just happened to be browsing on GDI the other day and came across this site;
http://www.sema.org/main/semaorghome.aspx?id=55158
in it (at the end), it mentions a new sort of hybrid engine whic seems to be a compression ignition gasoline vehicle... not sure if it really fits the bill as far as your ideas are concerend, but I thought I'd mention it anyway;
There is no reason why gasoline shouold not be used in a CI engine, as long as you can control the tendency for pre-ignition... I guess that's why direct injection would be used for the above concept. (by the way, although gas oil is the 'normal' fuel used for diesel engines, they use kerosine in dscandinavia as gas oil tends to form wax crystals at lower temps (even with flow modifiers...)One of the interesting aspects of GDI is that, in some respects, it makes a gasoline engine more like a diesel. While we will discuss diesels later, it’s important to note that there is another technology under development which promises to be better than either gasoline or diesel. It’s called Homogeneous Charge Compression Ignition (HCCI), and it amounts to basically a gasoline-fueled engine that, at times, thinks it’s a diesel. While it does behave like a normal spark-ignited gasoline engine under some circumstances, under others it disables the sparkplugs and ignition system and relies solely upon spontaneous combustion due to compression, just like a diesel. The advantage of this dual personality is that gasoline does have certain benefits relative to diesel when it comes to emissions and availability. Furthermore, the fuel itself is generally less expensive and is more suitable for cold climates. Let’s face it, gasoline is the preferred fuel today and will likely stay that way for the near to moderate future. While technologies such as GDI and others we will discuss later have greatly improved the efficiency of gasoline engines, they are still at an inherent disadvantage to diesels in some respects, primarily having to do with pumping losses. HCCI tries to combine the strengths of both gasoline and diesel engines in a way that reduces their weak points. The end result is expected to be a gasoline engine that is cheaper to build than a diesel yet has as good or better fuel efficiency with lower emissions and superior performance. At least that’s the goal. While there currently are no HCCI engines in production, it’s very likely that we will see one soon, probably from an Asian manufacturer. Since the cost of the technology will at first be relatively higher than for a standard gasoline engine, it probably will first appear on luxury and/or performance models that are likely of interest to SEMA members.