The four-cylinder engine, also called four-cylinder engine, is a type of reciprocating piston engines, particularly internal combustion engines.
It is usually performed as a series of engine or boxer engine, both gasoline and less likely to be a V- engine and can be interpreted as a diesel engine. In the passenger car construction it is usually water-cooled, in some cases (especially as a boxer engine ) and air-cooled.
A special feature is the arrangement as a " square engine ", consisting of two series- splinted parallel twin cylinders with two crankshafts. This design was used in only a few vehicles, such as the Ariel Square Four or the Suzuki RG 500 Gamma.
Four -cylinder engines are by far the most commonly used as a drive by car to the middle class drive (in rare cases also in sports cars and cars of the upper middle class ) because they are relatively compact and can be made cheap. There are also often on motorcycles, light trucks, light rail vehicles, light aircraft ( boxer engines American type ), small vessels ( as auxiliary motor) drive generators and in other applications.
Four-stroke, four-cylinder in-line engines have free mass forces on second order which inconveniently coincide with the firing frequency. However, the forces can be compensated with two counter- rotating at twice crankshaft speed balancer ( Lanchester balancer ). The two ways of firing order ( 1-3-4-2 or 1-2-4-3 ) do not differ indeed in place and direction of ground forces, but in the quietness.
Even away from internal combustion engines, there are four-cylinder, including a reciprocating pumps or compressors.