ISO 6855-1:2012

Overview

ISO 6855-1:2012 - "Mopeds - Measurement method for gaseous exhaust emissions and fuel consumption - Part 1: General test requirements" defines the fundamental test requirements for measuring gaseous exhaust emissions and fuel consumption of mopeds (as defined in ISO 3833). It applies to mopeds with spark-ignition engines (four‑stroke, two‑stroke or rotary piston). The standard sets out measurement scope, reference conditions, required equipment, accuracy criteria and general procedures that support Parts 2 and 3 of the ISO 6855 series.

Key topics and technical requirements

• Scope and definitions: Clarifies terms such as moped kerb mass, reference mass, equivalent inertia and gaseous exhaust emissions (CO, THC, NOx, CO2).
• Standard reference conditions: Environmental and reference parameters used to correct volumes and emissions.
• Test methods overview: Describes measurement approaches for gaseous emissions and fuel consumption, including the carbon balance method and fuel flow measurement method.
• Measurement equipment: Requirements for chassis dynamometers, constant volume sampling (CVS) or open-type CVS systems, gas collection and analytical instrumentation, cooling and fuel measurement devices.
• System checks and accuracy: Procedures to verify CVS system accuracy, metering of calibration gases, instrument accuracy and statistical criteria for fuel consumption measurements.
• Sampling, analysis and calculations: Procedures for sampling diluted exhaust, determining dilution factors, correcting for background concentrations, and calculating mass emissions and fuel consumption (e.g., g/km, L/100 km).
• Annexes: Normative and informative annexes include fuel flow measurement methods, carbon balance principles, dilution factor determination, and two‑stroke engine fuel consumption specifics.

Practical applications and users

ISO 6855-1:2012 is intended for organizations that conduct moped emissions and fuel consumption testing, including:

• Vehicle and engine manufacturers validating design and compliance
• Accredited emissions test laboratories and certification bodies
• Regulatory agencies setting or verifying mopeds’ emission and fuel-consumption limits
• Research institutions studying small‑vehicle environmental performance
• Test facility designers selecting chassis dynamometer setups and CVS systems

Using ISO 6855-1 helps ensure repeatable, comparable test results and compliance with international good practice for moped emissions testing and fuel consumption measurement.

Related standards

• ISO 6855-2:2012 - Test cycles and specific test conditions
• ISO 6855-3:2012 - Fuel consumption measurement at a constant speed
• ISO 3833 - Road vehicles - Terms and definitions
• ISO 28981 - Methods for setting running resistance on a chassis dynamometer

Keywords: ISO 6855-1:2012, moped emissions testing, fuel consumption measurement, gaseous exhaust emissions, carbon balance method, chassis dynamometer, CVS system.