Mazda to go Sky high with Mazda3

MAZDA has confirmed that its ground-breaking new SkyActiv engine and transmission fuel-saving technology will debut in its facelifted Mazda3 later this year.

The rollout will gather pace from 2012 with the arrival of the SkyActiv CX-7 replacement, which will debut at next month’s Geneva motor show as the Minagi Concept, as well as the third-generation midsized Mazda6.

As well as the new engines and gearboxes, the latter two will embrace the full SkyActiv chassis and body technologies, making the most of lower weight and higher safety, rigidity and aerodynamics properties to significantly improve efficiencies, safety and driving pleasure alike.

Touted under the ‘Sustainable Zoom-Zoom’ banner, the next Mazda6 Diesel – fitted with the new Sky-D four-cylinder unit – achieves an average fuel consumption of 4.2 litres per 100km and a carbon dioxide emissions rating of 112g/km from a 130kW/420Nm 2.2-litre four-cylinder turbo-diesel engine.

Mazda says this is an example of its commitment to reducing fuel consumption of its entire fleet by 30 per cent between 2008 and 2015.

Further aiding such efficiencies will be the stepped adoption of new technology under Mazda’s Building Block Strategy regime, beginning with i-Stop idle-stop to cuts emissions, as well as regenerative braking.

HEV hybrid electric vehicles – using Toyota’s Synergy Hybrid device – will come later.

All the mainstream production vehicles will be “organised” around a common architecture concept as well as a flexible manufacturing process known as ‘Monotsukuri Innovation’, which – through the diversification and commonisation of components and processes – allows for the deployment of “high-grade, high-performance technologies over a wider range of vehicle models as well as the ability to respond to customer demand more quickly,” according to Mazda.

In the interests of affordability and competitiveness, Mazda says it made the decision in 2007 not to go down the expensive downsizing/forced induction path like many other car-makers such as Volkswagen (TSI tech) and Ford (EcoBoost).

Top and middle: Mazda6-based prototype from the Mazda Technology forum. Bottom: SkyActiv-G engine.

Nevertheless, efficiencies have been gained, Mazda claims, led by the change of compression ratio of both the petrol and diesel engine to 14:1, although petrol engines in Australia will not achieve such high compression due to fuel variability here.

Typically, petrol engines are about 10:1, while diesels often exceed 17:1.

Two closely related families of petrol and diesel engines are coming on line.

In both SkyActiv-G direct-injection petrol and SkyActiv-D diesel guises, the ‘medium’ engines for smaller vehicles will be torque-limited to 270Nm, while the ‘large’ units will be capable of 460Nm, for bigger cars and SUVs.

The SkyActiv-G will be as small as 1.3 litres for the next-gen Mazda2 (2013) while a 1.6-litre SkyActiv-D is thought to be in the pipeline.

Compared with today’s heavier MZR-CD diesel, fuel economy improves 20 per cent, while responses are smoother and more linear from low to medium speeds (the adoption of a twin turbochargers – where one small and one large turbo are operated according to driving conditions – helps here), and engine speeds increase from about 4500rpm to 5200rpm.

Consequently, SkyActiv-D engines also meet all stringent exhaust gas emissions regulations without the need for expensive after-treatment technology such as the urea selective catalytic reduction device fitted to the current CX-7 diesel, which counteracts nitrogen oxide (NOX) emissions but adds about $1000 to the price of the vehicle.

Mazda powertrain manager Susumu Niinai said the target of the diesel was to achieve economy of a petrol car from two classes down.

In the SkyActiv-G petrol engines, fuel consumption falls 15 per cent compared with the current MZR equivalent while offering 15 per cent higher torque in the low and mid ranges.

Cutting ‘knocking’ (abnormal combustion) issues was a priority, since it causes significant torque drops. Reducing weight and friction were further aims, while the implementation of multi-hole Piezo injectors aid cold-start performance and help to eliminate misfiring.

Besides the compression ratio advances, Mazda says all SkyActiv engines address other typical internal combustion engine inefficiencies such as exhaust, cooling, pumping and mechanical losses.

The introduction of a new 4-2-1 exhaust manifold design also assists efficiency significantly, as it impacts potentially prohibitive temperature rates.

On the gearbox front, in-house six-speed transaxles replace the existing five-speed and Aisin-Warner six-speed auto gearboxes for a four to seven per cent improvement.

For the SkyActiv-Drive (automatic), Mazda says it has chosen a torque converter and stepped transmission that combines some of the best characteristics of a DCT dual clutch transmission (speed, driver feel, economy) and CVT continuously variable transmission (low-speed economy, shift smoothness) in order to achieve a direct-drive feel, high-efficiency gearbox.

Among its new technologies are an expanded lock-up range that is claimed to suppress noise and vibration, and an ECU that optimises the hydraulics within the gearbox for quicker, smoother and more efficient control.

Mazda says it is investigating seven, eight and even nine-speed automatic gearboxes in the midterm, but for now, for mass-market front-engine/front-drive configurations, six speeds are it.

Meanwhile, the six-speed manual transmission has been designed to feel more like an MX-5s – short, fast and fun. Among its advances is greatly reduced friction that helps improve operation and economy, and a smaller, lighter casing. The reverse idle shaft has also been dropped from the manual because it is no longer necessary, cutting mass.

Comparing today’s Mazda6 with its successor, Mazda says body rigidity rises by 30 per cent for top crash test performance, even though the body-in-white weight slips eight per cent by employing straight and continuous framework front to rear and from side to side to greatly improve strength and rigidity.

Where curvature was necessary, more bonding has been used.

The upper body also adheres to this new principle. The suspension mounting positions are directly (weld) bonded with the underbody framework for a ‘dual brace’ effect.

Four ring structures, including the roof rail and B-pillar, add reinforcement, while more crossmembers for the suspension create both local and overall rigidity gains.

Plus, the adoption of multi-load path structures help with the dispersion of crash energy throughout the car, and work in lateral as well as rear collision events. Leveraging high-tensile steel more frequently – from 40 to 60 per cent – also contributes to weight loss.

In fact, paring weight to the tune of at least 100kg per model – with the chassis of the next Mazda6 weighing some 14 per cent less than today’s car – while greatly boosting rigidity and safety attributes has also driven the SkyActiv Chassis development.

Here, too, new production technologies contribute, as does the implementation of more high-tensile steels and other new materials, as well as computer-aided engineering.

Finalising the locations of the powertrain, chassis and other components was the first step to these goals, resulting in what Mazda calls “an ideal body structure”.

Mazda says achieving ‘driving pleasure of oneness between car and driver’ is paramount, underpinned by top-level comfort and security.

Or, in other words, better low and mid-speed agility, combined with improved high-speed stability and ride comfort over the existing models, is key.

To this end, the company’s engineers have redesigned the front and rear suspension (MacPherson strut and multi-link from the C-segment Mazda3 upwards), fitted a new lightweight high-rigidity crossmember and developed a new electric power steering system.

Expect every next-generation model from the Mazda2 to the CX-9 replacement to employ a hefty chunk of related chassis architecture.

Even the future MX-5 and RX sports car ranges will incorporate aspects of this approach despite their rear-drive layout.

Drive impressions:THE problem with driving a future production car is that the current models seem so, well, yesterday.

And so it was with the first Australian drive of a Mazda Sky Activ technologies prototype.

The pre-production mule – officially known as ‘technology prove-out vehicles’, or TPVs – was flown to Australia in upcoming 130kW/420Nm 2.2-litre turbo-diesel form with six-speed automatic transmission specifically for evaluation by the local media.

Compared with the earlier versions GoAuto drove in Germany last year, this TPV evolved in all areas, bringing it closer to what the production vehicles based on this all-new chassis design would be like.

Wearing current-gen Mazda6 sedan clothing – but with the longer and wider wheelbase bulging out underneath like a child’s face just dying to blurt out a secret – the weathered white prototype looked decisively ordinary on the Sandown Raceway circuit. Australian law prohibited the company demonstrating the future tech on public roads in an unregistered vehicle.

For fun, Mazda also brought along a current-gen Mazda6 MZR-CD diesel manual, as well as its petrol auto stablemate.

Now, in isolation, few would really complain about the existing Mazda6’s dynamics, although the raceway revealed a propensity for body lean and some high-speed instability.

Compared with the Mazda SkyActiv Technologies TPV prototype – a completely different car other than the scarred Mazda6 body and bitsy interior – the existing models may as well have been running on near-flat tyres.

Despite some diesel-like clatter at idle, the TPV’s engine does not sound nor feel like a diesel drinker from behind the wheel.

And unlike most diesels, the Sky Activ D revs with a zingy eagerness to the 5500rpm limit without sounding too strained.

But it was the energetic step-off acceleration and wads of low-down torque that really impressed us. Just feathering the throttle produced an instantaneous response, and that flexibility remained right to the red line.

It brought to mind modern twin-turbo BMW diesels – the TPV prototype’s engine was that good.

Did we mention that this will be the first production Mazda diesel passenger car with an automatic gearbox? We wondered if the Japanese company had not quietly slipped a DCT dual-clutch transmission under the bonnet, so swift and smooth were the gear changes.

Bolt-like decisiveness, with no DSG-like low-down lag at take-off, it will make the long wait for a Mazda diesel auto totally worthwhile. We just hope the production SkyActiv-D with SkyActiv-Drive (what a mouthful!) is as good as Mazda’s mature test mule.

Just as noteworthy is the chassis. At Sandown, the TPV felt like it combined the sharpness of a feisty Ford set-up with the lightness of, well, a BMW, if not an MX-5. The Japanese engineers on hand told us that the prototype’s weight distribution was slightly better than Mazda’s current sedan crop, but still in the vicinity of 60:40 front-to-rear.

Whatever. Low-speed turn in was satisfyingly crisp and composed, yet the fast slalom changes revealed a tied-down rear end. This car is some 140kg lighter than the equivalent current Mazda6 and – boy – it shows.

We had to remind ourselves that the steering was electric. Surely this prototype has the potential to morph into the sportiest and most interactive Mazda sedan.

The only real advance we could not ascertain was the ride quality – a racetrack is no place to assess suspension comfort. But on the strength of all the other attributes, we have high hopes indeed.

And we didn’t even notice if that notorious Mazda road noise issue was present in the TPV. The engineers claim that this issue, too, will be exorcised from the future product. We’ll have to wait and see.

Later in the day, a drive in today’s regular diesel manual Mazda6 showed just how far the Japanese engineers are progressing with the new chassis, engine, suspension and other SkyActiv technologies. Not that the current vehicle is lacking. It just feels soggy and old by comparison.

Unfortunately it will be at least 18 months before we can try the full production SkyActiv package for ourselves on Australia’s public roads.

On the strength of the Sandown raceway run, we are definitely Sky-hooked.