Low-displacement, turbo engines produce good efficiency but within a narrow power band.

In the race to hit future fuel economy requirements, Mazda believes that its new Skyactiv-X engine is a better alternative than the modern trend of automaker’s using small-displacement, turbocharged powerplants. The Japanese automaker’s upcoming powertrain family uses spark-controlled compression ignition, which means that combustion process generally happens without using the spark plugs. Instead, the mill operates more like a diesel by compressing the air-fuel mixture until it ignites. 

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"We don't necessarily believe in what the other guys are doing," Mazda North America powertrain engineer Jay Chen told Road & Track. "We believe the internal-combustion engine is here to stay, we believe our approach is better."

“Drive your Mazda3 in a lower gear. Then you'll know exactly what this drives like," Chen told Road & Track about the experience of operating the Skyactiv-X engine.

Mazda’s engineers believe that the recent trend of automaker’s using low-displacement, turbocharged engines and CVTs is simply a way to earn good numbers in fuel economy tests. The firm thinks these powertrains have a narrow band of operating at peak efficiency, which means they generally aren’t very good to drive on regular roads.

Gallery: 2018 Mazda6

Mazda sees that turbocharging has its uses, though. For example, the company’s new SKYACTIV-G 2.5 T is a 2.5-liter turbo four-cylinder that produces 250 horsepower (186 kilowatts) and 310 pound-feet (420 Newton-meters) of torque in the CX-9 and upcoming 2018 Mazda6 (above).

The first Mazda vehicles with Skyactiv-X engines will arrive in 2019, and there will be a plug-in hybrid version in 2021. Chen told Road & Track that the current-generation Miata won’t be among the models getting the new powertrain tech. Spy photos show the automaker already testing the Skyactiv-X tech on the road under the hood of modified examples of the current Mazda3.

Source: Road & Track

Gallery: Mazda3 Spied Testing Skyactiv-X Engine