compression-ignited ethanol engines are used in brazil since a long time ago, but retained the original compression ratio... the main problems are the cold starts (in some cases there are 2 injection pumps: one to cold starts using diesel and the other to the ethanol running, but if there wasn't enough ethanol diesel could be used without any trouble) and the fuel pump lubrication and the rusty effects of the ethanol in some metals, but are almost 100% solved... with the common-rail systems diesel and ethanol can be more easily blended in any proportion, just like in a flexfuel gas/ethanol engine... mwm, brazilian subsidiary of international engines, made a lot of dual-pump diesel/ethanol engines for tractors and trucks (mostly dodge and volkswagen, but some ford trucks used those engines), and a co-development for a tri-fuel engine to run on ethanol, gas and diesel is on course with mahindra because of a brazilian stupid law that forbids the usage of diesel in a 2wd vehicle with payload lower than a ton, like mahindra xylo, that is currently being made in india just with a diesel engine option...