While not a hybrid technology, it supposedly helps reduce fuel consumption and emissions. If you're not familiar with the technology it's a revolutionary engine design that Mazda developed that uses a type of HCCI (homogenous-charge compression-ignition) cycle. This is considered the holy grail of internal combustion engines because it takes what makes diesels more efficient (high compression and extremely fast burn) and uses a homogenous air-fuel mix, made with gasoline and air, that eliminates the emissions penalties of diesel engines (so no soot or high NOx emissions). The result is a highly efficient engine (even without hybrid technology) with extremely low emissions. I was considering one for my next car. But there's one big problem. I live in the USA where it was never made available. So, forget that one. Next...
US gas prices are too low. Most would be unwilling to pay for the added expense for the improved efficiency. It's why hybrid options to ICE models were low seller for a long time. Even when its price was lower, diesels were a smaller part of the car market than hybrids.
The idea is that a very lean charge that isn't apt to ignite merely under pressure in a predictable way is compressed, then a small rich charge is added and ignited so as to spike the pressure in the cylinder that causes the lean gasoline mix to ignite. I have never driven one. I understand from reading that they give 15 to 20% better torque that mostly shows up in the upper rev range. Reliability seems very good too. This should be a good engine for a cheap car without having to add a turbo to get it to move more quickly. I've read that the sound may not be beautiful. A youtuber noted that the engine confers no marketing advantage over normal engines. An owner can't brag about saving the planet with a hybrid or think he has something very sporty because he has a turbo. Another youtuber noted that new car buyers expect a lot of torque at all engine speeds, especially in the US/canadian market, and don't like having to get an engine over 4krpm to get a car really moving. In a future with smaller, simpler and less expensive cars, a hatch with one of these engines is a choice I'd like to have.
Mazda has long taken on extra risk in advanced combustion science for their engines. The way I see it, they lack access to broad enough markets to apply what they're coming up with. I could see this tech working out well for larger motorcycles, but Mazda doesn't make those.
I understand that Mazda has a size problem, but they can also make a product that is endearing. I have a Scion iA, a badge engineered Mazda2. It barely makes more than 100hp, and is engaging in a way a Prius isn't while turning in more than 50mpg in suburban driving. They can tune their products, like a mini-minivan, with a bit of character. From what I've gathered, the skyactiv x hasn't displayed any downsides in the years it has been out in other markets.
