Sounds somewhat similar to an engine Mazda is working on, though their engine does have a spark plug for when the engine needs to put out maximum power. Compression-ignition engines typically take a long time to burn the fuel dully, so the expansion cycle is long, as they noted in this article. This is good for maximum efficiency, but not for maximum horsepower. The Mazda engine is like this Hyundai engine in that it runs on compression ignition most of the time, but can switch to spark ignition when more power is needed, such as under acceleration. To me that combines the best of both engine types better than this Hyundai engine does. It is just a gasoline-powered diesel that achieves high enough pressure for ignition through clever shaping of the piston and direct injection. That"s interesting, but limited. It lets you run gasoline instead of diesel fuel, which is great, as diesel fuel is much more in demand, and more expensive.