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The 21st-century diesel engine

Mazda6 2.2L SkyActiv-D



Diesel engines over the years have had a bad ‘knock’ — pardon the pun — over the years because of their reputation for poor emissions, that audible chatter, and their association with commercial vehicles as rough engines.

European releases of late have totally dispelled those archaic notions. Yet few have the mass-market appeal and the reasonable pricing Japan’s Mazda can provide.

The Hiroshima-based automaker recently launched a new trim of the Mazda6 that now uses its state-of-the-art SkyActiv-D engine, which naturally piqued my interest.

Hmmm…..diesel on a mid-size? I test it out for weekend to see what all the hype is about.



Inside the Skyactiv-D

The level of engineering that went into the Mazda SkyActive-D engine is simply astounding.

Defying conventional methods, Mazda found ways to make a diesel engine lighter while squeezing out more power, increasing fuel economy and lowering emissions.

The key was dropping the compression ratio (CR) to an astonishing 14:1. This makes the Skyactiv-D the only diesel engine in the world with the lowest CR, which effectively delays combustion by just ‘half a millisecond’ according to Mazda. All that info may just bounce off you but read on to see how it will change the way you see diesel from here on end.

Delayed combustion allows the fuel and air to mix more thoroughly for emissions that shatter diesel stereotypes and pass Euro 6 standards.

It also gave Mazda the chance to adjust the combustion timing and increase the expansion stroke, making the Skyactiv-D more fuel-efficient than a typical diesel engine.

The low CR also results in less engine stress — this means Mazda can use a lighter crank and pistons, and an aluminum block to shave 10-percent off its total weight.



Diesel performance

Let’s get the numbers out of the way first — the Mazda 2.2L Skyactiv-D puts out a rather modest amount of horsepower at 175 PS but it more than makes up for it with a very healthy 420 Nm of torque.

Lugging around an almost 3,500-pound (1,537-kg) body should make it feel sluggish, but this engine and the torque it produces more than compensate for the curb weight of the Mazda6.

Even without manually paddle-shifting the SkyActiv-Drive six-speed AT one gear down for more power, it has enough torque to stay in the same gear and just pull its way into that overtaking maneuver.

It may not feel as sexy as a 5.0L V8, and it may take a split-second longer, but it still gets the job done and in a more efficient manner if I may add.

The smaller of the twin turbochargers takes care of the torque at low speeds while the larger one handles power at high speeds. So no matter the driving situation, the Skyactiv-D has got you covered.

Connecting with the Mazda6 using ‘jinba ittai’ or the oneness between car and driver, I felt the throttle response clearly represented the power-to-weight ratio at play.

Gunning for a quick start required a generous amount of foot pressure to get the engine to unleash all that torque. That means pressing almost halfway down on the accelerator and that simply isn’t a fuel-efficient way to drive, especially in Metro Manila.

Unless you’re Lewis Hamilton going for pole in qualifying, I don’t ever see the need to go beyond the weight of your Cole Haans to prod the Skyactiv-D for enough power for a fun drive.

After resetting the trip computer, I spent most of my time in the city — in heavy traffic — and tested the heck out of the 2.2L Skyactiv-D. I still managed to eke out 11 kilometers to a liter of diesel fuel.

This is not really surprising knowing that diesel engines are more fuel-efficient than their petrol counterparts. But it is nice to see a product work as advertised in both efficiency and performance.

It still has the familiar diesel clatter that’s weirdly audible in the cabin when the engine is idle, but not so much outside. Compared to commercial vehicles, it is much more toned down.



Price to pay

With more technology engineered under the hood, along with more power, better fuel economy and a higher level of performance, it is more than fair that Mazda charges P1.985 million for the Mazda6 2.2L Skyactiv-D.

Sure, your monthly car payments may be higher, but think about the ear-to-ear grin you’ll sport every time you top-up: the lower fuel cost, the destinations you can drive to because of the higher fuel mileage, plus the extra horsepower and torque you’re getting!

A recent Harvard research indicated that paying for experiences is more rewarding than buying stuff, but why settle for one when you can get both?

The Mazda6 2.2L SkyActiv-D offers all of the above plus its inimitable driving experience and voila, you get the best of both worlds.