ISO 21755-1:2019
(Main)Motorcycles — Measurement method for evaporative emissions — Part 1: SHED test procedure
Motorcycles — Measurement method for evaporative emissions — Part 1: SHED test procedure
This document specifies a basic measurement method by using the SHED (Sealed Housing for Evaporative Determination) test procedure for evaporative emissions from motorcycles. It is applicable to motorcycles equipped with a spark ignition engine (four-stroke engine, two-stroke engine or rotary piston engine).
Motocycles — Méthode de mesure pour les émissions par évaporation — Partie 1: Procédure d'essai SHED
General Information
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 21755-1
First edition
2019-07
Motorcycles — Measurement method
for evaporative emissions —
Part 1:
SHED test procedure
Motocycles — Méthode de mesure pour les émissions par
évaporation —
Partie 1: Procédure d'essai SHED
Reference number
ISO 21755-1:2019(E)
©
ISO 2019
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ISO 21755-1:2019(E)
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ISO 21755-1:2019(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Evaporative emissions, SHED test . 2
4.1 Description of SHED test . 2
4.2 Test motorcycles and test fuel . 3
4.2.1 Test motorcycles . 3
4.2.2 Test fuel . 3
4.3 Test equipment . 3
4.3.1 Chassis dynamometer . 3
4.3.2 Evaporative emission measurement enclosure (SHED) . 4
4.3.3 Analytical systems . 4
4.3.4 Fuel tank heating . 4
4.3.5 Temperature recording . 5
4.3.6 Fans . 5
4.3.7 Gases . 5
4.3.8 Additional equipment . . 6
4.4 Test procedure . 6
4.4.1 Test preparation . 6
4.4.2 Conditioning phase . 6
4.4.3 Test phases . 6
4.5 Calculation of results . 8
5 Calibration of equipment for evaporative emission testing .10
5.1 Calibration frequency and methods .10
5.2 Calibration of the enclosure .10
5.2.1 Initial determination of enclosure internal volume .10
5.2.2 Determination of enclosure background emissions .10
5.2.3 Calibration and hydrocarbon retention test of the enclosure.10
5.2.4 Calculations .11
5.3 Checking of hydrocarbon analyser .11
5.3.1 Detector response optimization .11
5.3.2 Calibration of the hydrocarbon analyser .11
5.3.3 Oxygen interference check and recommended limits .11
5.4 Calibration of the hydrocarbon analyser .12
6 Presentation of results .12
6.1 The evaporative emission .12
6.2 Test report .12
Annex A (informative) Running loss test procedure .13
Annex B (normative) Running-in test procedure for evaporative emission control devices .18
Annex C (normative) Presentation of results for evaporative emissions .20
Bibliography .24
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ISO 21755-1:2019(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 22, Road vehicles, Subcommittee SC 38,
Motorcycles and mopeds.
A list of all parts in the ISO 21755 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 21755-1:2019(E)
Introduction
Recently, exhaust emissions from tailpipes of motorcycles have been dramatically reduced. Accordingly,
evaporative emissions have begun to attract attention. Therefore, measurement methods for evaporative
emissions are specified as an international standard for multi-application, e.g. certification, research,
developments. This document specifies the basic measurement method by using the SHED (Sealed
Housing for Evaporative Determination) test procedure for evaporative emissions from motorcycles.
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INTERNATIONAL STANDARD ISO 21755-1:2019(E)
Motorcycles — Measurement method for evaporative
emissions —
Part 1:
SHED test procedure
1 Scope
This document specifies a basic measurement method by using the SHED (Sealed Housing for
Evaporative Determination) test procedure for evaporative emissions from motorcycles. It is applicable
to motorcycles equipped with a spark ignition engine (four-stroke engine, two-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 6460-1, Motorcycles — Measurement method for gaseous exhaust emissions and fuel consumption —
Part 1: General test requirements
ISO 6460-2, Motorcycles — Measurement method for gaseous emissions and fuel consumption — Part 2:
Test cycles and specific test conditions
ISO 9277:2010, Determination of the specific surface area of solids by gas adsorption — BET method
ISO 11486, Motorcycles — Methods for setting running resistance on a chassis dynamometer
ISO 7117, Motorcycles — Measurement method for determining maximum speed
ISO 4106, Motorcycles — Engine test code — Net power
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http: //www .electropedia .org/
— ISO Online browsing platform: available at https: //www .iso .org/obp
3.1
evaporative emissions
hydrocarbon vapours lost from the fuel storage and supply system of a motorcycle and not those from
tailpipe emissions
3.2
SHED test
motorcycle test in a constant temperature sealed house for evaporation determination, in which a
special evaporative emission test is conducted
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ISO 21755-1:2019(E)
3.3
tank diurnal breathing loss
hydrocarbon emissions caused by temperature changes in the fuel storage
3.4
hot soak loss
hydrocarbon emissions arising from the fuel system of a stationary motorcycle after a period of driving
3.5
non-exposed type fuel tank
fuel tank and fuel delivery system, except the fuel tank cap, which are not directly exposed to radiation
of sunlight
3.6
rated capacity
fuel capacity of the fuel tank as declared by the manufacturer
4 Evaporative emissions, SHED test
4.1 Description of SHED test
The evaporative emission SHED (Sealed Housing for Evaporative Determination) test consists of a
conditioning phase and a test phase (see Figure 1):
a) conditioning phase:
1) test cycle;
2) motorcycle soak;
b) test phase:
1) tank diurnal breathing loss test;
2) test cycle;
3) hot soak loss test.
Running loss test may be conducted during the test cycle and if it is conducted, the test procedure shall
be in accordance with Annex A.
Mass emissions of hydrocarbons from the tank diurnal breathing loss and the hot soak loss phases are
added together to provide an overall result for the test. If running loss test is conducted in the test
cycle, mass emissions of hydrocarbons from the diurnal breathing loss, the running loss and the hot
soak loss phases are summed to provide an overall result for the test.
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ISO 21755-1:2019(E)
Figure 1 — Flow chart of evaporative emission SHED test
4.2 Test motorcycles and test fuel
4.2.1 Test motorcycles
The test motorcycle shall be run in at least 1 000 km after first start on the production line.
4.2.2 Test fuel
The test fuel shall be selected in accordance with agreement among the parties involved or the
manufacturer's requirements, and the specifications of test fuel shall be reported. The record form is
given in Annex C.
NOTE This test is influenced by the vapour pressure of the fuel property greatly, therefore the test vapour
pressure is decided among the parties because the market fuel vapour pressure largely varies according to the
season depending on the area.
4.3 Test equipment
4.3.1 Chassis dynamometer
The dynamometer shall have a single roll with a diameter of at least 0,400 m.
The dynamometer shall be equipped with a roll revolution counter for measuring actual distance
travelled.
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ISO 21755-1:2019(E)
The methods for setting running resistance on a chassis dynamometer shall be in accordance with
ISO 11486.
4.3.2 Evaporative emission measurement enclosure (SHED)
The evaporative emission measurement enclosure shall be a gas-tight rectangular measuring chamber
able to contain the motorcycle under test. The motorcycle shall be accessible from all sides when
inside and the enclosure when sealed shall be gas tight. The inner surface of the enclosure shall be
impermeable and non-reactive to hydrocarbons. At least one of the surfaces shall incorporate with a
flexible impermeable material or other devices to allow the equilibration of pressure changes resulting
from small changes in temperature. Wall design shall be such as to promote good dissipation of heat,
and if artificial cooling is used, interior surface temperatures shall not be less than 293 K.
4.3.3 Analytical systems
4.3.3.1 Hydrocarbon analyser
4.3.3.1.1 The atmosphere within the enclosure shall be monitored using a hydrocarbon detector of
the flame ionisation detector (FID) type. Sample gas shall be drawn from the midpoint of one side wall
or the roof of the enclosure and any bypass flow shall be returned to the enclosure, preferably to a point
immediately downstream of the mixing fan.
4.3.3.1.2 The hydrocarbon analyser shall have a response time to 90 % of final reading of less than
1,5 seconds. Its stability shall be better than 2 % of full scale at zero and at 80 % ± 20 % of full scale over
a 15 minute period for all operational ranges.
4.3.3.1.3 The repeatability of the analyser expressed as one standard deviation shall be better than
1 % of full-scale deflection at zero and at 80 % ± 20 % of full scale on all ranges used.
4.3.3.1.4 The operational ranges of the analyser shall be chosen to give best resolution over the
measurement, calibration and leak checking procedures. The leak checking procedure shall be
accordance with analyser manufacture.
4.3.3.2 Hydrocarbon analyser data recording system.
The hydrocarbon analyser shall be fitted with a device to record electrical signal output either by strip
chart recorder or other data-processing system at a frequency of at least once per minute. The recording
system shall have operating characteristics at least equivalent to the signal being recorded and shall
provide a permanent record of results. The record shall show a positive indication of the beginning
and end of the fuel tank heating and hot soak periods together with the time elapsed between start and
completion of each test.
4.3.4 Fuel tank heating
4.3.4.1 The fuel tank heating system shall consist of two separate heat sources with two temperature
controllers. Typically, the heat sources will be electric heating strips, but other sources may be used at
the request of the manufacturer. Temperature controllers may be manual, such as variable transformers,
or automated. Since vapour and fuel temperature are to be controlled separately, an automatic controller
is recommended for the fuel. The heating system shall not cause hot-spots on the wetted surface of the
tank which would cause local overheating of the fuel. Heating strips for the fuel should be located as
low as practicable on the fuel tank and shall cover at least 10 % of the wetted surface. The centre-line of
the heating strips shall be below 30 % of the fuel depth as measured from the bottom of the fuel tank,
and approximately parallel to the fuel level in the tank. The centre line of the vapour heating strips, if
used, shall be located at the approximate height of the centre of the vapour volume. The temperature
controllers shall be capable of controlling the fuel and vapour temperatures to the heating function
described in 4.4.3.1.7.
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ISO 21755-1:2019(E)
4.3.4.2 With temperature sensors positioned as in 4.3.5.2, the fuel heating device shall make it possible
to evenly heat the fuel and fuel vapour in the tank in accordance with the heating function described in
4.4.3.1.7. The heating system shall be capable of controlling the fuel and vapour temperatures to ±1,7 K
of the required temperature during the tank heating process.
4.3.4.3 Notwithstanding the requirements of 4.3.4.2, if a manufacturer is unable to meet the heating
requirement specified, due to use of thick-walled plastic fuel tanks for example, then the closest possible
alternative heat slope shall be used, and the-alternative heat slope shall be reported.
4.3.5 Temperature recording
4.3.5.1 The temperature in the enclosure is recorded at two points by temperature sensors, which are
connected so as to show a mean value. The measuring points are extended approximately 0,1 m into the
enclosure from the vertical centre line of each side wall at a height of 0,9 m ± 0,2 m.
4.3.5.2 The temperatures of the fuel and fuel vapour shall be recorded by means of sensors positioned
in the fuel tank as described in 4.4.2. When sensors cannot be positioned as specified in 4.4.2, e.g. where
a fuel tank with two ostensibly separate enclosures is used, sensors shall be located at the approximate
mid-volume of each fuel or vapour containing enclosure. In this case, the average of these temperature
readings shall constitute the fuel and vapour temperatures.
4.3.5.3 Throughout the evaporative emission measurements, temperatures shall be recorded or
entered into a data processing system at a frequency of at least once per minute.
4.3.5.4 The accuracy of the temperature recording system shall be within ±1,7 K and capable of
resolving to 0,4 K.
4.3.5.5 The recording or data processing system shall be capable of resolving time to ±15 s.
4.3.6 Fans
4.3.6.1 It shall be possible to reduce the hydrocarbon concentration in the enclosure to the ambient
hydrocarbon level by using one or more fans or blowers with the SHED door(s) open.
3
4.3.6.2 The enclosure shall have one or more fans or blowers of likely capacity 0,1 to 0,5 m /s
with which to thoroughly mix the atmosphere in the enclosure. It shall be possible to attain an even
temperature and hydrocarbon concentration in the enclosure during measurements. The motorcycle in
the enclosure shall not be subjected to a direct stream of air from the fans or blowers.
4.3.7 Gases
4.3.7.1 The following pure gases shall be available for calibration and operation:
a) purified synthetic air (purity: <1 ppm C equivalent, ≤1 ppm CO, ≤400 ppm CO , ≤0,1 ppm NO);
1 2
oxygen content between 18 % and 21 % by volume;
b) hydrocarbon analyser fuel gas (40 % ± 2 % hydrogen, and balance helium with less than 1 ppm C
1
equivalent hydrocarbon, less than 400 ppm CO );
2
c) propane (C H ): 99,5 % minimum purity.
3 8
4.3.7.2 Calibration and span gases shall be available containing mixtures of propane (C H ) and
3 8
purified synthetic air. The true concentrations of a calibration gas shall be within ±2 % of the stated
figures. The accuracy of the diluted gases obtained when using a gas divider shall be to within ±2 % of
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ISO 21755-1:2019(E)
the true value. The concentrations specified in 4.3.7.1 may also be obtained by the use of a gas divider
using synthetic air as the diluting gas.
4.3.8 Additional equipment
The barometric pressure in the test area shall be measurable within ±0,1 kPa.
4.4 Test procedure
4.4.1 Test preparation
The motorcycle is mechanically prepared before the test as follows:
a) the exhaust system of the motorcycle shall not exhibit any leaks;
b) the motorcycle may be steam cleaned before the test;
c) the fuel tank of the motorcycle shall be equipped with temperature sensors so that the temperature
of the fuel and fuel vapour in the fuel tank can be measured when the fuel tank is filled to 50 % ± 2 %
of its rated capacity;
d) additional fittings, adaptors or devices may optionally be fitted to allow a complete draining of the
fuel tank. Alternatively, the fuel tank may be evacuated by means of a pump or siphon that prevents
fuel spillage; and
e) the evaporative emission control devices shall be run-in in accordance with running-in test
procedures described in Annex B.
4.4.2 Conditioning phase
4.4.2.1 The vehicle shall be taken into the test area where the ambient temperature is between 293,2 K
and 303,2 K.
4.4.2.2 The motorcycle is placed on a chassis dynamometer and driven through the selected test cycle
specified in ISO 6460-2, in both conditioning phase and test phase.
4.4.2.3 The motorcycle shall be parked in the test area for periods stated in Table 1.
Table 1 — Minimum and maximum soak periods SHED test
Engine capacity Minimum (hours) Maximum (hours)
3
<170 cm 6 36
3
170 cm ≤ engine capacity 8 36
3
<280 cm
3
≥280 cm 12 36
4.4.3 Test phases
4.4.3.1 Tank diurnal breathing evaporative emission test
4.4.3.1.1 The measuring enclosure shall be vented/purged for several minutes immediately before the
test until a stable background is obtainable. The enclosure mixing fan(s) shall be switched on at this
time also.
4.4.3.1.2 The hydrocarbon analyser shall be set to zero and spanned immediately before the test.
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ISO 21755-1:2019(E)
4.4.3.1.3 The fuel tank(s) shall be emptied as described in 4.4.1 and refilled with test fuel at a
temperature of between 283,2 K and 287,2 K to 50 % ± 2 % of its normal volumetric capacity.
4.4.3.1.4 The test motorcycle shall be brought into the test enclosure with the engine switched off and
parked in an upright position. The fuel tank sensors and heating device shall be connected, if necessary.
Immediately begin recording the fuel temperature and the air temperature in the enclosure. If a venting/
purging fan is still operating, it shall be switched off at this time.
4.4.3.1.5 The fuel and vapour may be artificially heated to the starting temperatures of 288,7 K and
294,2 K ± 1 K respectively.
4.4.3.1.6 As soon as the fuel temperature reaches 287,2 K:
a) Install the fuel filler cap(s);
b) Turn off the purge blowers, if not already off at that time; and
c) Close and seal enclosure doors.
4.4.3.1.7 As soon as the fuel reaches a temperature of 288,7 K ± 1 K the test procedure shall continue
as follows:
a) the hydrocarbon concentration, barometric pressure and the temperature shall be measured to
give the initial readings C , P and T for the tank heat build test;
HCi i i
b) a linear heat build of 13,3 K or 20 K ± 0,5 K over a period of 60 min ± 2 min shall begin.
The temperature of the fuel and fuel vapour during the heating shall conform to the result of
Formulae (1), (2) and (3), (4) within ±1,7 K, or the closest possible function as described in 4.3.4.3:
for exposed type fuel tanks:
Tt=+0,,3333 288 5 (1)
F
Tt=+0,,3333 294 0 (2)
V
for non-exposed type fuel tanks:
Tt=+0,,2222 288 5 (3)
F
Tt=+0,,2222 294 0 (4)
V
where
T is required temperature of fuel, K;
F
T is required temperature of vapour, K;
V
t is time from start of the tank heat build in minutes.
An initial vapour temperature up to 5 K above 294 K is permissible. In this circumstance vapour shall
not be heated at the start of the diurnal test. When the fuel temperature has been raised to 5,5 K below
the vapour temperature by following the T function, the remainder of the vapour heating profile shall
f
be followed.
4.4.3.1.8 The hydrocarbon analyser is set to zero and spanned immediately before the end of the test.
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ISO 21755-1:2019(E)
4.4.3.1.9 If the heating requirements in 4.4.3.1.7 have been met over the 60 min ± 2 min period of
the test, the final hydrocarbon concentration in the enclosure is measured (C ). The time of start and
HCf
time of end or elapsed time of this measurement is recorded, together with the final temperature and
barometric pressure T and p .
f f
4.4.3.1.10 The heat source is turned off and the enclosure door unsealed and opened. The heating device
and temperature sensor are disconnected from the enclosure apparatus. The motorcycle is now removed
from the enclosure with the engine switched off.
4.4.3.1.11 To prevent abnormal loading of the canister, fuel tank caps may be removed from the
motorcycle during the period between the end of the diurnal test phase and the start of the test cycle.
The test cycle shall begin within 60 min of the completion of the tank diurnal breathing loss test.
4.4.3.2 Test cycle
Following the tank diurnal breathing losses test, the motorcycle is pushed or otherwise manoeuvred
onto the chassis dynamometer with the engine switched off. It is then driven through the test cycle
specified in 4.4.2.2.
4.4.3.3 Hot soak loss test
The determination for evaporative emissions is concluded with the measurement of hydrocarbon
emissions over a 60-minute hot soak period. The hot soak loss test shall begin within 7 min of the
completion of the test cycle specified in 4.4.3.2 and within two minutes of engine shutdown.
4.4.3.3.1 Before the completion of the test run the measuring enclosure shall be purged for several
minutes until a stable hydrocarbon background is obtained. The enclosure mixing fan(s)
...
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