3-Cylinder vs 4-Cylinder Engines. Does More Mean Better?

Why are automobile manufactures going smaller with their engine?

If you are looking to buy a hatchback today, you are quite spoilt for choice; with the i20 from Korea, Maruti Suzuki’s Baleno and Swift, the Freestyle and Figo by the American giants and we also have India contributing to this list with the Tata Tiago and their brand new Altroz. While all these cars offer more or less the same with regards to displacement, power, overall dimensions, weight, interior finish quality and even technology, one aspect separates these cars, dividing them into two categories; whether the engine is a 4-cylinder or a 3-cylinder.

Nowadays, while majority hatchbacks and even sedans in India are available with 4-cylinder engines, a few cars are available with one less cylinder. These 3-cylinder engines are common with the relatively new vehicles such as the Nexon, Tiago and Altroz by Tata and even the Freestyle and Figo Blu by Ford. So why are automobile manufactures deciding to get rid of one cylinder and create brand new engines for their newer automobiles? Starting from scratch and building an entirely new engine is not cheap; a lot of research and development along with resources and money is required. And truth be told, it’s frankly way cheaper to remap the previous 4-cylinder engine to create more power, and shuffle it between different vehicles within the automobile provider’s line-up.

This trend of reducing a piston or two and even downsizing the displacement of engines has been going around for some time now. The 2005 BMW E60 M5, used a naturally aspirated 5.0-litre V10 that produced 500 bhp, this V10 was the last of its kind and was replaced in the successor M5, the F10 with a 4.4-litre twin-turbocharged V8 that produced 50 more bhp as compared to its predecessor. Similarly, the first-generation Ford GT used a supercharged 5.4-litre V8 which produced 550 bhp, this massive V8 was, however, replaced by a more compact Twin-turbocharged 3.5-litre V6 Eco-boost that produced 660 bhp. I’m sure this must have been a hard decision for Ford to make, having to get rid of their iconic V8. Popular for its massive muscle V8, Ford must have replaced it with the smaller V6 with quite a heavy heart. But it was a necessary step since firstly, the design of the next generation GT was compact making no room for a massive V8 and secondly, why use a fuel-guzzling V8 when you can have a more economical and smaller engine that produces 110 more bhp as compared to its predecessor?

30 years back the 3-cylinder engines had gotten popular due to rise in fuel prices, demanding OEMs to create smaller and mileage friendly engines. But these engines were more popular for being extremely noisy and creating harsh vibrations at low RPMs and were soon switched back for the 4-cylinder 4 stroke engines. Now, however, 3-cylinder engines have made a massive comeback and are powering quite a few popular cars as well. The BMW 1.5 litre 3-cylinder is seen on the famous present generation Mini Cooper, this engine also happens to be powering the futuristic hybrid i8. Lastly and most recently, we get to see the first-ever hypercar that is powered by a 3-cylinder 2.0-litre twin-turbocharged engine that produces 600bhp which coupled with 3 electric motors produces a total of 1700 Swedish horses, yes, you guessed it right, I am talking about the hybrid Koenigsegg Gemera.

Coming back to the more affordable common man’s vehicle, companies like Ford and Tata have decided to replace their in-line 4-cylinder engines with smaller and more compact 3-cylinder engines for similar reasons. Like previously mentioned these engines are compact hence they fit into various engine bays, making it possible to mass-produce such engines and fit them into different vehicles belonging to the same automobile manufacturer. An example of this would be the 3-cylinder engine used in the Tata Tiago which is the same as the one used in the Nexon, apart from the addition of the turbocharger which helps the Nexon produce more horse-power. Next, because these engines are smaller and weigh less, they provide better mileage. To second the mileage argument, since one piston has been removed the number of moving parts within engine has reduced, this in turn, reduces the loss of energy due to friction, which results in better mileage and a longer life span of the engine.

The cons of a 3-cylinder engine are rather less as compared to the pros and in my opinion, are overruled, but nevertheless, let’s cover them for the sake of argument. Yes, it's true that 3-cylinder engine is noisier and vibrates more as compared to their rival, and this is primarily because of the odd number of cylinders and the 60-degree power lag that one experiences in a 3-cylinder during the course of a four-stroke. But these issues have been taken care of by modern advancements in metallurgy, engine design and fuel injection designs. Another advancement used by auto manufactures to prevent the rocking action of these odd cylinder engines is by providing a heavier crankshaft, which even though excessive is a necessary step towards creating a smoother 3-cylinder engine.

Having covered the basic logistics as to why OEMs are reducing the size of their engines and having also discussed the pros and cons of a 3-cylinder engine; let me know your thoughts in the comment section. Do you agree that smaller, turbocharged and fewer cylinder engines are better and the way forward or should companies instead stick to bigger naturally aspirated engines?

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