What is the difference between a 3-cylinder and a 4-cylinder engine?
2 Answers
The difference between a 3-cylinder and a 4-cylinder engine lies in the number of cylinders: a 3-cylinder engine has three cylinders, while a 4-cylinder engine has four cylinders. The working principles of both 3-cylinder and 4-cylinder engines are as follows: 1. Compression stroke: The piston moves from the bottom dead center to the top dead center, with both the intake and exhaust valves closed; 2. Intake stroke: The piston is driven by the crankshaft from the top dead center to the bottom dead center, while the intake valve opens and the exhaust valve closes; 3. Exhaust stroke: The exhaust valve opens, and the piston moves from the bottom dead center to the top dead center, expelling exhaust gases as the piston rises; 4. Combustion and expansion stroke: Both the intake and exhaust valves close, the spark plug ignites, and the air-fuel mixture burns vigorously.
I've been driving for over thirty years and have tried many three-cylinder and four-cylinder models. Three-cylinder engines, like those in some compact cars such as the Focus, have one less cylinder, are lighter, and offer lower fuel consumption, which is indeed economical in city traffic jams. However, you can feel vibrations during startup and idling, which modern technologies like balance shafts help to mitigate. In comparison, four-cylinder engines are more common in mid-size and large cars like the Accord, with less vibration and smoother operation, providing a more comfortable experience on long drives. The power delivery is also more even, unlike three-cylinder engines that sometimes lack sufficient torque. In terms of maintenance, four-cylinder parts are easier to find, while three-cylinder engines save on repair costs. For long-term driving, especially on highways, four-cylinder engines are more reliable, whereas three-cylinder engines are sufficient for city commuting. The price difference isn't significant; the key is matching the engine to your driving needs.
