Global Technical Regulation No. 19

Name:Global Technical Regulation No. 19
Description:Evaporative Emission Test Procedure for the Worldwide Harmonized Light Vehicle Test Procedure (WLTP EVAP).
Official Title:Global Technical Regulation on the Evaporative Emission Test Procedure for the Worldwide Harmonized Light Vehicle Test Procedure (WLTP EVAP).
Country:ECE - United Nations
Date of Issue:2017-08-25
Amendment Level:Amendment 2 of September 24, 2019
Number of Pages:32
Vehicle Types:Bus, Car, Light Truck
Subject Categories:Emissions and Fuel Consumption
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Keywords:

fuel, vehicle, tank, test, annex, evaporative, canister, carbon, system, procedure, paragraph, emissions, temperature, emission, pressure, vehicles, gtr, diurnal, sealed, requirements, loss, depressurisation, regulation, reference, puff, volume, wltp, ambient, soak, vapour, means, loading, technical, enclosure, measured, measurement, hot, global, performed, manufacturer, conditions, procedures, systems, relief, case, paragraphs, control, refuelling, air, hydrocarbon

Text Extract:

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ECE/TRANS/180/Add.19/Amend.2
September 24, 2019
GLOBAL REGISTRY
Created on November 18, 2004, Pursuant to Article 6 of the
AGREEMENT CONCERNING THE ESTABLISHING OF GLOBAL TECHNICAL
REGULATIONS FOR WHEELED VEHICLES, EQUIPMENT AND PARTS WHICH
CAN BE FITTED AND/OR BE USED ON WHEELED VEHICLES
(ECE/TRANS/132 and Corr.1)
DONE AT GENEVA ON JUNE 25, 1998
Addendum 19:
UN GLOBAL TECHNICAL REGULATION No. 19
UN GLOBAL TECHNICAL REGULATION ON THE EVAPORATIVE EMISSION TEST
PROCEDURE FOR THE WORLDWIDE HARMONIZED LIGHT VEHICLE TEST PROCEDURE
(WLTP EVAP)
(ESTABLISHED IN THE GLOBAL REGISTRY ON JUNE 21, 2017)
Incorporating:
Amendment 1
dated September 20, 2018
Amendment 2
dated September 24, 2019

UN GLOBAL TECHNICAL REGULATION No. 19
UN GLOBAL TECHNICAL REGULATION ON THE EVAPORATIVE EMISSION TEST
PROCEDURE FOR THE WORLDWIDE HARMONIZED LIGHT VEHICLE TEST
PROCEDURE (WLTP EVAP)
I. STATEMENT OF TECHNICAL RATIONALE AND JUSTIFICATION
A. INTRODUCTION
1. The compliance with emission standards is a central issue of vehicle certification worldwide.
Emissions comprise criteria pollutants having a direct (mainly local) negative impact on
health and environment, as well as pollutants having a negative environmental impact on a
global scale. Regulatory emission standards typically are complex documents, describing
measurement procedures under a variety of well-defined conditions, setting limit values for
emissions, but also defining other elements such as the durability and on-board monitoring
of emission control devices.
2. Most manufacturers produce vehicles for a global clientele or at least for several regions.
Albeit vehicles are not identical worldwide since vehicle types and models tend to cater to
local tastes and living conditions, the compliance with different emission standards in each
region creates high burdens from an administrative and vehicle design point of view. Vehicle
manufacturers, therefore, have a strong interest in harmonizing vehicle emission test
procedures and performance requirements as much as possible on a global scale.
Regulators also have an interest in global harmonization since it offers more efficient
development and adaptation to technical progress, potential collaboration at market
surveillance and facilitates the exchange of information between authorities.
3. As a consequence stakeholders launched the work on the Worldwide harmonized Light
vehicle Test Procedure (WLTP) which aims at harmonizing emission-related test procedures
for light duty vehicles to the extent this is possible. One of the aspects covered within the
mandate for WLTP is the evaporative emission test procedure.
4. Evaporative emissions from vehicles is a complex phenomenon which depends on multiple
factors, that range from climate conditions to fuel properties, from driving and parking
patterns to the technology used to control these emissions.
5. Evaporative emissions from a vehicle can be defined, in a very generic way, as Volatile
Organic Compounds (VOCs) emitted by the vehicle itself in different operating conditions
but not directly derived from the combustion process. In petrol vehicles the most important
potential source of evaporative emissions is the loss of fuel through the evaporation and
permeation mechanisms from the fuel storing system. Fuel-related evaporative emissions
may occur during any vehicle operation including parking events, normal driving and vehicle
refuelling.
6. VOCs may also be emitted by specific components of the vehicle such as tyres, interior trim,
plastics or by other fluids (e.g. windshield washer fluid). These non-fuel related emissions
are usually quite low, not dependent on how the vehicle is used or on the quality of the fuel,
and tend to decrease over time. Evaporative emissions in general do not represent a
significant problem for diesel vehicles due to the very low vapour pressure of diesel fuel.

13. Another important source of evaporative emissions is the refuelling operation. When liquid
fuel is delivered into the tank the air/petrol vapour mixture present in the tank is displaced
and may be released into the atmosphere. Refuelling emissions are partially controlled
through the maximum allowed fuel vapour pressure by reducing its value during the hot
season. In addition, evaporative emissions during the refuelling operation can be controlled
in two different ways. One method is the so-called "Stage II" vapour recovery system. The
fuel nozzle is designed to draw the air/petrol vapour mixture displaced by the liquid fuel
entering the tank and route it to the underground petrol storage tank of the service station.
An alternative method is an "On-board Vapour Recovery System" (ORVR), which forces the
displaced vapours to be routed to the carbon canister instead of escaping from the refuelling
port.
14. An unintended source of HC emissions may occur from leaks in the system. Leaks may
occur in the vapour and/or the liquid system as a result of deterioration and/or faulty
operations. Examples of deterioration are corrosion of metallic components (e.g. fuel lines,
tanks), cracking of rubber hoses, hardening of seals, mechanical failures. On-board
diagnostic systems have been developed to check the integrity of the fuel system and are
required in some regions.
15. In the existing regional type approval procedures, the various situations that can lead to
significant evaporative emissions have been addressed either by developing different tests
or by adopting different measures. As an example, in certain regions refuelling emissions
are controlled by mandating the use of the Stage II vapour recovery system while in other
regions the ORVR approach has been chosen.
16. The need to represent real driving conditions as much as possible to make the performance
of vehicles at certification and in real life comparable puts therefore some limitations on the
level of harmonization to be achieved since, for instance, ambient temperatures vary widely
on a global scale while other potential sources of evaporative emissions are addressed in
different ways across the regions (e.g. refuelling emissions or potential leaks).
17. At this time, the WLTP EVAP test procedure focuses only on the evaporative emissions that
can occur during parking events. Running losses and refuelling emissions are out of the
scope of the current WLTP EVAP procedure. However the venting of vapour from a sealed
tank immediately prior to refuelling (also known as depressurisation puff loss emissions) is
within the scope of this procedure.
18. The purpose of a UN Global Technical Regulation (UN GTR) is its implementation into
regional legislation by as many Contracting Parties as possible. However, the scope of
regional legislations in terms of vehicle categories concerned depends on regional
conditions and cannot be predicted for the time being. On the other hand, according to the
rules of the 1998 Agreement, Contracting Parties implementing a UN GTR must include all
equipment falling into the formal UN GTR scope. Care must be taken so that an unduly
large formal scope of the UN GTR does not prevent its regional implementation. Therefore
the formal scope of this UN GTR is kept mainly for light duty vehicles. However, this
limitation of the formal UN GTR scope does not indicate that it could not be applied to a
larger group of vehicle categories by regional legislation. In fact, Contracting Parties are
encouraged to extend the scope of regional implementations of this UN GTR if this is
technically, economically and administratively appropriate.

C. BACKGROUND ON TEST PROCEDURES
23. For the development of the WLTP EVAP test procedure, the EVAP Task Force took into
account existing legislation as well as the recent review and revision of the European
evaporative emission test procedure.
24. The WLTP evaporative emission test procedure focuses only on evaporative emissions that
can occur during parking events from vehicles with petrol-fuelled engines (including bi-fuel
gas vehicles and hybrid vehicles combining an electric motor with a petrol-fuelled engine).
25. The WLTP evaporative emission test procedure is designed to measure evaporative
emissions from a parked vehicle using a sealed housing for evaporative emissions
determination (SHED). Two specific situations are considered:
(a)
(b)
Evaporative emissions occurring immediately after the end of a trip due to residual
fuel tank heating and the high temperatures of the engine and fuel system (hot soak
test);
Evaporative emissions occurring during a simulated extended parking event (48h)
while the vehicle is exposed to temperature fluctuations according to a specific profile.
This is intended to represent the temperature profile of a hot day (diurnal test). The
result of the diurnal test is represented by the total amount of VOCs released in the
SHED over a 48h period.
For sealed fuel tank systems, two other situations are addressed by the WLTP
evaporative emission test procedure:
(c)
(d)
Evaporative emissions that may occur if there is the need to depressurise the fuel
tank system before refuelling to ensure a safe operation. In order to reduce the
pressure inside the tank, the air/fuel vapours mixture released through the pressure
relief valve are stored in the canister(s). This operation should also avoid excessive
evaporative emissions through the filler neck when the fuel cap/fuel lid is opened.
This latter aspect requires that inside the tank there is very limited overpressure
compared to the ambient pressure when the fuel cap (or any alternative system used
to close the filler neck) is opened.
Evaporative emissions that may occur when the pressure inside the system exceed
the fuel tank relief pressure. The pressure relief valve opens to avoid the risk of a
rupture of the system. In these conditions the emissions could be uncontrolled in the
case of a fully saturated canister. This has been taken in to account when developing
the test procedure in order to reduce the frequency of this possibility or, alternatively,
to control these emissions by means of the carbon canister.
26. The performance of the evaporative emission control system strongly depends on the initial
condition of the carbon canister which is expected to adsorb the vapours generated in the
tank. In order to simulate realistic conditions, prior to starting the hot soak and diurnal tests,
the carbon canister is loaded to breakthrough and then purged by driving the vehicle over a
specific combination of WLTC sections (conditioning drive). The conditioning drive cycle
was extensively assessed and discussed also on the basis of real world activity data to take
into account that the most critical conditions are represented by short trips in urban areas.
For this reason, the conditioning drive for Class 2 and 3 vehicles includes one low phase,
two medium phases and one high phase. The extra-high phase was excluded. The
conditioning drive for Class 1 vehicles includes four low phases, two medium phases.

II.
TEXT OF THE GLOBAL TECHNICAL REGULATION
1. PURPOSE
This UN Global Technical Regulation (UN GTR) aims at providing a worldwide
harmonized method to determine the levels of evaporative emission from light-duty
vehicles in a repeatable and reproducible manner designed to be representative of real
world vehicle operation. The results will provide the basis for the regulation of these
vehicles within regional type approval and certification procedures.
2. SCOPE AND APPLICATION
This UN GTR applies to vehicles of Categories 1-2 and 2, both having a technically
permissible maximum laden mass not exceeding 3,500kg, with positive ignition engines
with the exclusion of mono-fuel gas vehicles, and to all vehicles of Category 1-1 with
positive ignition engines with the exclusion of mono-fuel gas vehicles.
3. DEFINITIONS
3.1. Test Equipment
3.1.1. "Accuracy" means the difference between a measured value and a reference value,
traceable to a national standard and describes the correctness of a result.
3.1.2. "Calibration" means the process of setting a measurement system's response so that
its output agrees with a range of reference signals.
3.2. Hybrid Electric Vehicles
3.2.1. "Charge-depleting operating condition" means an operating condition in which the
energy stored in the Rechargeable Electric Energy Storage System (REESS) may
fluctuate but decreases on average while the vehicle is driven until transition to
charge-sustaining operation.
3.2.2. "Charge-sustaining operating condition" means an operating condition in which the
energy stored in the REESS may fluctuate but, on average, is maintained at a neutral
charging balance level while the vehicle is driven.
3.2.3. "Not Off-vehicle Charging Hybrid Electric Vehicle" (NOVC-HEV) means a hybrid
electric vehicle that cannot be charged from an external source.
3.2.4. "Off-vehicle Charging Hybrid Electric Vehicle" (OVC-HEV) means a hybrid electric
vehicle that can be charged from an external source.
3.2.5. "Hybrid Electric Vehicle" (HEV) means a hybrid vehicle where one of the propulsion
energy converters is an electric machine.
3.2.6. "Hybrid Vehicle" (HV) means a vehicle equipped with a powertrain containing at least
two different categories of propulsion energy converters and at least two different
categories of propulsion energy storage systems.

4. ABBREVIATIONS
General abbreviations
BWC
PF
APF
OVC-HEV
NOVC-HEV
WLTC
REESS
Butane working capacity
Permeability factor
Assigned permeability factor
Off-vehicle charging hybrid electric vehicle
Not off-vehicle charging hybrid electric vehicle
Worldwide light-duty test cycle
Rechargeable electric energy storage system
5. GENERAL REQUIREMENTS
5.1. The vehicle and its components liable to affect the evaporative emissions shall be
designed, constructed and assembled so as to enable the vehicle in normal use and
under normal conditions of use such as humidity, rain, snow, heat, cold, sand, dirt,
vibrations, wear, etc. to comply with the provisions of this UN GTR during its useful life
determined by Contracting Parties.
5.1.1. This shall include the security of all hoses, joints and connections used within the
evaporative emission control systems.
5.1.2. For vehicles with a sealed fuel tank system, this shall also include having a system
which, just before refuelling, releases the tank pressure exclusively through a carbon
canister which has the sole function of storing fuel vapour. This ventilation route shall
also be the only one used when the tank pressure exceeds its safe working pressure.
5.2. The test vehicle shall be selected in accordance with Paragraph 5.5.2. of this UN GTR.
5.3. Vehicle Testing Condition
5.3.1. The types and amounts of lubricants and coolant for emissions testing shall be as
specified for normal vehicle operation by the manufacturer.
5.3.2. The type of fuel for testing shall be as specified in Annex 2 to this UN GTR.
5.3.3. All evaporative emissions controlling systems shall be in working order.
5.3.4. The use of any defeat device is prohibited.

5.5.2. The vehicle shall be considered to produce worst-case evaporative emissions and shall
be used for testing if it has the largest ratio of fuel tank capacity to BWC300 within the
family. The vehicle selection shall be agreed in advance with the responsible authority.
5.5.3. The use of any innovative system calibration, configuration, or hardware related to the
evaporative control system shall place the vehicle model in a different family.
5.6. The responsible authority shall not grant type approval if the information provided is
insufficient to demonstrate that the evaporative emissions are effectively limited during
the normal use of the vehicle.
6. PERFORMANCE REQUIREMENTS
6.1. Limit Values
The following limit values shall apply:
(a)
(b)
For Contracting Parties which adopt the calculation defined in Paragraph 7.2. of
Annex 1, the limit value shall be 2.0g/test;
For Contracting Parties which adopt the alternative calculation defined in
Paragraph 7.3. of Annex 1, the limit value shall be determined by the Contracting
Party.

4.3. Analytical Systems
The analytical systems shall meet the requirements of Paragraph 4.3. of Annex 7 and
Paragraphs 3. to 3.2. inclusive of Appendix 1 to Annex 7 to the 07 series of amendments to
UN Regulation No. 83. Continuous measuring of hydrocarbons is not mandatory unless the
fixed volume type enclosure is used.
4.4. Temperature Recording System
The temperature recording system shall meet the requirements of Paragraph 4.5. of
Annex 7 to the 07 series of amendments to UN Regulation No. 83.
4.5. Pressure Recording System
4.6. Fans
The pressure recording system shall meet the requirements of Paragraph 4.6. of Annex 7 to
the 07 series of amendments to UN Regulation No. 83.
The fans shall meet the requirements of Paragraph 4.7. of Annex 7 to the 07 series of
amendments to UN Regulation No. 83, except that the capacity of the blowers shall be
0.1 to 0.5m /s instead of 0.1 to 0.5m /min.
4.7. Calibration Gases
The gases shall meet the requirements of Paragraph 4.8. of Annex 7 to the 07 series of
amendments to UN Regulation No. 83.
4.8. Carbon Canister Weighing Scale for Depressurisation Puff Loss Overflow
Measurement
The carbon canister weighing scale shall have an accuracy of ±0.02g.
5. PROCEDURE FOR CARBON CANISTER BENCH AGEING AND PF DETERMINATION
5.1. Carbon Canister Bench Ageing
Before performing the hot soak and diurnal losses sequences, the carbon canister shall be
aged according to the procedure described in Figure A1/1.

5.1.2. Ageing through Exposure to Vibration
Following the temperature ageing procedure, the carbon canister shall be shaken vertically
with the carbon canister mounted as per its orientation in the vehicle with an overall Grms
(root mean square acceleration) >1.5m/s with a frequency of 30 ± 10Hz. The test shall last
12h.
5.1.3. Ageing through Exposure to Fuel Vapour and Determining BWC300
5.1.3.1. Ageing shall consist of repeatedly loading with fuel vapour and purging with laboratory air.
5.1.3.1.1. After temperature and vibration ageing, the carbon canister shall be further aged with a
mixture of market fuel as specified in Paragraph 5.1.3.1.1.1. of this Annex and nitrogen or
air with a 50 ± 15% fuel vapour volume. The fuel vapour fill rate shall be 60 ± 20g/h.
The carbon canister shall be loaded to 2g breakthrough. Alternatively, loading shall be
considered to be completed when the hydrocarbon concentration level at the vent outlet
reaches 3,000ppm.
5.1.3.1.1.1. The market fuel used for this test shall fulfil the same requirements as a reference fuel with
respect to:
(a)
(b)
(c)
(d)
(e)
(f)
Density at 15°C;
Vapour pressure;
Distillation (70°C, 100°C, 150°C);
Hydrocarbon analysis (olefins, aromatics, benzene only);
Oxygen content;
Ethanol content.
5.1.3.1.2. The carbon canister shall be purged between 5 and 60min after loading with
25 ± 5l per minute of emission laboratory air until 300 bed volume exchanges are reached.
5.1.3.1.3. The procedures set out in Paragraphs 5.1.3.1.1. and 5.1.3.1.2. of this Annex shall be
repeated 300 times after which the carbon canister shall be considered to be stabilised.
5.1.3.1.4. The procedure to measure the butane working capacity (BWC) with respect to the
evaporative emission family in Paragraph 5.5. of this UN GTR shall consist of the following.
(a)
(b)
(c)
(d)
The stabilised carbon canister shall be loaded to 2g breakthrough and subsequently
purged a minimum of 5 times. Loading shall be performed with a mixture composed
of 50% butane and 50% nitrogen by volume at a rate of 40g butane per hour.
Purging shall be performed according to Paragraph 5.1.3.1.2. of this Annex.
The BWC shall be recorded after each loading.
BWC300 shall be calculated as the average of the last 5 BWCs.
5.1.3.2. If the aged carbon canister is provided by a supplier, the vehicle manufacturer shall inform
the responsible authority in advance of the ageing process to enable the witnessing of any
part of that process.

5.2.1. The fuel tank system representative of a family shall be selected and mounted on a rig in a
similar orientation as in the vehicle. The tank shall be filled to 40 ± 2% of its nominal
capacity with reference fuel at a temperature of 18°C ± 2°C. The rig with the fuel tank
system shall be placed in a room with a controlled temperature of 40°C ± 2°C for 3 weeks.
5.2.2. At the end of the third week, the tank shall be drained and refilled with reference fuel at a
temperature of 18°C ± 2°C to 40 ± 2% of its nominal capacity.
Within 6 to 36h, the rig with the fuel tank system shall be placed in an enclosure. The last 6h
of this period shall be at an ambient temperature of 20°C ± 2°C. In the enclosure, a diurnal
procedure shall be performed over the first 24h period of the procedure described in
Paragraph 6.5.9. of this Annex. The fuel vapour in the tank shall be vented to the outside of
the enclosure to eliminate the possibility of the tank venting emissions being counted as
permeation. The HC emissions shall be measured and the value shall be recorded as HC .
5.2.3. The rig with the fuel tank system shall be placed again in a room with a controlled
temperature of 40°C ± 2°C for the remaining 17 weeks.
5.2.4. At the end of the seventeenth week, the tank shall be drained and refilled with reference fuel
at a temperature of 18°C ± 2°C to 40 ± 2% of its nominal tank capacity.
Within 6 to 36h, the rig with the fuel tank system shall be placed in an enclosure. The last 6h
of this period shall be at an ambient temperature of 20°C ± 2°C. In the enclosure, a diurnal
procedure shall be performed over a first period of 24h of the procedure described
according to Paragraph 6.5.9. of this Annex. The fuel tank system shall be vented to the
outside of the enclosure to eliminate the possibility of the tank venting emissions being
counted as permeation. The HC emissions shall be measured and the value shall be
recorded in this case as HC .
5.2.5.
The PF is the difference between HC
and HC
in g/24h calculated to 3 significant digits
using the following equation:
PF = HC − HC
5.2.6. If the PF is determined by a supplier, the vehicle manufacturer shall inform the responsible
authority in advance of the determination to allow witness check in the supplier’s facility.
5.2.7. The manufacturer shall provide the responsible authority with a test report containing at
least the following:
(a)
(b)
A full description of the fuel tank system tested, including information on the type of
tank tested, whether the tank is metal, monolayer non-metal or multilayer, and which
types of materials are used for the tank and other parts of the fuel tank system;
The weekly mean temperatures at which the ageing was performed;
(c) The HC measured at week 3 (HC );
(d) The HC measured at week 20 (HC );
(e)
The resulting permeability factor (PF).

Figure A1/4
Test Procedure Flow Charts

6.5.6. Dynamometer Test
The test vehicle shall be pushed onto a dynamometer and shall be driven over the cycles
described in Paragraph 6.5.3.(a) or Paragraph 6.5.3.(b) of this Annex. OVC-HEVs shall be
operated in charge-depleting operating condition. The engine shall be subsequently shut off.
Exhaust emissions may be sampled during this operation and the results may be used for
the purpose of exhaust emission and fuel consumption type approval if this operation meets
the requirement described in Annex 6 or Annex 8 of UN GTR No.15.
6.5.7. Hot Soak Evaporative Emissions Test
6.5.8. Soak
Within 7min after the dynamometer test and within 2min of the engine being switched off,
the hot soak evaporative emissions test shall be performed in accordance with
Paragraph 5.5. of Annex 7 to the 07 series of amendments to UN Regulation No. 83. The
hot soak losses shall be calculated according to Paragraph 7.1. of this Annex and recorded
as M .
After the hot soak evaporative emissions test, the test vehicle shall be soaked for not less
than 6h and not more than 36h between the end of the hot soak test and the start of the
diurnal emission test. For at least the last 6h of this period the vehicle shall be soaked at
20°C ± 2°C.
6.5.9. Diurnal Testing
6.5.9.1. The test vehicle shall be exposed to two cycles of ambient temperature in accordance with
the profile specified for the diurnal emission test in Appendix 2 to Annex 7 to the 07 series of
amendments to UN Regulation No. 83 with a maximum deviation of ±2°C at any time. The
average temperature deviation from the profile, calculated using the absolute value of each
measured deviation, shall not exceed ±1°C. Ambient temperature shall be measured and
recorded at least every minute. Temperature cycling shall begin at time T = 0, as
specified in Paragraph 6.5.9.6. of this Annex.
6.5.9.2. The enclosure shall be purged for several minutes immediately before the test until a stable
background is obtained. The chamber mixing fan(s) shall also be switched on at this time.
6.5.9.3. The test vehicle, with the powertrain shut off and the test vehicle windows and luggage
compartment(s) opened, shall be moved into the measuring chamber. The mixing fan(s)
shall be adjusted in such a way as to maintain a minimum air circulation speed of 8km/h
under the fuel tank of the test vehicle.
6.5.9.4. The hydrocarbon analyser shall be zeroed and spanned immediately before the test.
6.5.9.5. The enclosure doors shall be closed and sealed gas-tight.
6.5.9.6. Within 10min of closing and sealing the doors, the hydrocarbon concentration, temperature
and barometric pressure shall be measured to give initial readings of hydrocarbon
concentration in the enclosure (C ), barometric pressure (P ) and ambient chamber
temperature (T ) for the diurnal testing. T = 0 starts at this time.
6.5.9.7. The hydrocarbon analyser shall be zeroed and spanned immediately before the end of each
emission sampling period.

6.6.1.5.1. Determination of Maximum Purge Volume
The maximum purge amount Vol shall be determined by the following equation. In the
case of OVC-HEVs, the vehicle shall be operated in charge-sustaining operating condition.
This determination can also be done at a separate test or during the preconditioning drive.
Where:
Vol
is the cumulative purge volume rounded to the nearest 0.1l measured using a
suitable device (e.g. flowmeter connected to the vent of the carbon canister or
equivalent) over the cold start preconditioning drive described in the
Paragraph 6.5.3. of this Annex, l;
Vol is the manufacturer’s nominal fuel tank capacity, l;
FCP
is the fuel consumption over the single purge cycle described in
Paragraph 6.5.3. of this Annex which may be measured in either warm or cold
start condition, 1/100km. For OVC-HEVs and NOVC-HEVs, fuel consumption
shall be calculated according to Paragraph 4.2.1. of Annex 8 of UN GTR 15;
Dist
is the theoretical distance to the nearest 0.1km of a single purge cycle
described in Paragraph 6.5.3. of this Annex, km.
6.6.1.6. Preparation of Carbon Canister Depressurisation Puff Loss Loading
After completing carbon canister loading and purging, the test vehicle shall be moved into
an enclosure, either a SHED or an appropriate climatic chamber. It shall be demonstrated
that the system is leak-free and the pressurisation is performed in a normal way during the
test or by a separate test (e.g. by means of pressure sensor on the vehicle). The test vehicle
shall be subsequently exposed to the first 11h of the ambient temperature profile specified
for the diurnal emission test in Appendix 2 to Annex 7 to the 07 series of amendments to
UN Regulation No. 83 with a maximum deviation of ±2°C at any time. The average
temperature deviation from the profile, calculated using the absolute value of each
measured deviation, shall not exceed ±1°C. The ambient temperature shall be measured
and recorded at least every 10min.
6.6.1.7. Carbon Canister Puff Loss Loading
6.6.1.7.1. Fuel Tank Depressurisation before Refuelling
The manufacturer shall ensure that the refuelling operation cannot be initiated before the
sealed fuel tank system is fully depressurised to a pressure less than 2.5kPa above ambient
pressure in normal vehicle operation and use. At the request of the responsible authority,
the manufacturer shall provide detailed information or demonstrate proof of operation (e.g.
by means of pressure sensor on the vehicle). Any other technical solution may be allowed
provided that a safe refuelling operation is ensured and that no excessive emissions are
released to the atmosphere before the refuelling device is connected to the vehicle.
6.6.1.7.2. Within 15min after the ambient temperature has reached 35°C, the tank relief valve shall be
opened to load the carbon canister. This loading procedure may be performed either inside
or outside an enclosure. The carbon canister loaded according to this Paragraph shall be
disconnected and shall be kept in the soak area.

6.6.1.12. Fuel Tank Depressurisation
The tank pressure shall be subsequently released so as not to abnormally raise the inside
pressure of the fuel tank. This may be done by opening the fuel cap of the vehicle.
Regardless of the method of depressurisation, the vehicle shall be returned to its original
condition within 1min. After this action, the vehicle carbon canister shall be connected again.
6.6.1.13. The procedures in Paragraphs 6.5.6. to 6.5.9.8. inclusive of this Annex shall be followed.
6.6.2. In the Case that the Fuel Tank Relief Pressure is Lower than 30kPa
The test shall be performed as described in Paragraphs 6.6.1.1. to 6.6.1.13. inclusive of this
Annex. However, in this case, the ambient temperature described in Paragraph 6.5.9.1. of
this Annex shall be replaced by the profile specified in Table A1/1 of this Annex for the
diurnal emission test.
Table A1/1
Ambient Temperature Profile of the Alternative Sequence for Sealed Fuel Tank System
Time (hours)
Temperature (°C)
0/24
20.0
1
20.4
2
20.8
3
21.7
4
23.9
5
26.1
6
28.5
7
31.4
8
33.8
9
35.6
10
37.1
11
38.0
12
37.7
13
36.4
14
34.2
15
31.9
16
29.9
17
28.2
18
26.2
19
24.7
20
23.5
21
22.3
22
21.0
23
20.2

7. CALCULATION OF EVAPORATIVE TEST RESULTS
7.1. The evaporative emission tests described in this Annex allow the hydrocarbon emissions
from the puff loss overflow, diurnal and hot soak tests to be calculated. Evaporative losses
from each of these tests shall be calculated using the initial and final hydrocarbon
concentrations, temperatures and pressures in the enclosure, together with the net
enclosure volume.
The following equation shall be used:
Where:
M is the mass of hydrocarbons, grams;
M is the mass of hydrocarbons exiting the enclosure in the case of fixed volume
enclosures for diurnal emission testing, grams;
M is the mass of hydrocarbon entering the enclosure in the case of fixed volume
enclosures for diurnal emission testing, grams;
C is the measured hydrocarbon concentration in the enclosure, ppm volume in C
equivalent;
V
is the net enclosure volume corrected for the volume of the vehicle with the
windows and the luggage compartment open, m . If the volume of the vehicle is
not known, a volume of 1.42m shall be subtracted;
T is the ambient chamber temperature, K;
P
H/C
H/C
H/C
k
i
f
is the barometric pressure, kPa;
is the hydrogen to carbon ratio
is taken to be 2.33 for puff loss overflow measurement in SHED and diurnal test
losses;
is taken to be 2.20 for hot soak losses;
is 1.2 × 10 × (12 + H/C), in (g × K/(m × kPa));
is the initial reading;
is the final reading;

ANNEX 2
REFERENCE FUELS
1. As there are regional differences in the market specifications of fuels, regionally different
reference fuels need to be recognised. Contracting Parties may select their reference fuels
either according to Annex 3 to UN GTR No. 15. or according to Paragraph 2. of this Annex.
2. SPECIFICATION OF REFERENCE FUEL FOR TESTING FOR MUTUAL RECOGNITION
The reference fuel listed in Table A2/1 is designed to be used as the reference fuel for
mutual recognition under the rules of the 1998 Agreement.
3. SPECIFICATION OF REFERENCE FUEL FOR REGIONAL TESTING
The reference fuel listed in Annex 3 to UN GTR No. 15. may be used for this purpose.

Evaporative Emission Test Procedure for the Worldwide Harmonized Light Vehicle Test Procedure (WLTP EVAP).