Internal Combustion Engine

1
Internal Combustion Engine

• Chapter 3
• Engine Cycle

2
Air-Standard Cycles
? ???? ???? ??? ?? ????. ? ??? ???? ???? ??
??? cycle analysis?? ?? ??? 3?? ???? ??? ??? ??.
??? ??? ???? ??? ?? ??? ??? ??? ??? ?? ????
?? ? ? ?? ????. ??? ??? ???? ????? ???? ?? ??
??? ???? ??? ??? ?? ??? modeling ? ? ??.
? Air-Standard Cycles 1. Closed system ?????
????? ???? open system? ??? ??? ?? ?? ??? ???
??? closed system?? modeling ??. ??? ?? ?? ???
?? ? ??? ??? ??? ?? ??? ?? ??? ?? ??? ???.
2. ?? ????? property ???? ??? ??? ?? ???
??? ????? ??? ??? ??, ??? ??, ?? ?? ??? ?????
??. ??? ???? ???? ???? ??? ?? ??? ???. ?? ?????
??? ?? ??? ??? ??? ??? ????? ????.
3
Air-Standard Cycles

• 3. ???? ????? ??? ?? ???? ?? ???? ???? ????
  modeling??.
• 4. ???? ? blowdown ?? ??? ???? ???? ????
  modeling??.
• 5. ??? ???? ?? ?????? modeling??.
• 6. ??, ???? ?? ????(isentropic process)??
  ????.

4
Otto Cycle

• ? Spark-ignition engine? ????? ??????? ??? ????
  modeling? cycle??. ???? ?????? ???? ??? ?? ?? ?
  ??? ?? ?? ????.

---(3-31)
? 3-31?? Otto cycle? ???? ???? ????? ???? ?
? ??. ??? ???? ???? ?? ?? ???? ??, ??? ??? ???
???? ??? ? ??? SI engine? ?? ?? ?????? knock? ???
? ???? ??? ???? ??? ??. ? ???(specific heat
ratio)? ??? ?? ???? ????. ??? ? ??? ???? ??? ???
???? CI engine?? GDI(Gasoline Direct
Injection)engine? ??? ??? ??? ?? ???? SI engine??
?? ????? ???? ?? ? ??.
5
Otto Cycle
Otto Cycle? ?? ??? ??? ?? ??? ??? ????
6
Real Air-Fuel Engine Cycles

• ? ??? ??? Otto cycle?? modeling ? ???? ??? ?? ???
  ?? ???? ??.
• 1. pumping loss
• ??? ????? ??
• 2. ??? ??
• ??????? ??? ?? ?? ?? ? ?? ????? ??
• 3. ????? ??? ??? property?? ??? ??? ???
• 4. ????? ?? ???? ???? ??
• ??? ??? ?????? ??? ?? ?? ?? ??
• 5. Blowdown??? ??? ?? ??? ??? ??? ??? ???. ???
  Blowdown? Air-Standard Analysis?? ?????? ????
  ???.
• ? ?? ??? ?? Ideal Cycle? Actual Cycle? ??? ???.
  ??? ? ??? ??? ?? ??. ??? Actual Cycle? ?? ? ???
  ?? Air-Standard Otto Cycle?? ??. ?? ???, ??, ??
  ??, ?? ???, ?? ?? ??? Blowdown, ?? ????.

7
SI Engine Cycle At Part Throttle

• ? SI engine? ??? ???? ??? ?? ?? ????. Throttle
  plate? ??? ??? ?? ??? ?? ???? ??? ???? ??? ??
  ???? ??? ????. Throttle plate? ??? ?? ??(WOT)???
  ????? ??? ????? ???? ????? ?? ???? ?? ??? ??
  negative work? ????. ?? pumping loss ?? ??
  pmep(pumping mean effective pressure)? ? 3-36? ??
  ????.

8
Exhaust Process

• ? ????? ?? BDC ??? ?? ??? ? ? ??? ? ????? ??? ??
  ??? ???? ??? ?? ????? ?? ???. ??? ??? ???? ?????
  ???? ?? ??? ??? ?? ??? ???? ?? ??? ???. ?? ??? ??
  ? ??? ????? ?? ???? ?? ?? ??? ????. ?? ???? ?? ?
  ?? ?? ????? ??? residual gas fraction?? ??.

9
Diesel Cycle

• ? ?? ????? ?? ??? ????? ?? ?? ?? ? ??? ? ??? ???
  ?? ??? ??? ??. ?? modeling? ?? diesel cycle??
  ???.
• ? cycle? ??? ? 3-73? ?? ???? ?? ???, ???, ???
  cutoff ratio(?????? ??? ??? ?? ???)? ????.

10
Dual Cycle

• ? ??? ??? SI engine, CI engine ?? ???? ???? ???
  ???? ???. ??? ??? modeling ? ?? Dual Cycle ??
  ???? ? ? ??? ? ??? ?? ??? model? ??? ???.

11
Comparison of Otto, Diesel, And Dual Cycles
??? ??? Otto, Diesel, and Dual Cycle? ?? ?? ???
?? ???? ??? ???. ???? ??? ?? ??? ? ????,
??? T-s????? ??? ???? ??? ? ??. ??(b)? ??? ??? ?
?? ???? ??? ?? ??,
???, ?? ?? ??? ? ?? ???? ??? ?? ??? ???? ???? ??
???? ?? ?? ?? ??? ??.
12
Comparison of Otto, Diesel, And Dual Cycles
??? ??? ? ?? ??? ??? Peak Pressure? ?? ??( ?? ??
??? ??), ??? ???? ??? ???.? ??,
? ??? ???? ?? ???? ??? ??? ???? ?? ????.
13
Miller Cycle
Atkinson Cycle
Miller Cycle
Miller Cycle? Atkinson Cycle? ????? ??? ?????. ?,
Atkinson Cycle???? ???? ????? ?? ?? ?? Miller
Cycle? ??? ?? ???? ????. Mazuda?? ?? ??? Miller
Cycle? ?? ??? ??? ??? ??.
14
Two-Stroke Cycles
? SI Engine 2???? SI Engine? ??,
Air-Standard Process? ????, 1-2 Isentropic
Power or Expansion stroke 2-3 Exhaust
Blowdown. 3-4-5 Intake Exhaust
scavengine. 5-6 Exhaust scavengine. 6-7
Isentropic Compression. 7-1 Constant-Volume
Heat Input.
15
Stirling Cycle

• ? Stirling Cycle Engine? ??? ??? ????? ???.
  Stirling Cycle Engine? ?
• ?? ??? Gas Chamber? ?? ???? ???? ??, ??? ? Gas
  Chamber??
• ???? ?? ??? ???? ?? ?? ????? ???? ?? ???? ?? ??.?
• ?? ??? ??? Stirling Cycle?? ????.