Diesel EnginesDiesel Engines

TransportationTransportationMr. O’RourkeMr. O’Rourke

HistoryHistory

Invented in the 1890’s in Germany by Invented in the 1890’s in Germany by Rudolf Diesel.Rudolf Diesel.

Invented because of the inefficiency of Invented because of the inefficiency of steam power (10% efficient) steam power (10% efficient)

How it Works:How it Works:

Internal Combustion engineInternal Combustion engine

Similar to gasoline poweredSimilar to gasoline powered

Compression ignition vs.Compression ignition vs.spark ignitionspark ignition

Usually 4-stroke, sometimes 2-strokeUsually 4-stroke, sometimes 2-stroke

http://www.youtube.com/watch?v=x9yS2xdPJSUhttp://www.youtube.com/watch?v=x9yS2xdPJSU

How it Works (cont’d):How it Works (cont’d):

Intake-Intake- The intake valve opens up, letting in The intake valve opens up, letting in air only.air only.

CompressionCompression-The piston moves back up and compresses the air. -The piston moves back up and compresses the air.

CombustionCombustion -As the piston reaches the top, fuel is injected at just the right -As the piston reaches the top, fuel is injected at just the right moment and ignited by heat from compression, forcing the piston back down. moment and ignited by heat from compression, forcing the piston back down.

ExhaustExhaust-The piston moves back to the top, pushing out the exhaust created -The piston moves back to the top, pushing out the exhaust created from the combustion out of the exhaust valve.from the combustion out of the exhaust valve.

Gas vs. Diesel EnginesGas vs. Diesel Engines

No Carburetor or port injection in DieselsNo Carburetor or port injection in Diesels

Uses direct injection into cylinderUses direct injection into cylinder

No spark plugsNo spark plugs

Glow plugs to heat engineGlow plugs to heat engine

Much more compression than gasoline Much more compression than gasoline engine (approx 2-3 times more)engine (approx 2-3 times more)

Highest thermal efficiency of all engine Highest thermal efficiency of all engine typestypes

Important Notes:Important Notes:

Compression heats air to approx 1000 Compression heats air to approx 1000 degrees F.degrees F.

Air intake is constant unless a turbo is Air intake is constant unless a turbo is usedused

Only fuel is added when throttle is appliedOnly fuel is added when throttle is applied

Fuel is added as a mist into cylinderFuel is added as a mist into cylinder

abrupt increase in pressure above the abrupt increase in pressure above the piston causes knocking soundpiston causes knocking sound

Advantages:Advantages:

Due to high compression and expansion Due to high compression and expansion ratio, diesels are 45% efficient compared ratio, diesels are 45% efficient compared to gasoline at 30%to gasoline at 30%

No high voltage electrical system needed No high voltage electrical system needed

Diesel engines usually last 2x longer than Diesel engines usually last 2x longer than gasoline due to stronger parts and better gasoline due to stronger parts and better lubricationlubrication

Advantages (cont’d):Advantages (cont’d):

Diesel fuel is safer than gasoline (not Diesel fuel is safer than gasoline (not explosive)explosive)

Fuel efficiency remains constantFuel efficiency remains constant

Much more torque than gas due to longer Much more torque than gas due to longer piston stroke (large diameter crankshaft piston stroke (large diameter crankshaft needed)needed)

More potential for power due to adding of More potential for power due to adding of turbo or sometimes superchargerturbo or sometimes supercharger

DisadvantagesDisadvantages::

Louder engine due to large amount of Louder engine due to large amount of rapidly expanding gasrapidly expanding gasDiesel fuel is more expensiveDiesel fuel is more expensiveHigher initial cost Higher initial cost Lower performance overall compared to Lower performance overall compared to gas in regular drivinggas in regular drivingProblematic in cold weatherProblematic in cold weatherLow sulfur fuel now used but exhaust can Low sulfur fuel now used but exhaust can still smell and smokestill smell and smoke

Uses:Uses:

90% of transportation industry 90% of transportation industry Power generatorsPower generatorsLarge boats/shipsLarge boats/shipsLocomotivesLocomotivesConstruction machineryConstruction machineryCars and trucksCars and trucksLargest diesel engine Largest diesel engine 109,000 hp @102rpm109,000 hp @102rpm

Costs/Future:Costs/Future:

Costs more per gallon due to demandCosts more per gallon due to demandHigher initial costs, lower overall costsHigher initial costs, lower overall costsNewer, cleaner fuels now being usedNewer, cleaner fuels now being usedMore cars using dieselMore cars using dieselQuieter, more available carsQuieter, more available cars

http://www.youtube.com/watch?http://www.youtube.com/watch?v=vGhlgphrBxAv=vGhlgphrBxA