Mazda’s new SKYACTIV-X engine provides the best of gasoline and diesel

Fuels |  2 min. read

If you have a car, odds are, the engine under the hood is an internal combustion engine.  That means, among other things, that every few hundred miles or so, you pull into a gas station and fill up the car’s fuel tank with gasoline or diesel.  That’s how it’s been since the first cars hit the road.

There are other ways to power a car – and 100 years from now, who knows what will be under the hood.  But today, and for the foreseeable future, it’s the internal combustion engine that will be getting us where we need to go.

Is that a bad thing?  Nope.

Nope – because it’s a proven, reliable, affordable engine – and because the internal combustion engine keeps getting better.

Better, as in 15 percent more fuel-efficient – and from the same engine, 15 percent more oomph (or torque, if you want to get technical). And it’s the engineers at Mazda and their new SKYACTIV-X engine which gets those new numbers.  We’ve mentioned it before, but today we thought we’d do a little Engine 101, and explain (a bit) how Mazda got to their new version of a classic.

The short (really short) explanation, is that Mazda combined a diesel and a gasoline engine into one engine.

(Photo from Mazda)

Here’s the slightly longer explanation:

  • Diesel fuel and gasoline are both made from the same barrel of oil – but there are differences between the engines that use them. Both engines get their power from burning the fuel.  Both engines use pistons that push up and down inside cylinders, which turns a crankshaft, which connects to the clutch, which connects to the gears, which connects to the axle, which moves the wheels.
  • But – in a diesel engine, the power comes from compressing the fuel. The piston moves up, and squeezes the fuel into such a small space that it gets hot and explodes, pushing the piston down, which turns the crankshaft, and so on.
  • In a gasoline engine, the power comes from setting the fuel on fire. The piston moves up, but not as much – and then a spark plug ignites the fuel, which explodes, pushes the piston, and so on.
  • Now, in the SKYACTIV-X, Mazda uses the fuel-squeezing compression of a diesel engine, and the ignition by spark plug from a gasoline engine. And that, along with some other engine tweaking, and some extra clean-up of the exhaust – gets the benefits of both a diesel and a gasoline engine, in one engine.

(Visual learners – you can watch Mazda’s version of Engine 101.)

And those benefits would be:  more power (like a diesel) – better fuel-efficiency (like a gasoline engine) – smooth, quick response when you put your foot on the gas (combination of both) – and, you fill up as always, at your local gas station.

So while we’re waiting for the nuclear fusion powered cars of the future, it turns out the trusty internal combustion engine has still got plenty up its (cylinder) sleeve.  Or as Mark Twain once said: “The report of my death was an exaggeration.”