ISO 6460-1:2022
(Main)Motorcycles — Measurement method for gaseous exhaust emissions and fuel consumption — Part 1: General test requirements
Motorcycles — Measurement method for gaseous exhaust emissions and fuel consumption — Part 1: General test requirements
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).
Motocycles — Méthode de mesure des émissions de gaz d'échappement et de la consommation de carburant — Partie 1: Exigences générales d'essai
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INTERNATIONAL ISO
STANDARD 6460-1
Second edition
2022-02
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
Reference number
© ISO 2022
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ii
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
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 (informative) 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
iv
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
HC
(R ) by the content analysis of fuel;
OC
— 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.
v
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
HC
(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.
vi
INTERNATIONAL STANDARD ISO 6460-1:2022(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
the capacity specified by the manufacturer.
3.2
gaseous exhaust emissions
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
a
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
a
ppm = parts per million.
Table 1 (continued)
a
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
d diameter of the SSV inlet pipe inner m
in
d diameter of the SSV throat m
v
D dilution factor —
f
E ethane conversion efficiency —
E
E methane conversion efficiency —
M
F specific fuel consumption km/l
c
F fuel consumption per 100 km l/100 km
c100
H absolute humidity in grams of water per kilogram of dry air —
a
H relative humidity of dilution air %
d
H relative humidity in the test room %
r
H standard relative humidity %
humidity correction factor used for the calculation of the mass emissions of
K —
H
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
CO
m mass of carbon dioxide in the gaseous exhaust emissions g/km
CO2
m mass of fuel consumed g
F
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
Pi
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
a
p saturated water vapour pressure during the test in the test room kPa
d
absolute pressure of the diluted exhaust mixture at the inlet of positive displace-
p kPa
p
ment pump
p absolute pressure at the venturi inlet kPa
v
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
a
ppm = parts per million.
Table 1 (continued)
a
Symbols Definition Unit
Q measured flow rate of venturi using the other gas flowmeter m /s
a
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
a
T fuel temperature measured at the burette K
F
temperature of diluted exhaust mixture at the positive displacement pump inlet
T K
p
during the test while samples are being collected
T temperature at the venturi inlet K
v
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
d
volume of the diluted exhaust mixture expressed corrected to the standard
V m /km
e
reference conditions
V gaseous exhaust emissions volume m
ex
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
p
one revolution
V total diluted exhaust mixture volume during one test m
s
−1
α coefficient of volumetric expansion for the fuel K
ρ carbon monoxide density at the standard reference conditions g/m
CO
ρ carbon dioxide density at the standard reference conditions g/m
CO2
ρ fuel density at 288,15 K kg/l
F
ρ non-methane hydrocarbon density at the standard reference conditions g/m
NMHC
nitrogen oxides density at the standard reference conditions, expressed in
ρ g/m
NOx
equivalent NO
ρ density of the pollutant i at the standard reference conditions g/l
Pi
ρ total hydrocarbon density at the standard reference conditions g/m
THC
ρ air volumetric mass at the standard reference conditions kg/m
a
ppm = parts per million.
5 Standard reference conditions
The standard reference conditions shall be as follows:
Total barometric pressure, p : 101,325 kPa;
Air temperature, T : 273,15 K;
Relative humidity, H : 65 %;
Air volumetric mass, ρ : 1,293 kg/m .
6 Tests
6.1 Measurement of gaseous exhaust emissions
6.1.1 Average gaseous exhaust emissions during conventional test cycles
The test shall be carried out in accordance with the procedure described in ISO 6460-2. The appropriate
test cycle shall be selected.
6.1.2 Measurement of gaseous exhaust emissions at an idling speed
The test shall be carried out in accordance with the procedure described in ISO 6460-2.
6.2 Measurement of fuel consumption
6.2.1 Average fuel consumption during conventional test cycles
The test shall be carried out in accordance with the procedure described in ISO 6460-2. The appropriate
test cycle shall be selected.
6.2.2 Fuel consumption at a constant speed
The test shall be carried out in accordance with the procedure described in ISO 6460-3.
7 Measurement equipment
7.1 General
Irrespective of the provisions in this clause, any measurement system(s) may be used when the
performance of the equipment is proven by the equipment manufacturer to be equivalent to the
constant volume sampler (CVS) system.
7.2 Chassis dynamometer
The chassis dynamometer shall be set in accordance with ISO 11486. The equivalent inertia mass for
the table method shall be in accordance with ISO 11486:2006, Table 4.
7.3 Gas-collection equipment
7.3.1 The gas-collection equipment shall be a closed type system that can collect all exhaust emissions
at the motorcycle exhaust outlet(s) providing that it satisfies the backpressure condition of ±1,25 kPa.
An open type system may be used as well if it is confirmed that all the exhaust emissions are collected.
The exhaust emissions collection shall be such that there is no condensation, which may appreciably
modify the nature of exhaust emissions at the test temperature.
7.3.2 The gas-collection equipment and connecting tube between the gas-collection equipment
and the exhaust emissions sampling system shall be made of stainless steel or of some other material
which does not affect the composition of the exhaust emissions collected and which withstands the
temperature of the exhaust emissions.
7.3.3 The CVS system with a critical flow venturi (CFV) or the CVS system with a positive displacement
pump (PDP) shall be used for the exhaust emissions sampling system.
7.3.3.1 The CVS system with CFV shall be applicable to the requirements in this subclause.
a) The capacity of CFV shall be large enough to ensure the inlet of all the diluted exhaust mixture.
b) An instrument capable of calculating the venturi flow rate based on the measuring results of
temperature and absolute pressure of the diluted exhaust mixture sucked into CFV shall be
equipped.
c) A dilution air sampling probe of the closed type exhaust emissions sampling system shall be set at
the lower reaches of the dilution air filter. This sampling probe shall be capable of collecting the
dilution air at a constant flow rate through the sampling pump, the filter and the flow meter during
the test. The dilution air sampling probe of the open type exhaust emissions sampling system shall
be set in the vicinity of and outside of the exhaust emissions sampling system of the open type CVS
system. This sampling probe shall be capable of collecting the dilution air at a constant flow rate
through the sampling pump, the filter and the flow meter during the test.
d) A diluted exhaust mixture sampling probe pointing to the upper reaches of the diluted exhaust
mixture shall be set at the upper part in the vicinity of CFV inlet. The diluted exhaust mixture shall
be collected at the flow rate in proportion to the diluted exhaust mixture flow rate through the
sampling pump, the filter and the flow meter during the test.
e) A flow rate integrator for integrating the diluted exhaust mixture flow rate during the test shall be
equipped.
7.3.3.2 The CVS system with PDP shall be applicable to the requirements in this subclause.
a) A heat exchanger shall be capable of limiting the temperature variation of the diluted exhaust
mixture at PDP inlet to ±5 K throughout the test. This exchanger shall be equipped with a preheating
system capable of bringing the exchanger to its operating temperature (with the tolerance of ±5 K)
before the test begins.
b) PDP for drawing in the diluted exhaust mixture shall be equipped with a motor capable of
controlling the diluted exhaust mixture flow speed to several constant speeds strictly. The capacity
of PDP shall be large enough to ensure the intake of all the exhaust emissions.
c) A device capable of continuous recording of the temperature of the diluted exhaust mixture
entering PDP shall be equipped. A device to allow continuous recording of the temperature of the
diluted exhaust mixture entering PDP shall be equipped.
d) An instrument capable of measuring the pressure depression of the diluted exhaust mixture
entering PDP relative to the atmospheric pressure and an instrument capable of measuring the
pressure difference between the inlet and the outlet of PDP shall be equipped.
e) A dilution air sampling probe of the closed type exhaust emissions sampling system shall be set at
the lower reaches of the dilution air filter. This sampling probe shall be capable of collecting the
dilution air through the sampling pump, the filter and the flow meter at a constant flow rate during
the test. A dilution air sampling probe of the open type exhaust emissions sampling system shall
be set in the vicinity of and outside of the exhaust emissions sampling system of the open type CVS
system. This sampling probe shall be capable of collecting the dilution air at a constant flow rate
through the sampling pump, the filter and the flow meter during the test.
f) A diluted exhaust mixture sampling probe pointing to the upper reaches of the diluted exhaust
mixture shall be set at the upper reaches of PDP. This sampling probe shall be capable of collecting
the diluted exhaust mixture at a constant flow rate through the sampling pump, the filter and the
flow meter during the test.
g) A revolution counter for counting the revolution of PDP during the test shall be equipped.
7.3.4 A device using a subsonic venturi (SSV) may also be used. The use of SSV for the CVS system is
based on the principles of flow mechanics. The flow rate of the diluted exhaust mixture is maintained
at a subsonic velocity which is calculated from the physical dimensions of the subsonic venturi and
measurement of the absolute temperature and pressure at the venturi inlet and the pressure in the
throat of the venturi. The flow rate is continually computed and integrated throughout the test.
7.3.5 In the case of the CVS system with CFV, the sampling venturi shall be set at the place where the
temperature and the absolute pressure are same as those of the main critical flow venturi inlet. The
sampling flow rates in proportion to the diluted exhaust mixture flow rate shall be obtained.
In the case of the CVS system with PDP, the diluted exhaust mixture flow rate and the sampling flow
rates shall be steady within ±5 %.
If the device cannot compensate for variations in the temperature of the mixture of exhaust emissions
and dilution air at the measuring point, a heat exchanger shall be used to maintain the temperature to
within ±6 K of the specified operating temperature for the CVS with PDP, and ±11 K for the CVS with
CFV and SSV.
7.3.6 A sampling system shall be equipped with the valves directing the samples either to the
sampling bags or to the atmosphere. The minimum sampling flow rate shall be 150 l/h.
7.3.7 The sampling bags shall be airtight for collecting the dilution air and the diluted exhaust
mixture, and shall have sufficient capacity so as not to impede the normal sample flow and not to change
the nature of the exhaust emissions to be measured. The sampling bags shall be equipped with the
automatic self-locking devices, and shall be easily and tightly connected either to the sampling system
during the sampling period and to the analysing system at the end of the test.
NOTE 1 Pay attention to the connecting method and the material or configuration of the connecting parts
because there is a possibility that each section (e.g. adapters, couplers) of the sampling system becomes very hot.
If the measurement cannot be performed normally due to the heat-damages of the sampling system, an auxiliary
cooling device is used as long as the exhaust emissions are not affected.
NOTE 2 In the case of the open type exhaust emissions sampling system, there is a risk of the incomplete
exhaust emissions collection and the exhaust emissions leakage into the test room. So it is important to make
sure that there is no leakage during the sampling period.
NOTE 3 If a constant CVS flow rate is used during the test using the test cycles including low speeds and high
speeds, it is important to pay attention to the water condensation in the high-speed range.
7.4 Analytical equipment
7.4.1 The sample probe shall consist of a sampling tube leading into the collecting bags, or of a
drainage tube. This sample probe shall be made of stainless steel or of some other material that will not
adversely affect the composition of the exhaust emissions to be analysed. The temperature of the tubes
connecting to the analyser, including the sampling probe, shall be same as the ambient temperature or
above.
7.4.2 Analysers shall be of the following types:
a) non-dispersive infrared absorption (NDIR) type for CO and CO ;
b) flame ionization (FID) type for THC;
c) either a gas chromatograph combined with an FID (GC-FID), or an FID combined with a non-
methane cutter (NMC-FID) for methane (CH );
d) chemiluminescence (CLD) type for NOx.
7.5 Cooling equipment
Throughout the test, a variable speed cooling blower shall be positioned in front of the test motorcycle,
so as to direct the cooling air to the test motorcycle in a manner which simulates actual operating
conditions. The blower speed shall be such that, within the operating range of 10 km/h to 50 km/h,
the linear velocity of the air at the blower outlet should be within ±5 km/h of the corresponding roller
speed. At the range of over 50 km/h, the linear velocity of the air shall be within ±10 % of roller speed.
At the roller speeds of less than 10 km/h, air velocity may be zero.
The air velocity shall be determined as an averaged value of 9 measuring points which are located at the
centre of each rectangle dividing the whole of the blower outlet into 9 areas (dividing both of horizontal
and vertical sides of the blower outlet into 3 equal parts). Each value at those 9 points shall be within
±10 % of the average value of the 9 points.
The blower outlet shall have a cross section area of at least 0,4 m and the bottom of the blower outlet
shall be between 5 cm and 20 cm above floor level. The blower outlet shall be perpendicular to the
longitudinal axis of the test motorcycle between 30 cm and 45 cm in front of its front wheel. The device
used to measure the linear velocity of the air shall be located at between 0 cm and 20 cm from the air
outlet.
7.6 Fuel consumption measurement
7.6.1 One of the following methods shall be used to measure the fuel consumption, depending on
the characteristics of each method and on the type of test to be performed (conventional test cycle or
constant speed):
a) carbon balance method;
b) volumetric method;
c) gravimetric method;
d) flowmeter method.
The carbon balance method shall be applied in accordance with 12.1.
Other methods may be used if it can be proved that the results given are equivalent.
7.6.2 Fuel shall be supplied to the engine by a device capable of measuring the quantity of fuel
supplied with an accuracy of ±1 % in accordance with Annex A, and which does not interfere with the
supply of fuel to the engine. When the measuring system is the volumetric method or the flowmeter
method, the temperature of the fuel in the device or in the device outlet shall be measured.
Switching from the normal supply system to the measuring supply system shall be done by means of a
valve system and shall take no more than 0,2 s.
Annex A gives the description and the methods of use of the appropriate devices for fuel flow
measurement.
7.7 Accuracy of instruments and measurements
7.7.1 The distance travelled by the test motorcycle shall be measured with an accuracy of ±1 %.
7.7.2 The speed of the test motorcycle shall be measured with an accuracy of ±1 % to the resolution
of 0,1 km/h. For speeds less than 10 km/h, the speed shall be measured to the resolution of 0,1 km/h.
7.7.3 The ambient temperatures shall be measured with an accuracy of ±1 K.
7.7.4 The atmospheric pressure shall be measured with an accuracy of ±0,2 kPa.
7.7.5 The relative humidity of the ambient air shall be measured with an accuracy of ±5 %.
7.7.6 The pressures considered in 7.3.3.1 b) and 7.3.3.2 d) shall be measured with an accuracy of
±0,4 kPa.
7.7.7 The analysers shall have a measuring range compatible with the accuracy required to measure
the content of the various pollutants and carbon dioxide with an accuracy of ±1 %, regardless of the
accuracy of the calibration gases. The overall response time of the analysing circuit shall be less than
1 min.
7.7.8 The cooling air speed shall be measured with an accuracy of ±5 km/h.
7.7.9 The duration of test cycles and the exhaust emissions collection shall be controlled with an
accuracy of ±1 s. These times shall be measured with an accuracy of 0,1 s.
7.7.10 The total volume of the diluted exhaust mixture shall be measured with an accuracy of ±2 %.
7.7.11 For the fuel consumption measurement at a constant speed specified in ISO 6460-3, the wind
speed on the test road shall be measured with an accuracy of ±5 % to the resolution of 0,1 m/s.
8 Preparing the test
8.1 Engine fuel and lubricants
The specification of test fuel shall be reported. An example of the record form is given in Annex B.
With regard to grade and quantity of oil, the lubrication of the engine s
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