The term spark-ignition is normally used to refer to internal combustion engines 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 commonly referred to as "gasoline engines" in US English and "petrol engines" in British English. However, these terms are 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 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.

Engine technology

محرك أوتو | Ottomotor | Ottomotor | Mesin bensin | Ottomotor | ガソリンエンジン | Бензиновый двигатель внутреннего сгорания | Zážihový motor | Bensinmotor | Ottomotor | Động cơ xăng | Benzinli motor | Бензиновий двигун | 点燃式发动机