Ship Propulsion Systems STEAM DIESEL OTHER Conventional Nuclear

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

DIESEL ENGINE NOMENCLATURE INTAKE VALVE FUEL INJECTOR EXHAUST VALVE PISTON CYLINDER

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

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)

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

DIESEL CYCLE: Intake STROKE 1

DIESEL CYCLE: Compression STROKE 2

DIESEL CYCLE: POWER STROKE 3

DIESEL CYCLE: Exhaust STROKE 4

DIESEL CYCLE: Intake

DIESEL CYCLE: Compression

DIESEL CYCLE: POWER

DIESEL CYCLE: Exhaust

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

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

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

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

Linear to Rotational Motion TIMING CIRCLE

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

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

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

2 S/C EVENTS

2 S/C EVENTS

2 S/C EVENTS – WITHOUT INTAKE VALVE INTAKE PORT

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

THE DIESEL CYCLE Comprised of INTAKE, COMPRESSION, POWER & EXHAUST EVENTS (fuel injection at beginning of power event) 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