1. Internal Combustion Engines – The Diesel

2. Objectives Uses for internal combustion engines
Thermodynamic principles involved
Components and purposes of each
Operation of systems
Two stroke engines
Four stroke engines

3. The Diesel is a Hacker

4. Engine Uses Emergency Diesel Generators (EDG) Propulsion
Certain amphibious landing ships
Mine warfare ships
Patrol craft
Tug boats
Small boats
Outboard motors

5. Thermodynamic Principles
All internal combustion
Open cycle, heated engine
Gasoline (Otto) engine
Spark ignition
Compresses air-fuel mixture
Diesel engine
Compressed ignition
Compresses air only

6. Structural Components
Cylinder Block
Part of engine frame that contains cylinders in which piston moves
Supports liners & head

7. Structural Components
Cylinder Head/Assembly
Serves to admit, confine, and release fuel/air
Cover to cylinder block
Supports valve train
Crankcase
Engine frame section that houses the crankshaft
Oil sump
Reservoir for collecting and holding lube oil

8. Moving Components Three Groups – according to motion
Reciprocating only (pistons and valves)
Reciprocation & rotary (connecting rods)
Rotary only (crankshafts and camshafts)

9. Moving Components Piston Piston Rings Piston Pin Connecting Rod
Acted on by combustion gases
Lightweight but strong/durable
Piston Rings
Transfer heat from piston to cylinder
Seal cylinder & distribute lube oil
Piston Pin
Pivot point connecting piston to connecting rod
Connecting Rod
Connects piston & crankshaft
reciprocating rotating motion

10. Moving Components Crankshaft Flywheel
Combines work done by each piston
Drives camshafts, generator, pumps, etc.
Flywheel
Absorbs and releases kinetic energy of piston strokes -> smoothes rotation of crankshaft

11. Moving Components Valves Camshaft & Cams
Intake: open to admit air to cylinder (with fuel in Otto cycle)
Exhaust: open to allow gases to be rejected
Camshaft & Cams
Used to time the addition of intake and exhaust valves
Operates valves via pushrods & rocker arms

12. Operation
Increased pressure of combustion gases acts on piston -> converted to rotary motion
Can be 2 or 4 stroke engines
2-stroke: 1 power stroke per 1 crankshaft rev
4-stroke: 1 power stroke per 2 crankshaft rev

13. Operation Engine stroke
A stroke is a single traverse of the cylinder by the piston (from TDC to BDC)
1 revolution of crankshaft = 2 strokes of piston

14. Four-Stroke Diesel Engine
Intake stroke
Intake valve open, exhaust valve shut
Piston travels from TDC to BDC
Air drawn in
Compression stroke
Intake and exhaust valves shut
Piston travels from BDC to TDC
Temperature and pressure of air increase

15. Four-Stroke Diesel Engine
Power stroke
Intake and exhaust valves shut
Fuel injected into cylinder and ignites
Piston forced from TDC to BDC
Exhaust stroke
Intake valve shut, exhaust valve open
Piston moves from BDC to TDC
Combustion gases expelled

16. Four-Stroke Diesel Engine
Strokes
Intake
Compression
Power
Exhaust

17. Two-Stroke Diesel Engine
1 power stroke every crankshaft revolution (vice every two w/ 4-stroke)
Uses pressurized air to simultaneously supply new air and expel combustion gases
Scavenging
Exhaust valve open, inlet port exposed
Pressurized air enters, expels combustion gases
Piston near BDC

18. Two-Stroke Diesel Engine
Compression
Intake and exhaust valves shut
Piston travels from BDC to TDC
Temperature and pressure of air increase
Power stroke
Fuel injected into cylinder and ignites
Piston forced from TDC to BDC

19. Two-Stroke Diesel Engine
Strokes
Compression
Power
(Intake/Exhaust)

20. Supporting Systems Air system Fuel System Supplies & removes air/gases
Air supplied at constant pressure by blower/compressor
Fuel System
Carburetor: mixes air & fuel in proper proportion (NOT on diesels)
Fuel injector: sprays fuel in (more efficient)

21. Supporting Systems Ignition system Cooling system Lubrication system
Diesel has compression ignition
Gasoline has spark plugs
Cooling system
Uses fresh water and/or salt water to cool
Lubrication system
Provide lubrication and cooling
Drive Train – Direct or Indirect

22. Safety Precautions
Noise
Fuel Flammability
Maintenance
Water Issues

23. Feed backs…!

24. Thank you….