Ship Propulsion Systems

1. STEAM DIESEL OTHER Conventional Nuclear Slow Speed Medium Speed Gas Turbine Combined Cycle Ship Propulsion Systems • DIESEL PROPULSION

2. FUEL INJECTOR INTAKE VALVE EXHAUST VALVE DIESEL ENGINE NOMENCLATURE PISTON CYLINDER

3. DIESEL ENGINE NOMENCLATURE TDC (Top Dead Center) BORE PISTON STROKE BDC (Bottom Dead Center)

4. THE DIESEL CYCLE 4 EVENTS • INTAKE (bring in fresh air charge) • COMPRESSION (raise pressure & temperature of charge) • POWER (inject and combust fuel – “exploding” gas expands) • EXHAUST (remove combustion products)

5. THE DIESEL CYCLE FOUR Stroke/Cycle [4 S/C] Engines Each event completed in one stroke • INTAKE (TDC  BDC) • COMPRESSION (BDC  TDC) • POWER (TDC  BDC) • EXHAUST (BDC  TDC) Cycle completed in TWO revolutions

6. DIESEL CYCLE: Intake STROKE 1

7. DIESEL CYCLE: Compression STROKE 2

8. DIESEL CYCLE:POWER STROKE 3

9. DIESEL CYCLE: Exhaust STROKE 4

10. DIESEL CYCLE: Intake

11. DIESEL CYCLE: Compression

12. DIESEL CYCLE:POWER

13. DIESEL CYCLE: Exhaust

14. Idealized DIESEL CYCLE • INTAKE—at atmospheric pressure • COMPRESSION—to TDC • POWER— • Fuel injected • Constant pressure heating • Expansion • EXHAUST—at atmospheric pressure PRESS DIESEL CYCLE: P-V Diagram POWER COMPRESSION EXHAUST INTAKE VOL BDC TDC

15. Idealized GASOLINE ENGINE PRESS OTTO CYCLE: P-V Diagram • INTAKE—Fuel & airat atmospheric pressure • COMPRESSION—to TDC • POWER— • Sparkplug ignition • Constant volume heating • Expansion • EXHAUST—at atmospheric pressure POWER COMPRESSION EXHAUST INTAKE VOL BDC TDC

16. DIESEL OTTO (Gasoline) PRESS PRESS DIESEL vs. OTTO CYCLE VOL VOL BDC BDC TDC TDC

17. PISTON RINGS WRIST PIN CONNECTING ROD CRANK PIN WEB CRANK SHAFT Linear to Rotational Motion

18. Linear to Rotational Motion TIMING CIRCLE

19. Crank-pin position as timing FUEL INJECTION SCAVENGING EXHAUST COMPRESSION POWER Fuel cut-off INTAKE VALVE OPENS INTAKE EXHAUST VALVE CLOSES TIMING CIRCLE

20. THE DIESEL CYCLE TWO Stroke/Cycle [2 S/C] Engines Each event completed in less than one stroke • POWER (TDC  before BDC) • EXHAUST (before to after BDC) • INTAKE (before to after BDC) • COMPRESSION (after BDC  TDC) Cycle completed in ONE revolution

21. 2 S/C timing FUEL INJECTION Fuel cut-off COMPRESSION POWER INTAKE EXHAUST EXAUST BEGINS SCAVENGING INTAKE BEGINS EXAUST ENDS INTAKE ENDS

22. 2 S/C EVENTS

23. 2 S/C EVENTS

24. 2 S/C EVENTS –WITHOUT INTAKE VALVE INTAKE PORT

25. MEP 0 psig PRESS Enclosed area: ∫P dV = Energy delivered per cycle 2 S/C DIESEL CYCLE MEP—Mean Effective Pressure (“average” pressure during cycle) Equivalent Area (Energy) MEP x STROKE P L A N = HP per Cylinder 33,000 • P– MEP [lbs/in2] • L– Stroke [ ft ] • A– cylnder area [in2] • N-- RPM VOL BDC TDC

26. 4 S/C Engines— Each event takes one stroke Cycle completed in two revolutions One power stroke every other revolution) Must have intake AND exhaust valves 2 S/C Engines— Cycle completed in one revolutions (Shorter) power stroke every revolution May have intake and exhaust valves, or Intake port and exhaust valve, or Intake and exhaust ports THE DIESEL CYCLE Comprised of INTAKE, COMPRESSION, POWER & EXHAUST EVENTS (fuel injection at beginning of power event)