"A gas engine is an internal combustion engine that runs on a gaseous fuel, such as coal gas, producer gas, biogas, landfill gas or natural gas. ...
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In the United Kingdom, the term is unambiguous. In the United States, due to the widespread use of "gas" as an abbreviation for gasoline (petrol), such an engine might also be called a gaseous-fueled engine or natural gas engine or spark ignited.
Generally in modern usage, the term gas engine refers to a heavy-duty industrial engine capable of running continuously at full load for periods approaching a high fraction of 8,760 hours per year, unlike a gasoline automobile engine, which is lightweight, high-revving and typically runs for no more than 4,000 hours in its entire life. Typical power ranges from 10 kW (13 hp) to 4 MW (5,364 hp)." - (en.wikipedia.org 19.12.2021)