Difference between revisions of "Fuel"

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m (→‎Tank: formatting)
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===Tank===
 
===Tank===
mountingmaterialform factor (exterior and interior)
+
mounting<br />
 +
material<br />
 +
form factor (exterior and interior)<br />
 
sloshing is a meme
 
sloshing is a meme
 +
 
===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

Revision as of 22:20, 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[1]

Chemistry

Gasoline

Gasoline is typically approached chemically as pure octane.


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[2].

Ethanol

System Design

Fuel Storage

I.C.1.2 Packaging Restrictions


volume determination

  • ways to pick factor of safety
    • competition strategy

Tank

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

Fuel Lines

Material
Internal Diameter [in] Pressure [psi] Cost [per foot] Minimum Bend Radius Supplier Notes
Hard Lines
Aluminum
3/8-1/2
250
2+   Russell link

pressure rating is wall thickness dependent

Soft Lines
Nitrile Rubber*
3/8
50
0.88   JEGS link


Buna-N* 3/16+ 50 1.1 1.25 McMaster link

yarn reinforced

Buna-N* 3/4+ 150 7 3 McMaster link

steel wire reinforced

Braided Lines
Nitrile Rubber* and Steel
1/4+ 50 3.50+   Spectre link



* not compatible with e85




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]

Fuel Strategy

Efficiency

Consumption vs. Thermal Efficiency

BSFC

  1. (2020).Formula SAE Rules 2020(v2.1) Location: FSAEonline. https://www.fsaeonline.com/cdsweb/gen/DocumentResources.aspx.
  2. Hillier, V.A.W.; Pittuck, F.W. (1966). "Sub-section 3.2".Fundamentals of Motor Vehicle Technology. London:Hutchinson Educational.ISBN 0 09 110711 3.