Subaru Reinvents The Boxer Engine, Minus The Direct Injection

Any news on a diesel making it to North America? There's Euro diesel version but I have no idea just how series of an effort it is on the part of Subaru.

I see some rather unsubstantiated claims about long stroke engines having better thermodynamic efficiency than short stroke ones. Can anyone cite some proper engineering references as to why this should be so? Because I've never run into any myself. In fact, the opposite claims are usually made. A larger bore allows bigger valves and better breathing, and the total distance for a flame front to travel from a central plug to the extremity of the cylinder is less, because the capacity of the cylinder increases as the square of the bore and only linearly with the stroke. Then. everyone goes on about long stroke engines having better torque. Hmm, like Hondas, you mean, which have a hard time removing the skins from rice puddings at low revs in my experience. Remember that a bigger piston puts more force onto the longer stroke, and there isn't much overall difference, as witness the old and new engines here. The only reason I can think of for the change is to make the pistons much lighter, and to make it easier to have a compact combustion chamber. But each ring will have to move farther and faster in the bore, and each rod big end will encounter more sliding friction on the crank. I'd have to say it's a bit of a wash, but allows the new engine to be more like the diesel casting. I'm open to anyone's referenced arguments as to the merits of a long stroke. But lowered volumetric efficiency with the smaller valves does not equate to higher efficiency, and the thermodynamic efficiency argument I've only read as anecdotes rather than real engineering findings.