Geely-Volvo’s CEVT engine boss explains why the Proton X50’s 3-cylinder is better than a 4-cylinder

Dr. Håkan Sandquist holds a Ph.D. in internal combustion engines from Sweden’s Chalmers University of Technology, which is located in Gothenburg, basically Volvo town. He has spent 20 years working on automotive engines, 10 of which are related to electrified drivetrains – hybrids and plug-in hybrids.

He currently works as Director of Powertrain Strategy at CEVT, a joint venture company between Volvo Cars and Geely, focusing on powertrain.

However, even someone like Dr. Sandquist is no match against the combined expertise of Facebook commenters, all of whom will tell you that 3 cylinder are bad; they are not entirely wrong, and car companies are to be blamed. More on that later.

Common sense tells us that bigger is better, especially when it comes to cars. The best engines are V12 ones. A 6-cylinder engine is better than a 4-cylinder. That’s what marketers at car companies have always told us!

Throughout the 134 years history of the automobile (since the 1886 Benz Patentwagen), consumers have been told that more cylinders are better. But now we are being told that less is more? A three-cylinder is better than a four? What rubbish is this?

The Proton X50’s 1.5-litre turbocharged engines (MPI and TGDi) are not the only 3-cylinder engines on the market. The all-new 2020 Nissan Almera also uses a 3-cylinder.

Going further up the hierarchy, BMW and MINI also use 3-cylinder engines in many of their models. The Toyota GR Yaris, which is developed with inputs from world rally champion Tommi Makkinen, also uses a 3-cylinder engine, and it costs more than a FK8 Honda Civic Type R!

So why are companies backpedalling their earlier message to customers that they should pay more for a bigger engine?

Someone a lot smarter than me once told me this, “When learning something new, you learn by following the rules, because it’s safer and easier. Then you work to master the craft, but somewhere down the line, you will reach the limit of current understanding because what you are trying to achieve is no longer normal. Moving beyond that normal limit requires you to unlearn, and even break the rules.”

Science didn’t progress for more than 1,700 years because Aristotle’s philosophies were thought to be the universal truth, until Galileo introduced quantitative, methodical methods to science.

Isaac Newton had to throw out Aristotelian worldview to properly explain the laws of motion. But classical Newtonian laws had to be smashed before Neils Bohr could understand movements in the invisible world of atoms, and after that, Planck, Einstein, and Schrödinger had to throw out the very foundation of 19th century science before mankind could understand the uncertain world of quantum physics.

For automotive engineers like Dr. Sandquist, they are facing a similar need to throw out conventional understanding before they can move forward. The car industry is now in a once in a 100 years revolution.

Conventional understanding has to be broken so cars can continue to remain road legal, especially in Europe and China, where emission standards are very strict now.

Starting 2021, the European Union will penalize manufacturers who exceed their set limit for their average fleet-wide CO2 emissions, which is around 98 g/km, depending on the manufacturer’s sales mix. In 2023, the China 6b emission standard will be one of the strictest in the world. Drastic measures are required if manufacturers want to remain in business.

Sandquist explained that the motivating reason to remove one cylinder from a traditional 4-cylinder engine is very simple. It’s so simple that you don’t need a Ph.D to see the logic behind it.

To further reduce CO2 emissions, electrification is necessary, even on compact cars, but there is just not enough room in the engine bay for additional components, especially since complex turbocharging is now the norm.

How do you create more room in today’s very tight engine bay? Just remove on cylinder. That’s it! How to solve the associated problems after you remove one cylinder however, requires a Ph.D.

Removing one cylinder is also a super effective in cutting down weight, which is directly related to fuel consumption and exhaust emissions. There’s also the added benefit of achieving better front:rear weight balance in front-wheel drive cars, which is the norm these days anyway.

The benefits of a 3-cylinder over a 4 is very clear. The challenge is to mitigate the vibration problems from a 3-cylinder’s uneven firing order. Solving it is complex, but not difficult if you know what you are doing. Technology for dampers and today’s understanding of engine harmonics is good enough to allow car companies to overcome the problem.

The Geely 1.5TD engine, which Malaysians know as the 1.5 TGDi (identical to 1.5 MPI except for fuel system), contains many of such countermeasures into its engine design.

Explaining them requires a Ph.D but Sandquist briefly said the use of counterweighted crankshafts, dual mass flywheel with centrifugal pendulum absorber damper, single balancing shaft, low noise timing belt, high stiffness oil pan, asymmetric oil pump impeller, engine compartment and vibration dampener – all hidden away from view, allows the 3-cylinder to run very smoothly.

Dr Sandquist adds that vibration (lack of) of the 1.5TD engine is not only controlled, but it’s actually better than some of their rivals’ 4-cylinder engines.

He added that refinement will be even better on hybrid versions of the engine, as engine the engine is used less during low speed driving, and standing start accelerations are done with assistance from a smooth operating electric motor.

The engine has also been tested and validated for to last 15 years or a distance of 350,000 km, which CEVT says is much higher than the industry standards of 10 years or 200,000 km.

Dr Sandquist explains that CEVT’s 1.5TD engine is developed based on the modular Volvo Engine Architecture (VEA). It’s not exactly a Volvo engine (but still shares 90 percent of the same suppliers), but is co-developed by both Geely and Volvo at the Gothenburg–based joint venture.

Building an engine is easy. You don’t need a Ph.D for that. Building an engine that’s profitable, can be used in a wide variety of models, in different parts of the world, that’s difficult.

VEA is designed to do both 4- and 3-cylinder layouts. Specific to the 1.5TD, it can be adapted to also work as a 48V mild hybrid, a full hybrid, or a plug-in hybrid. It can also use different fuel systems – port or direct fuel injection – as well as different combustion cycles, including a Miller cycle version for the hybrid.

It’s one of the most flexible engines on the market, with multiple configurations to meet various market and budget requirements.

Next year, Perodua is expected to launch a compact SUV, codenamed D55L. The model is rumoured to also be powered by a 3-cylinder turbocharged engine, but only at 1-litre capacity, same as the Nissan Almera.

Three is the new four, and SUVs are the new sedans/hatchbacks. Get used to it.