What are the differences between three-cylinder and four-cylinder engines?
2 Answers
The differences between three-cylinder and four-cylinder engines are: 1. Different number of cylinders: A three-cylinder engine has three cylinders; a four-cylinder engine has four cylinders. 2. Different ignition intervals: The firing order of a three-cylinder engine is 1, 3, 2 with an ignition interval of 240 degrees; the firing order of a four-cylinder engine is 1, 3, 4, 2 with an ignition interval of 180 degrees. Common cylinder configurations for automotive engines include 3, 4, 5, 6, 8, 10, and 12 cylinders. Engines with displacement below 1 liter typically use three cylinders, 1 to 2.5 liters usually employ four cylinders, around 3 liters generally use six cylinders, approximately 4 liters utilize eight cylinders, and above 5.5 liters adopt twelve cylinders.
From a mechanical perspective, a three-cylinder engine has only three cylinders. With fewer cylinders, the ignition intervals are uneven, resulting in stronger vibrations and a rougher engine sound. The shaking is noticeably felt while driving, especially during idling or acceleration. To balance the vibrations, many three-cylinder cars are equipped with balance shafts or active suspension systems, which lower costs but add extra components that increase maintenance risks. In contrast, a four-cylinder engine has one more cylinder, providing a more regular firing sequence, smoother vibrations, and quieter operation, running as smoothly as silk. The engine lifespan is usually longer, though it is slightly heavier and takes up more space. Having worked on many cars, I can say that the three-cylinder engine design saves weight by omitting one cylinder, but it demands higher-quality cylinder block materials—once wear occurs, repairs can be troublesome. The four-cylinder structure is more balanced and suitable for most road conditions, though it consumes more materials overall. During routine inspections, the vibration issues of three-cylinder engines require extra attention to the condition of vibration-damping components to prevent long-term damage to the suspension system.
