-in for the purpose of the subsequent test, while still having a tread depth of not less than 60 per cent of the original tread depth.

4.2.2.2. Tyre condition The tyres shall not be older than 1 year after production date. The tyres may not be specially conditioned or treated for the purpose of the subsequent test, other than a normal run-in on the road, while still having a equal tread depth of not less than 80 per cent of the original tread depth over the full width of the tyre.

OR

4.2.2.2. Tyre condition The tyres used for the test shall:- not be older than 1 year after production date,- not be specially conditioned or treated,- shall be run-in on a road,- shall have a constant tread depth of not less than 80 per cent of the original tread depth over the full tread width of the tyre.

4.2.2.3. Tyre pressure

The front and rear tyres shall be inflated to the lower limit of the tyre pressure range for the selected tyre, as specified by the vehicle manufacturer.

4.2.2.3.1. Tyre-pressure adjustmentIf the difference between ambient and soak temperature is more than 5 K, the tyre pressure shall be adjusted as follows:(a) the tyres shall be soaked for more than 4 h at 10 per cent above the target pres-sure. (b) prior to testing, the tyre pressure shall be reduced to the inflation pressure as spe-cified in 4.2.2.3., adjusted for difference between the soaking environment temperat-ure and the ambient test temperature at a rate of 0.8 kPa per 1 K using the following equation:

Pt = 0.8 x (Tsoak - Tamb)

where

Pt is the tyre pressure adjustment, in kilopascals (kPa);0.8 is the pressure adjustment factor, in kilopascals per kelvin (kPa/K);Tsoak is the tyre soaking temperature, in kelvin (K);Tamb is the test ambient temperature, in kelvin (K).

4.2.3. InstrumentationAny instruments, especially for those installed outside the vehicle, shall be installed on the vehicle in such a manner as to minimise effects on the operating characterist-ics of the vehicle.

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4.2.4. Vehicle warm-up 4.2.4.1. Before warm-up, the vehicle shall be decelerated with the clutch disengaged by

moderate braking from 80 to 20 km/h within 5 to 10 seconds. After this braking, there shall be no further manual adjustment of the braking system.

4.2.5. Warming up is done by vehicle driving only. Driving shall be cruising and speed limit

is 10 km/h above the coastdown starting speed. In the split coasting down, the same condition is applied.

4.2.5. Warming up shall be achieved solely by driving the vehicle no higher than 10 km/habove the coastdown starting speed. In split coasting down, the same condition shall apply.

Clarified condition is necessary. (This means we raise above proposal continuously.) *JustificationIn case intermediate warming up is required before each coastdown, stable and longer coastdown time could be available and it is influenced with warming up condition. It would be difficult or impossible to detect by the statistical accuracy (p). Therefore the clarified con-dition is necessary.The identical vehicle condition at road load determination and derivation is very important for appropriate dynamometer-setting value as mentioned at LabProcICE meeting in March, 2012. The clarified condition is necessary to achieve this.

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4.3. Measurement of total resistance by the coastdown method total resistance shall be determined by using the multi-segment (4.3.1), the average deceleration (4.3.2) or the direct regression method (4.3.3).The total resistance shall be determined by using the multi-segment (4.3.1), the aver-age deceleration (4.3.2), the direct regression method (4.3.3), or on-board anemo-meter method.

4.3.1. Multi-segment method

4.3.1.1. Selection of speed points for road load curve determinationIn order to obtain a road load curve as a function of vehicle speed, a minimum of six speed points, Vj (j = 1, 2, etc.) shall be selected. The highest speed point shall not be lower than the highest reference speed, and the lowest speed point shall not be higher than the lowest reference speed. The interval between each speed point shall not be greater than 20 km/h.

4.3.1.2. Data collectionDuring the test, elapsed time and vehicle speed shall be measured and recorded at a maximum of 0.2 s intervals, and wind speed and wind direction shall be measured by stationary anemometry at a maximum of 1.0 s intervals.

4.3.1.3. Vehicle coastdown procedure

4.3.1.3.1 Following warming up, and immediately prior to each test measurement, the vehicle shall be driven at the highest reference speed for no more than 1 min, if neces-

sary. The vehicle shall be accelerated to at least 5 km/h above the speed at which the coastdown time measurement begins (Vj + V) and the coastdown shall begin immediately.

4.3.1.3.2. During coastdown, the transmission shall be in neutral, and the engine shall run at idle. For vehicles with manual transmissions, the clutch shall be engaged. Steering wheel movement shall be avoided as much as possible, and the vehicle brakes shall not be operated until the end of the coastdown.

4.3.1.3.3. The test shall be repeated. Coastdowns shall be performed at the same speeds and under the same conditions.

4.3.1.3.4. Although it is recommended that each coastdown run be performed without interruption, split runs are permitted if data cannot be collected in a continuous way for the entire speed range. For split runs, care shall be taken so that vehicle con-

ditions remain as stable as possible at each split point.

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4.3.1.4. Determination of total resistance by coastdown time measurement

4.3.1.4.1. The coastdown time corresponding to the speed Vj as the elapsed time from the vehicle speed (Vj + V) to (Vj - V) shall be measured. It is recommended that V be 10 km/h when the vehicle speed is more than 60 km/h, and 5 km/h when the vehicle speed is 60 km/h or less.

WEB/TELEPHONE CONFERENCE WEDNESDAY, NOVEMBER 21 STOPS AT §4.3.1.4.1.

4.3.1.4.2. These measurements shall be carried out in both directions until a minimum of three consecutive pairs of figures have been obtained which satisfy the statistical accuracy p, in per cent, defined below.

p= t∗s√n

×100ΔT j

≤3 %

where

n is the number of pairs of measurements;Tj is the mean coastdown time at speed Vj, in seconds (s), given

by the equation:

ΔT j=1n∑i=1

n

ΔT ji

Tji is the harmonised average coastdown time of the ith pair of measurements at speed Vj, in seconds (s) given by the equation:

ΔT ji= 2(1 / ΔT jai )+(1/ ΔT jbi )

Tjai and T jbi are the coastdown times of the ith measurement at speed Vj in each direction, respectively, in seconds (s);

s is standard deviation, in seconds (s), defined by:

s=√ 1n−1∑i=1

n

( ΔT ji−ΔT j)2

t is a coefficient given in Table 2 below.

Table 2

t n t/√n t n t/√n

4.3 3 2.48 2.2 10 0.73

3.2 4 1.60 2.2 11 0.66

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2.8 5 1.25 2.2 12 0.64

2.6 6 1.06 2.2 13 0.61

2.5 7 0.94 2.2 14 0.59

2.4 8 0.85 2.2 15 0.57

2.3 9 0.77

4.3.1.4.3. If, during a measurement in one direction, the driver causes any sudden change of direction of the vehicle, that measurement and the paired measurement in the opposite direc-tion shall be rejected.

4.3.1.4.4. The total resistances, Fja and Fjb at speed Vj in directions a and b, in newtons, are de-termined by the equations:

F ja=− 13 .6

×(m+m r )×2×ΔvΔT ja

F jb=− 13 . 6

×(m+m r )×2× ΔvΔT jb

where

m is the average of the test vehicle masses at the beginning and end of road load determination, kg;

mr is the equivalent effective mass of all the wheels and vehicle components rotating with the wheels during coastdown on theroad, in kilograms (kg); mr shall be measured or calculated using an appropriate technique. Alternatively, mr may be estimated to be 3 per cent of the unladen vehicle mass;

Tja and Tjb are the mean coastdown times in directions a and b, respect-ively, corresponding to speed Vj, in seconds (s), given by the

equations:

ΔT ja=1n∑i=1

n

ΔT jai

ΔT jb=1n ∑i=1

n

ΔT jbi

4.3.1.4.5. The total resistance curve shall be determined as follows. The following regression curve shall be fit to the data sets (Vj, Fja) and (Vj, Fjb) corresponding to all the speed points Vj (j = 1, 2, etc.) and direction (a, b) to determine f0, f1 and f2:

Fa = f0a + f1aV + f2aV2

Fb = f0b + f1bV+ f2bV2

where

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Fa and Fb are the total resistances in each direction, N;f0a and f0b are constant terms in each direction, N;f1a and f1b are the first-order term coefficients of the vehicle speed in

each direction, N·h/km; f2a and f2b are the second-order term coefficients of the vehicle speed

in each direction, N·(h/km)2;V is vehicle speed, km/h.

The average total resistance Favg shall be calculated by:

Favg = f0 + f1V + f2V2

where the coefficients f0, f1 and f2 shall be calculated using the following equations:

f 0=f 0a+f 0 b

2

f 1=f 1 a+ f 1b

2

f 2=f 2 a+ f 2b

2where:

f0, f1 and f2 are the average coefficients

4.3.1.4.5.1. As an alternative to the above calculation, the following equation may be applied to compute the average total resistance, where the harmonised average of the alternate coastdown time shall be used instead of the average of alternate total resistance.

F j=− 13 . 6

×( m+m r )× 2×ΔVΔT j

where:

Tj is the harmonised average of alternate coastdown time measurements at speed Vj, in seconds (s), given by the equation:

ΔT j= 2(1/ ΔT ja)+(1/ ΔT jb )

where:

Tja and Tjb are the coastdown times at speed Vj in each direction, respectively, in seconds (s).

The coefficients f0, f1 and f2 in the total resistance equation shall be calculated with regression analysis.

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4.3.2. Average deceleration method As an alternative to the determination in 4.3.1, the total resistance may also be determined by the procedures described in 4.3.2.1 to 4.3.2.4.

4.3.2.1. Selection of speed points for road load curve determinationSpeed points shall be selected as specified in 4.3.1.1.

4.3.2.2. Data collectionData shall be measured and recorded as specified in 4.3.1.2.

4.3.2.3. Vehicle coastdown procedureVehicle coastdown shall be conducted as specified in 4.3.1.3.

4.3.2.4. Determination of total resistance by coastdown measurements

4.3.2.4.1. The speed versus time data during coastdown from vehicle speed (Vj + V) to (Vj + V) (Vj + V) to (Vj - V) shall be recorded, where V is more than 10 km/h.

4.3.2.4.2. The following function shall be fit to the group of data by polynomial regression to determine the coefficients A0, A1, A2 and A3:

Va(t) = A0a + A1at + A2at2 + A3at3

Vb(t) = A0b + A1bt + A2bt2 + A3bt3

where

Va(t), Vb(t) is vehicle speed, in kilometres per hour (km/h), in directions a and b;

t is time, in seconds (s);A0a, A1a, A2a, A3a, A0b, A1b, A2b and A3b are coefficients.

4.3.2.4.3. The deceleration, j, in metres per second squared, at speed Vj , shall be determined as follows:

γ j= 13.6

×( A 1+2×A 2 t j+3×A 3 t j2 )

where

tj is the time at which the vehicle speed given by the function in 4.3.2.4.2 is equal to Vj.

4.3.2.4.4. The measurements shall be repeated in both directions, until a minimum of four consecutive pairs of the data have been obtained which satisfy the statistical accuracy p, in percent, below. The validity of the data shall be decided in accordance with 4.3.1.4.3.

p= t∗s√n

×100Γj

≤3 %

where

n is the number of pairs of measurements;

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j is the mean average deceleration at the speed Vj, in metres per second squared (m/s2), given by the equation:

Γ j= 1n∑i=1

n

Γ ji

where

Γ j=12×( γ jai+γ jbi )

jai and jbi are the decelerations of the ith measurement at the speed Vj defined in 4.3.2.4.3 for each direction, respectively, in metres per second squared (m/s2);

s is the standard deviation, in metres per second squared (m/s2), defined by the equation:

s=√ 1n−1∑i=1

n

( Γ ji−Γ j )2

t is the coefficient given in Table 2.

4.3.2.4.5. The total resistance Fj at speed Vj shall be determined by the following equation, us-ing m and mr as defined in 4.3.1.4.4:

Fj = (m + mr) * j

4.3.2.4.6. Total resistance curve determinationDetermine the total resistance curve as specified in 4.3.1.4.5.

4.3.3. Direct regression method As an alternative to the determination in 4.3.1.4.5, the total resistance may also be determined by the following mathematical approach.

4.3.3.1. Selection of speed range for road load curve determination The test speed range (i.e. the maximum speed and the minimum speed) shall be so determined that it covers the range of the reference speeds, over which total resistance is measured. If the test is carried out using split runs, each split speed range shall be determined accordingly.

4.3.3.2. Data collectionData shall be measured and recorded as specified in 4.3.1.2.

4.3.3.3. Vehicle coastdown procedureVehicle coastdown shall be conducted as specified in 4.3.1.3.

4.3.3.4. Determination of total resistance by coastdown measurementThe coefficients f0, f1 and f2 shall be calculated by approximating the relation between

V and t to tangent with Equation (4), of which the mathematical process is as follows.

4.3.3.4.1. Total resistance force F shall be calculated using equations (1) and (2):

25

F = f0 + f1V + f2V2 (1)

F=− 13. 6

×(m+m r )×dVdt (2)

where

F is the total resistance, N;f0 is a constant term, N;f1 is the coefficient of the first-order term, N·(h/km);f2 is the coefficient of the second-order term, N(h/km)2;m is the test vehicle mass, kg;mr is the equivalent effective mass of all the wheels and vehicle

components rotating with the wheels during coastdown on the road, kg;mr should be measured or calculated by an appropriate technique; as an alternative, mr may be estimated as 3 per cent of the unladen vehiclemass;

V is the vehicle speed, km/h.

4.3.3.4.2. Equation (3) is derived from equations (1) and (2).

−3.6×dtm+m r

= dVf 0+ f 1V + f 2V 2 (3)

4.3.3.4.3. Equation (4) is obtained from equation (3).

V=√4× f 0 f 2−f 12

2×f 2tan [−3 . 6×√4×f 0 f 2− f 12

2×(m+m r )xt−C 0 ]− f 1

2∗f 2 (4) where

t is the time, in seconds (s);C0 is the integration constant.

4.3.3.4.4. Equation (4) shall be replaced with equation (5).

V = Atan * (Bt + C) + D (5)

4.3.3.4.5. Calculate A, B, C and D in the approximate equation (5) by the least-squares method, and determine the coefficients f0, f1 and f2 using the following equations:

f 0=− 13 . 6

×(m+m r )× BA

×( A2+D2)

f 1= 13.6

×(m+m r )×2×BDA

f 2=− 13 .6

×(m+m r )× BA

If coastdowns are carried out using split runs, the total resistance, F, shall be calculated as fol-lows:

(a) The road load force for each reference speed included in the actual coastdown speed range shall be calculated.

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(b) Split data shall be placed into one set, one road load force equation shall be calcu-lated for each direction a and b.

4.3.3.4.6. Total resistance curve determinationThe total resistance curve shall be determined as specified in 4.3.1.4.5.

############################################# 4.4. On-board anemometer-based coastdown method As an alternative to the determination in 4.3.1, 4.3.2 or 4.3.3, total resistance may also be determined by the procedure described in 4.4.1 to 4.4.5. This method is applicable to a wind speed range up to 10 m/s on a test road as given in Table 1.

4.4.1. Selection of speed range for road load curve determination The test speed range as specified in 4.3.3.1. shall be selected.

4.4.2. Data collection The following data shall be measured and recorded at a maximum of 0.2 s intervals during the test. a) elapsed time; b) vehicle speed (measured by on-board anemometry); c) wind speed and direction (measured by on-board anemometry).

4.4.3. Vehicle coastdown procedure Vehicle coastdown shall be conducted as specified in 4.3.1.3.1. to 4.3.1.3.4. with an onboard anemometer installed on the vehicle. The anemometer shall be installed in a position such that the effect on the operating characteristics of the vehicle is minimised. It is recommended to install the anemometer at the vehicle’s forward aero dynamic stagnation point and approximately 2 m in front of it. Before the coastdown, the anemometer shall be installed on the vehicle and calibrated as specified by the manufacturer. An example of an anemometer calibration procedure is given in Annex A.

4.4.4. Determination of coefficients amech, bmech and cmech

Each coefficient shall be calculated by the following equation with multi-regression analysis, using coastdown time and wind data.

− 13. 6

×(m+mr )×dVdt

=a mech+b mech v+c mech v2+ 12×ρ sv r2×(a 0+a 1 θ+a 2 θ2+a 3 θ3+a 4 θ4 )

where

m is the test vehicle mass, kg; mr is the equivalent effective mass of all the wheels and vehicle components rotating with the wheels during coastdown on the road,kg; mr should be measured or calculated using an appropriate technique; as an alternative, mr may be estimated to be 3per cent of the unladen vehicle mass; dV/dt is acceleration, (km/h)/s; amech is a first order coefficient of mechanical drag, N; bmech is a second order coefficient of mechanical drag, N/(km/h);

27

cmech is a third order coefficient of mechanical drag, N/(km/h)2; V is vehicle speed, km/h; Vr is relative wind speed, km/h; is air density, in kilograms per cubic metre (kg/m3); S is the projected frontal area of the vehicle, m2; ai (i = 0 to 4) is the aerodynamic drag coefficient as a function of yaw angle, in degrees-n; is the yaw-angle apparent wind relative to the direction of vehicle travel, in degrees.

If the wind speed is close to 0 km/h, the equation theoretically cannot separate cmech

and (1/2) x a0 S appropriately. Therefore, a constrained analysis, where a0 is fixed if it is previously determined, for example in a wind tunnel, or cmech is assumed to be zero, may be employed.

4.4.5. Determination of total resistance using coastdown measurements

The total resistance, F, shall be calculated where all the wind effects are eliminated, by the following equation with the coefficients obtained in 4.4.4.

F=a mech+b mechV +[c mech+ 12×a0 ρS]V 2

#############################################4.5. Measurement of running resistance by the torque meter method

As an alternative to the coastdown methods, the torque meter method may also be used, in which the running resistance is determined by measuring wheel torque as described in 4.5.1. to 4.5.3.

4.5.1. Installation of torque meterOne or more torque meter(s) shall be installed on the drivetrain of the test vehicle. Wheel torque meters shall be installed on each driven wheel.

4.5.2. Procedure and data sampling

4.5.2.1. Start of data collectionData collection may be started following warm-up and stabilisation of the vehicle at the speed Vj, where the running resistance is to be measured.

4.5.2.2. Data collectionAt least 10 data sets of speed, torque and time over a period of at least 5 s shall be recorded.

4.5.2.3. Speed deviationThe speed deviation from the mean speed shall be within the values in Table 3.

Table 3

Time period,seconds

Speed deviation, km/h

5 0.210 0.4

28

15 0.620 0.825 1.030 1.2

4.5.3. Calculation of mean speed and mean torque

4.5.3.1. Calculation process Mean speed Vjm,(km/h) and mean torque Cjm, (N·m) over a time period, shall be calcu-

lated as follows:

V jm= 1k ∑i=1

k

V ji

and

C jm=1k ∑i=1

k

C ji−C js

whereVji is vehicle speed of the ith data set, in kilometres per hour

(km/h);k is the number of data sets;Cji is torque of the ith data set, in newton metres (N·m);Cjs is the compensation term for speed drift, in newton metres

(N·m), given by the following equation:Cjs = (m + mr) * j rj

(Cjs shall be no greater than 5 per cent of the mean torque before compensation, and may be neglected if j is no greater than 0.005 m/s2)

m and mr are the test vehicle mass and the equivalent effective mass, respectively, kg, defined in 4.3.1.4.4;

rj is the dynamic radius of the tyre, m, given by equation:

r j= 13 .6

∗ v jm

2×πN

whereN is the rotational frequency of the driven tyre, in revolutions per

second (s-1);αj is the mean acceleration, in metres per second squared (m/s2),

which shall be calculated by the equation:

α j= 13 . 6

×k∑

i=1

k

t i v ji−∑i=1

k

t i∑i=1

k

v ji

k∑i=1

k

t i2−[∑i=1

k

t i ]2

ti is the time at which the ith data set was sampled, in seconds (s).

29

4.5.3.2. Accuracy of measurementThese measurements shall be carried out in both directions until a minimum of four

consecutive figures have been obtained which satisfy accuracy p, in per cent, below. The validity of the data shall be decided in accordance with 4.3.1.4.2.

ρ= ts√k

×100Cj

≤3 %

wherek is the number of data sets;Cj is the running resistance at the speed Vj, in newton metres

(N·m), given by the equation:

Cj=1k ∑i=1

k

C jmi

whereCjmi is the average torque of the ith pair of data sets at speed

Vj, in newton metres (Nm), given by the equation:

C jmi=12×(C jmai+C jmbi)

Cjmai and Cjmbi are the mean torques of the ith data sets at speed Vj determined in 4.5.3.1 for each direction, a and b respectively, in newton metres (Nm);

s is the standard deviation, in newton metres Nm), defined by the equation:

s=√ 1k−1∑i=1

k

(C jmi−C j )2

t is the coefficient given by replacing n in Table 2 with k.

4.5.3.3. Validity of the measured average speed

The average speed Vjmi, shall not deviate by more than 2 km/h from its mean, V̄ j.

Vjmi and V̄ j shall be calculated as follows:

V j=1k ∑i=1

k

V jmi

V jmi=12×(V jmai+V jmbi )

where

Vjmai and Vjmbi are the mean speeds of the ith pair of data sets at speed Vj determined in 4.5.3.1 for each direction, a and b respectively, in kilometres per hour (km/h).

4.5.4. Running resistance curve determinationThe following regression curve shall be fitted to all the data pairs (Vjm, Cjma) and (Vjm,

Cjmb) for both directions a and b at all speed points Vj (j = 1, 2, etc.) described in 4.3.1.1. to determine c0a, c0b, c1a, c1b, c2a and c2b:

30

Ca = c0a + c1aV + c2aV2

Cb = c0b + c1bV + c2bV2

whereCa and Cb are the running resistances in each direction, in newton

metres (N·m);c0a and c0b are constant terms in each direction, in newton metres

(N·m);c1a are c1b are the coefficients of the first-order term in each

direction, in newton metres per hour per kilometre (Nm(h/km)); c1 may be assumed to be zero, if the value of c1V is no greater than 3 per cent of C at the reference speed(s); in this case, the coefficients c0 and c2 shall be recalculated;

c2a and c2b are the coefficients of the second-order term in each direction, in newton metres per hour per kilometre squared (Nm(h/km)2);

V is vehicle speed, in kilometres per hour (km/h).

The average total torque equation is calculated by the following equation:

Cavg = c0 + c1V + c2V2

where the average coefficients c0, c1 and c2 shall be calculated using the following equations:

c 0= c 0 a+c 0 b

2

c 1= c 1a+c 1 b

2

c 2= c 2a+c 2 b

2

31

4.6. Correction to standard atmospheric reference conditions

4.6.1. Correction factors

4.6.1.1. Determination of correction factor for air resistanceThe correction factor for air resistance K2 shall be determined as follows:

K 2= T293

×100ρ

where

T is the mean atmospheric temperature, in kelvins (K); is the mean atmospheric pressure, in kilopascals (kPa).

4.6.1.2. Determination of correction factor for rolling resistance The correction factor, K0, for rolling resistance, in reciprocal Kelvins, may be determined based on empirical data for the particular vehicle and tyre test, or may be assumed as follows:

K0 = 8.6 x 10-3 x K-1

4.6.1.3. Wind correction

4.6.1.3.1. Wind correction, for absolute wind speed alongside the test road, shall be made by subtracting the difference that cannot be cancelled by alternate runs from the constant term f0

given in 4.3.1.4.5, or from c0 given in 4.5.4.

4.6.1.3.2. The wind correction shall not apply in the on-board-anemometer-based coastdown method (4.4) as the wind correction is made during the series of data sampling and subsequent analysis. The wind correction resistance w1 for the coastdown method (4.3) or w2 for the torque meter method shall be calculated by the equations:

w1 = 3.62 x f2v2w or w2 = 3.62 x c2v2

w

where

w1 is the wind correction resistance, in newtons (N);f2 is the coefficient of the aerodynamic term determined in

4.3.1.4.5; vw is the average wind speed alongside the test road during the test,

in metres per second (m/s);w2 is the wind correction resistance, in newtons (N);c is the coefficient of the aerodynamic term determined in 4.5.4.

4.6.2. Road load curve correction

4.6.2.1. The curve determined in 4.3.1.4.5. shall be corrected to reference conditions as fol-lows:

F* =(( f 0− w 1 )+ f 1 V )⋅(1 + K 0( T - 293))+K 2 f 2 V 2

where

F* is the corrected total resistance in newtons (N);f0 is the constant term, in newtons (N);

32

f1 is the coefficient of the first-order term, in newtons hour per kilometre (N·(h/km));

f2 is the coefficient of the second-order term, in newtons per hour per kilometre squared (N(h/km)2);

K0 is the correction factor for rolling resistance, as defined in 4.6.1.2.;

K2 is the correction factor for air resistance, as defined in 4.6.1.1.;

V is vehicle speed, in kilometres per hour (km/h);w1 is the wind correction resistance, as defined in 4.6.1.3.

4.6.2.2. The curve determined in 4.4.5. shall be corrected to reference conditions as follows:

F * =(a mech+ b mech V + c mech V2 ) x (1 + K 0 x (T - 293) )+ 12×K 2 a 0 ρ SV 2

where

F* is the corrected total resistance, in newtons (N);amech is the coefficient of mechanical drag, in newtons (N);bmech is the coefficient of mechanical drag, in newtons per kilometre

per hour (N/(km/h));cmech is the coefficient of mechanical drag, in newtons per kilometre

per hour squared (N/(km/h)2); is air density, in kilograms per cubic metre (kg/m3);S is the projected frontal area of the vehicle, in square metres

(m2);a0 is the coefficient for aerodynamic drag, as a function of yaw

angle;K0 is the correction factor for rolling resistance, as defined in

4.6.1.2.;K2 is the correction factor for air resistance as defined in

4.6.1.1.;V is vehicle speed, in kilometres per hour (km/h).

4.6.2.3. The curve determined in 4.5.4. shall be corrected to reference conditions as follows:C* =((c 0− w 1 )+ c 1V ) x (1 + K 0×(T - 293 ))+K 2 c 2 V 2

where

C* is the corrected total running resistance, in newton metres (N·m);

c0 is the constant term, in newton metres (N·m);c1 is the coefficient of the first-order term, in newton metre per

hour per kilometre (N·m (h/km));c2 is the coefficient of the second-order term, in newton metres

per hour per kilometre squared (Nm(h/km)2);K0 is the correction factor for rolling resistance as defined

in 4.6.1.2.;K2 is the correction factor for air resistance as defined in

4.6.1.1.;V is vehicle speed, in kilometres per hour (km/h);w2 is the wind correction resistance as defined in 4.6.1.3..

33

5. Road load measurement using a combination of a wind tunnel and chassis dynamo-meter

The processes described in sections 5.1. and 5.2. below may be conducted simultan-eously in a wind tunnel providing the test equipment meets the specifications pre-scribed in both sections.

5.1. Aerodynamic drag measurement in wind tunnel

5.1.1. Requirements for wind tunnel

The wind tunnel design, the test methods and the corrections shall be sufficient to provide a value of S * Cd representative of the on-road S * Cd value.

5.1.2. Testing procedure

5.1.2.1. The test vehicle shall be positioned according to the specifications of the wind tunnel laboratory, so as to ensure that the air stream is parallel to the longitudinal axis of the test vehicle. The test vehicle’s ground clearance shall be checked according to the vehicle manufacturer’s specification, and shall be adjusted if required. The engine bonnet, moveable panels and all windows shall be closed. The test vehicle shall be affixed in a way that minimises the effect on the airflow.The vehicle shall be prepared as described in section 4.2. of this annex.

5.1.2.2. The measurement shall be conducted according to the specification of the wind tunnel laboratory. It is recommended to use the test section wind speed of 140 km/h, but the lowest wind speed shall be 80 km/h.Two measurements shall be conducted. If the difference in the resultant SCd values is greater than 1 per cent, the test vehicle set-up and the wind tunnel set-up shall be checked and corrected if necessary. Two further tests shall then be performed. This procedure shall be repeated until a difference of no more than 1 per cent between two values is obtained.

5.1.3 Test resultDetermine the test result (S * Cd), in square metres, by averaging a pair of the measurement values.

5.2. Rolling resistance determination with a chassis dynamometer or a moving belt

5.2.1 Testing device5.2.1.1. The chassis dynamometer shall have:(a) a single roller (double single rollers for permanent four-wheel-drive vehicles);(b) roller diameters of no less than 1.2 m;(c) roller surface be of smooth steel, or other equivalent materials, or textured and shall be kept clean. In cases where a textured surface is used, this shall be noted in the test report, and the surface texture shall be 180 µm deep (80 grit).

5.2.1.2. The moving belt shall: (a) be flat with no parasitic forces,(b) have a polyurethane surface, or other equivalent materials, and shall be clean,

34

(c) have a width and length which exceeds the tyre footprints.

An external vehicle-cooling fan shall have the characteristics according to §1.1. inAnnex 5 Test equipment and Calibrations.

5.2.2. Testing procedureThe rolling resistance of the front and rear wheels shall be measured. When a double-single-axis type chassis dynamometer is used for a permanent four-wheel-drive vehicle, the resistance of both axles shall be measured simultaneously. During the test, the vehicle shall be cooled with an external cooling fan.This procedure is based on force measurement at several steady speed points and not under deceleration.

5.2.2.1. The vehicle conditions as specified in 4.2.1.1. shall be adjusted.

5.2.2.2. The test room temperature shall be adjusted to 293 +6/-2 K. The chassis dynamometer shall be warmed up according to the chassis dynamometer spe-

cifications. Measure the chassis dynamometer running losses.

5.2.2.3. The non-driving wheels shall be placed in the normal front-driving direction on the chassis dynamometer and the following shall be performed;a) restrain the vehicle, taking care not to apply an abnormal load on the measured

axle;b) warm up the axle until the chassis dynamometer force is stabilised, or up to a

maximum of 30 minutes at the highest reference speed;c) measure the axle rolling resistance for this speed;d) decrease the speed to the immediate lower reference speed;e) measure the axle rolling resistance for this new speed;f) repeat c) to e) for each reference speed;g) once the loads have been measured for each reference speed, repeat the entire

measurement procedure from c) to f);h) if the difference is greater than 4 per cent at any reference speed, the test vehicle

set-up and the chassis dynamometer set-up shall be checked and corrected, if necessary. Two further tests shall then be performed. This procedure shall be repeated until a difference of no more than 4 per cent between two values, at any reference speed, is obtained;

i) once two satisfactory measurements have been obtained, the final result shall be the average of the two measurements for each reference speed.

WEB/TELEPHONE CONFERENCE WEDNESDAY, OCTOBER 31 STOPS HERE.

5.2.2.4. The driving axle shall be placed on the chassis dynamometer and the following shall be performed;

a) restrain the vehicle, taking care not to apply an abnormal load on the measured axle;

b) adjust the chassis dynamometer load to an appropriate value;c) warm up the axle until the chassis dynamometer force is stabilised, or up to a

maximum of 30 min at the highest reference speed, running the engine on the appropriate gear;

35

d) return the engine to idle, shift the transmission into neutral, and re-engage the clutch in the case of a manual transmission vehicle;

e) stabilise the speed at the highest reference speed;f) measure the axle rolling resistance for this speed;g) decrease the speed to the immediate lower reference speed;h) measure the axle rolling resistance for this new speed;i) repeat e) to h) for each reference speed;j) once the loads have been measured for each reference speed, repeat the entire

measurement procedure from e) to i);k) if the difference is greater than 4 per cent at any reference speed, the test vehicle

set-up and the chassis dynamometer set-up shall be checked and corrected, if necessary. Two further tests shall then be performed. This procedure shall be repeated until a difference of no more than 4 per cent between two values at any reference speed is obtained;

l) once two satisfactory measurements have been obtained, the final result shall be the average of the two measurements for each reference speed.

5.2.3 Test resultsFor each reference speed Vj, the total rolling resistance shall be calculated using the following equation:

Rrt,j = Rrf,j + Rrr,j – 2 x Rrloss,j

where

Rrt,j is the total rolling resistance, in newtons (N);Rrf,j is the rolling resistance of the front wheel, in newtons (N);Rrr,j is the rolling resistance of the rear wheel, in newtons (N);Rrloss,j are the chassis dynamometer losses, in newtons (N).

The Rrt,j result shall be corrected as per Annex B of ISO 10521-1.

5.3. Total resistance calculationThe total road load resistance shall be calculated for each reference speed Vj by the

following equation, using S * Cd obtained in §5.1. and Rrt,j in §5.2.:

F j= 13 . 62

× ρ SCdV j2

2+Rr tj

whereFj is the total road load resistance, in newtons (N); is the air density, in kilograms per cubic metre (kg/m3);S is the projected frontal area of the vehicle, in square metres

(m2);Cd is the aerodynamic drag coefficient; Vj is the vehicle speed, in kilometres per hour (km/h).

5.4. Total resistance curve determinationIf necessary, the total resistance curve shall be determined by fitting the following regression curve using the least-squares method:

F = f0 + f1V + f2V2

36

whereF is total resistance, in newtons (N);f0 is a constant term, in newtons (N);f1 is a coefficient of the first-order term, in newton hour per

kilometre (N⋅h/km);f2 is a coefficient of the second-order term, in newtons per hour

per kilometre squared ((N(h/km)2);V is vehicle speed, in kilometres per hour (km/h).

5.5 It is recommended that the value of the total rolling resistance measured with chassis dynamometers should be corrected. Examples of three correction methods may be found in Annex B to ISO 10521-1.

37

6. Transferring road load to a chassis dynamometerCheck speed range of load setting and road load determination. Upper and lower limits shall be the same.

6.1. Preparation for chassis dynamometer test

6.1.1. Laboratory condition

6.1.1.1. RollerThe chassis dynamometer roller(s) shall be clean, dry and free from foreign material which might cause tyre slippage. For chassis dynamometers with multiple rollers, the dynamometer shall be run in the same coupled or uncoupled state as the subsequent Type I test. Chassis dynamometer speed shall be measured from the roller coupled to the power-absorption unit.

Input from JAMA: Concern: If tyre slip on roller of dynamometer due to lack of the weight of vertical direction, it should be allowed to set additional weight to prevent slip.But this makes heavier road load.

Proposal: If additional weight to the driving axle is necessary to avoid slip on roller, manufac-turers may perform load setting on chassis dynamometer with the additional weight.In this case the weight shall be put on the vehicle both for load setting and emission /fuel con-sumption tests.The information of additional weight (kg, location) shall be recorded on the test report.

6.1.1.2. Room temperatureThe laboratory atmospheric temperature shall be within 293 K to 303 K at a set point of 298 ± 5 K as the standard condition, unless otherwise required by the subsequent test.

6.2. Preparation of chassis dynamometer

6.2.1. Inertia mass settingThe equivalent inertia mass of the chassis dynamometer shall be set in accordance with the vehicle mass or vehicle mass category.

6.2.1. Inertia mass setting (Annex 4) The equivalent inertia mass of the chassis dynamometer shall be set to the actual test mass used at the corresponding road load determination, the vehicle mass or vehicle mass category increased by 50% of mr (see 4.3.3.4.1) in case the non-driven wheels are not driven by the chassis dynamometer. If the chassis dynamometer is not capable to meet this setting, the next higher inertia setting shall be applied.

### Comment from Japan ### Following rotating mass shall be added to the inertia mass setting.On 2WD dyno: Non-rotating part of ‘mr’ used at calculation of the road load. (e.g. 4.3.1.4.4., 4.3.3.4.1.) If 3 percent is used at calculation, non-rotating part is defined as 1.5 percent.On 4WD dyno: none. (Since all wheels are rotating on 4WD dyno.)

38

6.2.2 Warming up the chassis dynamometerThe chassis dynamometer shall be warmed up in accordance with the dynamometer manufacturer’s recommendations, or as appropriate, so that friction losses of the dynamometer can be stabilised.

6.3. Vehicle preparation

6.3.1. Tyre pressure adjustmentThe tyre pressure shall be set to no more than 50 per cent (see §4.2.2.3.) above the lower limit of the tyre pressure range for the selected tyre, as specified by the vehicle manufacturer.

The following from JAMA: Concern: Needs clear description;

Position: If there is any safety issue on dynamometer, it is allowed to increase tyre pressure up to 50%.

However the increased pressure shall be used for both of dynamometer setting and emission/fuel consumption testing (Annex 6 1.2.4.7.)

Increased pressure is recorded on the test report.

6.3.2. If the determination of dynamometer settings cannot meet the criteria described in paragraphs 7.1.3. due to non-reproducible forces, the vehicle shall be equipped with a vehicle coastdown mode. The explanation of such coasting mode shall be approved and recorded by the authority.

6.3.2.1. If a vehicle is equipped with a vehicle coastdown mode, it shall be engaged both dur-ing road load determination and on the chassis dynamometer.

6.3.3. Vehicle settingThe tested vehicle shall be installed on the chassis dynamometer roller in a straight position and restrained in a safe manner. In case of a single roller, the tyre contact point shall be within 25 mm or 2 per cent of the roller diameter, whichever is smaller, measured from the top of the roller.

6.3.4. Vehicle warming upThe power-absorption unit of the chassis dynamometer shall be set as specified in 7.1.1.1. or 7.2.1.1., so that an adequate load will be applied to the test vehicle during warming up.Prior to the test, the vehicle shall be warmed up appropriately until normal vehicle operating temperatures have been reached. This condition is deemed to be fulfilledwhen three consecutive coastdowns are completed within the given tolerance of Annex/chapter XXX. The dynamometer load for the vehicle warm-up shall be set asdescribed in 7.1.1.1.

It is recommended that the vehicle should be driven at the most appropriate reference speed for a period of 30 min. During this warming up period, the

vehicle speed shall not exceed the highest reference speed.

39

7. Chassis dynamometer load setting

7.1. Chassis dynamometer setting by coastdown methodThis method is applicable when the road load is determined using the coastdown method or the wind tunnel and chassis dynamometer method as specified in 4.3., 4.4.or 5.

7.1.1. Initial load settingFor a chassis dynamometer with coefficient control, the chassis dynamometer power-absorption unit shall be adjusted with the arbitrary initial coefficients, Ad, Bd and Cd, of the following equation:

Fd = Ad + BdV+ CdV2

where

Fd is the chassis dynamometer setting load, in newtons (N);V is the speed of the chassis dynamometer roller, in kilometres per

hour (km/h).

The following are recommended coefficients to be used for the initial load setting:

a) Ad = 0,5 x At, Bd = 0,2 x Bt, Cd = Ct, for single-axis chassis dynamometers, or

Ad = 0,1 x At, Bd = 0,2 x Bt, Cd = Ct, for dual-axis chassis dynamometers,

where At, Bt and Ct are the target road load coefficients;

b) empirical values, such as those used for the setting for a similar type of vehicle.For a chassis dynamometer of polygonal control, adequate load values at each speed point shall be set to the chassis dynamometer power-absorption unit.

### Comment from Japan ### Another procedure tested at RLD validation (refer to SAE J2264)For the fixed-run procedure, the dynamometer software will automatically run three coastdowns adjusting the Dynoset coefficients for each run using the difference between the previous run's Dynomeasured and Dynotarget coefficients. The final Dynoset coefficients are then calculated by subtracting the 3-run average of the Dynovehicle coefficients from the Dynotarget coefficients. Optionally, a single stabilization coastdown may be performed be-fore beginning the 3-run averaging sequence.

40

7.1.2. CoastdownThe coastdown test on the chassis dynamometer shall be performed once with the procedure given in 4.3.1.3.1 and 4.3.1.3.2. Then proceed to 7.1.3.

7.1.3. Verification

7.1.3.1. The target road load value shall be calculated using the target road load coefficient At, Bt and Ct for each reference speed Vj.

Ftj = At + BtVj + CtVj2

where

Ftj is the target road load at reference speed Vj, in newtons (N);Vj is the jth reference speed, in kilometres per hour (km/h).

7.1.3.2. The error, j , in per cent of the simulated road load Fsj, shall be calculated using the method specified in A.1, for target road load Ftj at each reference speed Vj, using the follow-ing equation:

ε j= [ Fsj−Ftj ]Ftj

×100

Fmj, obtained in Appendix I section 1.1, may be used in the above equation instead of Fsj.Verify whether errors at all reference speeds satisfy the following error criteria in two consecutive coastdown runs, unless otherwise specified by regulations:

j ≤ 3 per cent for Vj ≥ 50 km/hj ≤ 2 per cent for Vj ≥ 50 km/h

j ≤ 5 per cent for 20 km/h < Vj < 50 km/hj ≤ 3 per cent for 20 km/h < Vj < 50 km/h

j ≤ 10 per cent for Vj = 20 km/h

If an error at any reference speed does not satisfy the criteria, 7.1.1.4. shall be used to adjust the chassis dynamometer load setting.

7.1.4. AdjustmentAdjust the chassis dynamometer setting load in accordance with the procedure spe-

cified in Appendix 2 section 1.7.1.1.2. and 7.1.1.3. shall be repeated.

7.2. Chassis dynamometer load setting using torque meter methodThis method is applicable when the road load is determined using the torque meter method, as specified in section 4.5.

7.2.1. Initial load settingFor a chassis dynamometer of coefficient control, the chassis dynamometer power-absorption unit shall be adjusted with the arbitrary initial coefficients, Ad, Bd and Cd, of the following equation:

41

Fd = Ad + BdV + CdV2

where

Fd is the chassis dynamometer setting load, in newtons (N);V is the speed of the chassis dynamometer roller, in kilometres

per hour (km/h).

The following coefficients are recommended for the initial load setting:

a) Ad = 0,5 x at/r’, Bd = 0,2 x bt/r’, Cd = ct/r’, for single-axis chassis dynamometers, orAd = 0,1 x at/r’, Bd = 0,2 x bt/r’, Cd = ct/r’, for dual-axis chassis dynamometers,

where

at, bt and ct are the coefficients for the target torque;r’ is the dynamic radius of the tyre on the chassis dynamometer, in

metres (m) that is obtained by averaging the rj′ values calculated in Appendix I section 2.1;

b) empirical values, such as those used for the setting for a similar type of vehicle.For a chassis dynamometer of polygonal control, adequate load values at each speed point shall be set for the chassis dynamometer power-absorption unit.

7.2.2. Wheel torque measurementThe torque measurement test on the chassis dynamometer shall be performed with the

procedure defined in 4.5.2. The torque meter(s) shall be identical with the one(s) used in the preceding road test.

7.2.3. Verification

7.2.3.1. The target road load value shall be calculated using the target torque coefficients at, bt, and ct for each reference speed Vj.

F tj=a t+b t V j+c t V j2

r 'where

Ftj is the target road load at reference speed Vj, in newtons (N);Vj is the jth reference speed, in kilometres per hour (km/h);r’ is the dynamic radius of the tyre on the chassis dynamometer, in

metres (m), that is obtained by averaging the rj′ values calculated in Appendix I section 2.1.

7.2.3.2. The error, j, in per cent of the simulated road load Fsi shall be calculated. Fsj is determined according to the method specified in Appendix I section 2, for target roadload Ftj at each reference speed Vj.

ε j=[ F sj−F tj ]

F tj×100

42

Cj m/r′ obtained in Appendix I section 2.1 and 7.2.1.3.1., respectively, may be used in the above equation instead of Fsj.

Verify whether errors at all reference speeds satisfy the following error criteria in two consec-utive coastdown runs, unless otherwise specified by regulations.

j ≤ 3 per cent for Vj ≥ 50 km/hj ≤ 2 per cent for Vj ≥ 50 km/h

j ≤ 5 per cent for 20 km/h < Vj < 50 km/hj ≤ 3 per cent for 20 km/h < Vj < 50 km/h

j ≤10 per cent for Vj = 20 km/hj ≤10 per cent for Vj = 20 km/h

If the error at any reference speed does not satisfy the criteria, then proceed to 7.2.1.4 for the adjustment of the chassis dynamometer setting load.

7.2.1.4. AdjustmentThe chassis dynamometer setting load shall be adjusted according to the procedure specified in Appendix 2 section 2. Paragraphs 7.2.2 and 7.2.3. shall be repeated.

7.3. Dynamometer preparation for settings derived from a running resistance table

7.3.1. Specified speed for the chassis dynamometer

The running resistance on the chassis dynamometer shall be verified at the specified speed v. At least four specified speeds should be verified. The range of specified speed points (the in-terval between the maximum and minimum points) shall extend either side of the reference speed or the reference speed range, if there is more than one reference speed, by at least v, as defined in paragraph 4. of Annex 7. The specified speed points, including the reference speed point(s), shall be no greater than 20 km/h apart and the interval of specified speeds should be the same.

7.3.2. Verification of chassis dynamometer

Immediately after the initial setting, the coastdown time on the chassis dynamometer corres-ponding to the specified speed shall be measured. The vehicle shall not be set up on the chassis dynamometer during the coastdown time measurement. When the chassis dynamo-meter speed exceeds the maximum speed of the test cycle, the coastdown time measurement shall start.

The measurement shall be carried out at least three times, and the mean coastdown time tE shall be calculated from the results.

The set running resistance force FE(vj) at the specified speed on the chassis dynamometer shall be calculated by the following equation:

43

FE (v j )=1

3 .6×mi×

2 ΔvΔt E

Equation 7-15

The setting error at the specified speed is calculated by the following equation:

ε=| FE (v j )−FT |

FT×100

Equation 7-16

The chassis dynamometer shall be readjusted if the setting error does not satisfy the following criteria:

ε ≤ 2 per cent for v ≥ 50 km/hε ≤ 3 per cent for 30 km/h ≤ v < 50 km/hε ≤ 10 per cent for v < 30 km/h

The procedure described above shall be repeated until the setting error satisfies the criteria. The chassis dynamometer setting and the observed errors shall be recorded. An example of the record form is given in Annex 10.

7.3.3. Chassis dynamometer setting based on running resistance table

Reference mass of vehicles

Equivalent Inertia

Power and load absorbed by the dynamometer at 80 km/h

Coefficients

a b

RW (kg) Kg kW N N N/(km/h)²

RW 450 420 3.7 167 3.8 0.0255450 < RW 510 480 4.0 178 4.0 0.0272510 < RW 570 540 4.2 189 4.3 0.0288570 < RW 630 600 4.4 199 4.5 0.0304630 < RW 690 660 4.6 209 4.7 0.0319690 < RW 750 720 4.9 219 5.0 0.0334750 < RW 810 780 5.1 229 5.2 0.0349810 < RW 870 840 5.3 238 5.4 0.0364870 < RW 930 900 5.5 248 5.6 0.0378930 < RW 990 960 5.7 257 5.8 0.0392990 < RW 1050 1020 5.9 266 6.0 0.0406

1050 < RW 1110 1080 6.1 275 6.2 0.04191110 < RW 1170 1140 6.3 283 6.4 0.04321170 < RW 1230 1200 6.5 292 6.6 0.04451230 < RW 1290 1260 6.7 300 6.8 0.04581290 < RW 1350 1320 6.8 308 6.9 0.04701350 < RW 1410 1380 7.0 315 7.1 0.04821410 < RW 1470 1440 7.2 323 7.3 0.04931470 < RW 1530 1500 7.3 330 7.4 0.05051530 < RW 1590 1560 7.5 338 7.6 0.05161590 < RW 1650 1620 7.7 345 7.8 0.05261650 < RW 1710 1680 7.8 351 7.9 0.05371710 < RW 1770 1740 8.0 358 8.1 0.05471770 < RW 1830 1800 8.1 364 8.2 0.05561830 < RW 1890 1860 8.2 371 8.3 0.0566

44

1890 < RW 1950 1920 8.4 376 8.5 0.05751950 < RW 2010 1980 8.5 382 8.6 0.05842010 < RW 2070 2040 8.6 388 8.7 0.05922070 < RW 2130 2100 8.7 393 8.8 0.06012130 < RW 2190 2160 8.9 398 9.0 0.06092190 < RW 2250 2220 9.0 403 9.1 0.06162250 < RW 2310 2280 9.1 408 9.2 0.06242310 < RW 2370 2340 9.2 413 9.3 0.06312370 < RW 2430 2400 9.3 417 9.4 0.06372430 < RW 2490 2460 9.4 421 9.5 0.06442490 < RW 2550 2520 9.5 425 9.5 0.06502550 < RW 2610 2580 9.5 429 9.6 0.06562610 < RW 2670 2640 9.6 433 9.7 0.06612670 < RW 2730 2700 9.7 436 9.8 0.06662730 < RW 2790 2760 9.8 440 9.9 0.06712790 < RW 2850 2820 9.8 443 9.9 0.06762850 < RW 2910 2880 9.9 445 10.0 0.06802910 < RW 2970 2940 10.0 448 10.0 0.06842970 < RW 3030 3000 10.0 450 10.1 0.06883030 < RW 3090 3060 10.1 453 10.1 0.06913090 < RW 3150 3120 10.1 455 10.2 0.06953150 < RW 3210 3180 10.1 456 10.2 0.06973210 < RW 3270 3240 10.2 458 10.2 0.07003270 < RW 3330 3300 10.2 460 10.3 0.07023330 < RW 3390 3360 10.2 461 10.3 0.07043390 < RW 3450 3420 10.3 462 10.3 0.07053450 < RW 3480 10.3 463 10.3 0.0707

45

Appendix I

Calculation of road load for the dynamometer test

1. Calculation of simulated road load using the coastdown methodWhen the road load is measured by the coastdown method as specified in 4.3 or 4.4, of this annex, calculation of the simulated road load Fsj for each reference speed Vj, in kilometres per hour, shall be conducted as described in 1.1. to 1.3. of this appendix.

1.1. The measured road load shall be calculated using the following equation:

F mj= 13 . 6

×( md+m r ' )×2×ΔVΔT j

where

Fmj is the measured road load for each reference speed Vj, in newtons (N);

md is the equivalent inertia-mass of the chassis dynamometer, in kilograms (kg);

m′r is the equivalent effective mass of drive wheels and vehicle components rotating with the wheels during coastdownon the dynamometer, in kilograms (kg); m′r may be measured or calculated by an appropriate technique. As an alternative, m′r may be estimated as 3 per cent of the unladen vehicle mass for a permanent four-wheel-drive vehicle, and 1.5 per cent of the unladen vehicle mass for a two-wheel drive vehicle;

### Comment from Japan ### This m’r shall be the same one as used at calculation of the road load.

ΔTj is the coastdown time corresponding to speed Vj, in seconds (s).

1.2. The coefficients As, Bs and Cs of the following approximate equation shall be determ-ined using least-square regression using the calculated Fmj :

Fs = As + BsV + CsV2

1.3. The simulated road load for each reference speed Vj shall be determined using the fol-lowing equation, using the calculated As, Bs and Cs:

Fsj = As + BsVj + CsVj2

2. Calculation of simulated road load using the torque meter methodWhen the road load is measured by the torque meter method as specified in 4.5., calculation of the simulated road load Fsj for each reference speed Vj, in kilometres per hour, shall be conducted as described in 2.1. to 2.3. of this appendix.

2.1. The mean speed Vj m, in kilometres per hour, and the mean torque Cj m, in newton- metres, for each reference speed Vj shall be calculated using the following equations:

46

V jm= 1

k∑i=1

k

V ji

and

C jm=1k ∑i=1

k

C ji−C jc

where

Vji is the vehicle speed of the ith data set, in kilometres per hour (km/h);

K is the number of data sets;Cji is the torque of the ith data set, in newton metres (N·m);Cjc is the compensation term for the speed drift, in newton

metres, which is given by the following equation:

Cjc = (md + mr′) αj r′j

Cjc shall be no greater than 5 per cent of the mean torque before compensation, and may be neglected if |αj| is no greater than 0,005 m/s2.

md and m′r are the equivalent inertia mass of the chassis dynamometer and the equivalent effective mass of drive wheels and vehicle components rotating with the wheel during coastdown on the chassis dynamometer,respectively, both in kilograms (kg), as defined in section 1 of this appendix;

αj is the mean acceleration, in metres per second squared (m/s2), which shall be calculated by the equation:

α j= 13 . 6

×k∑

i=1

k

t i V ij−∑i=1

k

t i∑i=1

k

V ji

k∑i=1

k

t i 2−(k∑i=1

k

t i)2

where

ti is the time at which the ith data set was sampled, in seconds (s).r′j is the dynamic radius of the tyre, in metres (m), given by the equation:

r ' j= 13 .6

× V jm

2×πNN is the rotational frequency of the driven tyre, in revolutions per second

(s-1).

2.2. The coefficients as, bs and cs of the following approximate equation by the least-square regression shall be calculated using the calculated Vj m and the Cj m.

47

F s= f s

r '

¿a s+b s V +c s V 2

r '

2.3. The simulated road load for each reference speed Vj shall be determined using the fol-lowing equation and the calculated as, bs and cs:

F sj=f sj

r '

¿a s+b s V j+c s V j 2

r '

48

Appendix 2

Adjustment of chassis dynamometer load setting

1. Adjustment of chassis dynamometer load setting using the coastdown methodThe chassis dynamometer load setting shall be adjusted using the following equations:

F*dj = Fdj - Fj

= Fdj – Fsj + Ftj

= (Ad + BdVj + CdVj2) - (As + BsVj + CsVj

2) + (At + BtVj + CtVj2)

= (Ad + At – As) + (Bd + Bt + Bs) Vj + (Cd + Ct – Cs) Vj2

Ad* = Ad + At - As

Bd* = Bd + Bt - Bs

Cd* = Cd + Ct - Cs

where

Fd j* is the new chassis dynamometer setting load, in newtons (N);Fj is the adjustment road load, which is equal to Fsj - Ftj , in

newtons (N);Fsj is the simulated road load at reference speed Vj, in newtons (N);Ftj is the target road load at reference speed Vj, in newtons (N);Ad*, Bd* and Cd* are the new chassis dynamometer setting coefficients.

2. Adjustment of chassis dynamometer load setting using the torque meter methodThe chassis dynamometer load setting shall be adjusted using the following equation:

F*dj = Fdj - Fej /r’= Fdj – Fsj + Ftj /r’= (Ad + BdVj + CdVj

2) - (as + bsVj + csVj2) /r’ + (at + btVj + ctVj

2) /r’= {Ad + (at – as) /r’ } + {Bd + (bt + bs) /r’} Vj + {Cd + (ct – cs) /r’} Vj

2

Ad* = Ad + (at - as) /r’ Bd* = Bd + (bt - bs) /r’ Cd* = Cd + (ct - cs) /r’

where

Fd j* is the new chassis dynamometer setting load, in newtons (N);fej is the adjustment road load, which is equal to fsj - ftj , in newtons (N);fsj is the simulated road load at reference speed Vj, in newtons (N);ftj is the target road load at reference speed Vj, in newtons (N);Ad*, Bd* and Cd*are the new chassis dynamometer setting coefficients.r′ is the dynamic radius of the tyre on the chassis dynamometer, in metres

(m), that is obtained by averaging the r′j values calculated in Appendix1 section 2.1.