INTERNATIONAL ISO
STANDARD 6460-1
Second edition
Motorcycles — Measurement method
for gaseous exhaust emissions and
fuel consumption —
Part 1:
General test requirements
Motocycles — Méthode de mesure des émissions de gaz
d'échappement et de la consommation de carburant —
Partie 1: Exigences générales d'essai
PROOF/ÉPREUVE
Reference number
ISO 6460-1:2021(E)
© ISO 2021
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ISO 6460-1:2021(E)
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ISO 6460-1:2021(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction .............................................................................................................................................................................................................................. vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Symbols .......................................................................................................................................................................................................................... 2

5 Standard reference conditions ............................................................................................................................................................. 5

6 Tests .................................................................................................................................................................................................................................. 5

6.1 Measurement of gaseous exhaust emissions ............................................................................................................... 5

6.1.1 Average gaseous exhaust emissions during conventional test cycles ................................ 5

6.1.2 Measurement of gaseous exhaust emissions at an idling speed .............................................. 5

6.2 Measurement of fuel consumption ....................................................................................................................................... 5

6.2.1 Average fuel consumption during conventional test cycles ........................................................ 5

6.2.2 Fuel consumption at a constant speed ............................................................................................................ 5

7 Measurement equipment ............................................................................................................................................................................ 5

7.1 General ......................................................................................................................................................................................................... 5

7.2 Chassis dynamometer ...................................................................................................................................................................... 5

7.3 Gas-collection equipment ............................................................................................................................................................. 5

7.4 Analytical equipment ....................................................................................................................................................................... 7

7.5 Cooling equipment .............................................................................................................................................................................. 8

7.6 Fuel consumption measurement ............................................................................................................................................ 8

7.7 Accuracy of instruments and measurements ............................................................................................................. 9

8 Preparing the test ............................................................................................................................................................................................... 9

8.1 Engine fuel and lubricants ........................................................................................................................................................... 9

8.2 Description of the test motorcycle ........................................................................................................................................ 9

8.3 Conditioning/preparation of the test motorcycle ................................................................................................... 9

8.4 Calibration and adjustment of analysers ..................................................................................................................... 10

8.4.1 Calibration of the analysers ................................................................................................................................... 10

8.4.2 Adjustment of the analysers ................................................................................................................................. 11

8.4.3 Reference gases and accuracy of the mixing device ........................................................................13

9 CVS system check procedure ...............................................................................................................................................................13

10 Procedure for sampling, analysing and measuring the volume of gaseous exhaust

emissions ..................................................................................................................................................................................................................14

10.1 Operations to be carried out before the test motorcycle start up ......................................................... 14

10.2 Beginning of sampling and volume measurement............................................................................................... 17

10.3 End of sampling and volume measurement ............................................................................................................... 17

10.4 Analysis ...................................................................................................................................................................................................... 17

10.5 Measuring the driving distance ........................................................................................................................................... 18

10.6 Open type CVS system .................................................................................................................................................................. 18

11 Determination of the quantity of gaseous exhaust emissions .........................................................................18

11.1 Total diluted exhaust mixture volume corrected to the standard reference

conditions ................................................................................................................................................................................................. 18

11.1.1 Total diluted exhaust mixture volume for the CVS system with CFV .............................. 18

11.1.2 Total diluted exhaust mixture volume for the CVS system with PDP .............................. 19

11.1.3 Total diluted exhaust mixture volume for the CVS system with SSV ............................... 19

11.2 Exhaust emissions sampling and the dilution factor ........................................................................................ 20

11.2.1 Exhaust emissions sampling ................................................................................................................................. 20

11.2.2 Dilution factor .................................................................................................................................................................... 20

11.3 Mass of the gaseous exhaust emissions ........................................................................................................................ 21

11.3.1 Mass of carbon monoxide ........................................................................................................................................ 21

iii
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ISO 6460-1:2021(E)

11.3.2 Mass of total hydrocarbons ................................................................................................................................... 22

11.3.3 Mass of non-methane hydrocarbons ............................................................................................................. 22

11.3.4 Mass of nitrogen oxides ............................................................................................................................................. 24

11.3.5 Mass of carbon dioxide ..............................................................................................................................................25

12 Determination of the fuel consumption ...................................................................................................................................25

12.1 Carbon balance method ...............................................................................................................................................................25

12.1.1 Fuel consumption for four-stroke engines ............................................................................................... 25

12.1.2 Calculation of results in litres per 100 km ............................................................................................... 26

12.2 Fuel flow measurement method .......................................................................................................................................... 26

12.2.1 Fuel consumption for four-stroke engines ............................................................................................... 27

12.2.2 Calculation of results in litres per 100 km ............................................................................................... 27

Annex A (normative) Method and equipment for measuring fuel consumption by the fuel

flow measurement method ....................................................................................................................................................................28

Annex B (informative) Example for record form of test fuel specifications...........................................................39

Annex C (informative) Exhaust emissions leakage check procedure for the open type CVS

system...........................................................................................................................................................................................................................40

Annex D (informative) Determination of the dilution factor .................................................................................................46

Annex E (normative) Principle of the carbon balance method for four-stroke engines ...........................55

Annex F (informative) Simplified determination method of the atom number ratio of

hydrogen and carbon, and that of oxygen and carbon in gasoline ..............................................................56

Annex G (informative) CVS system check procedure ......................................................................................................................57

Bibliography .............................................................................................................................................................................................................................58

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ISO 6460-1:2021(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to

the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see

www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 32, Road vehicles, Subcommittee SC 38,

Motorcycles and mopeds.

This second edition cancels and replaces the first edition (ISO 6460-1:2007), which has been technically

revised. It also incorporates the Amendment ISO 6460-1:2007/Amd.1:2015.
The main changes are as follows:

— addition of a detailed description of a critical flow venturi (CFV) as a flow measurement principle to

the CVS system;

— permission to use of the subsonic venturi (SSV) as a flow measurement principle to the CVS system;

— addition for the measurement of methane (CH ) concentration, either a GC-FID (flame ionization

detector with gas chromatograph) or an NMC-FID (flame ionization detector with non-methane

cutter);
— addition of a calculation method for non-methane hydrocarbons (NMHC);

— permission to determine the ratio of hydrogen and carbon (R ) and the ratio of oxygen and carbon

(R ) by the content analysis of fuel;

— addition of calculation methods for the mass of the gaseous exhaust emissions and the fuel

consumption when using oxygenated fuels;
— deletion of descriptions related two-stroke engines and diesel fuel.
A list of all parts in the ISO 6460 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
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ISO 6460-1:2021(E)
Introduction

For the measurement of motorcycle fuel consumption, the carbon balance method, where the fuel

consumption is calculated from analysis of the carbon quantity in the exhaust emissions, is now widely

used in addition to the conventional fuel flow measurement. Therefore, the measurement of exhaust

emissions pollutants and fuel consumption are inseparably related to each other.

This document defines the fundamental elements such as the measurement accuracy, test motorcycle

conditions and the details of the carbon balance method. The measurement of gaseous exhaust emissions

and fuel consumption during test cycles can be conducted by means of this document and ISO 6460-2.

Additionally with ISO 6460-3, these three documents provide details of those measurements at a

constant speed.
The following revisions are mainly made in this document.

— The detailed description of a critical flow venturi (CFV), adopted by most of the manufacturers as

well as a positive displacement pump (PDP), is added as a flow measurement principle to the CVS

system. Also, the use of the subsonic venturi (SSV) is also permitted as a CVS flow measurement

principle.

— For measurement of methane (CH ) concentration in the diluted exhaust mixture, either a GC-FID

(flame ionization detector with gas chromatograph) or an NMC-FID (flame ionization detector with

non-methane cutter) shall be used as the analytical instrument. The formula for calculating non-

methane hydrocarbons (NMHC) is also defined.

— Instead of obtaining the ratio of hydrogen and carbon (R ) and the ratio of oxygen and carbon

(R ) from the exhaust emissions analysis, R and R shall be determined by the fuel analysis. In

OC HC OC

addition, when using the oxygenated fuels such as gasoline (E5) and gasoline (E10), the mass of the

gaseous exhaust emissions and the fuel consumption also can be calculated.

— As there has been no need for newly development of two-stroke engines and compression ignition

engines in recent years, the description regarding two-stroke engines and diesel fuel is to be deleted.

If these are required, see ISO 6460-1:2007.
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INTERNATIONAL STANDARD ISO 6460-1:2021(E)
Motorcycles — Measurement method for gaseous exhaust
emissions and fuel consumption —
Part 1:
General test requirements
1 Scope

This document specifies the general test requirements for measurement of the gaseous exhaust

emissions from motorcycles, and for determining the fuel consumption of motorcycles as defined in

ISO 3833. It is applicable to motorcycles equipped with a spark ignition engine (four-stroke engine or

rotary piston engine).
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 3833, Road vehicles — Types — Terms and definitions

ISO 6460-2:2014, Motorcycles — Measurement method for gaseous exhaust emissions and fuel consumption

— Part 2: Test cycles and specific test conditions

ISO 6460-3:2007, Motorcycles — Measurement method for gaseous exhaust emissions and fuel consumption

— Part 3: Fuel consumption measurement at a constant speed

ISO 11486:2006, Motorcycles — Methods for setting running resistance on a chassis dynamometer

3 Terms and definitions

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

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
equivalent inertia

total inertia of the rotating masses of the chassis dynamometer, determined with respect to the

reference mass of the test motorcycle, which is total unladen mass of the test motorcycle increased by a

uniform figure of 75 kg, which represents the mass of a rider

Note 1 to entry: Total unladen mass of the test motorcycle includes mass of the vehicle with bodywork and all

fitted equipment, electrical and auxiliary equipment for normal operation of vehicle, including liquids, tools, fire

extinguisher, standard spare parts, chocks and spare wheel, if fitted.

The fuel tank shall be filled to at least 90 % of rated capacity and the other liquid containing systems to 100 % of

emissions of gaseous pollutants from the tailpipe of test motorcycles, such as carbon monoxide (CO),

total hydrocarbons (THC), non-methane hydrocarbons (NMHC), nitrogen oxides (NOx) as gaseous

pollutants and carbon dioxide (CO )
4 Symbols
Table 1 — Symbols
Symbols Definition Unit

c methane concentration in the dilution air, expressed in ppm carbon equivalent ppmC

CH4,d
methane concentration in the diluted exhaust mixture, expressed in ppm carbon
c ppmC
CH4,e
equivalent
volumetric concentration of methane in the diluted exhaust mixture, expressed in
c ppmC
CH4,ec
ppm carbon equivalent, corrected to take account of methane in the dilution air
c carbon monoxide concentration in the dilution air ppm
CO,d
carbon monoxide concentration in the dilution air with the water vapour and
c ppm
CO,dm
carbon dioxide absorbent
c carbon monoxide concentration in the diluted exhaust mixture ppm
CO,e
volumetric concentration of carbon monoxide in the diluted exhaust mixture,
c ppm
CO,ec
corrected to take account of carbon monoxide in the dilution air
carbon monoxide concentration in the diluted exhaust mixture with the water
c ppm
CO,em
vapour and carbon dioxide absorbent
c carbon dioxide concentration in the dilution air %
CO2,d
c carbon dioxide concentration in the diluted exhaust mixture %
CO2,e
volumetric concentration of carbon dioxide in the diluted exhaust mixture, cor-
c %
CO2,ec
rected to take account of carbon dioxide in the dilution air
hydrocarbon concentration measured by the NMC-FID with sample gas flowing
c ppmC
HC(w/ NMC)
through the NMC, expressed in ppm carbon equivalent
hydrocarbon concentration in the dilution air with sample gas flowing through
c ppmC
HC(w/ NMC),d
the NMC, expressed in ppm carbon equivalent
hydrocarbon concentration in the diluted exhaust mixture with sample gas
c ppmC
HC(w/ NMC),e
flowing through the NMC, expressed in ppm carbon equivalent
volumetric concentration of hydrocarbon in the diluted exhaust mixture with

c sample gas flowing through the NMC, expressed in ppm carbon equivalent, cor- ppmC

HC(w/ NMC),ec
rected to take account of hydrocarbon in the dilution air
hydrocarbon concentration measured by the NMC-FID with sample gas bypassing
c ppmC
HC(w/o NMC)
the NMC, expressed in ppm carbon equivalent
hydrocarbon concentration in the dilution air with sample gas bypassing the
c ppmC
HC(w/o NMC),d
NMC, expressed in ppm carbon equivalent
hydrocarbon concentration in the diluted exhaust mixture with sample gas
c ppmC
HC(w/o NMC),e
bypassing the NMC, expressed in ppm carbon equivalent
volumetric concentration of hydrocarbon in the diluted exhaust mixture with
c sample gas bypassing the NMC, ppm C, expressed in ppm carbon equivalent, ppmC
HC(w/o NMC),ec
corrected to take account of hydrocarbon in the dilution air
volumetric concentration of non-methane hydrocarbon in the diluted exhaust
c mixture, expressed in ppm carbon equivalent, corrected to take account of ppmC
NMHC,ec
non-methane hydrocarbon in the dilution air
c nitrogen oxides concentration in the dilution air ppm
NOx,d
c nitrogen oxides concentration in the diluted exhaust mixture ppm
NOx,e
ppm = parts per million.
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ISO 6460-1:2021(E)
Table 1 (continued)
Symbols Definition Unit
volumetric concentration of nitrogen oxides in the diluted exhaust mixture,
c ppm
NOx,ec
corrected to take account of nitrogen oxides in the dilution air
c oxygen concentration in the dilution air %
O2,d

concentration of the pollutant i in the diluted exhaust mixture, corrected to take

c ppm
Pi,ec
account of the amount of the pollutant i contained in the dilution air
total hydrocarbon concentration in the dilution air, expressed in ppm carbon
c ppmC
THC,d
equivalent
total hydrocarbon concentration in the diluted exhaust mixture, expressed in
c ppmC
THC,e
ppm carbon equivalent
volumetric concentration of total hydrocarbon in the diluted exhaust mixture,

c expressed in ppm carbon equivalent, corrected to take account of total hydro- ppmC

THC,ec
carbon in the dilution air
C discharge coefficient of the SSV —
d diameter of the SSV inlet pipe inner m
d diameter of the SSV throat m
D dilution factor —
E ethane conversion efficiency —
E methane conversion efficiency —
F specific fuel consumption km/l
F fuel consumption per 100 km l/100 km
c100
H absolute humidity in grams of water per kilogram of dry air —
H relative humidity of dilution air %
H relative humidity in the test room %
H standard relative humidity %
humidity correction factor used for the calculation of the mass emissions of
K —
nitrogen oxides
k critical flow venturi correction factor —
k ratio of pressure to temperature at the standard reference conditions —
k collection of constants and unit conversions —
m mass of carbon monoxide in the gaseous exhaust emissions g/km
m mass of carbon dioxide in the gaseous exhaust emissions g/km
CO2
m mass of fuel consumed g
m mass of non-methane hydrocarbon in the gaseous exhaust emissions g/km
NMHC
m mass of nitrogen oxides in the gaseous exhaust emissions g/km
NOx
m mass emission of the pollutant i g
m mass of total hydrocarbon in the gaseous exhaust emissions g/km
THC
number of revolutions of positive displacement pump during the test while sam-
N —
ples are being collected
p mean barometric pressure during the test in the test room kPa
p saturated water vapour pressure during the test in the test room kPa

absolute pressure of the diluted exhaust mixture at the inlet of positive displace-

p kPa
ment pump
p absolute pressure at the venturi inlet kPa
p absolute pressure of the diluted exhaust mixture at the venturi inlet kPa
v (t)
p total barometric pressure at the standard reference conditions kPa
ppm = parts per million.
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ISO 6460-1:2021(E)
Table 1 (continued)
Symbols Definition Unit
Q measured flow rate of venturi using the other gas flowmeter m /s
Q measured flow rate of venturi at standard reference conditions m /s
cal

r ratio of the SSV throat pressure to inlet absolute static pressure, 1−(Δp / p ) —

x v

r ratio of the SSV throat diameter d to the inlet pipe inner diameter d , d / d —

y v in v in
R atom number ratio of hydrogen and carbon in the gaseous exhaust emissions —
HC,ex
R atom number ratio of hydrogen and carbon in the fuel —
HC,F
R atom number ratio of oxygen and carbon in the gaseous exhaust emissions —
OC,ex
R atom number ratio of oxygen and carbon in the fuel —
OC,F
R response factor of CH for an FID —
f,CH4 4
R response factor of C H for an FID —
f,C3H6 3 6
R response factor of C H for an FID
f,C3H8 3 8
R response factor of C H for an FID —
f,C7H8 7 8
S running distance actually travelled km
t time s
t total test time s
test
T measured ambient temperature during the test in the test room K
T fuel temperature measured at the burette K
temperature of diluted exhaust mixture at the positive displacement pump inlet
T K
during the test while samples are being collected
T temperature at the venturi inlet K
T temperature of diluted exhaust mixture at the venturi inlet K
v (t)
T air temperature at the standard reference conditions K
V measured volume of fuel consumed l
V dilution air volume m
volume of the diluted exhaust mixture expressed corrected to the standard
V m /km
reference conditions
V gaseous exhaust emissions volume m
volume of the diluted exhaust mixture in one test under the standard reference
V l
i,e
conditions
diluted exhaust mixture volume pumped by the positive displacement pump per
V l
one revolution
V total diluted exhaust mixture volume during one test m
α coefficient of volumetric expansion for the fuel K
ρ carbon monoxide density at the standard reference conditions g/m
ρ carbon dioxide density at the standard reference conditions g/m
CO2
ρ fuel density at 288,15 K kg/l
ρ non-methane hydrocarbon density at the standard reference conditions g/m
NMHC
nitrogen oxides density at the standard reference conditions, expressed in
...

ISO/PRF 6460-1

Motorcycles -- Measurement method for gaseous exhaust emissions and fuel consumption

Motorcycles -- Measurement method for gaseous exhaust emissions and fuel consumption

Motocycles -- Méthode de mesure des émissions de gaz d'échappement et de la consommation de carburant

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Motorcycles -- Measurement method for gaseous exhaust emissions and fuel consumption

Motocycles -- Méthode de mesure des émissions de gaz d'échappement et de la consommation de carburant

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