Objectives

1. Lab T1: Compression Ignition (Diesel) Engine LabInstructor: SoheilAkbari (soa554@mail.usask.ca)

2. Objectives • To become familiar with the operation of a compression-ignition (diesel) engine • To determine the effect of load variation at constant speed on • Mechanical efficiency • The primary characteristics of in-cylinder pressure development • To perform an energy balance on the engine

3. Engine Nomenclature Fuel Injector Valves Cylinder Piston Connecting Rod Crankshaft Piston at top dead center (TDC), cylinder volume least Piston at bottom dead center (BDC), cylinder volume greatest. Swept Volume = Volume A – Volume B Compression Ratio = Volume A / Volume B

4. Operation of a 4-stroke compression ignition engine http://www.shareswf.com/game/4504/working-of-diesel-engine

5. B- Intake Stroke Maximum cylinder pressure Combustion commences Cylinder Pressure Fuel injection commences Exhaust Cylinder Volume TDC BDC Physical & chemical ignition delay Operation of a 4-stroke compression ignition engine C A B

6. Maximum cylinder pressure Combustion commences Cylinder Pressure Fuel injection commences Exhaust Induction Cylinder Volume TDC BDC Physical & chemical ignition delay Operation of a 4 stroke compression ignition engine D C

7. Maximum cylinder pressure Combustion commences Cylinder Pressure Fuel injection commences Exhaust Induction Cylinder Volume TDC BDC Physical & chemical ignition delay Operation of a 4 stroke compression ignition engine C to E is called the Compression Stroke E D C

8. Maximum cylinder pressure Combustion commences Cylinder Pressure Fuel injection commences Exhaust Induction Cylinder Volume TDC BDC Physical & chemical ignition delay Operation of a 4 stroke compression ignition engine E to G is called the Power Stroke F – Power Stroke E G

9. Maximum cylinder pressure Combustion commences Cylinder Pressure Fuel injection commences H- Exhaust Stroke Induction Cylinder Volume TDC BDC Physical & chemical ignition delay Operation of a 4 stroke compression ignition engine G A

10. Apparatus Schematic

11. Petter Diesel Engine Injector Pump PLUNGER FUEL SPILL PORT FUEL SUPPLY PORT HELIX (The position of the helix to the fuel spill port meters the amount of fuel delivered to the injector by changing the effective stroke of the pluger.)

12. Injector Needle Lift and Fuel Line Pressure Injector Fuel Injection Pump Rack Displacement Transducer Pfuel Fuel Supply Fuel Spill Port Injector Needle Rotate Shaft to Adjust Cam at ½ Engine Speed

13. In Lab Procedure • Collect data at four operating points. • Constant RPM (N=1050 RPM) • Increase fuel injection and obtain N=1050 by increasing load • At each operating point • Await steady state (constant exhaust gas temp.) • Fill out data sheets • Capture Pcyl and V vs time waveform on oscilloscope • At intermediate operating point (3rd operating point) • 4 Pcyl and V vs. time for single cycles • Injector needle lift, Pfuel, Pcyl , vs time

14. Brake Power • Indicated Power • Need to plot P-V diagrams for each load • Specific Fuel Consumption • Volumetric Efficiency • Air/Fuel Ratio • Mechanical Efficiency • Brake Thermal Efficiency • Mass flow rate of Exhaust • “Willans Line” Test • Energy Balance • Plot a Pcyl and V vs. t diagram for a cycle at the 3rd load condition • Pcyl vs. t for 4 cycles at 3rd test condition • V vs. t for 4 cycles at 3rd test condition • Plot injector needle lift, fuel line pressure, and Pcyl vs. time • Plot the first derivative of Pcyl on a Pcyl vs. t diagram Calculations and Discussion • Preliminary Discussion • Operation of fuel injector pump • Timing of fuel pressure, injector needle lift, pcyl • Discuss Signals on the scope • Predictions of how performance measures will change between operating points • How does the data differ from the idealized Diesel cycle (what assumptions are not valid in a real engine)

15. 1. Brake Power Rotational speed of engine [rev/s] Brake Power [W] Brake load [N] Load arm radius [m]

16. Maximum cylinder pressure Combustion commences Cylinder Pressure Fuel injection commences Exhaust Induction Cylinder Volume TDC BDC Physical & chemical ignition delay 2. Indicated Power: Proportional to the area within the power and compression strokes minus the area within the intake and exhaust strokes. Only 2 of 4 strokes considered Area under P-V Area within intake and exhaust strokes is very small and can be neglected!

17. Step 1: Plot P-V Diagram P V

18. Offsets and Filtering

19. P-V Diagram after Offsets and Filtering P V

20. Indicated Power

21. Indicated Power Indicated Mean Effective Pressure Why N/2 ?

22. Numerical Integration 1 2

23. Numerical Integration

24. Indicated Mean Effective Pressure

25. 3. Specific Fuel Consumption Fuel consumption (kg/h) Brake Power (W or kW)

26. 4. Volumetric Efficiency Orifice coefficient Orifice area Ambient Differential pressure across Orifice (Pa)

27. 5. Air/Fuel Ratio

28. 6. Mechanical Efficiency Brake Power Indicated Power

29. 7. Brake Thermal Efficiency Mass flow rate of fuel Lower heating value for fuel

30. 8. Mass Flow Rate of Exhaust • Conservation of Mass

31. 9. Willans Line for Mechanical Losses Fuel Consumption Without Mechanical Losses Brake Power (kW) Mechanical Losses ~ 0.8 kW

32. 10. Energy Balance IN OUT Calculate heat transferred to atmosphere:

33. 11. Pcyl and V vs. t • Label the four strokes on a Pcyl and V vs. t diagram for one of the four cycles observed at the 3rd test condition. P V

34. 12. Pcyl vs. t • Plot Pcyl vs. t for all four cycles taken at the 3rd load condition. • Comment on the cyclic variation between the four cycles.

35. 13. V vs. t • Plot V vs. t for all four cycles taken at the 3rd load condition. • Comment on the cyclic variation between the four cycles.

36. 14. Injector Needle Lift, Fuel Line Pressure, and Pcyl vs. t • Plot injector needle lift, fuel line pressure, and Pcyl vs. time on a single plot. • Comment on the relationship between these three. (Focus on the order and timing of when things occur).

37. 15. • Calculate the first derivative of in-cylinder pressure for ONE cycle taken at the 3rd load condition. • Plot it on the corresponding Pcyl vs. time diagram and comment on the relationship of this graph to the operation of the engine.

40. Questions? • Final Reports • Do all calculations and plots, and explain what EACH means. • Explain the differences in performance values between the four load conditions. • Limit Background info, focus on discussions. • SAFE!