FprCEN/TR 18238

SLOVENSKI STANDARD
01-oktober-2025
Goriva za motorna vozila - Bencin E20 - Ozadje zahtevanih parametrov, njihovih
omejitev in utemeljitve
Automotive fuels - E20 petrol - Background on the parameters required, their respective
limits and justification
Kraftstoffe - E20 Ottokraftstoffe - Hintergrund zu den erforderlichen Parametern, ihren
jeweiligen Grenzwerten und ihrer Bestimmung
Carburants automobiles - Essence E20 - Historique des paramètres requis, leurs limites
respectives et leur justification
Ta slovenski standard je istoveten z: FprCEN/TR 18238
ICS:
75.160.20 Tekoča goriva Liquid fuels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

FINAL DRAFT
TECHNICAL REPORT
RAPPORT TECHNIQUE
TECHNISCHER REPORT
August 2025
ICS 75.160.20
English Version
Automotive fuels - E20 petrol - Background on the
parameters required, their respective limits and
justification
Kraftstoffe - E20 Ottokraftstoffe - Hintergrund zu den
erforderlichen Parametern, ihren jeweiligen
Grenzwerten und ihrer Bestimmung

This draft Technical Report is submitted to CEN members for Vote. It has been drawn up by the Technical Committee CEN/TC 19.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a Technical Report. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a Technical Report.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. FprCEN/TR 18238:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 5
1 Scope . 7
2 Terms and definitions . 7
3 Considerations for generally applicable requirements – Table 1 of
FprCEN/TS 18227:2025 . 7
3.1 Introduction . 7
3.2 Research octane number (RON) and motor octane number (MON) . 9
3.2.1 Octane and auto-ignition . 9
3.2.2 Impact of RON . 10
3.2.3 Impact of MON and fuel sensitivity . 12
3.2.4 Determining minimum octane limits in the E20 CEN/TS 18227 . 13
3.3 Lead content . 14
3.4 Density . 14
3.5 Sulfur content . 14
3.6 Manganese content. 14
3.7 Oxidation stability . 14
3.8 Existent gum content . 14
3.9 Corrosion protection . 14
3.9.1 Corrosion by water . 14
3.9.2 Corrosion by sulfur. 15
3.10 Water content . 15
3.11 Appearance . 16
3.12 Hydrocarbon type content and final boiling point (FBP) . 16
3.13 Benzene content . 17
3.14 Oxygen content . 17
3.15 Oxygenates . 18
4 Considerations for climate dependent requirements – Table 2 of the
FprCEN/TS 18227:2025 . 18
4.1 Volatility requirements table . 18
4.2 Overview of volatility limit proposals . 19
4.3 E70 . 19
4.4 E100 . 20
4.5 E150 . 22
4.6 Final Boiling Point (FBP) . 22
4.7 Distillation residue . 23
4.8 Vapour Lock Index (VLI) . 23
5 Considerations about vapour pressure requirements . 23
5.1 Vapour pressure limits . 23
5.2 Vapour pressure waiver – volatility Class A . 23
6 Test method validity . 25
Annex A (informative) Overview discussion oxygenates in CEN/TC 19 WG21 (Specification for
unleaded petrol) . 26
A.1 Elastomer compatibility . 26
A.2 Impact of oxygenates on octane and other performance metrics . 28
A.2.1 General . 28
A.2.2 Southwest Research Institute (SwRI) Studies . 30
A.2.3 NREL Study . 38
A.3 Oxygenate effects on WTW GHG emissions . 48
A.4 Studies of oxygenate effects on pollutant emissions . 50
A.5 Oxygenate limits . 52
A.5.1 Ethanol . 52
A.5.2 C5+ ethers . 55
A.5.3 Methanol . 57
A.5.4 Other oxygenates . 57
Annex B (informative) Test method validity E20 petrol . 58
Bibliography . 62

European foreword
This document (FprCEN/TR 18238:2025) has been prepared by Technical Committee CEN/TC 19
“Gaseous and liquid fuels, lubricants and related products of petroleum, synthetic and biological origin”,
the secretariat of which is held by NEN.
This document is currently submitted to the Vote on TR.

Introduction
Commonly available petrol blends include E5 (corresponding to blends oxygenated with C5+ fuel ethers
(e.g. MTBE, ETBE, TAME) up to 22 % (V/V) and/or up to 5 % (V/V) ethanol content) and E10
(corresponding to blends oxygenated with C5+ fuel ethers (e.g. MTBE, ETBE, TAME) up to 22 % (V/V)
and/or up to 10 % (V/V) ethanol content). Both fuel specifications are defined in the European petrol
standard EN 228 [1].
The Renewable Energy Directive (RED) and subsequent amendments encourage the use of renewable
fuels as blending components in petrol. At the CEN/TC 19 meeting in May 2011, a priority was placed on
“E10+” petrol in order to be prepared for future market and legislative decisions. It was agreed that a
detailed assessment of biofuels and blends in Europe over the coming decade was needed that should be
prepared through a multi-stakeholder approach. To develop this longer-term vision, CEN/TC 19 worked
together as Industry and Stakeholder partners to complete this assessment and outline the possible
constraints and advantages of a future E10+ petrol. This led to the publication of CEN/TR 16514 [2].
In April 2023, European regulation 2023/851 was adopted that dictates that all new cars and vans
registered in Europe after 2035 should not produce any tailpipe CO emissions, which effectively means
a ban on new light-duty vehicles powered by internal combustion engines (ICEs) using fuels containing
carbon. However, light-duty vehicles equipped with ICEs will continue to operate for several decades, so
renewable fuels are needed in increasing amounts to replace fossil fuels and help meet the increasing
targets for lower carbon and greenhouse gas emissions from the transport sector.
In 2022, a Task Force (TF) under CEN/TC 19 was formed with the intent of developing consensus on
technical requirements for an E10+ fuel specification, with the following terms of reference:
The scope of work of the TF is to ‘study the DIN and CUNA work to develop consensus on technical
requirements for an E10+ fuel specification what could be formed into a CEN/TS (Technical Specification)
and supported with sufficient technical substantiation to be written into a CEN/TR (Technical Report)’. In
layman’s words: the group of experts shall take what has been done already and draft a fuel quality
specification for petrol blended with more than 3,7 % (m/m) of oxygen-containing products. That shall be
presented to CEN/TC 19 WG21 for discussion, agreement and continual balloting. In parallel, all
deliberations and discussions around each property, limit as well as test method applicability, should be
recorded to become an official technical background report by CEN.
Motivated by the decarbonisation of the transport sector, several organisations executed studies with
alternative fuels that formed the basis of this Technical Specification. In 2017, ENI and FCA (Fiat) started
a study on an alternative alcohol-based fuel (15 % methanol and 5 % ethanol – A20) to validate a fuel
with a maximum oxygen content of 10 % (m/m). The fuel was tested in five cars. Eventually, CUNA (Italian
Technical Commission for Unification in the Automotive Industry) published a specification for this A20
fuel [3]. In 2021 and 2022, DIN executed a study with the intentio
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