ENVI 405 Lecture Notes - Lecture 2: Gas Engine, Spark Plug, Viscosity
- the higher the carbon, the thicker the viscosity
heating value
- energy released per mass
- units: MJ/kg
HHV = LHW + Hv (nH2O,out/nfuel,in)
Stoichiometric combustion
ideal combustion where fuel is burned completely
Combustion Equation - memorize
FUEL + O2 --> CO2 + H2O
Flame temperature
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Lean Conditions
Fuel consumption:
- more O2 than fuel
Power
- less power
Emissions:
- NO <-- the chemical
- Hydrocarbons
If lean with higher temperatures, more fuel is burned
Rich Conditions
Fuel consumption:
- more fuel than O2
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Power:
- more power
Emissions:
- lots of CO especially with higher temps
- hydrocarbons with hotter temps
Combustion with Gas engine
occurs within an engine chamber, where the expelled energy is converted to useful work by a piston and
crankshaft.
- 4 stroke
1. intake
2. compression
3. power - spark plug ignites
4. exhaust
Combustion with Diesel Engine
same as gas engine, but glow plug ignites the fuel on the third step
Comparing
1. Air fuel ratio:
○ Gasolie is held ostat at λ = 1.
○ Diesel ais for λ > 1 lea, ut aries greatl.
2. Fuel injection:
○ Gasolie ies fuel ad air prior to the haer.
○ Diesel ijets fuel diretl ito the haer.
3. Ignition:
○ Gasolie uses spark plugs.
○ Diesel uses glo plugs (e.g., heating elements).
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Document Summary
The higher the carbon, the thicker the viscosity heating value. Stoichiometric combustion ideal combustion where fuel is burned completely. If lean with higher temperatures, more fuel is burned. Lots of co especially with higher temps. Combustion with gas engine occurs within an engine chamber, where the expelled energy is converted to useful work by a piston and crankshaft. 4 stroke: intake, compression, power - spark plug ignites, exhaust. Combustion with diesel engine same as gas engine, but glow plug ignites the fuel on the third step. Gasoli(cid:374)e is held (cid:272)o(cid:374)sta(cid:374)t at = 1. Diesel ai(cid:373)s for > 1 (cid:894)lea(cid:374)(cid:895), (cid:271)ut (cid:448)aries greatl(cid:455): fuel injection: Gasoli(cid:374)e (cid:373)i(cid:454)es fuel a(cid:374)d air prior to the (cid:272)ha(cid:373)(cid:271)er. Diesel i(cid:374)je(cid:272)ts fuel dire(cid:272)tl(cid:455) i(cid:374)to the (cid:272)ha(cid:373)(cid:271)er: ignition: Diesel uses glo(cid:449) plugs (e. g. , heating elements): power control: Gasoli(cid:374)e throttles air i(cid:374)take (cid:894)e. g. , adjusts air prior to (cid:272)ha(cid:373)(cid:271)er(cid:895). Diesel i(cid:374)je(cid:272)ts (cid:373)ore fuel (cid:449)he(cid:374) po(cid:449)er is (cid:374)eeded (cid:894)e. g, < 1(cid:895).
