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The new 2.9-litre, four-cylinder SkyActiv engine in the 2012 Mazda3 is rated at 155 horsepower and 148 lb-ft of torque. (Mazda)
The new 2.9-litre, four-cylinder SkyActiv engine in the 2012 Mazda3 is rated at 155 horsepower and 148 lb-ft of torque. (Mazda)

Technology

Revving up the fuel economy race Add to ...

Here’s some important news for Canadians: American car buyers are shedding their gas-guzzling ways, increasingly turning to four-cylinder engines rather than sixes and V-8s.

The simple truth is that what Americans want, Canadian car buyers get and that means more fuel-efficient, high-performance four-bangers are heading our way.

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Among them is Mazda’s new SkyActiv four-cylinder now arriving in dealerships. If you are planning to buy a Mazda3, give the SkyActiv version a long look.

For 2012, Mazda Canada will in fact offer three engine choices with the 3. The first two are carryover engines, a 2.0-litre rated at 148 horsepower and a 2.5-litre at 167 hp. Neither is particularly special.

The Mazda3 you want is the one with the SkyActiv four. It starts in the GS model at $18,995 and gets 4.9 litres/100 km on the highway from that all-new 155-hp, 2.0-litre engine under the hood.

Don’t be deceived by the engine size and power output, either. Numbers are useful to a point, but the real story here is – and forgive the pun – the real-world performance. No other normally aspirated four-cylinder powertrain is as responsive and as fuel-efficient as the SkyActiv one. Period.

Still, Mazda’s rivals all offer pretty good fours. They have no choice. According to trade journal Automotive News, IHS Automotive says 43 per cent of U.S. light vehicles sold in the first half of 2011 came with a four. In addition, J.D. Power and Associates reports that when one strips out fleet buyers the sales numbers are even more interesting. More than half of all vehicles sold to retail customers had four cylinders – up from one-third in 2006

Canadians went down this road long ago, shifting to fours and downsizing to compact and subcompact vehicles in larger numbers to counter the impact of high fuel prices. The Canadian car market has been 50 per cent compact and subcompact for years now.

Meanwhile, auto makers from Mazda to General Motors and from BMW to Mercedes-Benz, are shrinking vehicles and engines to meet tougher 2016 federal fuel economy rules in both the United States and Canada. This means we’ll see more high-tech engines in a growing number of smaller cars. And not just econo-boxes. Both BMW and Mercedes-Benz are getting back to four-cylinder offerings in a big way with future products.

Yes, car companies are racing to remake engines, pushing refinements and technology to squeeze out more oomph per piston. Mazda, a tiny auto maker by global standards, is betting the company’s entire future on a short- and medium-term bid to refine the traditional internal combustion engine while also rolling out technologies that save fuel in even the smallest ways.

Mazda’s marketing spin calls its approach “sustainable zoom-zoom.” The essence of this gambit is to eliminate all waste and inefficiency in the ICE (internal combustion engine) and the powertrain of today overall, making way for more ambitions moves into hybrids and full electric-drive vehicles at the end of this decade and beyond.

For Mazda’s SkyActiv Mazda3, the gas engine delivers more efficient combustion and the transmissions – manual and automatic – are lighter, smoother and more responsive. The chassis bits are lighter, too, (to save fuel) and even the sheet metal is cleaner: the 2012 Mazda3 sedan has a 0.27 coefficient of drag, while the four-door hatchback comes in at 0.29. That’s quite slippery for a family runabout.

To understand SkyActiv, imagine a team of engineers and stylists grinding out every imaginable and cost-effective detail in a car’s performance, all with an eye to improving fuel efficiency without compromising go-power.

Mazda is hardly alone, though. Ford is aiming for a similar goal, with its centrepiece engine technology being downsized and turbocharged EcoBoost engines in several vehicles and six-speed transmissions across its entire North American lineup.

Like Mazda, Ford does not want consumers ever to feel they are giving up power. Indeed, Ford's EcoBoost engines typically deliver 120 horsepower per litre, compared to 80 hp per litre in normally aspirated engines.

Car companies are scrambling to find inexpensive ways to reduce friction inside engines with simple changes such as going to thinner oil – oil with a lower viscosity. As well, before very long buyers will find that almost every four-banger sold in Canada will have direct fuel injection and variable valve timing (to improve engine breathing). Other ways to get more power on demand while using less fuel in most situations: turbocharging, cylinder shutdown and stop-start systems that turn off the engine when you’re stuck in traffic or at a stoplight.

The race to reduce friction offers the most promise for the least investment, however. As Kenichiro Sarawatari, the Mazda3 program manager notes, in a typical gas engine, 70 to 90 per cent of the fuel energy is lost when you work the throttle, depending on the engine load. The search, then, is for more efficient combustion in a reduced-friction motor.

Mazda calls its chase to cut friction losses part of a larger “gram strategy” – the idea being that Mazda’s engineers will look for savings of as small as a gram – literally and metaphorically – to save fuel. That said, Mazda is part of a long list of auto companies looking for ways to limit the problems associated with metal-to-metal contact within an engine – the kind that produces heat and therefore reduces engine power.

Honda, for instance, has an Odyssey minivan that arrived all-new last year with a 3.5-litre V-6 boasting reduced engine friction by 4 per cent. Like Mazda with the SkyActiv 3, which has a new piston design, the Odyssey’s piston assembly is designed to reduce power losses.

Over at Mercedes, a coating process called Nanoslide helps to reduce piston friction within the engine cylinder walls. Honda has applied a coating treatment of its own to reduce friction inside the 1.8-litre four that powers the 2012 Civic.

As the old saying goes, the devil is in the details – and one of those details is to design new four-bangers with very tight tolerances that among other things reduce engine oil splashing around inside, creating drag and inefficiencies. Mazda has gone with a smaller combustion chamber in the 3 to improve performance in both fuel economy and power. In a nutshell, powertrain engineers now spend the bulk of their time reducing energy losses wherever possible.

The Mazda types argue they have made the greatest commitment in the car business to squeezing out everything possible in a gas engine, year after year and not just for 2012. Certainly no one has gone further. SkyActiv combines direct injection, high compression and (coming) stop-start engine technology with a new, more fuel-efficient transmission to improve fuel economy.

What sets Mazda apart from so many rivals is its public commitment to a complete powertrain overhaul, along with new vehicle designs and lightweight chassis structures. The overall aim is to save fuel without sacrificing the “zoominess” that Mazda says sets it apart from the Hondas and Fords and Toyotas and Chevys of the world.

“SkyActiv is a holistic approach,” says Don Romano, Mazda Canada president and Mazda’s North American chief marketing officer, “that includes everything from lighter, more responsive and more fuel-efficient engines, new transmissions, weight reductions and manufacturing improvements, combined for fuel economy improvements up to 30 per cent by 2015 (from 2008 levels).”

SkyActiv is now being rolled out globally, including the powertrain option in the Mazda3. Later this month, the CX-5 small crossover will arrive as the first Mazda model with a combined SkyActiv engine, transmission and chassis.

Mazda may have the best buzz words for what’s happening here, but all the auto makers are heading in a direction designed to save you money at the pump without sacrificing performance and while also meeting 2016 fuel rules.

All this means that gas guzzlers are about to become about as sexy as a garbage truck.

Follow on Twitter: @catocarguy

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