Gen-X Mazda takes on EVs
Compressionignition petrol can be cleaner than plug-in power, says Mazda. We drive 2019’s SkyActiv-X technology. By David Linklater.
We’ve just been to Germany to drive the most hi-tech Mazda3 in existence. It looks thoroughly unremarkable save amatt-black paint job, the interior is seemingly made of plastic scraps and it has no airbags or stability control.
But underneath the familiar sheet metal is Mazda’s nextgeneration SkyActiv-X engine and platform technology.
The Japanese maker’s current powertrains are SkyActiv-G (petrol) and SkyActiv-D (diesel). The next step is called ‘‘X’’ because it crosses those petrol and diesel technologies over into one engineering package. SkyActiv-X is still fuelled by petrol, but employs compression-ignition just like a diesel, resulting in a 20-30 per cent improvement in efficiency.
Mazda claims that the efficiency advantages of SkyActiv-X will make it environmentally superior to many electric vehicles (EVs) on a ‘‘well-to-wheel’’ (or fuel extraction to driving) basis.
In New Zealand, more than 80 per cent of electric power comes from renewable resources. But that’s not the case in other parts of the word. Mazda claims that if you compare a SkyActiv-X car with a 21.2kWh EV, the petrol model is potentially cleaner once you account for non-renewable electricity generation: 142g/km for SkyActiv-X, compared with 200g for an EV powered by coal-fired electricity and 156g if the charge comes from petroleum-produced power.
The cleanest thermal power generation method is Liquid Natural Gas and according to Mazda’s sums it’s the only one that beats SkyActiv petrol: 100g/km.
SkyActiv-X is integral to Mazda’s stated aim of reducing well-to-wheel emissions to 50 per cent of 2010 levels by 2030. It’s also a reality check, says the company: with internal combustion engines (ICE) expected to be at the core of 80 per cent of new-car powertrains well beyond 2030, that’s where the biggest eco-gains can be made.
Mazda has been talking about lean-burn compression-ignition petrol engines for a long time. The main issue has been achieving stable combustion in the face of low temperature, insufficient time and inconsistent fuel density.
The breakthrough for SkyActivX is the use of the spark plug to completely control the switch between combustion types and broaden the operating region of compression-ignition. The spark is used as an ‘‘expanding fireball’’ that becomes the right size to ensure optimum air-fuel mixture and ignition timing. Mazda calls it Spark Controlled Compression Ignition (SCCI).
Mazda claims SkyActiv-X brings major improvements in performance and economy. Launch response is better because the throttle valve can remain more open, while acceleration continues to expand at high engine speeds (unlike conventional diesel).
SCCI technology also gives a flatter fuel consumption curve, which means better ‘‘real world’’ economy, says Mazda.
In short, the ‘‘crossover’’ technology of SkyActiv-X is intended to bring together the fuel economy, torque and response of a diesel with the power and cleaner exhaust of a petrol.
The hand-built prototype cars we drove in Germany near Mazda’s R&D centre at Oberursel, near Frankfurt, were still very far from production. But the SkyActivX technology was present and about 80 per cent correct on our 100km loop of urban and motorway/Autobahn driving, in both manual-transmission and automatic variants.
The most striking initial impression is how quiet the new powertrain is – even more remarkable when you consider the rudimentary clothing it’s wearing.
The second is the linear and responsive way the engine delivers its power. We drove both manual and automatic versions on the same loop and the fluid nature of the powerplant made manual driving a breeze even in heavy traffic. Admittedly, the three-pedal gearbox had an advantage because it’s direct-drive, whereas there’s still much calibration work to do on the six-speed automatic.
Mazda engineers logged fuel consumption in real-time for our drive-loops, comparing them to a reference figure from a currentmodel Mazda3 SkyActiv-G 2-litre. My car registered a 15 per cent improvement, which I’ll claim as a huge win because I pretty much ignored the instruction to cruise at 100kmh on the open road. What’s the point of travelling to Germany to drive on the Autobahn if you don’t cruise at 180kmh?
The powerplant is just one newgen element of these prototype vehicles. They’re also riding on Mazda’s next-generation SkyActiv platform – the first major upgrade to the architecture since 2012. Here’s where it gets ethereal: Mazda claims to have studied human motion carefully and tried to replicate that ‘‘dynamic balance’’ in its platform configuration.
Huh? Well, as you walk the motion of your pelvis is regular, with the upper body moving in the opposite direction and the legs transferring reaction force from the ground. Mazda says its new platform and carryover technology (G-Vectoring Control for example) all work towards replicating this human state.
There’s a new front-seat design shaped around the ‘‘gravity centre’’ of your rib cage, a new multi-directional ‘‘ring structure’’ in the chassis to better control diagonal force from the suspension and redesigned vibration damping that is not only supposed to reduce noise, but also control the direction it comes from to increase what the company calls the ‘‘quality of quietness’’.
The first production SkyActiv-X car will come in 2019. While Mazda won’t confirm what that will be, it was a prototype Mazda3 we drove, there’s an all-new Mazda3 due at that time and... well, you get it. Aside from the new powertrain and platform, that model will also introduce the next generation of Mazda’s Kodo styling philosophy.
So it’ll be all change, although the SkyActiv-X engine won’t dominate Mazda’s model lines.
It will be sold alongside G and D, both of which will be further evolved. The X-generation is also well-suited to mild-hybrid technology, and we’ll see that alongside Mazda’s pure EVs – targeted at countries with renewable power generation, NZ hopefully included – from 2019.
Mazda’s development of plug-in hybrids has taken second place to the potential of SkyActiv-X so they won’t come until much later, from 2021.