Pros and Cons of a 3-cylinder Engine

While four-and six-cylinder engines were the norm in cars for the longest time, the industry is once again showing signs of change. A case in point would be the rise of the three-cylinder engine.

Also known as a straight-three engine, inline-triple, or inline-three, a 3-cylinder engine, is a reciprocating piston internal combustion engine with three cylinders arranged in a straight line or plane, side by side.

Even though 3-cylinder engines have been around since the 1960s, they were used mostly in Kei cars, and were not as popular as four- and six-pot mills. Here's a look at some quick pros and cons of a 3-cylinder engine:

Stricter emission rules and challenging economic landscapes require manufacturers to constantly do things as cost-efficiently as possible, which has resulted in more brands resorting to reducing the number of cylinders.

Obviously, the main difference between a 3 and a 4 cylinder engine is the number of cylinders, but besides that, the way these engines fire is also different, as the crankshaft rotation rate varies from one another. Popular cars with a 3-cylinder engine include the Ford Fiesta EcoBoost, and the BMW i8.

So, like most things in the world, the 3-cylinder engine also has its pros and cons. On the upside, lesser cylinders mean lesser parts, which translates into lower manufacturing costs.

And since there is one cylinder less, there is less friction and less weight, which means that lesser fuel is needed to generate power.

So, if fuel efficiency is what you’re aiming for, a 3-cylinder engine is just what you would want. Lesser parts also mean lesser things to maintain and worry about, which translates into cheaper maintenance costs for the owner.

But that’s not all. A smaller engine means that there is more space to play with, which gives manufacturers the freedom to make the cabin as spacious as possible since most cars with 3-cylinder engines are compacts.

Now, remember the difference in crankshaft rotation between 3- and 4-cylinder engines above? As much as it contributes to low fuel consumption, this difference also makes the three-pot engine idle in a slightly rougher and noisier manner than a four-pot mill.

Another downside of a 3-cylinder engine is that the power delivery is not as seamless as four-pot engines. This is because a 3 cylinder engine is a little sluggish at low rpm, but as the revs increase, the crankshaft gets ample conserved momentum and it is able to produce a healthy power output.

A 4-cylinder engine on the other hand, does not suffer from this problem as it has no lag in the firing order. Things are just smoother throughout the rev range.

So, all in all, the three-cylinder engine, just like its bigger counterparts, has its ups and downs, but the downs are nothing serious.

Plus, with technology like turbocharging, supercharging and electric motors providing the extra “oomph” these small engines lacked once upon a time, they are just as impressive as four-cylinder engines when it comes to delivering power to the ground. Couple that with low fuel consumption and cheap road tax, and we have the ideal recipe for modern day urban motoring.