Mercedes Benz introduced something very similar to this ten years ago[1]. The engine was using HCCI at low RPM and conventional spark-plug ignition at higher RPM.
That was purely experimental though - Mazda's is going on sale to the public which indicates that this is a much more evolved product.
Whilst most other manufacturers have persued downsizing and turbos to get efficciency on paper (at the expense of real world emmissions) Mazda have gone another road with their SkyActiv technology and it seems to be paying off for them.
Whilst most other manufacturers have persued downsizing and turbos to get efficciency on paper (at the expense of real world emmissions) Mazda have gone another road with their SkyActiv technology and it seems to be paying off for them.