Originally Posted by pedex
increases in compression and rpm range = less engine life all else being equal
Who said anything about increases in compression and rpm range? Granted, the
EPA test used a TDI engine, but that's only because it's the only stock/cheap engine with a VNT and EGR cooler iirc. So, when running high rates of EGR, they didn't have to make many modifications to the engine, only run SAFI (Stand Alone Fuel Injection). The point of the paper was that higher octane fuels allow for more EGR, which fills up the cylinder and minimizes low load pumping losses. This can be done with lower compression engines, all that's needed is turbocharging/EGR cooling. The same system was mentioned in a Uni of Wisconsin paper. In fact, the engine would probably last longer because it's more efficient. It won't have to inject extra gas just to overcome the pressure difference between the cylinder and crankcase on the intake stroke.
Originally Posted by pedex
I would guess the extra things needed to be done to ICE engines to handle more compression like whats done with diesels would more than likely offset any gains even done on a massive scale.
Hardly. If this were the case we wouldn't have drive by wire, VVT-whatever, or anything else. The only thing needed for this would be a turbocharger, EGR cooler, and associated hardware. I bet a reasonable approximation could be done w/o turbocharging via internal EGR.