Various regulatory agencies and other engine classification schemes have categories called non-road engine for engines that are used for other purposes than a motor vehicle that is used on a public roadways. The term is commonly used by to classify the engines in order to control their emissions. Non-road engines are used in an wide range of applications which may include machinery and non-road vehicles. In many jurisdictions, the term non-road engine is assumed to refer to the engines that have mobility or portability which is separated from the term stationary engine. The definition of non-road engine may explicitly exclude certain non-road vehicles such as aircraft, locomotives, and ocean-going marine vessels.
Classifications
There are many classifications of the non-road engines based on the jurisdictions. The following are common classifications:
The rationale for establishing emission standards for non-road engines is that they are a significant source of pollution. The engines of on-road vehicles have advanced emission controls which are not found on those non-road engines. The non-road engines also emit air pollution particles at much higher rates. The emission standards are based on the engine classifications and vary in various jurisdictions. The main model regulations that are used by many countries are the United States Environmental Protection Agency through the section 213 of the Clean Air Act and the directive of the European Commission. The directives cover diesel engines, spark-ignition engines, constant-speed engines, railcars, locomotives and inland waterway vessels. In Europe, the regulations are specifically clarified on the mobility by using the term "non-road mobile machinery".
Other countries
The standards for non-road diesel engines are more harmonized. Many countries adopt the emission standards derived from either the US or the European models. Canada adopted the US standards in 1999. Korea modeled its Tier 2 standards from the US Tier 2. Russia adopted the European Stage I standards. Turkey adopted the European standards but with different implementation dates. China adopted the European Stage I/II standards in 2007. India introduced its own standards in 2006 called Bharat Stage II and Bharat Stage III. Japan introduced its own standards that are similar but not harmonized to the US Tier 3 and Europe Stage III A. Brazil adopted the resolution in 2011 to set emission standards that are equivalent to US Tier 3 and European Stage III A. In Australia, the definition includes some stationary engines such as electric generators and pumps.
