The term spark-ignition is normally used to refer to [[internal combustion engine]]s where the fuel-air mixture is ignited with a spark. The term contrasts with compression-ignition engines, where the heat from compression alone ignites the mixture. Spark-ignition engines can be either two-stroke or four-stroke, and are sometimes referred to as "gasoline engines." However, this nomenclature is not preferred, since spark-ignition engines can (and increasingly are) run on fuels other than gasoline, such as methanol , ethanol  , CNG  , hydrogen  , and nitromethane  . A four-stroke spark-ignition engine is an Otto cycle engine.
Until recently, a major distinction between spark-ignition and compression-ignition engines has been where the fuel is mixed - spark-ignition engines mix fuel outside the the cylinders and compression-ignition engines mix fuel inside the cylinders. However, both two-stroke and four-stroke spark-ignition engines are increasingly being designed with direct injection, eliminating this distinction.
|This page uses Creative Commons Licensed content from Wikipedia (view authors).|