In the current market, the number of cylinders on car engines is mostly an even number such as 4, 6 or 8.
Even in high-performance cars, the number of cylinders is 10, 12 or 16. Engines with an odd number of cylinders are now only 3 cylinders, the 5 cylinder engines that Audi was once famous for have disappeared and the 7 cylinder engine is completely absent. , Why so?
According to the description of the page drivetribePhysical and technical factors are the main reasons why cars do not have 7-cylinder engines.
The number of cylinders on an engine is usually chosen to be an even number, especially for engines with a large number of cylinders. With an even number of cylinders, the engine structure will help the extra force generated by the cylinders to oppose and cancel each other. Due to this, the engine runs smoothly and vibrations are not transmitted to the passenger compartment, helping to improve the user experience.
Meanwhile, engines with an odd number of cylinders do not have such advantages. The most complex is probably the 3-cylinder engine when the 3 pistons of this engine work with different cycles and therefore do not cancel the forces. This engine must use a balance shaft to dissipate the force to achieve the same smoothness as an engine with the same number of cylinders.
The 5-cylinder engine, due to the addition of 2 new cylinders, has multiple cycles that overlap and thus produce forces that cancel each other out. Audi’s time with this engine series was very successful.
With a 7-cylinder engine, the forces generated continue to oppose each other and cancel themselves out to produce smoothness and better reduce vibration. However, a 7-cylinder engine can achieve optimum results only with an in-line cylinder structure.
This 7-cylinder structure requires an extremely heavy crankshaft that cannot be used on any other engine (such as an 8-cylinder car that can use a 4-cylinder crankshaft) and is therefore very expensive to build. . Along with development, production also.
Furthermore, the above structure does not give a 7-cylinder vehicle the same smoothness as a 6- or 8-cylinder engine. All these factors do not make any car company interested in manufacturing the above engine.