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RE: One True Test
By aeroengineer1 on 5/2/2008 6:44:48 PM , Rating: 4
I think that you are missing the point here. We tend to think of systems by their individual components, and while you are trying to tie the whole system together there are some things that need to be added into your thoughts. It is true that engine efficiency is proportional to compression ratio, but we already have fuels that can take the high compression without the alcohol content. These fuels, though sold for aviation use, and have other environmental concerns, are much more efficient than any alcohol based fuel when considering power per mass or per volumetric unit. This is the reason that many of these fuels have not taken hold.

Let's say that you boost you compression ratio, the results of that are that you will need to strengthen the engine block, which will increase weight. This can be offset by increasing power output. A diesel engine does this because its fuel has a higher energy content than gasoline, but with alcohol based fuels you will not get the increased energy output unless you add more fuel to the engine. This can be done, but by doing so you fuel efficiency will go down.

The way to go is diesel. It seems when you read the news so many focus on the smaller group that is making gasoline substitutes, but the real gains have been made in the diesel/jet fuel substitutions. There are many methods being explored and tested, with strong government backing because our airforce relies on heavy fuels, not gasoline. With the fact that the cycle describing the combustion for a diesel engine being more efficient over that of a gasoline engine, I think that it would be best to follow Europe's lead in diesel fueled vehicles. The issue of reducing emissions can be dealt with much easier, and will reduce overall oil dependency. This combined with nuclear advancements as well as batteries will allow for a new, but diversified approach to the energy situation in front of us. Other technologies will also make advances, but I think that these are things that we have had right before us, but due to public perception we have ignored them thinking that we will just wait and make the big leap to the next thing. We have spend 30 years waiting for solar, wind and hydrogen to become the next generation, and for some of those technologies we will wait another 30 years.

