Diesel Ethanol Hybrid

Well, my first post in who knows how long, and I've been toying with this idea for a long time now, even posting one a long time ago kind of similar.

It would appear that a change from gasoline needs to be made. The only real alternatives that are well known are biodiesel, ethanol, and hydrogen. Now hydrogen seems the worst to me since it takes electricity to generate from H20, and no matter where the electricity comes from (a power plant, windmill, solar panel, etc.) it is still far less efficient than using that electricity to charge batteries for an electric motor instead. So then there is ethanol, which is good in that it isn't oil and is relatively clean burning, however it also takes a fair amount of energy to create. Biodiesel actually makes a lot of sense, since you can get vegetable oil basically from just squeezing vegetables (think Italian olive press). It also can be run almost seemlessly in diesel engines, which are already very efficient.

So in theory it would make a lot of sense to just build a whole lot of diesel engines to run on biodiesel, however there are downsides. Diesels are more expensive to build, since they need to withstand much higher forces and are much heavier than gasoline engines. They also almost always require a turbocharger which also adds weight, cost, and complexity. Finally, the fact that the fuel is injected almost exactly at TDC gives it almost no time to mix with the air before combusting, resulting in more emissions. So it seems to me that the best way of running biodiesel would be in an otto cycle. The problem being that biodiesel cannot spark-ignite... But ethanol can.

What I propose would be a fairly simple modification to existing Otto cycles companies already manufacture. I propose an Otto cycle that runs on both ethanol and biodiesel at the same time. Right before being injected into the cylinder by high pressure direct injection, precicely measured amounts of both are blended in small chambers by fast moving fans. This mixture is then injected while the piston is already moving up for compression and bang, the spark plug is able to ignite the mixture because of the alcohol content and there is combustion.

The other benefit of the ethanol as the ignitable fuel is that it has about a 110 octane rating, so blended in the right amounts it would make the mixture able to not preignite. The key feature I was thinking of in this design is that the ratio of biodiesel:ethanol could change depending on compression related factors (ie: RPM, load, throttle, etc.) so that a mixture with more biodiesel that would normally preignite in other conditions can be used in certain circumstances such as idling, low throttle cruising, high-RPM passing, etc. when the engine is least likely to preignite.

The benefit to this would be an engine not run on gasoline that would give all of the same characteristics while also being more efficient, since the energy content of biodiesel is higher than gasoline. It would also pollute virtually no harmful emissions. Any thoughts?