While most major automakers have been preparing for the wholesale conversion of their future fleet to alternative-fuel powertrains such as hybrid, electric, and fuel-cell vehicles, Mazda has been fine-tuning the good ol’ internal-combustion engine (ICE) for better miles per gallon.
This strategy has paid off: Over the past five years Mazda has had the highest corporate average fuel economy of any automaker in the US, at close to 30mpg.
Of course, Mazda offers a limited number of vehicles—mostly small to midsize cars and crossovers and no large trucks. While this helps give it an overall fuel economy advantage over larger “full line” automakers, within each vehicle segment Mazda also rank at or near the top in fuel economy over competitors.
So as other automakers double down on alternative fuel vehicles—which currently make up only a small sliver of the overall market—Mazda is focusing on wringing the most fuel efficiency out of its ICE power trains. It’s been successfully doing this via its Skyactiv technology that was introduced in 2011 and, simply put, uses high compression within an engine’s cylinders to increase fuel efficiency as well as engine output.
Mazda USA recently invited a group of media (including yours truly) to preview and road test its next-generation ICE engine technology, called SkyActiv-X, near its Orange County headquarters. I came away impressed with not only the new power train’s performance—Mazda’s marketing is slogan is “Driving Matters,” after all—but also the way Mazda is positioning SkyActiv-X technology for the future.
Mazda’s X Factor
The next-generation SkyActiv-X engine uses what’s known as homogeneous charge compression ignition (HCCI). While other automakers have experimented with HCCI engines, the technology’s high compression characteristics make it susceptible to “knocking” (when combustion of the air-fuel mixture in the cylinder is mistimed), which can result in engine damage.
Mazda came up with a solution to this problem by leveraging a leaner fuel mixture (less fuel is mixed with air in each cylinder) to control engine knocking. It also devised a method to carefully control pressure in the combustion chamber at various ambient temperatures and humidity levels, which can significantly affect the combustion process.
To prove the effectiveness of this new approach, Mazda gave us the opportunity to drive prototypes based on a Mazda3 equipped with SkyActiv-X engines. We had about 30 minutes behind the wheel of both manual and automatic transmission models. Besides enhancing efficiency, the high compression ratio gives the SkyActiv-X extra low-end, which was especially evident in the prototype with the manual transmission.
The current 2.0-liter SkyActiv-G engine in the Mazda3 is rated at 155 horsepower and 150 lb-ft of torque. According to Mazda, the prototype SkyActiv-X engine produces about 178 horsepower and 170 lb-ft—and this extra seat-pinning torque oomph was very noticeable during our test drive. Mazda also said that SkyActiv-X approach extends to the “every aspect of the vehicle,” including the car body, chassis, and transmission to maximize efficiency, reduce weight, and improve aerodynamics.
I detected a bit of knocking under hard acceleration, particularly with the manual transmission, but it was barely noticeable. Mazda said it’s still working on final calibration, and an engineer riding shotgun with me said the automaker expects to have the knocking resolved before production.
Mazda is targeting a 20 percent improvement in fuel economy with the new SkyActiv-X platform, and it will be combined with a mild hybrid system, which wasn’t on the prototypes we drove. This indicates that Mazda isn’t completely married to ICE engines, and it plans to ramp up production of its own alternative-fuel vehicles, mainly hybrids and EVs, over the next decade.
But Mazda believes ICE engines will play a critical role even as hybrids and plug-in electric hybrids become prevalent. Dave Coleman, a vehicle development engineer at Mazda, also noted that “SkyActiv technology can be used in all hybrids to improve overall fuel economy.”
Mazda believes ICE engines will play a prominent role in cars at least until 2050, which is why the automaker hasn’t completely climbed on the alt-fuel bandwagon compared to much larger competitors. And Mazda’s SkyActiv technology allows the niche automaker to zig—or zoom-zoom—as other car companies zag.