Mazda3 SKYACTIV-X Prototype 2018 Review

Mazda3 SKYACTIV-X
Pre-production prototype drive
Oberursel, Germany

Next year’s fourth-generation Mazda3 will introduce revolutionary combustion engine technology that promises significant performance and economy gains – at the same time.

But it’s not just the engine room that’s new – under our mule’s bodged-up current bodywork is a next-gen Mazda chassis as well.

Mazda’s bravery regularly surprises me. In terms of global automotive scale, it’s a minnow – and yet that little fish is never shy of taking a punt. Think rotary. Think the re-invention of the small roadster. Think the Miller-cycle engine.

And think SKYACTIV.

When the first generation of SKYACTIV technology was rolled out, the world was in turbo downsizing freefall. Cars that once had 2.0- or even 2.5-litre four-cylinder naturally-aspirated engines were being replaced by models with turbo 1.4- or even 1.2-litre mills.

And, by the way, green diesels were then the squeaky-clean future…

Global giants were preaching their downsizing doctrine and claiming fuel and emission parsimony that seemed too good to be true. Yet, there was Mazda rolling out new technology that consisted of bigger engines, sky-high compression-ratio petrol engines and record-low compression ratio turbo-diesels.

While Europe and others were blitzkrieging in one direction, Mazda was wandering off into its own private Idaho… Or as the case actually was, Berlin – the site for the original reveal of SKYACTIV to the world.

Roll forward seven years, cue #Dieselgate and cue fuel economy fraud… It turned out that downsized turbo efficiency claims were largely too good to be true… And the little Japanese company that could was right all along…

Bright sparks
And so we’re in another German city and Mazda is being brave again. And world-beating -- at least in terms of slapping around the heads of premium brands like Mercedes-Benz and some of the world’s largest corporations (read: General Motors) to the HCCI punch.

Homogenous Charge Compression Ignition is the combustion engineer’s nirvana. It’s a state where a petrol engine can run on half the fuel it would normally require and at the same time produce 50 per cent more torque and ultra-low emissions.

And all without the need for a spark plug (sort of).

For a while it looked like the four-wheeled equivalent of cold fusion – great in theory but unachievable in practice. Although other manufacturers have test run petrol HCCI engines, they encountered challenges with real-world application.

Compression-ignition combustion is usually only achievable over a narrow rpm and engine load range, or so it seemed.

And then the Hiroshima’s bright sparks got serious. And now they’re about to deliver it in a production car.

Ironically, the technology Mazda’s boffins have used to achieve the first true production application for the so-called HCCI ‘sparkless’ petrol engine is, wait for it, a spark plug!

Via patented and ultra-fine control of fueling, ignition timing and around nine other engine and environmental parameters, Mazda’s SKYACTIV-X Spark Controlled Compression Ignition (SPCCI) engine uses a spark-initiated ‘fireball’ within the combustion chamber to boost combustion pressures and initiate compression ignition across a wide range of conditions -- with all the attendant benefits.

How do turbo-diesel levels of torque and economy, ultra-low emissions and the refinement and responsiveness of a high-performance petrol engine sound?

Got your attention?

X marks the spot
Of course, it’d be way too linear for Mazda to debut ground-breaking engine technology in isolation. So, last week’s Global Tech Forum at Mazda’s European development centre at Oberursel near Frankfurt, had quite a bit more squeezed into the one-day program.

Not the least of which was the debut of considerably altered SKYACTIV chassis and man-machine interface concepts.

The new body-in-white features the building blocks of the next generation of Mazda models and fittingly is being debuted in the brand’s best-selling, most important model – the C-segment Mazda3.

We’ll see more of it at next month’s Tokyo show and the new car proper is expected to debut next year.

For the time being Mazda is being tight-lipped on dimensional changes between generations. The cars we sampled at the Global Tech Forum were ‘mules’ mating existing 3 bodywork to the chassis and running gear of the next-generation models.

The accurate side profile match of the old bodywork on the new ‘frame’ indicates that wheelbase and height are largely unchanged. Closer observation suggests there has, however, been a track increase of in the order of 10-15mm.

Underneath the tweaked existing Mazda3 panels of the mules we drove is a whole new chassis that is claimed to deliver myriad improvements – not the least of which is a substantial improvement in the long-time Mazda bugbear: noise, vibration and harshness.

What has evolved is the way the new chassis distributes forces within its structure and how it copes with noise transmission and attenuation.

A new “multi-direction ring structure” is incorporated in the new platform design, which makes the chassis stiffer and refines load paths in both normal and crash scenarios.

The focus in normal conditions is to reduce road shock and noise but to also reduce the delay in energy transfer from suspension to the structure. This, Mazda says, along with better suspension component and seat design, improves the connection between driver and car.

So does it?

Behind the wheel
The matt-black Mazda3 mules we’ll drive to sample the next generation of SKYACTIV look remarkably normal as we’re introduced. One of my colleagues jokes in his best ‘Cherman’ accent that he wishes they were a bit more “Frankenschteeen”…

Inside, however, they are clearly bolted together in a manner resembling Ms Shelley’s Creature. There’s hard (or in some places, no) plastic trim and the air-con is channeled through two ‘agi’ pipe offcuts in the centre of the dash.

Our Mazda engineer chaperones warn us that only the anti-lock brakes work as advertised – no stability control, no lane keeping, no autonomous braking, etc, etc. Just like driving in the old days…

Yet the cars themselves are only a couple of weeks old and had only been in-country for a few days after being airfreighted from Hiroshima.

We’ll drive both auto and manuals but there’s only initial calibrations installed in terms of engine software and best guess in terms of the interface with the six-speed transmissions ‘borrowed’ from the existing Mazda3.

That’s Mazda -- being brave again.

How much can I tell you that’s relevant, given the brief drive of what’s essentially a proof of concept vehicle? Plenty – and chiefly because the engine works and is remarkably polished, despite the lack of validation miles and fine tuning.

The first impression of the car is lower noise levels and the relative muscularity of the powerplant. Sure, there are glitches in the matching of engine and transmission in the auto I drive first, but overall the power delivery is smooth and cultured… And there’s a good quotient of ‘go’ available under your right foot.

Engine response is sharp and immediate. Indeed, compared to a normal ‘atmo’ 2.0-litre, the SKYACTIV-X 2.0 is noticeably livelier -- even without resorting to kicking down a gear or two.

It’s easy to cruise at 160km/h on the unrestricted autobahn section but more importantly (for Oz) is the response in simulated overtaking from around 100km/h. Having recently driven over 2500km in a manual 2.0-litre petrol Mazda3 I can vouch for the added real-world performance.

Fuel economy measurements taken from the mule indicate the automatic version is returning between 7.3-7.7L/100km across the loop despite my “aggressive” driving. Simulations suggest a conventional SKYACTIV-G powered petrol 3 would have returned 8.5-8.8L/100km in the same conditions. That’s an improvement of more than 14 per cent.

Mazda promises better than turbo-diesel economy from the final versions – and a much closer alignment between testing cycle numbers and real-world economy.

For more than 90 per cent of the prototype drive, the SKYACTIV-X engine is operating in SPCCI compression ignition mode, says Mazda’s onboard instrumentation.

At very light throttle openings and at low speed you can detect a slight change in engine feel, but Mazda’s engineers believe that when calibrations and development is complete there will be next to know recognisable ‘steps’.

The manual mule I drive second isn’t as well behaved and uses a touch more fuel. It’s fast and smooth in normal driving but at idle the engine is ‘hunting’ up and down from 1200-2300rpm or thereabouts.

It’s a fault that’s just occurred and hardly surprising given the cars’ prototype status.

The other noticeable difference is noise. Even at this mule stage, it’s clear this is a quieter car than the fully developed current Mazda3. Just how much so we’ll have to wait for the finished version to quantify.

In terms of driver involvement and interface, that part of the update is extremely hard to comment on – given the type of road loop and traffic conditions we experienced. Yes, the ride is better on initial impressions – and even despite the fact the car seems to be a touch stiffer in terms of roll characteristics.

The steering has a good solid feel on centre. My feeling when I emerge from the car was that it is remarkably easy to place ‘just so’ on the road and has very good stability even at high speeds.

Is the above a factor contributed to by the chassis changes? I’m sure Mazda would like to thinks so. Again, we’ll need to drive properly calibrated production cars to pass proper judgment.

All the pointers are there, however…

Moving the game on
Back in 2010, I wrote of the then-new SKYACTIV Mazda6 mules we drove in Berlin that presented as impressively complete. Seven years on, Mazda’s bravery has been rewarded again.

It’s foolhardy to suggest the new Mazda3 previewed here will change the small-car game. There’s solid performance and refinement in the making, but my guess is that will really only bring the car up to the benchmark that Volkswagen’s Golf 7.5 has reset.

The same can’t be said of the SKYACTIV-X engine technology.

Mazda says it is committed to debuting a production EV with the option of a rotary range-extending system in 2019. The company’s first mild-hybrids are confirmed on the same timeline, with a plug-in hybrid on the books for “2021 and beyond”. But SKYACTIV-X is a technology that changes the event horizon for petrol engines.

Indeed, Mazda says SKYACTIV-X will keep internal combustion engines relevant though to beyond 2035. Even then, Mazda estimates that in combination with varying levels of electrification, 84 per cent of the vehicles it sells will still feature a combustion engine of some type.

Our initial, unrefined experience of SKYACTIV-X was impressive. If even 75 per cent of Mazda’s claims for the new technology’s efficiency and performance are true, then the internal combustion engine has turned over a new leaf.