ISO 8178-4:2020

Overview

ISO 8178-4:2020 defines procedures for measuring gaseous and particulate exhaust emissions from reciprocating internal combustion (RIC) engines coupled to a dynamometer. The standard covers both steady‑state and transient test cycles that are representative of different engine applications. It applies to mobile, transportable and stationary RIC engines (excluding on‑road passenger and goods vehicles) and can, with restrictions, be used for on‑site measurements. ISO 8178-4 is part of the broader ISO 8178 series on engine emission measurement.

Key topics and technical requirements

• Test cycles and mapping
  • Specification of steady‑state cycles (discrete mode, ramped‑modal) and transient cycles (including the Non‑Road Transient Cycle, NRTC, and LSI‑NRTC).
  • Engine mapping requirements for transient and variable‑speed testing.
• Test conditions
  • Laboratory and site test conditions, engine intake air and exhaust restrictions, auxiliaries, cooling and lubrication considerations.
  • Requirements for engines fitted with charge‑air cooling or exhaust after‑treatment systems.
• Instrumentation and sampling
  • Gas analyser validation, proportional flow control for batch sampling, PM sampling media preparation and tare weighing.
  • Sampling system decontamination, contamination checks (e.g., HC), and calibration procedures.
• Test run procedures
  • Pre‑test preparation, engine start/restart rules, sequence for discrete, ramped and transient cycles, and post‑test verification.
• Data evaluation and calculation
  • Calculation of mass emissions for gaseous species and particulate matter, dry/wet corrections, humidity and temperature corrections for NO, cycle work and specific emissions, particle number evaluation and effective weighting for PM.
• Special considerations
  • Crankcase emissions, engines with regenerating emission controls, and applicability to non‑road equipment such as earth‑moving machines and generating sets.

Applications and users

ISO 8178-4:2020 is used by:

• Engine manufacturers and OEMs for emissions design verification and development testing
• Accredited emission test laboratories and dynamometer facilities
• Regulatory and certification bodies for non‑road and stationary engine compliance assessments
• Research institutions studying combustion, after‑treatment and particulate behaviour
• Component and after‑treatment suppliers validating system performance under steady and transient driving/use cycles

Practical benefits include consistent, repeatable measurement methods, traceable PM and gaseous emission data, and harmonized test cycles that facilitate comparisons across engines and technologies.

Related standards

• Part of the ISO 8178 series (other parts cover instrumentation, test procedures and reporting) and commonly used in conjunction with national/regional emissions regulations and laboratory accreditation standards.

Keywords: ISO 8178-4:2020, exhaust emission measurement, steady‑state and transient test cycles, reciprocating internal combustion engines, non‑road engines, dynamometer testing, particulate and gaseous emissions, NRTC, engine emissions testing.