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|
|Number of Pages:||24|
|Vehicle Types:||Bus, Car, Light Truck|
|Subject Categories:||Emissions and Fuel Consumption|
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fuel, test, vehicle, tank, evaporative, emissions, system, annex, canister, emission, procedure, paragraph, temperature, vehicles, gtr, regulation, wltp, diurnal, reference, requirements, pressure, vapour, global, soak, technical, hot, means, type, ageing, conditions, manufacturer, cycles, capacity, carbon, air, regional, butane, procedures, measurement, evap, authority, control, responsible, testing, petrol, enclosure, jis, working, contracting, measured
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August 25, 2017
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
GLOBAL TECHNICAL REGULATION NO. 19
GLOBAL TECHNICAL REGULATION ON THE EVAPORATIVE EMISSION TEST
PROCEDURE FOR THE WORLDWIDE HARMONIZED LIGHT VEHICLE TEST PROCEDURE
(ESTABLISHED IN THE GLOBAL REGISTRY ON JUNE 21, 2017)
GLOBAL TECHNICAL REGULATION NO. 19
I. STATEMENT OF TECHNICAL RATIONALE AND JUSTIFICATION
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 ranges 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 deriving 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
6. VOCs may also be emitted by specific components of the vehicle like tyres, interior trim or
by other fluids (e.g. windshield washer fluid). These emissions are usually quite low and
do not depend on how the vehicle is used or on the quality of the fuel. Evaporative
emissions in general do not represent a significant problem for diesel vehicles due to the
very low vapour pressure of the diesel fuel.
12. 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.
13. 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
14. 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.
15. 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.
B. PROCEDURAL BACKGROUND AND FUTURE DEVELOPMENT OF THE WLTP EVAP
16. In its November 2007 session, the World Forum for Harmonization of Vehicle Regulations
(WP.29) decided to set up an Informal Working Group (IWG) under the Working Party on
Pollution and Energy (GRPE) to prepare a road map for the development of WLTP. After
various meetings and intense discussions, WLTP presented in June 2009 a first road map
consisting of three phases, which was subsequently revised a number of times and
contains the following main tasks:
Phase 1 (2009–2014): Development of the worldwide harmonized light duty driving
cycle and associated test procedure for the common measurement of criteria
compounds, CO , fuel and energy consumption;
Phase 2 (2014–2018): Low temperature/high altitude test procedure, durability,
in-service conformity, technical requirements for On-Board Diagnostics (OBD),
Mobile Air-Conditioning (MAC) system energy efficiency, off-cycle/real driving
emissions, and evaporative emission;
Phase 3 (2018-…): Emission limit values and OBD threshold limits, definition of
reference fuels, comparison with regional requirements.
24. The test procedure includes also specific provisions to take into account the potential
deterioration of the evaporative emission control system efficiency especially in the
presence of ethanol in the fuel. The evaporative emission test is carried out with a carbon
canister aged both mechanically and chemically according to a specific procedure. In
addition, a permeation factor is used to take into account the potential increase over time
of the full permeation rate through the tank walls.
25. As far as the fuel is concerned, its vapour pressure and composition (especially ethanol
content) have a large effect on evaporative emissions and need therefore to be clearly
specified. However, due to regional differences in the market specifications of fuels and in
the measurement methods of their relevant properties, 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 Annex 2 of this UN GTR.
D. TECHNICAL FEASIBILITY, ANTICIPATED COSTS AND BENEFITS
26. In designing and validating the WLTP EVAP procedure, strong emphasis has been put on
its practicability, which is ensured by a number of measures explained above.
27. In general, the WLTP EVAP test procedure has been defined taking into account the
technology available for evaporative emission control as well as the existing test facilities.
28. The best available technology performance significantly exceeds the stricter requirements
on evaporative emissions which will be introduced in some regions as a result of the
adoption of the WLTP EVAP procedure. In general, compared to the technology needed to
comply with the requirements based on the 24h diurnal test still in force in many regions,
the additional cost per vehicle is considered quite limited and eventually compensated by
the emission reduction and the fuel savings.
29. Performing a test according to the WLTP EVAP test procedure and complying with the
emission limits should not represent a major issue in most cases. Since in many regions
the current evaporative test procedure is based on the 24h diurnal test, limited upgrades to
existing SHEDs might be required to run the 48h diurnal test. In other cases, additional
SHEDs might be necessary to take into account the longer time needed to complete an
evaporative emission test. Nevertheless, 48h diurnal tests are already being performed by
most of the car manufacturers since 48h and 72h diurnal test are already requested for
30. For a more accurate assessment, costs and benefits would have to be quantified on a
regional level since they largely depend on the local conditions (climate, fleet composition,
fuel quality, …).
31. As pointed out in the technical rationale and justification, the principle of a globally
harmonized light duty vehicle test procedure offers potential cost reductions for vehicle
manufacturers. The design of vehicles can be better unified on a global scale and
administrative procedures may be simplified. The monetary quantification of these benefits
depends largely on the extent and timing of implementations of the WLTP in regional
3.3.3. "Butane Working Capacity" (BWC) means the measure of the ability of an activated
carbon canister to adsorb and desorb butane from dry air or nitrogen under specified
3.3.4. "BWC50" means the butane working capacity after 50 cycles of fuel ageing cycles
3.3.5. "BWC300" means the butane working capacity after 300 cycles of fuel ageing cycles
3.3.6. "Permeability Factor" (PF) means the factor determined from hydrocarbon losses over a
period of time and used to determine the final evaporative emissions.
3.3.7. "Monolayer tank" means a fuel tank constructed with a single layer of material, excluding
metal tank, but including fluorinated/sulfonated materials;
3.3.8. "Multilayer tank" means a fuel tank constructed with at least two different layered
materials, one of which is a hydrocarbon barrier material;
3.3.9. "Sealed fuel tank system" means a fuel tank system where the fuel vapours are stored
under pressure over the 24h diurnal test;
3.3.10. "Evaporative emissions" means the hydrocarbon vapours lost from the fuel system of a
motor vehicle other than those from exhaust emissions;
3.3.11. "Mono-fuel gas vehicle" means a mono-fuel vehicle that primarily runs on Liquefied
Petroleum Gas, Natural Gas/biomethane, or hydrogen but may also have a petrol system
for emergency purposes or starting only, where the petrol tank does not contain more than
15l of petrol.
Butane Working Capacity
Assigned Permeability Factor
Off-Vehicle Charging Hybrid Electric Vehicle
Worldwide Light-duty Test Cycle
5.4.4. Manufacturers using programmable computer code systems shall deter unauthorised
reprogramming. Manufacturers shall include enhanced tamper protection strategies and
write-protect features requiring electronic access to an off-site computer maintained by the
manufacturer. Methods giving an adequate level of tamper protection will be approved by
the responsible authority.
5.5. Evaporative Emission Family
5.5.1. Only vehicles that are identical for the following parameters (a) to (d) and are similar or,
where applicable, within the stated tolerance for the following parameters (e) and (f) may
be part of the same evaporative emission family:
(a) Fuel tank system material and construction;
(b) Vapour hose material, fuel line material and connection technique;
(c) Sealed tank or non-sealed tank system;
(d) Fuel tank relief valve setting (air ingestion and relief);
(e) Canister Butane Working Capacity (BWC300) within a 10% range (for canisters with
the same type of charcoal, the volume of charcoal shall be within 10% of that for
which the BWC300 was determined);
Purge control system (for example, type of valve, purge control strategy).
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 canister butane working
capacity within the family. If the ratio is identical, the lowest purge volume over the single
purge cycle described in Paragraph 5.3.6. of Annex 1 shall be considered for the worst
case selection. The vehicle selection shall be agreed in advance by the responsible
5.5.3. The use of any innovative system calibration, configuration, or hardware related to the
evaporative control system places the vehicle model in a different family.
6. PERFORMANCE REQUIREMENTS
6.1. Limit Values
The following limit values shall apply:
(a) For Contracting Parties which adopt the calculation defined in Paragraph 220.127.116.11. of
Annex 1, the limit value shall be 2.0g/test;
(b) For Contracting Parties which adopt the alternative calculation defined in
Paragraph 18.104.22.168. of Annex 1, the limit value shall be determined by the Contracting
Testing shall be performed according to the Type 4 test as described in Annex 1 using the
appropriate fuel as described in Annex 2.
For Non-sealed Fuel Tank System
For sealed fuel tank system [Reserved]
5.1.1. Temperature Conditioning Test
Canister Bench Ageing Procedure
The canister shall be cycled between temperatures from -15°C to 60°C in a dedicated
temperature enclosure with 30min of stabilisation at -15°C and 60°C. Each cycle shall last
210min (see Figure A1/3).
The temperature gradient shall be as close as possible to 1°C/min. No forced air flow should
pass through the canister.
The cycle shall be repeated 50 times consecutively. In total, this procedure lasts 175h.
Temperature Conditioning Cycle
22.214.171.124.4. After 50 and 300 fuel ageing cycles, BWC shall be measured. This consists of loading the
canister according to Paragraph 126.96.36.199. of Annex 7 to Regulation No. 83-07 until
breakthrough. The BWC shall be recorded.
The canister shall be subsequently purged according the Paragraph 188.8.131.52.2. of this annex.
The operation of butane loading shall be repeated 5 times. The BWC shall be recorded after
each butane loading step. The BWC50 and BWC300 shall be calculated as the average of
the 5 BWCs and recorded.
In total, the canister shall be aged with 300 fuel ageing cycles + 10 butane cycles and shall
be considered to be stabilised.
184.108.40.206. If an aged canister is provided by a supplier, the manufacturer shall inform the responsible
authority in advance of the ageing process to enable witnessing any part of the ageing in the
220.127.116.11. The manufacturer shall provide the responsible authority a test report including at least the
Type of activated carbon;
5.2.2. At the end of the third week, the tank shall be drained and refilled with fresh reference fuel
at a temperature of 18°C ± 2°C to 40 ± 2% of the 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 in
Paragraph 5.3.9. 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 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 fresh
reference fuel at a temperature of 18°C ± 2°C at 40 ± 2% of the 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 5.3.9. 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 as HC .
The PF is the difference between 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 a test report containing at least the
A full description of the fuel storage system tested, including information on the type
of tank tested, whether the tank is monolayer or multilayer, and which types of
materials are used for the tank and other parts of the fuel storage 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 );
The resulting permeability factor (PF).
5.2.8. As an exception to Paragraphs 5.2.1. to 5.2.7. inclusive of this annex, the manufacturer
using multilayer tanks or metal tanks may choose to use the following Assigned
Permeability Factor (APF) instead of the complete measurement procedure mentioned
APF multilayer/metal tank = 120mg /24h
5.3.6. Dynamometer Test
The vehicle shall be driven over the cycles as described in Paragraph 5.3.3. of this annex.
The engine shall be subsequently shut off. Exhaust emissions may be sampled during this
operation but the results shall not be used for the purpose of exhaust emission type
5.3.7. Hot Soak Evaporative Emissions Test
5.3.8. Third Soak
After the dynamometer test, the hot soak evaporative emissions test shall be performed in
accordance to Paragraph 5.5. of Annex 7 to Regulation No. 83- 07. The hot soak losses
result shall be calculated according to Paragraph 6. of Annex 7 to Regulation No. 83-07 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 6h of this period the vehicle shall be soaked at 20°C ± 2°C.
5.3.9. Diurnal Testing
18.104.22.168. The test vehicle shall be exposed to two cycles of ambient temperature according to the
profile specified for the diurnal emission test in Appendix 2 to Annex 7 to Regulation
No. 83-07 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 at least every minute.
Temperature cycling begins when time T = 0, as specified in Paragraph 22.214.171.124. of this
126.96.36.199. 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.
188.8.131.52. The test vehicle, with the engine 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.
184.108.40.206. The hydrocarbon analyser shall be zeroed and spanned immediately before the test.
220.127.116.11. The enclosure doors shall be closed and gas-tight sealed.
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.
18.104.22.168. The hydrocarbon analyser shall be zeroed and spanned immediately before the end of each
emission sampling period.
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.
Research octane number, RON
Density at 15°C
EN ISO 5164
EN ISO 12185
– evaporated at 70°C % v/v 34.0 46.0 EN ISO 3405
– evaporated at 100°C % v/v 54.0 62.0 EN ISO 3405
– evaporated at 150°C % v/v 86.0 94.0 EN ISO 3405
– olefins % v/v 6.0 13.0 EN 22854
– aromatics % v/v 25.0 32.0 EN 22854
EN ISO 20846
EN ISO 20884