We’ve tested Mazda’s ‘Holy Grail’ Of Engine Tech…

Derryn Wong

…it works, and will be in next year’s new Mazda 3. Skyactiv X engine technology explained, tested in person – and what it means for you
Photos: Mazda, Derryn Wong
Mine Proving Ground, Yamaguchi Prefecture, JAPAN-
Internal combustion engines are dead. Diesel’s fast running out of steam because of particulate matter emissions and the belated realisation it’s not as clean as Europe made it out to be.
Gasoline will soldier on, but it’s a dead horse walking, staggering on until the complete takeover of electric cars, upon which it’ll be taken out to pasture and shot (electrocuted?) to death.
But the rumours of gasoline’s demise are premature –  not if Mazda has anything to say about it.
At 2017’s Tokyo Motor Show, Mazda announced it had perfected a form of homogeneous charge compression ignition (HCCI) for gasoline engines. As covered previously in CarBuyer the technology is nothing short of revolutionary, previously seen as an unattainable Holy Grail of combustion engine technology.
That Mazda, only the world’s 16th largest automaker, has made this technology production ready is something of a coup as it succeeded where bigger companies have failed.
But does it really work, and why should you, Mr Regular Singaporean Car Buyer, care?

Mazda says Skyactiv X will be the most efficient gasoline engine ever, and will deliver diesel-like torque at the same time.
Skyactiv X is quite easy to understand on a conceptual level: The respective pluses of gasoline (cleaner, wide powerband) and diesel (big torque, efficiency) combined into one engine. It also runs better on less expensive gasoline.

Besides the fact that the engine will allow for advances in fuel efficiency and drivability previously unseen in gasoline cars, both Skyactiv X and Mazda’s new platform (above) will be in the full-production Mazda 3 (shown in concept form here). It’s due for a global debut in Q3 2019, and shortly after that, a launch in Singapore.

In other words, it’s not just halo, theoretical technology – you’ll actually be able to buy it next year.
Driving The X
To that end, CarBuyer has come to Mine Proving Ground to test Mazda’s prototype machine, endowed not only with Skyactiv X, but also Mazda’s next-generation vehicle architecture.

Our test drive involved driving the current Mazda 3 hatchback, with the 2.0-litre Skyactiv-G gasoline engine, and then the prototype cars, running on the next-gen Skyactiv platform, powered by the 2.0-litre Skyactiv X engine.
The cars were driven along the same route at Mazda’s Mine Proving Grounds, with both six-speed manual and six-speed automatic gearboxes in turn.

The matte-black prototypes appear to be identical to the current Mazda 3 hatchback in appearance, but as mentioned, it’s the newer platform that underpins them (see box), a fact betrayed by the rear bumper section bring not-quite flush. 
The interior is much more prototype-esque, with jury-rigged air-con vents and hard, project plastic covering the shifter. But the way it drives is far more polished than its appearance suggests.
What we first noticed when driving the prototype wasn’t actually the increased torque, but the smoothness of the power delivery. Against the X engine, the G model seemed almost raw and rough edged – we could feel and hear the engine burr come through at certain points in the cabin, and through the pedals.
This could be down to the new platform as well, but the smoothness continued throughout the rev range. 
“We thought of the best ways for the engine to deliver torque in a smoothly-connected manner and tested many of them. Also, by utilising the spark, we can carefully control overall combustion, and achieved better operation,” said Hiroshi Tokushige, Mazda’s deputy general manager of powertrain development.
READ MORE: Skyactiv Platform’s next groovy step, or why Mazda wants to make sure your pelvis is doing ok
There was an obvious, brief rattle, which kicked in just a moment or two before the natural upshift point, but Mazda says it’s aware of the issue, which all the prototypes display, and it will be fixed before mass production. After all these cars aren’t even production prototypes, but technology test beds.
“Before we achieve mass production for Skyactiv X, we need to do lots of research, checking fuel, atmospheric and climate conditions, for many different markets, so there are a lot of areas we still need to complete,” said Mr Tokushige, on the development left before Skyactiv X is ready for production. 
It’s a pity, but we had no way of measuring fuel consumption. After all, Mr Tokushige mentioned in his technical briefing prior to the drive that Skyactiv X “has the best fuel economy of any gasoline engine in the world.”
The G cars had fuel consumption displays, but not the prototypes, while the X cars had a iPad rigged to show if the engine was operating in spark-controlled compression ignition (SPCCI), or just plain ole’ spark ignition (SI).
Skyactiv X works with the spark ignition ‘always on’ so to speak, SPCCI happens during most of the rev range, but above 4,000rpm or so, it reverts to being a regular SI-only engine.
On paper, the 2.0 X engine makes more power and torque than the current 2.0 G unit: 190hp and 230Nm of torque, versus 165hp and 210Nm of torque.
While a different of 20Nm doesn’t sound like a big difference, the X engine feels much gruntier, flexible and diesel like, probably because it has a wider torque band (peak torque is made earlier, and for longer) than the G engine.
On Mine Circuit though, we found ourselves shifting gears more often with the G engine, whereas pulling a ‘lazy taxi driver’  in the X car was more feasible. 
The test course hit all speeds, from low-speed parking lot manoeuvres, to 120km/h on a gently cresting straight, plus uphill and downhill corners.

READ MORE: Why Skyactiv X might run better on cheaper fuel – and what Mazda said when we asked about the next RX-7

With the X, I left it in third-gear the entire time, and didn’t bother to downshift for climbs. The protoype simply grunted it way up hills easily, and it didn’t peak out at our highest speeds either, indicative of a wide and useful torque band.
And for totally logical reasons, I also tried running the Skyactiv X engine into higher revs, watching the computer readout indicate spark ignition operation only. As the revs climbed, the torque dipped a little – just like a gasoline engine – though there was still plenty of it, and with it the slight roughness of the G engine.
In short, If you drove it sight unseen, you would have been convinced it’s a turbodiesel – if not for the complete absence of the usual clatter,  and a higher rev range.
X Multiplier
So far, so good, so prototype. But will it really be what Mazda claims?
On the face of it, Mazda has hit a home run at least in terms of on-road, torque-rich performance. We would have loved to have seen proof of improved economy – it claims as much as 30 percent, real-world, diesel-like economy – and it Skyactiv X can behave like it does with torque as it does with efficiency, there’s no reason that can’t be achievable.
Also, that’s not considering other fuel-saving tech that Mazda has in its cupboard, such as start-stop, which could add even more efficiency.
“Skyactiv X also has improved fuel efficiency at idle, and if we use i-Stop, fuel consumption can be improved even further beyond the 20-30 percent quoted,”said Mr Hiroshi.
Yet, with the electric vehicle (EV) revolution spinning up, and if combustion engines are on the way out, what’s the whole point?
From left to right: Mr Hidetoshi Kudo, Mazda’s executive officer in charge of research and development, and product strategy. Mr Hiroshi Tokushige, Mazda’s deputy general manager of powertrain development. Mr Akira Kyomen, program manager for Mazda’s vehicle development division

Chapter Next
Mazda probably wouldn’t go all-in on this technology if it wasn’t at least a little future proof, and it says combustion engines have plenty of life left in them.
“The combustion engine will help power the majority of vehicles globally for many years to come, and can make the biggest contribution to CO2 reduction,” says Mr Hidetoshi Kudo, Mazda’s executive officer in charge of research and development, and product strategy.
Combustion engines are a proven thing, and the entire support infrastructure is in place already, even in the least developed markets. Also, it’s accepted that the transition from combustion to electrics will take place on a gradual spectrum, both over time and with model adoption, with hybrids, plug-in hybrids and more.
Mazda says that even in 30 years time, 84 percent of cars will still use some form of combustion engine technology. Given its benefits, and if proven reliable, who’s to say a significant percentage of them won’t be powered by Skyactiv X?
Its next wave of products include all forms of electrification. It’s currently in a tech partnership with Toyota for hybrids, while it declined to give further details, it will launch a mild hybrid vehicle, and a full EV by 2019, with a plug-in hybrid by 2021.
“Electrification is something all car makers require,” says Akira Kyomen, program manager for Mazda’s vehicle development division, “our aim with next-gen Skyactiv architecture is to reduce battery size, and to develop a very compact and light hybrid system. We can use Skyactiv X as the basis for this.”
Mazda’s also geared up for an entirely new future, including electrification, new design language, infotainment, and autonomous driving technology.
2019 will see a new Mazda Connect infotainment system, and the next evolution of Mazda’s design language, Kodo Design 2.
In short, it looks as if the next Mazda 3 is going to be a seriously impressive piece of machinery, packing innovations from tip to toe.
But coming back to Skyactiv X, it’s still a bit surreal because: 1. There’s an engine that actually does combine the best characteristics of gasoline and diesel. 2. It’s going into full-scale production next year and 3. It’s coming from Mazda, which is merely the sixteenth largest automaker.
Gasoline won’t go away overnight, and it’ll still be hugely relevant in places where EVs can’t go, structurally, technologically, or economically. Conventional gasoline engines will remain for many years to come, and it seems like Mazda’s Skyactiv-X engines will certainly be around for the longest of all.


architecture future mazda mazda 3 platform skyactiv-x technology

About the Author

Derryn Wong

CarBuyer's chief editor brings 15 years of experience in automotive journalism. Previously, he was the editor for Top Gear Singapore, and a presenter for CNA's Cruise Control motoring segment. He's contributed to The Business Times, Today, and many other publications, and also covered technology as editor of Stuff magazine. An avid motorcyclist and photographer, he is the Chief Slave of two cats. Follow him on Instagram @werryndong

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