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Start. Four Stroke, Two Stroke Diesel, & Wankel Engine Theory and Operation. 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

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  1. Start...

  2. Four Stroke, Two StrokeDiesel, & Wankel Engine Theory and Operation

  3. Four Stroke, Two Stroke,Diesel, & Wankel TheoryPresentation 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...

  4. 3.0 Diesel Engine Theory • Operation • Variations • Advantages/limitations • 4.0 Wankel Engine Theory • Operation • Variations • Advantages/limitations

  5. 1.0 Four Stroke Engine Theory • Intake • Compression • Power • Exhaust

  6. Intake Stroke

  7. Compression Stroke Valves closed

  8. Power Stroke Valves closed

  9. Exhaust StrokValve Timing Diagram

  10. 2.0 Two Stroke Engine Theory • Up stroke • Down stroke

  11. 2 Stroke Up Stroke Compression occurs Transfer Port Crank Case Reed Valve Carburetor

  12. 2 Stroke Down Stroke Intake Power Exhaust Occurs Transfer Port + Reed Valve Carburetor

  13. Fuel 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 !!!

  14. Advantage of Two Strokes • Runs in any position • More horsepower for size • Fewer moving parts • Lighter

  15. Limitations of Two Strokes • Uses more fuel than four strokes • Fuel and oil must be mixed • Plugs foul easily • Poor emissions

  16. 3.0 Diesel Engine Theory

  17. 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

  18. Diesel Compression Ratio • 20:1 up to 25:1 common • Needed to ignite fuel • No spark plugs

  19. 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

  20. 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

  21. Disadvantages of Diesel Power • Expensive to repair • Hard starting in cold weather • Higher initial cost

  22. Gasoline and Diesel Engine Comparison • Gasoline power stroke = 460 psi; Diesel = 1200psi • Diesel heat efficiency about 5% higher than gasoline

  23. Air Only Injection Line High Pressure Injection Spray Injector Delivering Fuel Induction System

  24. 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 Glow Plugs

  25. Typical Diesel Engine

  26. 4.0 Wankel Engine Theory

  27. History of RCE(Rotary Combustion Engines) • 1924 - Wankel’s idea for RCE • 1933 - patent was applied • 1936 - patent received • 1957 - engine runs

  28. Epitrochoidal Bore Apex Seal Intake Port Rotor Spark Plugs Exhaust Port One of Three Chambers

  29. Sometimes called a “Rotary Piston” Receives power impulse from fuel air mixture Rotor has three faces Apex seals at tips-like rings Rotor and Apex Seals Apex Seal Location

  30. Same purpose as the cylinder walls of the piston engine Epitrochoid curve, generated by rolling a circle around another circle Epitrochoidal BoreE-Bore Basic shape of epitrochoid curve

  31. Rotors Eccentric Shaft E-Bore

  32. Advantages and Limitations • Fewer moving parts • Single motion allows smoother running • Compact engine, allows for more space • Few manufacturers produce this engine any longer

  33. 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

  34. 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

  35. The End

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