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Four Stroke, Two StrokeDiesel, & Wankel Engine

Theory and Operation

Four Stroke, Two StrokeDiesel, & Wankel Engine

Theory and Operation

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Four Stroke, Two Stroke,Diesel, & Wankel Theory

Presentation Outline

Four Stroke, Two Stroke,Diesel, & Wankel Theory

Presentation Outline

1.0 Four Stroke Engine Theory• Internal combustion principles• Valve operation• Four cycles• Valve timing

2.0 Two Stroke Engine Theory• Two cycle operation• Lubrication• Variations• Advantages/ limitations more...

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3.0 Diesel Engine Theory•Operation•Variations•Advantages/limitations

4.0 Wankel Engine Theory•Operation•Variations•Advantages/limitations

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1.0 Four Stroke Engine Theory

1.0 Four Stroke Engine Theory

Intake Compression Power Exhaust

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Intake StrokeIntake Stroke

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Compression StrokeCompression Stroke

Valves closed

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Power StrokePower Stroke

Valves closed

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Exhaust StrokValve Timing Diagram

Exhaust StrokValve Timing Diagram

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2.0 Two Stroke Engine Theory

2.0 Two Stroke Engine Theory

Up stroke Down stroke

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Reed Valve

Transfer Port

Carburetor

2 Stroke Up Stroke

Compressionoccurs

CrankCase

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IntakePowerExhaustOccurs

Transfer Port

Reed Valve

2 StrokeDown Stroke

Carburetor

+

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Fuel MixFuel Mix

Uses a premix of gas and oil Oil injectors used in some Normal mixes range from 16:1 to 50:1 Typical “hot” engines 16:1 Typical “cool engine” 50:1 CHECK OWNERS MANUAL !!!

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Advantage of Two StrokesAdvantage of Two Strokes

Runs in any position More horsepower for size Fewer moving parts Lighter

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Limitations of Two StrokesLimitations of Two Strokes

Uses more fuel than four strokes Fuel and oil must be mixed Plugs foul easily Poor emissions

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3.0 Diesel Engine Theory3.0 Diesel Engine Theory

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Introduction• Invented by Rudolf Diesel between

1892 and 1893

• Internal Combustion Engine

• Reciprocating Engine

• Intermittent Combustion Engine

• Utilizes liquid fuel

• Compression Ignition vs. Spark Ignition

• Heavy Duty Applications

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Diesel Compression RatioDiesel Compression Ratio

20:1 up to 25:1 common Needed to ignite fuel No spark plugs

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Compression Ratios “Squeeze” on air/fuel mixture before

combustion Efficiency increases with higher CR About 9:1 on gas autos 17:1 to 24:1 for diesel engines About 24:1 CR max:• too high compression for starting• limiting strength of materials• power loss- leakage around valves

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Advantages of the Diesel Engine

• High reliability• Low fuel cost• High power / lb. of engine• Low fuel consumption • Low fire hazard• High torque at low RPM• Greater heat efficiency- 30% (25% gas)• Longer service intervals

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Disadvantages of Diesel Power

Disadvantages of Diesel Power

Expensive to repair Hard starting in cold weather Higher initial cost

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Gasoline and Diesel Engine Comparison

Gasoline and Diesel Engine Comparison

Gasoline power stroke = 460 psi; Diesel = 1200psi

Diesel heat efficiency about 5% higher than gasoline

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Induction System

High PressureInjection Spray

Injection Line

Injector DeliveringFuel

Air Only

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Glow PlugsGlow Plugs

Resistance unit to heat cold engines Installed in cylinder head, sometimes in

special pre-combustion chamber Some use intake heaters In addition, block heaters for cold weather

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Typical Diesel Engine

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4.0 Wankel Engine Theory4.0 Wankel Engine Theory

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History of RCE(Rotary Combustion Engines)

History of RCE(Rotary Combustion Engines)

1924 - Wankel’s idea for RCE 1933 - patent was applied 1936 - patent received 1957 - engine runs

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One of Three Chambers

Apex Seal

SparkPlugs

Rotor

IntakePort

ExhaustPort

Epitrochoidal Bore

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Rotor and Apex SealsRotor and Apex Seals

Sometimes called a “Rotary Piston”

Receives power impulse from fuel air mixture

Rotor has three faces

Apex seals at tips-like rings

Apex Seal Location

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Epitrochoidal BoreE-Bore

Epitrochoidal BoreE-Bore

Same purpose as the cylinder walls of the piston engine

Epitrochoid curve, generated by rolling a circle around another circle Basic shape of epitrochoid

curve

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Rotors

Eccentric

Shaft

E-Bore

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Advantages and LimitationsAdvantages and Limitations

Fewer moving parts Single motion allows smoother

running Compact engine, allows for more

space Few manufacturers produce this

engine any longer

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Summery (Cont)Summery (Cont)

What are the major differences in parts between a 2 stroke & 4 stroke?• Ports vs. Valves• Reed valve vs. Valves

How is the fuel ignited in a deisel engine?• Compression

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Summery (Cont)Summery (Cont)

The Rotory (Wankel) engine uses what type of bore?• E- Bore

What act like rings in a rotory engine?• Apex seals

Air can be __________, while water can not?• Compressed

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The End