Road Vehicles -- Aerosol separator performance test for internal combustion engines

This document defines standardized and repeatable test procedures for the evaluation of blowby oil aerosol separators and filtering devices and specifies laboratory fractional separation efficiency in both open and closed crankcase ventilation systems. Filter life is not evaluated in this document. The conditioned portion of this test only applies to filters that can meet the Dp stability requirements referenced in ISO/TS 17536-2. Conformance of a device to legislation is outside of the scope of this document. Due to limited precision using current equipment, this document is not suitable for filters above an efficiency of 99 %.

Véhicules Routiers -- Essai de performance du séparateur d'aérosols pour les moteurs à combustion interne

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Publication Date
14-Nov-2019
Current Stage
6060 - International Standard published
Start Date
17-Oct-2019
Completion Date
15-Nov-2019
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INTERNATIONAL ISO
STANDARD 17536-4
First edition
2019-11
Road Vehicles — Aerosol separator
performance test for internal
combustion engines —
Part 4:
Laboratory fractional efficiency test
method
Véhicules Routiers — Essai de performance du séparateur d'aérosols
pour les moteurs à combustion interne —
Partie 4: Méthode d'essai de l'efficacité fractionnelle en laboratoire
Reference number
ISO 17536-4:2019(E)
ISO 2019
---------------------- Page: 1 ----------------------
ISO 17536-4:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

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Published in Switzerland
ii © ISO 2019 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 17536-4:2019(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms, definitions, and abbreviated terms ............................................................................................................................... 1

3.1 Terms and definitions ....................................................................................................................................................................... 1

3.2 Abbreviated terms ............................................................................................................................................................................... 2

4 Measurement accuracy .................................................................................................................................................................................. 2

5 Test materials and conditions ................................................................................................................................................................ 2

5.1 Absolute filter, wall flow trap and leakage ...................................................................................................................... 2

5.2 Test temperature ................................................................................................................................................................................... 2

5.3 Test conditions ........................................................................................................................................................................................ 2

6 Test procedure ........................................................................................................................................................................................................ 3

6.1 General ........................................................................................................................................................................................................... 3

6.2 Test equipment ....................................................................................................................................................................................... 3

6.3 Aerosol generator ................................................................................................................................................................................. 4

6.4 Aerosol sampling system ............................................................................................................................................................... 4

6.5 Particle sizing and counting monitor(s) ........................................................................................................................... 5

7 Apparatus qualification testing ............................................................................................................................................................ 5

7.1 Test stand verification ...................................................................................................................................................................... 5

7.2 Concentration limit of the particle instrument ........................................................................................................... 6

7.3 100 % efficiency test and development of purge time ......................................................................................... 6

7.4 Correlation test ....................................................................................................................................................................................... 6

7.5 Test duct air leakage test ................................................................................................................................................................ 6

7.6 Apparatus maintenance .................................................................................................................................................................. 7

8 Fractional efficiency test .............................................................................................................................................................................. 7

8.1 General ........................................................................................................................................................................................................... 7

8.1.1 New state (if possible) ................................................................................................................................................ 7

8.1.2 Conditioned state as per ISO/TS 17536-2 ................................................................................................. 7

8.2 Method ........................................................................................................................................................................................................... 7

8.3 Calculations ................................................................................................................................................................................................ 7

8.4 Correlation and tare ........................................................................................................................................................................... 7

8.5 Fractional efficiency test ................................................................................................................................................................. 8

9 Calculations and data acceptance criteria ................................................................................................................................. 9

9.1 Symbols used in following formulae .................................................................................................................................... 9

9.2 Symbols ......................................................................................................................................................................................................... 9

9.3 Subscripts used in the following formulae ..................................................................................................................... 9

9.4 Average used in the following formulae ............................................................................................................................ 9

9.5 Test sampling ......... ................................................................................................................................................................................... 9

9.6 Correlation ratio .................................................................................................................................................................................11

9.7 Penetration / Fractional efficiency .....................................................................................................................................12

9.8 Efficiency ...................................................................................................................................................................................................12

9.9 Data reduction ......................................................................................................................................................................................12

9.9.1 Correlation ratio data reduction .....................................................................................................................12

9.9.2 Correlation ratio data acceptance criteria ..............................................................................................15

9.9.3 Penetration data reduction ..................................................................................................................................15

9.9.4 Penetration Data Acceptance Criteria ........................................................................................................17

9.9.5 Penetration maximum background counts ...........................................................................................18

9.9.6 Penetration minimum upstream counts ..................................................................................................18

9.9.7 Efficiency .............................................................................................................................................................................18

© ISO 2019 – All rights reserved iii
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ISO 17536-4:2019(E)

Annex A (normative) Poisson statistics ..........................................................................................................................................................19

Annex B (informative) Aerosol separator laboratory fractional efficiency test report ................................21

Annex C (normative) Test equipment ...............................................................................................................................................................23

Bibliography .............................................................................................................................................................................................................................25

iv © ISO 2019 – All rights reserved
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ISO 17536-4:2019(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 22, Road vehicles, Subcommittee SC 34,

Propulsion, powertrain and powertrain fluids.
A list of all parts in the ISO 17536 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.
© ISO 2019 – All rights reserved v
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ISO 17536-4:2019(E)
Introduction

Engine crankcase blowby is composed of combustion exhaust gases, which have escaped to the

crankcase via piston ring seals, and lube oil aerosols generated by thermal and mechanical action

within the engine. These gases are vented from the crankcase to prevent a build-up of high pressure.

The constituents of vented engine blowby gases are recognized as an undesirable contaminant and

technology for their containment is therefore evolving.

The device used to separate oil aerosols from the blowby typically releases cleaned gases to atmosphere

or into the air inlet prior to the engine or turbo compressor (if present). The latter has led to the

requirement for a pressure control device to isolate the engine from turbo inlet suction.

It is the purpose of this document to define standardized and repeatable test procedures for the

evaluation of blowby oil aerosol separators and filtering devices using this laboratory fractional

efficiency test method.
vi © ISO 2019 – All rights reserved
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INTERNATIONAL STANDARD ISO 17536-4:2019(E)
Road Vehicles — Aerosol separator performance test for
internal combustion engines —
Part 4:
Laboratory fractional efficiency test method
1 Scope

This document defines standardized and repeatable test procedures for the evaluation of blowby oil

aerosol separators and filtering devices and specifies laboratory fractional separation efficiency in

both open and closed crankcase ventilation systems.
Filter life is not evaluated in this document.

The conditioned portion of this test only applies to filters that can meet the Dp stability requirements

referenced in ISO/TS 17536-2.
Conformance of a device to legislation is outside of the scope of this document.

Due to limited precision using current equipment, this document is not suitable for filters above an

efficiency of 99 %.
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 17536-1:2015, Road vehicles — Aerosol separator performance test for internal combustion engines —

Part 1: General

ISO/TS 17536-2, Road vehicles — Aerosol separator performance test for internal combustion engines —

Part 2: Laboratory test method
3 Terms, definitions, and abbreviated terms

For the purposes of this document, the terms and definitions given in ISO 17536-1 and the following 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/
3.1 Terms and definitions
3.1.1
fractional separation efficiency

ability of the separator to remove particles of a specified size expressed as a percentage

© ISO 2019 – All rights reserved 1
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ISO 17536-4:2019(E)
3.1.2
particle instrument
instrument for sizing and/or counting aerosol particles

Note 1 to entry: Recommended particle instruments are LSAS's, or other instruments demonstrating they can

measure results to within 5 % of an LSAS.
3.2 Abbreviated terms
PSD particle size distribution
PSE particle size removal efficiency

PSL polystyrene latex, referring to commercially available particles of various specific sizes

LSAS light scattering aerosol spectrometer
4 Measurement accuracy

The measurement accuracy of this document shall be in accordance with ISO 17536-1:2015, Clause 3.

5 Test materials and conditions
5.1 Absolute filter, wall flow trap and leakage

The provisions related to the absolute filter (if present), the downstream wall flow trap (if present) and

leakage shall be in accordance with ISO 17536-1.
5.2 Test temperature

The volume directly outside of the unit under test (UUT) and internal temperature of the efficiency test

shall be either:
— Condition A: 80 °C ± 3 °C
— Condition B: 23 °C ± 5 °C
The condition that is run shall be documented in the test report (see Annex B).
5.3 Test conditions
All test measurements shall be performed under the following stable conditions:

a) Flow rate: Air flow rate and mass oil flow are specified by the customer or by the test requestor.

b) Clean condition: The user should run a clean pressure loss test as specified in ISO/TS 17536-2.

The clean pressure loss test is conducted before any oil aerosol is allowed to enter the unit under

test (UUT).

c) If gravimetric efficiency (per ISO/TS 17536-2) and fractional efficiency tests are being performed

simultaneously, once the oil flow has been started for a test the air flow and oil flow shall not be

interrupted until the completion of the fractional efficiency test.

d) The conditioned fractional efficiency is measured after reaching the condition specified in

ISO/TS 17536-2.

NOTE Aerosol size distribution is not specified in this document, however two possible distributions are as

follows. D50: 0,85 µm to 0,9 µm (same as ISO/TS 17536-2) or to the customer’s specification.

2 © ISO 2019 – All rights reserved
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ISO 17536-4:2019(E)
6 Test procedure
6.1 General

Performance tests shall be performed on a complete aerosol separator assembly. The tests shall

consist of a fractional efficiency test and a conditioned fractional efficiency test (when applicable). If a

gravimetric efficiency test, conditioned gravimetric efficiency test, pressure loss, crankcase pressure

control test (when pressure regulator is present), or a drain interval test (when applicable) will be

performed, it shall be done in accordance with ISO/TS 17536-2.
6.2 Test equipment

NOTE The definitions of the following terms related to the test equipment are defined in ISO 17536-1;

upstream particle instrument, particle instrument calibration, maximum particle concentration and particle

instrument flow.

6.2.1 The duct material shall be electrically conductive and electrically grounded (metal duct), have

a smooth interior finish, and be sufficiently rigid to maintain its shape at the operating pressures. The

background air shall be tested with a particle instrument.

6.2.2 The test bench used to determine fractional efficiency shall be the same as one of the benches

that are shown in Annex C.

6.2.3 Use an aerosol generator which is capable of dosing oil mist over the range of sizes required as

per customer specification.

6.2.4 An upstream wall flow trap should be used between the oil mist generator and the inlet duct to

eliminate any oil wall flow to the inlet duct. Use a wall flow trap conforming to ISO 17536-1.

6.2.5 Use an inlet piezometer tube conforming to ISO 17536-1. The cross-section shall be the same

as the aerosol separator inlet. In the case of non-uniform flow conditions caused by special inlet ducts,

special precautions may be required.

6.2.6 Use a manometer or other differential pressure measuring device with the specified accuracy

described in ISO 17536-1.

6.2.7 A downstream wall flow trap should be used between the unit under test and the outlet

piezometer tube described in 6.2.5 (if present) to eliminate any oil wall flow. Use a wall flow trap

conforming to ISO 17536-1.

6.2.8 Use an outlet duct conforming to ISO 17536-1. The cross-section shall be the same as the aerosol

separator outlet. In the case of non-uniform flow conditions caused by special inlet ducts, special

precautions may be required.

6.2.9 Use an air flow rate measuring system having the accuracy described in ISO 17536-1. The device

needs to be calibrated to the environmental conditions inside the inlet duct at the test conditions used.

6.2.10 Use an air flow rate control system with a refresh rate greater than or equal to 2 Hz capable of

maintaining the indicated flow rate to within 5 % of the selected value.

6.2.11 Use compressed air/blower/exhauster for controlling air flow through the system, which has

adequate flow rate and pressure characteristics for the oil separators to be tested.

© ISO 2019 – All rights reserved 3
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ISO 17536-4:2019(E)

6.2.12 If the unit under test has a pressure regulator or bypass, the use of a blower/exhauster on the

downstream of the system can be used to regulate the pressure on the outlet of the unit under test.

Devices with pressure regulators shall have air pushed through the inlet, because the pressure regulator

device regulates the amount of vacuum allowed on the system.
6.3 Aerosol generator

6.3.1 Aerosol concentration shall be measured by particle counting. The concentration shall be

documented in the test report.

6.3.2 The test oil shall be documented for surface tension, density and viscosity. The temperature of

the aerosol flow shall be measured at the filtration system inlet. Run test at conditions specified in 5.3.

Periodically check these parameters.
6.4 Aerosol sampling system

6.4.1 The design criterion for the sampling system should be to provide a particle transport of >95 %

for 3 μm diameter particles from the sample probe inlet within the test duct to the inlet of the particle

instrument.

This shall be verified by experimental measurement or by numerical calculation of particle transport

based upon the geometry of the sampling system, the sampling flow rate, and particle deposition

associated with diffusion, sedimentation, turbulent flow, and inertial forces, as described in

Reference [1].

6.4.2 The use of a sampling system is allowed to optimize particle transport from the inlet probe to the

particle instrument. The sampling system shall meet the following criteria:

6.4.2.1 The portion of the sampling line in the duct shall block less than 25 % of the duct cross-

sectional area.

6.4.2.2 Isokinetic sampling (to within +0 % to -10 %) shall be maintained on both upstream and

downstream probes for the requestors specified flow rate of the UUT.

6.4.2.3 Flow through the sampling system shall be measured to within 5 % with volumetric devices

(e.g. orifice plates and variable area flowmeters).

Sampling air flow should be considered in total flow rate (e.g. 3 l/min sampling at 30 l/min rated flow).

6.4.2.4 Combined particle losses in the system should be <5 % for 3 μm diameter particles, based on

particle transport modelling.

6.4.2.5 The upstream and downstream sampling systems shall be of equal length and equivalent

geometry.

6.4.2.6 Where the upstream sampling system flow rate is greater or equal to 20 % of the system air

flow rate, compensation of the downstream particle count system flow rate shall account for the flow

through the particle sizer to maintain UUT constant flow rate.

6.4.2.7 Where the downstream sampling system flow rate is greater than or equal to 20 % of the

system air flow rate, compensation of the downstream particle count system flow rate shall account for

the flow through the particle sizer to maintain UUT constant flow rate.
4 © ISO 2019 – All rights reserved
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ISO 17536-4:2019(E)

6.4.2.8 Position of auxiliary components (i.e. wall flow trap) shall not change PSD, will need to verify

by measurement.

6.4.2.9 User shall verify the dilution ratio and ensure that the dilution does not change the particle

distribution.

6.4.2.10 Ground all metal tubing and/or use grounded plastic tubing (carbon or embedded wire). The

upstream and downstream sample lines should be nominally identical in geometry and shall use the

minimal length of tubing possible.

6.4.2.11 The inlet nozzles of upstream and downstream sample probes shall be sharp edged

(<15° included angle) and of appropriate entrance diameter to maintain isokinetic sampling within

+0 to -10 % at the test airflow rate.
6.5 Particle sizing and counting monitor(s)

Permissible instruments used to measure the size and concentration of the aerosol shall meet the

following criteria:

6.5.1 Shall measure particle diameters between 0,3 um and 5 um particles and group them into at

least 8 channels per decade.

6.5.2 At least 90 % of all observed counts shall register between 0,7 μm to 1,3 μm when the particle

instrument is challenged with monodisperse 1,0 μm diameter PSL particles.
6.5.3 Shall have at least 50 % counting efficiency at 0,3 um.
6.5.4 Shall have less than 10 % coincidence loss during the measurement.

6.5.5 Shall measure no more than 10 counts per min over the 0,30 μm to 5 μm range with a HEPA filter

mounted at the inlet of the counter.

6.5.6 The particle instrument shall be periodically calibrated according to manufacturer specifications.

6.5.7 The particle instrument shall be calibrated to measure oil particles.

NOTE Particle counters often are calibrated for dust, which can give erroneous results when used for this test.

7 Apparatus qualification testing
7.1 Test stand verification

7.1.1 Apparatus qualification tests shall verify quantitatively that the test rig and sampling procedures

are capable of providing reliable particle size efficiency measurements. The tests shall be performed in

accordance with Table 1.
Table 1 — System qualification measurement requirements
Parameter Requirement
100 % efficiency test: based on HEPA filter test >99 %
Correlation ratio test See Clause 9, Table 7
© ISO 2019 – All rights reserved 5
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ISO 17536-4:2019(E)
Table 1 (continued)
Parameter Requirement
Duct leakage:
ratio of leak rate to test airflow rate <1,0 %

Particle instrument zero count check: based on HEPA filter attached <10 counts per min over the

to the instrument’s inlet 0,30 μm to 10 μm range

Particle instrument sizing accuracy check: based on sampling of aero- Relative maximum shall appear in the

solized monodisperse PSL spheres of known size appropriate sizing channel
7.2 Concentration limit of the particle instrument

7.2.1 A series of initial efficiency tests shall be performed over oil aerosol concentrations to determine

a total concentration level for the PSE tests that does not overload the particle instrument(s). The lowest

total concentration level shall be less than 1 % of the instrument’s stated total concentration limit. The

tests shall be performed following the procedures of 8.1 through 8.5 on a device using a range of upstream

aerosol concentrations. The tests shall be performed at 10 %, 50 %, 100 % and 200 % of rated flow.

7.2.2 The aerosol for these tests shall be generated using the same system and procedures as described

in Clause 8 for fractional efficiency tests.

7.2.3 The tests shall be performed over a sufficient range of total challenge concentrations to

demonstrate that the particle instrument(s) is not overloaded at the intended test concentration.

7.3 100 % efficiency test and development of purge time

7.3.1 An initial efficiency test shall be performed using a HEPA filter as the test device to ensure that

the test duct and sampling system are capable of providing a >99 % efficiency measurement. The test

procedures for determination of PSE given in Clause 9 shall be followed, and the test shall be performed

at 10 %, 50 %, and 100 % of test systems flow rate range.
7.3.2 The computed PSE values shall be greater than 99 % for all particle sizes.

7.3.3 One parameter affecting the efficiency during the 100 % efficiency test is the purge time. The

purge time is too short if, after switching from the upstream to the downstream line, residual particles

from the upstream sample are counted during the downstream sampli
...

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