SKYACTIV-X is a revolutionary engine, a world first. It employs a method of combustion—compression ignition—that the combined might of the motoring sector has been trying to master for over two decades.
Why SKYACTIV-X is a defining moment for the industry
The development of this technology comes from Mazda’s “Well-to-Wheel” approach, which considers real-world emissions over a car’s entire life cycle. Of course, Mazda plans to introduce electric vehicles to areas that have clean energy sources and will add hybrid and plug-in vehicles from 2020, but the internal combustion engine will continue to be the base power unit for 85 percent of all cars up until 2035. That’s why SKYACTIV-X is such an important breakthrough in Mazda’s goal to reduce “Well-to-Wheel” carbon dioxide emissions to 50 percent of 2010 levels by 2030, and a staggering 90 percent reduction by 2050.
Here’s how the SKYACTIV-X works…
In a gasoline engine, the fuel-air mixture is ignited by a spark from the spark plug. In a diesel engine, the fuel-air mix is compressed and ignites through pressure and heat alone. Diesel is more energy dense than gasoline, which also means more air and less fuel goes in, making for better fuel economy. And although diesel engines tend to release less carbon dioxide than gasoline engines, they emit particulates that, unless trapped or treated, can cause pollution. Diesels, which are often turbocharged, have a reputation for having lots of torque even at low revs, while gasoline engines can rev higher and produce more horsepower at those high revs.
SKYACTIV-X offers the best of both diesel and gasoline engines with none of the disadvantages. It does this thanks to a new technology called Spark Controlled Compression Ignition (SPCCI). Running on regular gasoline, SPCCI works by compressing the fuel-air mix at a much higher compression ratio, with a very lean mix. The SKYACTIV-X engine uses a spark to ignite only a small, dense amount of the fuel-air mix in the cylinder. This raises the temperature and pressure so that the remaining fuel-air mix ignites under pressure (like a diesel), burning faster and more completely than in conventional engines.