EN ISO 5165:2018

SLOVENSKI STANDARD
01-april-2018
1DGRPHãþD
SIST EN ISO 5165:1999
1DIWQLSURL]YRGL'RORþHYDQMHNDNRYRVWLYåLJDGLHVHOVNLKJRULY&HWDQVNRãWHYLOR
SRPRWRUQLPHWRGL,62
Petroleum products - Determination of the ignition quality of diesel fuels - Cetane engine
method (ISO 5165:2017)
Mineralölerzeugnisse - Bestimmung der Zündwilligkeit von Dieselkraftstoffen - Cetan-
Verfahren mit dem CFR-Motor (ISO 5165:2017)
Produits pétroliers -- Détermination de la qualité d_inflammabilité des carburants pour
moteurs diesel -- Méthode cétane (ISO 5165:2017)
Ta slovenski standard je istoveten z: EN ISO 5165:2018
ICS:
75.160.20 7HNRþDJRULYD Liquid fuels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 5165
EUROPEAN STANDARD
NORME EUROPÉENNE
January 2018
EUROPÄISCHE NORM
ICS 75.160.20 Supersedes EN ISO 5165:1998
English Version
Petroleum products - Determination of the ignition quality
of diesel fuels - Cetane engine method (ISO 5165:2017)
Produits pétroliers - Détermination de la qualité Mineralölerzeugnisse - Bestimmung der Zündwilligkeit
d'inflammabilité des carburants pour moteurs diesel - von Dieselkraftstoffen - Cetan-Verfahren mit dem CFR-
Méthode cétane (ISO 5165:2017) Motor (ISO 5165:2017)
This European Standard was approved by CEN on 27 November 2017.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATIO N

EUROPÄISCHES KOMITEE FÜR NORMUN G

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 5165:2018 E
worldwide for CEN national Members.

Contents Page
European Foreword . 3
European Foreword
This document (EN ISO 5165:2018) has been prepared by Technical Committee ISO/TC 28 " Petroleum
and related products, fuels and lubricants from natural or synthetic sources" in collaboration with
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 European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by July 2018, and conflicting national standards shall be
withdrawn at the latest by July 2018.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 5165:1998.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 5165:2018 has been approved by CEN as EN ISO 5165:2018 without any modification.

INTERNATIONAL ISO
STANDARD 5165
Fourth edition
2017-12
Petroleum products — Determination
of the ignition quality of diesel fuels —
Cetane engine method
Produits pétroliers — Détermination de la qualité d'inflammabilité
des carburants pour moteurs diesel — Méthode cétane
Reference number
ISO 5165:2017(E)
©
ISO 2017
ISO 5165:2017(E)
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2017 – All rights reserved

ISO 5165:2017(E)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 3
5 Reagents and reference materials . 3
6 Apparatus . 4
7 Sampling and sample preparation . 8
8 Basic engine and instrument settings and standard operating conditions .8
8.1 Installation of engine equipment and instrumentation . 8
8.2 Engine speed . 8
8.3 Valve timing . 9
8.4 Valve lift . 9
8.5 Fuel pump timing . 9
8.6 Fuel pump inlet pressure . 9
8.7 Direction of engine rotation . 9
8.8 Injection timing . 9
8.9 Injector nozzle opening pressure . 9
8.10 Injection flow rate . 9
8.11 Injector coolant passage temperature . 9
8.12 Valve clearances . 9
8.13 Oil pressure .10
8.14 Oil temperature .10
8.15 Cylinder jacket coolant temperature .10
8.16 Intake air temperature .10
8.17 Basic ignition delay .10
8.18 Cylinder jacket coolant level.10
8.19 Engine-crankcase lubricating oil level .10
8.20 Crankcase internal pressure .10
8.21 Exhaust back-pressure .10
8.22 Exhaust and crankcase breather system resonance .10
8.23 Piston over-travel .11
8.24 Belt tension .11
8.25 Injector opening or release pressure .11
8.26 Injector spray pattern .11
8.27 Indexing handwheel reading .11
8.27.1 General.11
8.27.2 Basic setting of variable compression plug .11
8.27.3 Setting handwheel micrometer drum and scale .11
8.27.4 Setting handwheel reading .12
8.28 Basic compression pressure .12
8.29 Fuel pump lubricating oil level.12
8.30 Fuel pump timing gear-box oil level .13
8.31 Setting instrumentation reference pickups .13
8.32 Setting injector pickup gap .13
9 Engine qualification .13
9.1 Engine conformity .13
9.2 Checking performance on check fuels .13
9.3 Check in the case of nonconformity .14
10 Procedure.14
10.1 General .14
ISO 5165:2017(E)
10.2 Sample introduction .14
10.3 Fuel flow rate .14
10.4 Fuel injection timing .14
10.5 Ignition delay .14
10.6 Equilibration .15
10.7 Handwheel reading .15
10.8 Reference fuel no. 1 .15
10.9 Reference fuel no. 2 .15
10.10 Number of blends of reference fuels .16
10.11 Repeat readings .16
11 Calculation .17
12 Expression of results .18
13 Precision .18
13.1 General .18
13.2 Repeatability, r . 18
13.3 Reproducibility, R . 18
13.4 Precision basis .19
14 Test report .19
Bibliography .20
iv © ISO 2017 – All rights reserved

ISO 5165:2017(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 on 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 the following
URL: www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 28, Petroleum products and related
products of synthetic or biological origin.
This fourth edition cancels and replaces the third edition (ISO 5165:1998), which has been technically
revised. It has been aligned with ASTM D613-15ae1.
The main changes compared to the previous edition are as follows:
— the Scope has been extended to paraffinic diesel from synthesis or hydrotreatment, in line with the
[1]
outcome of the interlaboratory study organized by CEN/TC 19 in 2013 ;
— the possibility to use, as an alternative, the new digital (XCP) cetane panel has been added;
— the possibility to rate a sample with primary reference fuels (hexadecane and heptamethylnonane)
has been added;
— a determinability limit has been introduced;
— a new procedure for measuring samples having cetane numbers expected to be greater than “T”
secondary reference fuel has been introduced;
— cross-references to annexes that have been deleted in ASTM D613-15ae1 have been removed.
INTERNATIONAL STANDARD ISO 5165:2017(E)
Petroleum products — Determination of the ignition
quality of diesel fuels — Cetane engine method
WARNING — The use of this document can involve hazardous materials, operations and
equipment. This document does not purport to address all of the safety problems associated
with its use. It is the responsibility of users of this document to take appropriate measures to
ensure the safety and health of personnel prior to the application of the document.
1 Scope
This document establishes the rating of diesel fuel oil in terms of an arbitrary scale of cetane numbers
(CNs) using a standard single cylinder, four-stroke cycle, variable compression ratio, indirect injected
diesel engine. The CN provides a measure of the ignition characteristics of diesel fuel oil in compression
ignition engines. The CN is determined at constant speed in a pre-combustion chamber-type
compression ignition test engine. However, the relationship of test engine performance to full scale,
variable speed and variable load engines is not completely understood.
This document is applicable for the entire scale range from 0 CN to 100 CN but typical testing is in the
range of 30 CN to 65 CN. An interlaboratory study executed by CEN in 2013 (10 samples in the range
[1]
52,4 CN to 73,8 CN) confirmed that paraffinic diesel from synthesis or hydrotreatment, containing up
to 7 % (V/V) fatty acid methyl ester (FAME) can be tested by this test method and that the precision is
comparable to conventional fuels.
This test can be used for unconventional fuels such as synthetics, vegetable oils, etc. However, the
relationship to the performance of such materials in full scale engines is not completely understood.
Samples with fluid properties that interfere with the gravity flow of fuel to the fuel pump or delivery
through the injector nozzle are not suitable for rating by this method.
NOTE This document specifies operating conditions in SI units but engine measurements are specified in
inch-pound units because these are the historical units used in the manufacture of the equipment, and thus some
references in this document include these units in parenthesis.
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 3170, Petroleum liquids — Manual sampling
ISO 3171, Petroleum liquids — Automatic pipeline sampling
ISO 3696, Water for analytical laboratory use — Specification and test methods
ISO 4787, Laboratory glassware — Volumetric instruments — Methods for testing of capacity and for use
ASTM D613-15ae1, Standard Test Method for Cetane Number of Diesel Fuel Oil
ASTM E832-81, Standard Specification for Laboratory Filter Papers
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO 5165:2017(E)
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 http://www.electropedia.org/
3.1
cetane number
CN
measure of the ignition performance of a diesel fuel oil obtained by comparing it to reference fuels in a
standardized engine test
Note 1 to entry: Ignition performance is understood to mean the ignition delay (3.3) of the fuel as determined
when the standard test engine is operated under controlled conditions of fuel flow rate, injection timing (3.4) and
compression ratio (3.2).
3.2
compression ratio
ratio of the volume of the combustion chamber including the pre-combustion chamber with the piston
at bottom-dead-centre (b.d.c.) to the comparable volume with the piston at top-dead-centre (t.d.c.)
3.3
ignition delay
period of time between the start of fuel injection and the start of combustion expressed in degrees of
crank angle rotation
3.4
injection timing
injection advance
time in the combustion cycle at which fuel injection into the combustion chamber is initiated expressed
in degrees of crank angle
3.5
handwheel reading
arbitrary numerical value, related to compression ratio (3.2), obtained from a micrometer scale that
indicates the position of the variable compression plug in the pre-combustion chamber of the engine
3.6
cetane meter
ignition delay meter
electronic instrument which displays injection timing (3.4) and ignition delay (3.3) derived from input
pulses of multiple transducers (pickups)
Note 1 to entry: Three generations of apparatus have been approved for use as cetane meters. These are (with
the year of introduction in parenthesis) the Mark II Ignition Delay Meter (1974), the Dual Digital Cetane Meter
(1990) and the XCP Cetane Panel (2014).
3.7
injector nozzle opening pressure
fuel pressure that overcomes the resistance of the spring which normally holds the injector nozzle
pintle closed, and thus forces the pintle to lift and release an injection spray from the nozzle
3.8
reference pickup
transducers or optical sensors mounted over the flywheel of the engine, triggered by a flywheel
pointer, used to establish a top-dead-centre (t.d.c.) reference and a time base for calibration of the
cetane meter (3.6)
3.9
injector pickup
transducer to detect motion of the injector pintle, thereby indicating the beginning of injection
2 © ISO 2017 – All rights reserved

ISO 5165:2017(E)
3.10
combustion pickup
pressure transducer exposed to cylinder pressure to indicate the start of combustion
3.11
primary reference fuel
PRF
hexadecane (n-cetane), heptamethylnonane (HMN) and volumetrically proportioned mixture of these
materials
Note 1 to entry: These PRFs now define the cetane number (CN) scale by the relationship given in the following
formula:
CN=+%,cetane 015 %HMN
()
Note 2 to entry: Alphamethylnaphthalene (1-methylnaphthalene), in its pure form, was originally defined as 0 and
n-cetane (hexadecane) as 100 for the CN scale. With blends of the two chemicals being used for the intervening
values, alphamethylnapthalene was subsequently replaced in 1962 by heptamethylnonane as the low reference
material, with an assigned value of 15, as it was more readily available and experience had shown that it had
better storage stability.
3.12
secondary reference fuel
SRF
volumetrically proportioned blend of two selected, numbered and paired hydrocarbon mixtures
designated “T fuel” (high CN) and “U fuel” (low CN) where each numbered paired set of “T fuel” and
“U fuel” is rated by the ASTM Diesel National Exchange Group (NEG) in various combinations by
comparison to primary reference fuel (3.11) blends
3.13
check fuel
diesel fuel oil having a cetane number (3.1) value determined by an interlaboratory comparison which
provides a guide for an individual laboratory to check the cetane rating performance of a specific
engine unit
4 Principle
The CN of a diesel fuel oil is determined by comparing its combustion characteristics in a test engine
with those for blends of reference fuels of known CN under standard operating conditions. This
is accomplished using the bracketing handwheel procedure, which varies the compression ratio
(handwheel reading) for the sample and each of two bracketing reference fuels to obtain a specific
ignition delay permitting the interpolation of CN in terms of handwheel reading.
5 Reagents and reference materials
5.1 Cylinder jacket coolant, water conforming to grade 3 of ISO 3696.
Water shall be used in the cylinder jacket for laboratory locations where the resultant boiling
temperature is 100 °C ± 2 °C (212 °F ± 3 °F). Water with commercial glycol-based antifreeze added in
a sufficient quantity to meet the boiling temperature requirement shall be used when the laboratory
altitude dictates. A commercial multi-functional water-treatment material should be used in the coolant
to minimize corrosion and mineral scale that can alter heat transfer and rating results.
[2]
5.2 Engine crankcase lubricating oil, an SAE 30 viscosity grade oil meeting current American
Petroleum Institute (API) service classification or compatible previous API service classification for
engines shall be used. It shall contain a detergent additive and have a kinematic viscosity of 9,3 mm /s
ISO 5165:2017(E)
to 12,5 mm /s at 100 °C (212 °F) and a viscosity index of not less than 85. Oils containing viscosity index
improvers shall not be used. Multi-graded lubricating oils shall not be used.
The suggested oil change interval is 50 engine-running hours.
5.3 Cetane primary reference fuel (PRF), hexadecane with a minimum purity of 99,0 %, as
determined by chromatographic analysis, shall be used as the designated 100 CN component.
5.4 Heptamethylnonane PRF, 2,2,4,4,6,8,8-heptamethylnonane with a minimum purity of 98 %, as
determined by chromatographic analysis, shall be used as the designated 15 CN component.
WARNING — PRFs are combustible and vapour harmful.
IMPORTANT — Store and use PRFs at temperatures of 20 °C or higher to avoid solidification of
hexadecane, which has a melting point of 18 °C.
5.5 Secondary reference fuels (SRFs), volumetric blends of two diesel fuels having widely different
CNs that have been round-robin engine calibrated by a recognized exchange testing group.
Storage and use of “T fuel” and “U fuel” should be at temperatures above 0 °C (32 °F) to avoid potential
solidification, particularly of “T fuel”. Before a container that has been stored at low temperature is
placed in service, it should be warmed to a temperature of at least 14 °C (26 °F) above its cloud point as
determined in accordance with ISO 3015. It should be held at this temperature for a period of at least
30 min and then the container should be thoroughly remixed.
SRF blends are rated in numbered pairs and are not interchangeable with SRF blends from other
batches.
WARNING — SRFs are combustible and the vapours harmful.
NOTE Blends of “T fuel” and “U fuel” that have been engine calibrated by the ASTM Diesel National Exchange
Group can be, and typically are, used for routine testing. The calibration data are incorporated in blend tables
that list the CNs assigned for various volume percentage blends of “T fuel” and “U fuel”. “T fuel” is typically in the
range of 73 CN to 75 CN and “U fuel” is typically in the range of 20 CN to 22 CN.
5.6 Check fuels, diesel fuel oils typical of the middle distillate type having a CN value determined by
an interlaboratory comparison.
WARNING — Check fuels are combustible and the vapours harmful.
NOTE Low cetane check fuel will typically be in the range of 38 CN to 42 CN. High cetane check fuel will
typically be in the range of 50 CN to 55 CN.
6 Apparatus
6.1 Test engine assembly.
As shown in Figure 1. It comprises a single cylinder engine consisting of a standard crankcase with
fuel pump assembly, a cylinder with separate head assembly of the pre-combustion type (see Figure 2),
thermal-siphon recirculating jacket coolant system, multiple fuel tank system with selector valving,
injector assembly with specific injector nozzle, electrical controls and a suitable exhaust pipe. Figure 3
shows the software screen interface of the XCP digital panel. The engine shall be belt connected to
a special electric power-absorption motor, which acts as a motor driver to start the engine and as a
means to absorb power at constant speed when combustion is occurring (engine firing).
4 © ISO 2017 – All rights reserved

ISO 5165:2017(E)
6.2 Instrumentation.
An electronic instrument to measure injection and ignition delay timing as well as conventional
thermometry, gauges and general purpose meters.
NOTE Engine equipment and instrumentation are available from the single source manufacturer, CFR
1)
Engines Inc. , N8 W22577 Johnson Drive, Pewaukee WI 53186, USA. CFR Engines Inc. also has authorized sales
and service organizations in selected geographic areas.
Key
A fuel tanks L injector assembly
B air heater housing M fuel injection pump
C air intake silencer N fuel selector valve
D fuel flow-rate burette O oil filter
E combustion pickup P crankcase oil heater control
F safety guard Q air heater switch
G variable compression plug (VCP) handwheel R engine start-stop panel
H VCP locking handwheel S instrument panel
I flywheel pickups T intake air temperature controller
J oil filter cap U Dual Digital Cetane Meter
K injection pump safety shutoff solenoid
Figure 1 — Cetane method test engine assembly
1) This information is given for the convenience of users of this document and does not constitute an endorsement
by ISO of the product named. Equivalent products may be used if they can be shown to lead to the same results.
ISO 5165:2017(E)
Key
1 VCP locking wheel 6 precombustion chamber
2 VCP handwheel 7 cylinder head
3 VCP micrometer 8 injector nozzle assembly
4 VCP 9 cylinder
5 combustion pickup hole 10 turbulence passage
Figure 2 — CFR engine cylinder head and handwheel assembly
6 © ISO 2017 – All rights reserved

ISO 5165:2017(E)
Key
1 cetane rating toolbar 15 handwheel position
2 fuel names 16 oil pressure
3 operators 17 injector passage temperature
4 procedure 18 coolant temperature
5 low CN 19 oil temperature
6 high CN 20 intake air temperature
7 begin rating 21 crankcase vacuum
8 clear data 22 injection timing standard deviation
9 meter 23 injector pickup in range
10 graph 24 ignition delay standard deviation
11 injection timing 25 start/stop engine
12 ignition delay 26 return to menu
13 sensor setup 27 for future use
14 messages
Figure 3 — XCP digital panel: software screen interface
6.3 Reference fuels dispensing equipment.
Calibrated burettes or volumetric ware having a capacity of 400 ml or 500 ml and a maximum
volumetric tolerance of ± 0,2 %. Calibration shall be verified in accordance with ISO 4787. Burettes
shall be outfitted with a delivery valve and delivery tip to accurately control dispensed volumes. The
delivery tip shall be of such size and design that shut-off tip discharge does not exceed 0,5 ml. The rate
of delivery from the dispensing system shall not exceed 500 ml/min.
NOTE ASTM D613-15ae1, Appendix X1 (Volumetric Reference Fuel Blending Apparatus and Procedures)
provides additional information for application of this document.
The use of blending systems for the preparation of the volumetrically defined blends by gravimetric
(mass) measurements, based on the density at 15 °C (60 °F) of the individual components, is allowed
provided the blending system meets the requirement of ±0,2 % blending tolerance limits.
ISO 5165:2017(E)
6.4 Injector nozzle tester.
The injector nozzle assembly shall be checked whenever the injector nozzle is removed and reassembled
to ensure that the initial pressure at which fuel is discharged from the nozzle is properly set.
IMPORTANT — It is also important to inspect the type of spray pattern which occurs. Commercial
injector nozzle testers which include a lever-operated pressure cylinder, fuel reservoir and
pressure gauge are available from several sources as common diesel engine maintenance
equipment.
6.5 Special maintenance tools.
A number of speciality tools and measuring instruments are available for easy, convenient and effective
maintenance of the engine and testing equipment.
NOTE Lists and descriptions of these tools and instruments are available from the manufacturers of the
engine equipment and those organizations offering engineering and service support for this document.
7 Sampling and sample preparation
Samples shall be collected in accordance with ISO 3170, ISO 3171 or an equivalent national standard.
To minimize exposure to UV emissions, collect and store samples in opaque containers such as dark
brown glass bottles, metal cans or minimally-reactive plastic containers.
Samples shall be brought to room temperature, typically 18 °C to 32 °C, before engine testing. If
necessary, samples shall be filtered through a Type 1, Class A filter paper, conforming to ASTM E832-
81, at room temperature and pressure before engine testing.
Inspect the sample for wax precipitation: if precipitates are present, bring the test sample to a
temperature of at least 14 °C above the expected cloud point of the material being tested, taking care
not to lose any lower boiling range components. The fuel sample should be homogeneous before engine
testing or filtration.
8 Basic engine and instrument settings and standard operating conditions
8.1 Installation of engine equipment and instrumentation
Locate the cetane test engine in an area where it will not be affected by certain gases and fumes that
can have a measurable effect on the CN test result.
Installation of the engine and instrumentation requires placement of the engine on a suitable foundation
and hook-up of all utilities. Engineering and technical support for this function is required, and the
user shall be responsible for conformity with all applicable codes and installation requirements. Proper
operation of the test engine requires assembly of a number of engine components and adjustment of
a series of engine variables to prescribed specifications. Some of these settings are established by
component specifications, others are established at the time of engine assembly or after overhaul
and still others are engine-running conditions that shall be observed and/or determined by operator
adjustment during the testing process.
8.2 Engine speed
The engine speed shall be 900 r/min ± 9 r/min when the engine is operating with combustion with a
maximum variation of 9 r/min occurring during a rating. Engine speed when combustion is occurring
shall not be more than 3 r/min greater than for motoring without combustion.
8 © ISO 2017 – All rights reserved

ISO 5165:2017(E)
8.3 Valve timing
The engine shall use a four-stroke cycle with two crankshaft revolutions for each complete combustion
cycle. The two critical valve events are those that occur near top-dead-centre (t.d.c.): intake valve
opening and exhaust valve closing. Intake valve opening shall occur 10,0° ± 2,5° after-top-dead-centre
(a.t.d.c.) with closing at 34° after-bottom-dead-centre (a.b.d.c.) on one revolution of the crankshaft and
flywheel. Exhaust valve opening shall occur 40° before-bottom-dead-centre (b.b.d.c.) on the second
revolution of the crankshaft or flywheel with closing at 15,0° ± 2,5° a.t.d.c. on the next revolution of the
crankshaft or flywheel.
8.4 Valve lift
Intake- and exhaust-cam lobe contours, while different in shape, shall have a contour rise of 6,223 mm
to 6,350 mm (0,245 in to 0,250 in) from the base circle to the top of the lobe so that the resulting valve
lift shall be 6,045 mm ± 0,05 mm (0,238 in ± 0,002 in).
8.5 Fuel pump timing
Closure of the pump plunger inlet port shall occur at a flywheel crank angle between 300° and 306° on
the engine compression stroke when the fuel flow-rate-micrometer is set to a typical operating position
and the variable timing device lever is at full advance (nearest to operator).
8.6 Fuel pump inlet pressure
A minimum fuel head is established by assembly of the fuel tanks (storage reservoirs) and flow-rate-
measuring burette so that the discharge from them is 635 mm ± 25 mm above the centreline of the fuel
injection pump inlet.
8.7 Direction of engine rotation
Clockwise rotation of the crankshaft shall occur when observed from the front of the engine.
8.8 Injection timing
This shall occur 13,0° b.t.d.c. for the sample and reference fuels.
8.9 Injector nozzle opening pressure
This shall be 10,3 MPa ± 0,34 MPa (1 500 psi ± 50 psi).
8.10 Injection flow rate
This shall be (13,0 ± 0,2) ml/min [(60 ± 1)s/13,0 ml].
8.11 Injector coolant passage temperature
This shall be 38 °C ± 3 °C (100 °F ± 5 °F).
8.12 Valve clearances
Engine running and hot clearance for both intake and exhaust valves shall be set to 0,20 mm ± 0,025 mm
(0,008 in ± 0,001 in) measured under standard operating conditions with the engine running at
equilibrium conditions on a typical diesel fuel oil.
ISO 5165:2017(E)
8.13 Oil pressure
This shall be 172 kPa to 207 kPa (25 psi to 30 psi).
NOTE The CFR engine unit is normally equipped with a pressure gauge in psi.
8.14 Oil temperature
This shall be 57 °C ± 8 °C (135 °F ± 15 °F).
NOTE The CFR engine unit is normally equipped with a temperature gauge in degrees Fahrenheit.
8.15 Cylinder jacket coolant temperature
This shall be 100 °C ± 2 °C (212 °F ± 3 °F).
8.16 Intake air temperature
This shall be 66 °C ± 0,5 °C (150 °F ± 1 °F).
8.
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