Quote:
Originally Posted by Kai Nui
DMan, I am all for electrical propulsion, but it is far more problematic than increasing the efficiency of an internal combustion engine. I am happy to reinvent the wheel if that can be done, but I do not have any ideas on how to do it.
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There is one major problem with increasing the efficiency of internal combustion engines:
It has already been done.
The engines we use now are the end results of all the major improvements that anybody has been able to think of. Many people would stand to make a lot of
money from further improvements, but it is a hard problem. We still see tiny incremental improvements happening, such as from computer control of car engines, but the the big steps have already been taken.
Here are a few other thoughts I have reading this thread:
If a major goal is independence from fossil fuels, you need to find a non-fossil-fuel energy source. Reforming natural gas, coal, or
oil into hydrogen is not a non-fossil-fuel energy source.
As mentioned before, hydrogen is not an energy source. You can, however, make hydrogen as a way to carry energy around.
It doesn't really matter how efficient this process is. It matters whether it is economical. For example, suppose it takes 10 times as much energy to make hydrogen for my car as there is in the gasoline it takes to drive the same distance. If I burn gasoline to make the hydrogen, I lose. If I use geothermal energy, the only question is whether the amortized cost of the geothermal plant, hydrogen infrastructure, and hydrogen car is less than the cost of the gasoline, gasoline infrastructure, and gasoline car.
That is, if I spend $20 / week driving to
work instead of $40 / week, I come out ahead even if my car can only use 5% of the energy. Of course, this only applies if the car doesn't cost more -- if it costs $50,000 for a hydrogen car and $20,000 for a gasoline car, I will have to get used to paying $5/gallon for gasoline.
The same sort of analysis applies to any proposed system.
Stirling engines lose if your
fuel is anything that could burn in an internal combustion engine. That is, you could get more energy out of the same fuel using a conventional engine. This applies whether your fuel is diesel, gasoline, natural gas,
propane, hydrogen, kerosene, canola oil, etc. A stirling engine may be a win if you have a large supply of free
wood to burn (can't burn
wood in internal combustion engines), though you would have to consider whether it would be better to gasify the wood and burn the resulting gas.
You have to consider the whole chain of manufacture of your energy. Ethanol from plant matter and plant oils are non-fossil-fuels, but you have to consider where you get the plants from. If you use petroleum-based fertilizers, you are still using fossil fuels and still contributing to global warming. If you burn petroleum to run the still, you are still dependent on fossil fuels. At least one analysis purports to show that burning ethanol in your car actually uses more petroleum than burning gasoline, because of the petroleum used in the manufacturing and distribution process. (Tax incentives make it economical.)
There, I managed to avoid beating the dead horse.