Diesel Engines

Question 1

Discuss basic diesel engine theory

Answer 1

-Internal combustion engine
-Convert chemical energy into mechanical energy

-Auto ignites due to high temp and pressure
-fuel injected

Question 2

Describe basic diesel engine major components

Answer 2

•Engine block (Piston,connecting rod,cylinders

•Crank shaft- converts reciprocal motion into rotary motion and drive the load

•Flywheel- mass provides inertia to reduce vibrations and connects the turning gear

•Cylinder head-sits on top of engine block and contains equip. that controls combustion

•Valves- Air intake, exhaust; spring closed and opened by cam shaft

•Fuel injectors

•Camshaft- operates intake valves, exhaust valve and fuel inj. Pump

•Drive gear- connects the camshaft to the crankshaft

•Bearings- journal bearings support weight of camshaft

•Camshaft lobes- physically compress the valves

•Turning gear- drives or locks flywheel for maintenance, PVGS turning gear is air operated

•turbo charger- improve efficiency and increase power; two turbos connected by shaft, driven by exhaust gas

•intercooler- Cools air that is compressed

•Governor-adds or reduces fuel depending on generator load

Question 3

Describe basic diesel engine operation

Answer 3

•Works on a 4 stroke cycle
-Intake
-compression
-combustion(power stroke)
-exhaust

-require rugged build for structure design cause of the power

Question 4

How does the number of cylinders effect operation

Answer 4

-The more cylinders means more power and less vibrations cause it’s more fluid

-PVGS DE has 20cylinders

*(flywheel also helps minimize vibration and power fluctuations)

Question 5

Describe diesel engine support systems

Answer 5

•Starting system- uses compressed air to force piston down during power stroke and the SBOG use a starter motor

•Lube oil- Uses motor driven or engine driven oil pump to lubricant and cool crankshaft, camshaft, turbo and generator (Motor circulates oil when not running to keep oil warm ready for E start)

•Cooling system- Jacket water to cool the engine block cylinders and maintains it warm when not running
•also inter cooler

Emergency Diesel generators use electric heaters for oil temp and jacket water to cool the oil