According to the cylinder arrangement, it can be divided into single row, double row and three row. The cylinders of a single-row engine are arranged in a row, generally arranged vertically, but in order to reduce the height, the cylinders are sometimes arranged inclined or even horizontally. The double-row engine arranges the cylinders in two rows, and the angle between the two rows is less than 180° (usually 90°), which is called a V-type engine. If the angle between the two rows is 180°, it is called an opposed engine. The three-row type arranges the cylinders in three rows to form a W-type engine.
Classification by stroke: Internal combustion engines can be divided into four-stroke internal combustion engines and two-stroke internal combustion engines according to the number of strokes required to complete a working cycle. Automobile engines generally use four-stroke internal combustion engines. A four-stroke internal combustion engine refers to the completion of a working cycle, the piston reciprocates up and down in the cylinder for four strokes, and the crankshaft rotates twice (720°); a two-stroke internal combustion engine is one-half of the working process.