they do make Small diesel engines in India. Ethanol is easier than diesel because diesel ignites from heat of compression, not spark ignition. Diesels usually run compression ratios in the 14 to 22:1 range. gasoline 7 to 12.5:1. Diesel engines do not have spark plugs because diesel fuel ignites at a much higher tmperature than gasoline. the heat of the air in the combustion chamber literally EXPLODES the diesel fuel being injected into the cylinder begining at about 10 btdc. air and gasoline are mixed before they enter the cylinder on a gas engine and are burned by spark ignition varying between 10 and 25 btdc depending on engine rpm. Diesel engines generally are much heavier than gas engine of the same displacement because of all the extra moving parts (high pressure 1000 to 5000 psi <!!!>fuel injection system, cams, valves<even 2-strokes like detroits>, gears ect...) and the heavier duty constuction of parts like pistons, cylinders, ect...
GM tried to convert a gas engine (5.7l, or 350 cid olds) into a diesel. was a horrible failure. the only thing good that came of it was that when you converted the engine block back to a gas engine, you could build the shit out of it!!! could bore (.125" over!!!) and stroke (could use an olds 455 crank) and make it into a 425cid small block!!! go around telling people it was 'just a 350..." after you whuped their ass in a drag race...