1 start.... 2 four stroke, two stroke diesel, & wankel engine theory and operation
TRANSCRIPT
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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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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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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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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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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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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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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