Best Ratio of Potential Chemical Energy vs. Cleanliness of Burn
 

Just wondering what would be the best ratio would be. Diesel has a high energy content but is very dirty. Gas/petrol is lower energy content, but cleaner. Is there any other fuel that would have a better ratio (maybe alcohol, natural gas, propane, bio-fuel, etc.)? I know bio-fuel is essentially zero carbon footprint, but leaving out the whole growing it first takes out CO2 thing...

Diesel has the highest energy content of any affordable commonly avaible fuel.
Its only dirty if you when you burn it at lower air fuel ratios.
Gasoline does the same thing in lower A/F ratios.

If you were to fumigate the intake of the diesel with natural gas or methanol, replacing diesel fuel energy with natural gas or alcohol it would run much cleaner.

You need to define this "ratio" more fully.
 

ANY of the common fuels available can be burned cleanly enough to meet Tier II - bin 5 levels. Are you speaking of measured cleanliness at the tailpipe? Or are you referring to "well to wheels" cleanliness?

If you are referring to the CO2 output per mile, it is hard to beat a diesel, all things being equal, for grams of CO2 per mile. If your bio - diesel is sourced from a low fossil fuel expended source, even better.

Waste vegetable oil in an older diesel application is about as low as you can go with this line of thinking of reducing CO2 emissions per mile.

Edison2 used E-85 in their Xprize car because they could/(were able to) burn it cleaner. They could have used gas or diesel and gotten the same phenomenal "MPGE," but as it stood with E85, their emissions were less than all the super aero electric cars charging from the grid.

But maybe there are other fuels like Hydrogen that pollute less or not all because of their chemical make up?

The Xprize did away with the emissions test.
 

At least with the original idea of running an FTP-75 cycle. In the end, it was a simple calculated grams per mile of CO2. By leveraging the bio-content of E85, Edison could show a "clean engine path". Meaning, they probably could pass the FTP-75 with a bit of work. They also could leverage the high octane of E85 to increase specific power and efficiency.

With the efforts to produce ethanol from cellulose sources, E85 could become a much more viable option. Thus, Edison could make the case for a fueling infrastructure.

Hydrogen is a clean fuel, if you can overlook the problems in production, storage and transport.

You are joking right?

I once read that water vapor is a greenhouse gas.

My original intention in this thought bubble was for tailpipe measurements, but "well to wheels" is certainly a very important figure as well, which I did not originally think about. Maybe an answer to both would be beneficial (if the answer would be different for both scenarios).

I was referring to all emissions, not just limited to CO2. Meaning sulfer dioxide, methane, particulates, etc. I wonder if bio-diesel pollutes those pollutants more or less than dino-diesel. I wonder if organic bio-diesel would be the best (cleanest) well-to-wheels fuel.

MMMMMMMMM. french fries!

I wonder if there is an efficient and clean way to "produce" hydrogen, like electrolysis. The issue with that though is the question of the efficiency of using energy to create the electrolysis vs. using that same energy to "fuel" a vehicle directly.

Is this in reference to current hydrogen production using natural gas as the source for H?

Yes sir! We talk about that in my Environmental Studies classes. We just don't generally refer to it as a GHG, because we don't see water vapor as "bad". But in essence, no matter what it is, if it is "up there", it will cause a greenhouse effect (to what degree and how unhealthy it is to our environment and our breathing is the deciding factor). Of course, water vapor can be considered bad if it mixes with molecules like sulfur dioxide, which creates acid rain.

Thanks for the replies guys!
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Found this article, pretty interesting: Clean Energy

Bio diesel burns much cleaner in my diesel and I have only used B20.
But I can't really use it during the winter.

Yes current and likely sources for the forseeable future.
Which will be natural gas, natural gas and coal at some point several decades down the road.

At the risk of sounding argumentative, how do you know bio-diesel burns cleaner? Have you tested it at a smog check or something? Why can't you use it during the winter? Is it because of crystal formation/solidification?