fourcylinders

Fourcylinders is a term used to describe an engine configuration consisting of four cylinders, arranged to convert the energy of combustion into rotational motion. The most common embodiment is the inline-four (I4), in which four cylinders align in a single row along a shared crankshaft. Less common are the V4, with two banks of cylinders in a V shape, and the flat or boxer-four, with opposing pistons moving in opposite directions.

Inline-four engines are popular in passenger cars due to their compact size, simplicity, and good balance between power and efficiency. They often employ overhead camshafts, variable valve timing, and turbocharging to achieve desired performance. V4 and boxer-four configurations have been used in smaller cars and motorcycles, but are less widespread due to packaging and manufacturing complexities.

Four-cylinder engines offer advantages including low weight, low manufacturing cost, and good fuel economy. Potential drawbacks include vibrations at certain RPM ranges, especially in early inline-fours that lacked balance shafts. Engineering solutions such as balance shafts, crank-pin offset, and dual-mass flywheels help mitigate these issues.

Applications include most modern compact and midsize cars, many motorcycles, and some industrial engines. In automotive use, four-cylinders can be naturally aspirated or turbocharged, with modern designs delivering competitive power outputs while meeting emissions standards.

Maintenance considerations for four-cylinder engines focus on regular timing belt/chain replacement, coolant and oil changes, and head gasket integrity. Common signs of trouble include misfires, rough idle, or cooling system leaks.