Does anyone know what ever happened to Mazda's skyactiv thing? Was supposedly going to help ICEs be more fuel efficient by adding an extra stroke cycle with water? Seemed very promising, but I haven't heard anything about it in years.
You’re probably thinking of Skyactiv-X [1] which is kind of hybrid between a normal spark ignition and compression ignition. It’s been in the 3 in Europe for a couple years but never came to the US. I’ve heard it’s a combination of cost and not-great horsepower, plus it runs louder. Basically for a lot more cost you get something inferior to hybrid in a lot of ways.