A small engine is a general term for a wide range of small-displacement, low-powered internal combustion engines used to power lawnmowers, generators, concrete mixers, and many other machines that require independent power sources. These engines often have simple designs, for example, an air-cooled single-cylinder petrol engine with a pull-cord starter, capacitor discharge ignition, and a gravity-fed carburetor.
Engines of similar design and displacement are also used in smaller vehicles such as motorcycles, motor scooters, all-terrain vehicles, and go-karts.
Compared to larger car engines, these engines are very small in terms of physical size and power output. The power output is usually less than 11 kilowatts (15 horsepower). The smallest one is used for handheld gardening machinery, such as string trimmers and chainsaws, with a displacement as small as 24 cubic centimeters (1.5 cubic inches). The production cost is usually a key consideration for small engines, so the design is relatively simple (for example, compared to car engines).
The most common configuration is an air-cooled single cylinder engine. The combustion cycle can be a two-stroke (lighter engine at a given power output) or a four stroke (producing lower levels of exhaust emissions). The fuel is usually gasoline or diesel.
The most common configuration is an air-cooled single cylinder engine. The combustion cycle can be a two-stroke (lighter engine at a given power output) or a four stroke (producing lower levels of exhaust emissions). The fuel is usually gasoline or diesel.