The National Vehicle and Fuel Emissions Laboratory (NVFEL) tests a portion of all heavy-duty diesel and small gasoline engines intended for sale in the United States to confirm compliance with EPA’s exhaust emissions standards. This includes onroad and nonroad diesel engines 200 horse power (HP) and larger, and nonroad gasoline engines 30HP and smaller.

To evaluate the engines’ in-use compliance with EPA’s regulations, NVFEL also measures the emissions from trucks, buses, and non-road equipment under typical “real-world” operating conditions using on-board Portable Emissions Measurement Systems (PEMS).  Engines are tested under standard test cycles specially designed to account for the unique conditions of each engine’s application, including cycles for onroad, nonoad and basic utility operation.

Starting in 2016, NVFEL will also have the capability to test mid-sized diesel engines in the range of 50-200HP that are often used in various non-road applications.  Also starting in 2016, the laboratory will have the capability to conduct in-use testing of onroad trucks and buses under more controlled conditions using Heavy-Duty chassis dynamometer.

More information on regulations related to engine test procedures.