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2 Four Stroke, Two Stroke Diesel, & Wankel Engine Theory and Operation

3 Four Stroke, Two Stroke, Diesel, & Wankel Theory Presentation Outline u 1.0 Four Stroke Engine Theory Internal combustion principles Valve operation Four cycles Valve timing u 2.0 Two Stroke Engine Theory Two cycle operation Lubrication Variations Advantages/ limitations more...

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

5 1.0 Four Stroke Engine Theory u Intake u Compression u Power u Exhaust

6 Intake Stroke

7 Compression Stroke Valves closed

8 Power Stroke Valves closed

9 Exhaust StrokValve Timing Diagram

Two Stroke Engine Theory u Up stroke u Down stroke

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

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

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

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

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

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

19 Compression Ratios u “Squeeze” on air/fuel mixture before combustion u Efficiency increases with higher CR u About 9:1 on gas autos u 17:1 to 24:1 for diesel engines u 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 u Expensive to repair u Hard starting in cold weather u Higher initial cost

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

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

24 Glow Plugs u Resistance unit to heat cold engines u Installed in cylinder head, sometimes in special pre-combustion chamber u Some use intake heaters u In addition, block heaters for cold weather

25 Typical Diesel Engine

Wankel Engine Theory

27 History of RCE (Rotary Combustion Engines) u Wankel’s idea for RCE u patent was applied u patent received u engine runs

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

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

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

31 Rotors Eccentric Shaft E-Bore

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33 How a RCE Works u Fuel air mix admitted into the peripheral housing through the intake port u Ignition of the fuel air mix begins rotation of rotor through epitrochoid curve u One face of rotor is compressing fuel air mix, another face is receiving mix

34 How a RCE Works u Otto cycle engine: Intake, compression, power, and exhaust happen in three chambers of epitrochoid curve u Rotor and eccentric shaft continuously rotate in same singular motion u Gases exhausted through exhaust port

35 Two Types of RCE u KKM Kreiskolbenmotor or planetary rotation motor One statonary peripheral housing Rotor moves in orbit and propels eccentric shaft Most modern rotary engine

36 Two Types of RCE u DKM Drehkolben Maschine First RCE Inner rotating housing and rotor moving around a fixed shaft Disassemble engine to change spark plugs Achieves speeds of 25,000 rpm

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

38 Summary u Name the four cycles of a four stroke: Intake Compression Power Exhaust

39 Summery (Cont) u What are the major differences in parts between a 2 stroke & 4 stroke? Ports vs. Valves Reed valve vs. Valves u How is the fuel ignited in a deisel engine? Compression

40 Summery (Cont) u The Rotory (Wankel) engine uses what type of bore? E- Bore u What act like rings in a rotory engine? Apex seals u Air can be __________, while water can not? Compressed

41 The End