Difference between revisions of "Fuel"
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Internal combustion engines can use a variety of '''fuels''', the fuels available at US competitions are gasoline of octane ratings 93 and 100, and E85. No fuel additives can be used. | Internal combustion engines can use a variety of '''fuels''', the fuels available at US competitions are gasoline of octane ratings 93 and 100, and E85. No fuel additives can be used. | ||
=Chemistry= | =Chemistry= | ||
| − | Gasoline is typically approached as pure octane. (Do we need to cover the actual reaction here?) | + | Gasoline is typically approached chemically as pure octane. (Do we need to cover the actual reaction here?) <br /> |
| − | <math> 2\text{C}_8\text{H}_{18}(l)+25\text{O}_2(g) \rightarrow 16\text{CO}_2(g) + 18\text{H}_2\text{O}(g) </math> <br /> | + | <math> 2\text{C}_8\text{H}_{18}(l)+25\text{O}_2(g) \rightarrow 16\text{CO}_2(g) + 18\text{H}_2\text{O}(g) </math> <br />that equation's a real doozy in math markup |
| − | that equation's a real doozy in math markup | + | |
| + | |||
| + | if we use atomic weights for carbon, hydrogen, and oxygen, we find that 2 mol of octane is 224 grams, 25 mol of oxygen is 800 grams which comes from 3809 grams of 21 percent air. This yields an air fuel ratio of 17. | ||
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| + | Since gasoline is not pure octane and air is not exactly 21% oxygen. Experimentation(?) yields the stoichiometric ratio of 14.7 grams of air per gram of fuel. | ||
==System Design== | ==System Design== | ||
===Fuel Storage=== | ===Fuel Storage=== | ||
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+weight<br /> - cost <br />-manufacturing<br />+pressure<br />- not as reusable year to year<br /> | +weight<br /> - cost <br />-manufacturing<br />+pressure<br />- not as reusable year to year<br /> | ||
====Soft Lines==== | ====Soft Lines==== | ||
| − | pressure and solvent rated<br />e85 sucks for this<br />+cost<br />+manufacturing<br /> | + | pressure and solvent rated<br />e85 sucks for this<br />+cost<br />+manufacturing<br />+reusable year to year / design to design<br />-pressure<br /> |
| − | +reusable year to year / design to design<br />-pressure<br /> | ||
====Braided==== | ====Braided==== | ||
| − | you're gonna poke you're eye out kid<br />- cost<br />- mfg<br />- i hate<br />+ reusable<br /> | + | you're gonna poke you're eye out kid<br />- cost<br />- mfg<br />- i hate<br />+ reusable<br />+ pressure rated<br /> |
| − | + pressure rated<br /> | ||
===Pump and Pressures=== | ===Pump and Pressures=== | ||
depends on injectors, we ran 3 bar, not sure what other people did | depends on injectors, we ran 3 bar, not sure what other people did | ||
| Line 35: | Line 38: | ||
===Bladder=== | ===Bladder=== | ||
just pour the gas in a kroger bag and let it flop in the wind /s | just pour the gas in a kroger bag and let it flop in the wind /s | ||
| − | |||
==Fuel Strategy== | ==Fuel Strategy== | ||
==Efficiency== | ==Efficiency== | ||
Revision as of 15:56, 17 May 2020
Internal combustion engines can use a variety of fuels, the fuels available at US competitions are gasoline of octane ratings 93 and 100, and E85. No fuel additives can be used.
Chemistry
Gasoline is typically approached chemically as pure octane. (Do we need to cover the actual reaction here?)
Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle 2\text{C}_8\text{H}_{18}(l)+25\text{O}_2(g) \rightarrow 16\text{CO}_2(g) + 18\text{H}_2\text{O}(g) }
that equation's a real doozy in math markup
if we use atomic weights for carbon, hydrogen, and oxygen, we find that 2 mol of octane is 224 grams, 25 mol of oxygen is 800 grams which comes from 3809 grams of 21 percent air. This yields an air fuel ratio of 17.
Since gasoline is not pure octane and air is not exactly 21% oxygen. Experimentation(?) yields the stoichiometric ratio of 14.7 grams of air per gram of fuel.
System Design
Fuel Storage
Fuel Lines
Hard Lines
only legends do this [citation needed]
+weight
- cost
-manufacturing
+pressure
- not as reusable year to year
Soft Lines
pressure and solvent rated
e85 sucks for this
+cost
+manufacturing
+reusable year to year / design to design
-pressure
Braided
you're gonna poke you're eye out kid
- cost
- mfg
- i hate
+ reusable
+ pressure rated
Pump and Pressures
depends on injectors, we ran 3 bar, not sure what other people did i think there are some comp rules on low pressure v high pressure systems
Injectors
Throttle Body Injection
basically electornic carb
Port Fuel Injection
Fuel Injected into the ports just before entering the combustion chamber. Usually leads to well mixed charge [citation needed]
Direct Fuel Injection
big boys do this [citation needed]
Tank
volume mounting material form factor (exterior and interior) sloshing is a meme
Bladder
just pour the gas in a kroger bag and let it flop in the wind /s
