DIESEL ENGINE COMBUSTION AND FUEL

      

1. What is the term given to the process of breaking up fuel oil into very fine particles for better combustion?/Atomizing

2. Turbulence in a diesel engine cylinder is of major   importance in providing _____________./complete fuel/air mixing

3. Poor combustion in a diesel engine can be caused by   ______________./low intake air temperature

4. Which of the following conditions will tend to increase the ignition delay period of combustion in a compression  ignition engine?/Decreasing the air charge temperature.

5. Combustion gas venting through the expansion tank can be caused by a _____________./cracked cylinder head

6. Combustion knock can occur in the cylinders of a diesel  engine under any condition permitting _____________./excess fuel in the combustion chamber

7. Turbulence of the compressed air charge in a diesel engine cylinder increases _____________./the efficiency of the engine

8. Combustion knock occurring in a diesel engine can be caused by _____________./prolonged ignition lag

9. Which of the following statements is a description of the combustion cycle?/The heat process which produces the force to initiate the movement of the engine parts.

10. An exhaust pipe from a internal combustion engine may not need to be insulated when _________./it is of the water jacketed type

11. Combustion knock occurring in a diesel engine can be caused by ________________./low coolant temperature

12. In a diesel engine, the time taken to heat the fuel   particles, turn them into vapor, and bring about combustion is called _____________./ignition delay

13. Diesel engines are classified as reciprocating internal  combustion engines because they ______________./burn fuel in a chamber where its energy moves a piston back and forth

14. The thermal energy produced by an internal combustion engine is transformed into ______________./mechanical energy

15. Which of the listed designs is effectively used to provide the turbulence necessary for proper combustion in a diesel engine cylinder?/Precombustion chamber

16. Which of the following statements represents the advantage of a precombustion chamber used in an auxiliary diesel  engine?/Timing of injection does not need to be exact.

17. One advantage obtained from the use of a precombustion  chamber in a diesel engine is _____________./smoother combustion

18. Precombustion chambers differ from turbulence chambers in that precombustion chambers _____________./contain a smaller portion of the total clearance volume

19. What is commonly used to create turbulence in a diesel engine combustion system?/Shape of the piston crowns.

20. Turbulence is created in the cylinders of a diesel engine to _____________./help mix fuel and air

21. The main operating characteristic of diesel engines which distinguishes them from other internal combustion engines is the _____________./method of igniting fuel

22. What determines the number of events occurring in a cycle of operation in an internal combustion engine?/Type of engine (diesel or gasoline)

23. Which of the following statements describes the operating characteristics of a precombustion chamber?/When fuel oil is injected into the precombustion chamber, it does not need to be as finely atomized as the fuel oil in diesel engines having direct injection.

24. Modern marine diesel engines using mechanical fuel   injection, operate on a combustion cycle which is _________./a combination of constant volume and constant pressure

25. Modern marine diesel engines equipped with mechanical fuel injection operate on a combustion phase within the cycle which is _________./a combination of constant volume and constant pressure

26. A multi-orifice fuel injection nozzle is usually used with which of the listed types of combustion chamber?/Open combustion chamber

27. Black smoke exhausting from an operating diesel engine is an indication of poor combustion which may be caused by  _____________./clogged air intake passages

28. In a modern internal combustion diesel engine, the load  carrying part of the engine is referred to as the _________./bedplate or base

29. According to U. S. Coast Guard Regulations (46 CFR),  internal combustion engine driven emergency generators shall be operated under load for at least two hours at least once ____________./a month

30. According to Coast Guard Regulations (46 CFR), how often shall internal combustion engine driven emergency generators be operated under load?/Once a month for two hours

31. Which of the following conditions is likely to develop if the thermocouple element of a pyrometer becomes coated with excessive amounts of combustion by-products?/Pyrometer responses will be retarded.

32. In a diesel engine, what is the advantage of precombustionchambers over the open type of combustion chamber? I. Precombustion chambers permit coarser fuel  atomization. II. Precombustion chambers allow lower fuel injection  pressure./both I and II

33. Modern marine diesel engines equipped with mechanical fuel injection operate on a combustion cycle which is _________./a combination of constant volume and constant pressure

34. Which internal combustion engine starting system uses avane type fluid motor?/Compressed air

35. Which of the following relationships should occur between the temperature developed in a combustion space, and the compression ratio of the engine?/Higher compression ratios create higher temperature.

36. Diesel engine blow-by is the leakage of combustion gases past the _____________./compression and scraper rings

37. In accordance with Coast Guard Regulations (46 CFR)   regarding internal combustion engine exhaust manifold  installations, which of the following statements is true?/They may be water-jacketed and cooled by the discharge from a pump which operates only when the engine is running.

38. Open combustion chambers are designed to _____________./provide proper fuel/air mixing

39. The primary purpose of the open combustion chamber used in diesel engines is to _____________./provide a place for combustion

40. Turbulence in the combustion chamber of a diesel engine can be induced by _____________./directional intake ports

41. The greatest turbulence in a diesel engine cylinder is  created by the _____________./shape of the combustion chamber

42. Combustion knock will most likely occur as a result of using a fuel with _____________./low ignition quality

43. Coast Guard Regulations (46 CFR) require a trial for  ignition period must not exceed ____________./15 seconds

44. The air supplied to a diesel engine is compressed to___________.I. provide heat for the ignition of the fuelII. decrease injection delay/I only is correct

45. For a given fuel, a change in the compression ratio will affect the ignition lag by which of the listed means?/An increase in compression ratio will decrease the ignition lag.

46. The longer the ignition delay period occurs in a diesel  engine, the _____________./more rapid will be the rise in combustion pressure

47. Which of the following conditions will tend to increase the ignition delay period of combustion in a compression  ignition engine?/Decreasing the air charge temperature.

48. The rate of pressure rise during the period following fuel ignition process in a diesel engine, is influenced chiefly by the ____________./length of the ignition delay period

49. Which of the following statements concerning the factors affecting ignition delay is correct?/An increase in coolant temperature will decrease ignition delay.

50. The time between injection and ignition of the fuel is known as _____________./ignition delay