Overview
ISO 17536-4:2019 specifies a laboratory fractional efficiency test method for evaluating oil aerosol (blowby) separators and filtering devices used in internal combustion engine crankcase ventilation systems. The standard defines reproducible test procedures to measure particle-size-resolved separation performance in both open and closed crankcase ventilation (CCV) configurations. It does not evaluate filter life, and it is not intended for assessing legal compliance. Because of instrument precision limits, this method is not suitable for filters with efficiencies above 99%.
Key technical topics and requirements
- Scope and limits
- Measures fractional separation efficiency (particle-size dependent removal).
- Conditioned tests apply only to filters that meet Dp stability requirements in ISO/TS 17536-2.
- Not intended for filters >99% efficiency or for legislative conformity.
- Test conditions
- Specified test temperatures: Condition A: 80 °C ± 3 °C or Condition B: 23 °C ± 5 °C; temperature used must be documented.
- Air flow rate and oil mass flow are specified by the customer or requester.
- Clean pressure-loss check required before aerosol exposure (per ISO/TS 17536-2).
- Instrumentation and measurements
- Particle sizing/counting instruments (recommended: LSAS - light scattering aerosol spectrometers) or equivalents that demonstrate comparable accuracy.
- Test equipment includes aerosol generator, sampling system, absolute filters/wall flow traps (if present) and leakage control.
- Measurement accuracy requirements referenced to ISO 17536-1:2015.
- Apparatus qualification and data treatment
- Includes test-stand verification, 100% efficiency checks, purge-time development, correlation tests and duct leakage tests.
- Data processing and acceptance criteria are defined (including Poisson statistics considerations in Annex A).
- Annex B provides a laboratory fractional efficiency test report template; Annex C lists normative test equipment.
Practical applications
- Product development and verification of oil mist separators, crankcase filters and CCV components.
- Comparative performance testing for R&D and design optimization (particle-size specific removal).
- Quality assurance and production testing where fractional efficiency data are required by customers.
- Supporting technical datasheets and customer specifications (note: not a legal compliance test).
Who should use this standard
- Automotive OEMs, engine and turbocharger manufacturers
- Filter and aerosol separator designers and manufacturers
- Independent test laboratories and R&D centers
- Product engineers responsible for CCV system performance
Related standards
- ISO 17536-1:2015 - Road vehicles - Aerosol separator performance test - General
- ISO/TS 17536-2 - Laboratory test method (conditioning, gravimetric tests and Dp stability)
Keywords: ISO 17536-4:2019, aerosol separator, blowby oil aerosol, fractional efficiency test, crankcase ventilation, LSAS, particle sizing, laboratory test method, oil mist separator.