Inline Engine

The inline or straight engine is a type of inline internal combustion engine with all cylinders mounted in a straight line, or plane along the crankcase. The single bank of cylinders may be oriented in either a vertical or an inclined plane with all the pistons driving a common crankshaft. Where it is inclined, it is sometimes called the slant. In a specification chart or when an abbreviation is used, an inline engine is listed as L.

The inline four layout is in perfect primary balance and confers a degree of mechanical simplicity which makes it popular for economy cars such as Proton, Perodua and etc. However , despite its simplicity, it suffers from a secondary imbalance which causes minor vibration in smaller engines. These vibrations become more powerful as engine size and power increase, so the more powerful engines used in larger cars generally are more complex designs with more than four cylinders.

Today almost all manufacturers of four cylinders engine for automobiles produce the inline-four layout, with Subaru and Porsche 718 flat four engines being notable exceptions, and so four-cylinder is usually synonymous with and a more widely used term than inline four. The inline four is the most common engine configuration in modern cars, while the V6 engine is the second most popular.

Toyota's 2JZ inline 6 engine

Today almost all manufacturers of four cylinders engine for automobiles produce the inline-four layout, with Subaru and Porsche 718 flat four engines being notable exceptions, and so four-cylinder is usually synonymous with and a more widely used term than inline four. The inline four is the most common engine configuration in modern cars, while the V6 engine is the second most popular.

Inline engine animation

The Inline engine is much smoother than one or two cylinder engines, and this has resulted in it becoming the engine of choice for most economy cars for many years. Its prominent advantage is the lack of rocking vibration, and the lack of need for heavy counterweight makes it easier to be sporty (quick revving up and down). However it tends to show secondary imbalance at high rpm because two pistons always moves together , making the imbalance twice as strong as other configuration without them.

Ford Focus RS
(The fastest Inline in production)