ISO 21866-1:2020

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 21866-1
ISO/TC 123/SC 2
Plain bearings — Automotive
Secretariat: DIN
engine bearing test rig using actual
Voting begins on:
2020-04-23 connecting rods —
Voting terminates on:
Part 1:
2020-06-18
Test rig
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 SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 21866-1:2020(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO 2020

---------------------- Page: 1 ----------------------
ISO/FDIS 21866-1:2020(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/FDIS 21866-1:2020(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Classification of bearing tests . 1
5 Test rig . 2
5.1 Test rig construction . 2
5.2 Rig frame construction . 3
5.3 Foundation structure . 3
5.4 Test using actual engine connecting rod . 4
5.4.1 Structure around the test bearing . 4
5.4.2 Structure around the support bearing . 4
5.4.3 Connection of the connecting rod with dynamic servo actuator . 5
5.4.4 Test shaft for different diameter of test bearings . 6
5.4.5 Temperature measurement for the test bearing . 6
5.4.6 Adjustment of the misalignment of the test bearing and the shaft . 7
Annex A (informative) An example for bearing seizure test . 9
Annex B (informative) An example for bearing fatigue test .11
Annex C (informative) Theoretical oil film conditions by the rigidity of the bearing housing .12
Annex D (informative) Resonance frequency by frame type (calculation).14
Bibliography .15
© ISO 2020 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO/FDIS 21866-1:2020(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 123, Plain bearings, Subcommittee SC 2,
Materials and lubricants, their properties, characteristics, test methods and testing conditions.
A list of all parts in the ISO 21866 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved

---------------------- Page: 4 ----------------------
ISO/FDIS 21866-1:2020(E)

Introduction
Recently, the rigidity of automotive engine bearings and their housings have been lowered due
to the demand for weight reduction, and they are getting easier to be deformed. On the other hand,
for achieving clean combustion with high heat efficiency, combustion pressure and bearing oil film
pressure have become higher. Also, the minimum oil film thickness for bearing has been made thinner
by using low-viscosity oil to reduce friction loss. The plain bearings for automotive engines have a tough
situation because of all these changes.
So far, the test rig used for plain bearings has been developed with the application of elasto-
hydrodynamic lubrication theory (EHL). But the serious problem stated above remains: the rigidity
of a connecting rod bearing for automotive engine is lowered in comparison with other machineries
because of the especial requirement of weight reduction.
Based on the abovementioned background, it is essential to evaluate the bearings for each car, using the
actual engines. Also, not only the magnitude and pattern of the load on a bearing but also the engine
speed are different between gasoline engine bearings and diesel engine bearings, so the different
bearings need to be developed accordingly. As a consequence, it has become essential to conduct a final
test with the engine of an actual car because the conventional test rig could not meet such requirements.
The aim of this document is to shorten the time and reduce the costs needed on engine bearing testing
in order to satisfy the requirements of automotive engine bearings at present and in future by using
connecting rods of actual cars.
© ISO 2020 – All rights reserved v

---------------------- Page: 5 ----------------------
FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 21866-1:2020(E)
Plain bearings — Automotive engine bearing test rig using
actual connecting rods —
Part 1:
Test rig
1 Scope
This document specifies the requirements for an engine bearing test rig that uses an actual connecting
rod to determine plain bearing performance in automotive engines, evaluating fundamental bearing
properties such as seizure resistance, wear resistance, fatigue resistance and resistance to the impact
of foreign material.
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 4378-1, Plain bearings — Terms, definitions, classification and symbols — Part 1: Design, bearing
materials and their properties
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4378-1 apply.
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/
4 Classification of bearing tests
Three stages of functional evaluation test methods of plain bearings using various kinds of test rigs are
shown in Table 1.
Table 1 — Examples of stages for bearing evaluation tests
Stage Purpose Bearing housing Test method
— pin on disc
screening of material proper-
Stage 1 — — block on ring
ties
— other
high rigidity connecting rod
evaluation of the bearing own test rig by bearing
Stage 2
connecting rod similar to the
function manufacturer
actual connecting rod
— actual engine
Stage 3 validation of the actual engine actual connecting rod
— actual car
© ISO 2020 – All rights reserved 1

---------------------- Page: 6 ----------------------
ISO/FDIS 21866-1:2020(E)

At stage 1, primary screening is conducted at the earliest stage of bearing material development,
selection or evaluation using fundamental test rigs such as pin on disc or block on ring.
At stage 2, the tests are conducted to evaluate the bearing material and design, using an actual plain
bearing constructed from material that has shown excellent performance during stage 1 testing. In this
stage, the operating conditions and assessment procedure provided in ISO 6281 are considered. Test
rigs appropriate for each testing purpose are used and the damage of the bearing is judged as described
in ISO 7146-1 and ISO 7146-2.
At stage 3, engine or vehicle testing of the actual bearing that has passed stage 2 is conducted as the
final verification before market launch.
Unexpected bearing damage can occasionally occur due to differences between actual application
operating conditions and test conditions at stage 2 and stage 3. Rectification late in the product
development timeframe can incur expense and delay. Therefore, it is imperative to develop an
alternative, more effective evaluation method at stage 2 and stage 3 by using an actual connecting rod
to improve the reliability of automotive engine bearings.
Examples of bearing seizure and fatigue tests using the test rigs specified in this document are shown
in Annex A and Annex B.
It is important to understand that connecting rod rigidity affects the housing deformation and oil
pressure distribution. For information, an example of the oil film calculation is shown in Annex C.
5 Test rig
5.1 Test rig construction
Figure 1 shows an example of the overall configuration of the test rig.
Key
1 test shaft 7 torque metre
2 test connecting rod 8 gear box
3 support bearing housing 9 torque limit clutch
4 oil feed equipment 10 drive motor
5 load cell 11 flexible coupling
6 dynamic servo actuator
Figure 1 — Overview of bearing test rig construction
One particular test rig that meets the requirements mentioned in the scope is described as follows.
To emulate mechanical conditions within the engine, an actual connecting rod is used. The test bearing
is assembled into the big end or small end of the connecting rod, and a dynamic load is applied. Figure 1
shows the overall structure of the test rig. A test bearing in the test connecting rod (2) is mounted on
the test shaft (1) which is driven by a speed-variable motor (10) via a torque metre (7) and a torque
2 © ISO 2020 – All rights reserved

---------------------- Page: 7 ----------------------
ISO/FDIS 21866-1:2020(E)

limit clutch (9). Friction of the test bearing is measured by the torque metre and the test rig is protected
from damage due to bearing failure by an emergency stop. A servo actuator (6) is capable of producing
dynamic loads with a frequency higher than the engine speed, measured by load cell (5). Oil is supplied
to the test bearing in the test connecting rod (2) by the oil supply equipment (4) to simulate the oil
supply through engine crankshaft. The dynamic load pattern is synchronized to the shaft oil-hole
pattern. Stable temperature measurement of the test bearing is shown in Figure 7, acco
...