The piston is inserted into the cylinder for reciprocating cycle of intake, compression, explosion and exhaust, which is a four-stroke engine. The single cylinder can also carry out this reciprocating cycle, but in order to improve the output, the exhaust volume should be increased, while taking into account the smooth operation, it needs a plurality of cylinders, starting from single cylinder to double cylinder, then continuously increasing to 4 cylinders, 6 cylinders, 8 cylinders, 12 cylinders have been practical.
Horizontal-to-horizontal engine cylinders lie horizontally and are combined in opposite directions, that is, horizontal-to-horizontal engine. Ford A carries horizontal-to-horizontal dual-cylinder engine. This kind of layout has existed for a long time, such as Lancia, VW, Porsche and so on. Subaru, Toyota Sport and Publica are all used in Japanese cars.
Cylinder settings can be divided into three categories: in-line, horizontal and V-type. In-line cylinders are used in most automobiles, such as double cylinders, three cylinders and four cylinders, while in-line six cylinders were used as standard engines for advanced vehicles, but they are long and heavy, and crankshaft rigidity will occur. Therefore, the status of in-line six cylinders has been given to V-type six cylinders. Horizontal type originally started from single cylinder, and then evolved to double cylinder to horizontal. Now there are 4 cylinders and 6 cylinders developed. Horizontal to horizontal 4 cylinders are single-sided and double cylinders, while 6 cylinders are single-sided and 3 cylinders. The length is shorter than in-line type, and the center of gravity is lower. These are its advantages, but the assembly and maintenance of parts are relatively special, so they are still a few. Pie.