International: Nonroad: ISO 8178

The ISO 8178 is an international standard for exhaust emission measurement from a number of non-road engine applications. It is used for emission certification and/or type approval testing in many countries, including the United States, European Union and Japan. Depending on the legislation, the cycle can be defined by reference to the ISO 8178 standard, or else by specifying a test cycle equivalent to ISO 8178 in the national legislation (as it is the case with the US EPA regulations).

The ISO 8178 includes a collection of steady-state engine dynamometer test cycles (designated as type C1, C2, D1, etc.) designed for different classes of engines and equipment. Each of these cycles represents a sequence of several steady-state modes with different weighting factors.

The ISO 8178 test cycle—or its 8-mode schedule C1 in particular—is also referred to as the Non-Road Steady Cycle, NRSC.

The particular engine modes and their weighting factors for B-type (11 mode) test cycles are listed below. The standard also includes an A-type 13-mode cycle, which is not listed in the table (ISO standards can be ordered through the ISO web site.