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4th Year Millwright > Stationary Engines > Flashcards

Flashcards in Stationary Engines Deck (76)
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1
Q

List main engine components

A

cylinder head and valves, block or frame, cylinders, pistons and rings, connecting rods, crankshaft, camshaft, lifters and rocker arms, flywheel, bearings, balancer, timing gears and auxiliary drives

2
Q

Define an engine

A

a mechanical device that converts the chemical energy stored in a fuel to heat then to mechanical energy

3
Q

Define power

A

the rate at which work is being done

4
Q

What is the power required to overcome engine frictional and pumping losses?

A

friction horsepower

5
Q

What is Indicated Horsepower?

A

The theoretical power of an engine.

6
Q

What is Brake Horsepower and how is it calculated?

A

BHP is the actual power measured at the end of the crankshaft, it’s calculated as:
Brake HP = Indicated HP - Friction HP

7
Q

Which engine would have a longer stroke length than bore diameter? What type of engine would normally have this characteristic?

A

an undersquare engine, diesel engines

8
Q

What are the characteristics of an oversquare engine?

A

larger bore diameter than stroke length

9
Q

What is the thermal efficiency for most engines?

A

25-40%

10
Q

On a HP-torque curve what point of the curve indicates the approximate RPM for maximum volumetric efficiency?

A

the high point

11
Q

What is volumetric efficiency?

A

the ratio of the volume of atmospheric air drawn into the cylinder on the intake stroke to the cylinder stroke

12
Q

What is the name of the leakage of burned and unburned gases that gets past the compression rings into the crankcase?

A

blowby

13
Q

What are the 4 strokes in one cycle of a 4-stroke engine?

A

intake, compression, power, exhaust

14
Q

When does ignition take place on an SI (spark ignition) engine?

A

as the piston reaches a few degrees BTDC (before top dead centre)

15
Q

How many crankshaft rotations does it take to complete a cycle on a 4-stroke engine?

A

2 revolutions (720 deg)

16
Q

Where is engine rotation determined from?

A

by viewing the engine from the flywheel end

17
Q

What is the main advantage to an integral engine?

A

it does not require coupling

18
Q

What engine type has the most bearing area per cylinder?

A

the in-line arrangement

19
Q

What are the 3 types of valve arrangements?

A

overhead valve (I head), multi-valve, and flat head (L head)

20
Q

What are two possible camshaft positions?

A

overhead cams (OHC), and cam in the block (pushrod engine, most common)

21
Q

Which is the most efficient valve arrangement?

A

overhead valve (I head)

22
Q

What do naturally aspirated engines use to get air into the cylinders?

A

atmospheric pressure

23
Q

Which type of engine requires some type of artificial means of pumping air into the cylinder?

A

2-stroke engines

24
Q

What should be done to the engine flywheel before entering the crankcase?

A

it should be pinned and locked out

25
Q

What is the crankshaft type that’s found in an engine with a one-piece block?

A

an underslung crankshaft

26
Q

When checking for coolant leaks on an engine block with a pressure-test, what is the maximum PSI you should use?

A

45 PSI

27
Q

What should the maximum deviation of the main bearing bores be?

A

no more than half the maximum allowable main bearing clearance (new condition)

28
Q

What are some methods of checking main bearing bore alignment?

A

piano wire, laser, optical methods, deflection gauge (if crankshaft is in place)

29
Q

Where is the highest wear area in a cylinder?

A

near the top of the liner due to high temperatures, pressures, and minimum lubrication

30
Q

What are 3 methods used to treat cylinder liners to reduce the rate of wear?

A

induction hardening, hard chrome, nitriding

31
Q

What are 3 types of cylinder liners?

A

dry liners, wet liners, air-cooled liners

32
Q

When do you measure and record liners for wear?

A

While they are in the cylinder block.

33
Q

What can you use to remove the ring that forms on the upper part of a cylinder under 6” in diameter?

A

a ridge reamer

34
Q

What does deglazing restore inside the cylinder?

A

The crosshatch pattern on the cylinder wall.

35
Q

What should you not use when cleaning the cylinder after deglazing?

A

solvents

36
Q

What two measuring tools would you use when checking the machined surfaces of the cylinder block for flatness?

A

straight edge, feeler gauge

37
Q

What would you not use to clean aluminium?

A

caustics

38
Q

What is opposite of the rod throws on a crankshaft, and used to balance the rotating mass?

A

counterweights

39
Q

What is used to stabilize speed fluctuations and store energy during power pulses to carry the engine to the next stroke?

A

flywheel

40
Q

What are tangs or dowels used for with shell-type engine bearings?

A

to locate (and also hold with the dowel) the bearing half in the block

41
Q

What is the purpose of bearing spread?

A

To keep the bearing from falling out during assembly.

42
Q

What is the most accurate method of checking bearing clearance?

A

measurement

43
Q

What is the most accurate method of tightening fasteners?

A

bolt stretch (elongation)

44
Q

Which has a larger diameter on a piston, the ring land or the skirt?

A

the skirt

45
Q

What type of piston has 2 pieces?

A

crosshead type (trunk-type is one piece)

46
Q

Which piston ring is held against cylinder with spring pressure?

A

oil ring

47
Q

On a 4-stroke engine, what is the speed of the camshaft in relation to the speed of the crankshaft?

A

camshaft speed is 1/2 crankshaft speed

48
Q

What is the purpose of the camshaft lifter (valve lifter)?

A

to transfer motion to the pushrod

49
Q

What component is the mechanical link between the pushrod and the valve?

A

the rocker arm

50
Q

Where are valves primarily cooled from? Where does other cooling come from?

A

Primarily through heat transfer to the valve seat and guide (from the face and stem), intake valves receive additional cooling from intake air.

51
Q

What could insufficient valve clearance cause?

A

burnt valves, poor engine performance

52
Q

Which valve (intake/exhaust) is made of higher quality material and why?

A

Exhaust valves are because of the higher temps and corrosive gases they are exposed to.

53
Q

What does the octane rating of a fuel refer to?

A

its ability to resist ignition due to compression (the higher the octane number, the more the fuel can resist self-ignition)

54
Q

What is to avg mixture of air to fuel (by weight) for gas engines?

A

from 14-16 parts of air to 1 part of fuel

55
Q

What determines how much of the air fuel mix enters the engine in a carburetor?

A

the throttle valve

56
Q

Which is the low voltage circuit of an ignition system, the primary or secondary circuit? The high voltage circuit?

A

the primary circuit is low voltage, secondary is high voltage

57
Q

Which ignition system creates its own power supply and distributes it to the coil?

A

the magneto ignition system

58
Q

Between gasoline, LPG, natural gas or diesel, which has the higher BTU value?

A

diesel

59
Q

What number indicates the ability of a fuel to ignite?

A

cetane number

60
Q

What is a cetane number used for?

A

To rate the ignition characteristics of diesel fuel.

61
Q

What components are in an induction system?

A

Pre-cleaner, air cleaner, intake manifold, may have a method of artificial respiration such as a turbo, blower, or a piston type air pump

62
Q

What’s a waste gate? Where is it located?

A

A component the is used to control the boost on a turbo, located between the turbine and the exhaust manifold.

63
Q

What’s the most commonly used coolant, and what’s a safer alternative to this coolant?

A

Ethylene Glycol based is the most common coolant, Propylene Glycol based is a safer alternative coolant.

64
Q

What device could you use to test the strength of an antifreeze solution?

A

a hydrometer or a refractometer

65
Q

What are the functions a lubricant serves in an engine lubrication system?

A

reduces friction, cools, seals, cleans and flushes, absorbs thrust

66
Q

What are the types of oil pumps used in engine lube systems?

A

positive displacement rotary pumps such as external gear pumps (most common), vane, internal gear, and gerotor

67
Q

Which oil filtration system filters all the oil after the oil pump before it reaches the bearings? How would the oil reach the bearings on a cold start up or when the filter is plugged?

A

The Full-Flow Filtration system, a bypass valve

68
Q

What is the main function of an engine cooling system?

A

To regulate the engine temperature.

69
Q

What is the most common type of thermostat?

A

wax pellet

70
Q

What are the 3 methods of lubrication?

A

splash, splash and pressure, full pressure

71
Q

What are the purposes of the pre and post lube pumps?

A

The pre-lube pump gets oil to critical parts of the engine before its turned over, the post-lube pump runs after the engine shuts down to cool down the engine and components, lube the bearings in the turbo as it winds down.

72
Q

What would happen to the oil pressure if the relief valve was stuck open?

A

the pressure would be low

73
Q

How big should the foundation for an engine (entire assembly) be in relation to the engine itself?

A

2.5 times the mass of the complete engine

74
Q

What type of anchor bolt should be avoided when fastening an engine to the foundation?

A

J bolts

75
Q

What are the 3 basic requirements for an engine to run?

A

air, fuel, ignition

76
Q

What is the main purpose of an engine control system?

A

To monitor/control the engine, and shut down the engine in case of a critical alarm.