What are the differences between a three-cylinder engine and a four-cylinder engine?

[LincolnLee]

The differences between a three-cylinder and a four-cylinder car: different balance and different ignition intervals. The three-cylinder engine uses a three-throw crankshaft. Without balancing measures, it can only achieve static balance but not dynamic balance. The four-cylinder engine uses a four-throw flat crankshaft, where not only the resultant centrifugal inertial force is zero, but the centrifugal inertial moment is also zero, achieving dynamic balance by itself. Here are the relevant details: 1. Different balance: For a four-stroke engine, the main difference between a three-cylinder and a four-cylinder engine is the balance. The balance of a three-cylinder engine is not as good as that of a four-cylinder engine. 2. Different ignition intervals: The ignition sequence of a three-cylinder engine is generally 1-3-2, with an ignition interval angle of 240 degrees. The crankshaft rotation angle for one stroke of the engine is 180 degrees, meaning that within the adjacent ignition intervals, there is a 60-degree crankshaft rotation where all three cylinders consume power simultaneously. The ignition sequence of a four-cylinder engine is generally 1-3-4-2, with an ignition interval angle of 180 degrees. The power strokes of each cylinder are tightly connected without any intervals.

[ColeRose]

As an ordinary person who drives frequently, I've tried two types of car engines. The three-cylinder engine has only three cylinders, is lightweight, and offers low fuel consumption, making it cost-effective for urban commuting—for example, my three-cylinder car saves 10% fuel per 100 kilometers. However, the downside is vibration, especially at idle when the steering wheel shakes slightly, which takes some getting used to. The four-cylinder engine, with four cylinders, has better balance, providing a smoother and quieter ride with more seamless acceleration. For long-distance driving, the four-cylinder offers greater comfort and reliability. In terms of maintenance, the three-cylinder has fewer parts, making oil changes cheaper, but long-term vibration may lead to wear. Newer models have added balance shafts to improve this, so it's advisable to test-drive extensively to gauge vibration levels when choosing a car. Overall, for city use, the three-cylinder is eco-friendly and economical, while the four-cylinder is a more reassuring choice for frequent highway driving.

[JamesRose]

I've been contemplating engine designs. Three-cylinder engines are compact with small footprints, making vehicles lighter overall. The downside is uneven power distribution and proneness to vibration; four-cylinder engines are naturally symmetrical with smoother rotation. In practical driving, three-cylinder engines excel in fuel efficiency, ideal for small cars to reduce emissions; four-cylinder engines offer linear power output and greater modification potential. Many manufacturers like Toyota now optimize three-cylinder engines by adding turbos to boost power, though cold starts can be slightly noisier. Comparatively, four-cylinder technology is more mature and reliable, especially under heavy loads or hill climbs. Maintenance-wise, three-cylinder engines require more frequent checks on vibration-damping components. Looking ahead, hybrids combining three-cylinder engines are trending.

[VonJoel]

I lean towards eco-friendly options. Three-cylinder engines emit less, with reduced cylinders lowering energy consumption. My hybrid paired with a three-cylinder cuts urban CO2 emissions. Compared to four-cylinders, three-cylinders are lighter and save ~15% fuel. Though vibration is an issue, new balancing systems like Mazda's Skyactiv mitigate it. When choosing engines, combining with battery power makes three-cylinders greener and more sustainable. Maintenance is simpler, with part longevity largely unaffected. Overall, while four-cylinders are reliable but thirstier, three-cylinders wisely advance low-carbon mobility.