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Diesel Fuel Injection Systems > 190203e Advanced Mechanical Fuel Injection Systems > Flashcards

190203e Advanced Mechanical Fuel Injection Systems Flashcards

0
Q

What changes the amount of fuel metered per injection in a port and helix?

A

By rotating the plunger, which changes its effective pumping stroke.

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1
Q

What two basic components make up the port and helix pumping element

A

Barrel and plunger

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2
Q

When the outlet port in the rotor & the injector nozzle outlet port align in a opposed plunger injection pump, what’s happening ?

A

Injection

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3
Q

How is plunger rotation controlled in a multi-plunger port and helix injection pump?

A

It is controlled by the control sleeve, gear and fuel control rack. Rack position is determined by throttle position and governor action .

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4
Q

When the charging port on the rotor aligns with the fuel inlet port in a opposed plunger injector pump, what’s happening ?

A

This is called “loading”

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5
Q

Where would you commonly find timing marks for positioning the engine

A

On the flywheel or the damper

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6
Q

List three effects of incorrect fuel injection pump timing

A

Reduced feel economy, excessive exhaust smoke emissions and reduced performance (poor starting and low-power)

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7
Q

What must you check on a four stroke engine when inserting a timing pin to ensure number one cylinder is on compression stroke

A

Remove valve cover and insure both valves are closed

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8
Q

Why should you always rotate the engine in the normal direction of rotation during injection timing procedures

A

In order to remove geartrain lash that could affect timing accuracy

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9
Q

Immediately after completing injection pump installation what must you remember to do to the pump and flywheel

A

Remove the timing pins to prevent damage

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10
Q

What effect does a cracked AFRC diaphragm have an engine

A

Reduced power output

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11
Q

What are four parts in the pumping element in the opposed plunger fuel injection pump

A

A rotor, hydraulic head, a pair of opposed plungers and cam ring

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12
Q

What component does an opposed plunger fuel injection pump look like on a gas engine

A

The fuel injection outlet fittings have a circular pattern or distributor shaped arrangement

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13
Q

True or false. In in a opposed plunger injection pump, high-pressure fuel is forced to the injector when the plungers are pushed apart by the cam ring lobes

A

False. Cam ring lobes push the plungers together

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14
Q

What effect does rotating the metering valve of an opposed plunger fuel injection pump have

A

The amount of fuel that enters the pumping element changes

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15
Q

As pump speed increases what is used to advance the timing

A

Fuel transfer pressure

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16
Q

Can you adjust the timing of unopposed plunger fuel injection pump while the engine is running

A

Nope. Personal injury and mechanical damage will occur

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18
Q

What are three major components that make up a fuel injector assembly

A

Nozzle body, nozzle assembly and nozzle retaining ring

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18
Q

What are two basic types of hydraulically operated fuel injection nozzles

A

Multi hole and pintle

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19
Q

What happens to an engine when you have a plugged or restricted return line on an opposed plunger injection pump pump

A

The engine shuts down or fails to start

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20
Q

What keeps the nozzle needle valve of a hydraulically operated fuel injector closed

A

Spring pressure

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21
Q

True or false. Pencil type fuel injectors allow the engine manufacturer to have cylinder heads with very small access passages for the fuel injectors

A

True

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22
Q

Identify three factors that affect the operation of the fuel injector and have a negative influence on fuel injector service life

A

Water, dirt and high heat loads

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23
Q

The spray pattern at the nozzle tip is determined by the nozzle manufacturer and is created for specific engine combustion chamber design. True or false

A

True

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24
Q

What precautions must you take when removing a fuel injection line in order to avoid disturbing or damaging the fuel injection pump or the fuel injector

A

Use two wrenches. Hold one in place and turn the other

25
Q

What action must you take prior to loosening or removing injection lines or fuel injectors from an engine

A

You must clean around the injector and fittings to avoid contamination

26
Q

What method would you use to check fuel lines for leaks without creating a personal safety hazard

A

If checking for high-pressure use a piece of cardboard

27
Q

List the three basic functions of a governor

A

Control low idle speed, control high idle speed and maintain a constant speed

28
Q

Define the term low idle speed

A

It’s the lowest no-load speed at which the engine will run without operator input

29
Q

true or false - use the holddown Fasner to pull the injector into the machine opening in the cylinder head

A

False injectors should slide in easily and not be forced

30
Q

True or false. High idle and full load speeds are only the same when speed droop is zero

A

True

31
Q

True or False. Governor stability refers to how quickly (or slowly) the engine governor reacts to changes in engine speed.

A

False. It’s the ability of a governor to maintain a required engine speed without hunting or surging.

32
Q

What are three conditions under which the governor may not be able to control engine speed

A

Load pushing the vehicle, engine overloaded and engine exposed to outside fuel sources (airborne)

33
Q

What are two governor classifications typically used in mobile equipment

A

Limiting speed and variable speed

34
Q

True or false. As engine speed increases, the flyweights oppose the force of the governor spring

A

True

35
Q

Pintle fuel injection nozzles are ________ hole design

A

Single

36
Q

True of false - Pintle nozzles have the same opening pressure as Multi-hole design fuel injector ?

A

Ture they both open at (1400-2500 psi)

38
Q

What should be done after each fuel line is removed?

A

Immediately cap the line and fuel inlet fitting with clean, tight fitting cap type plugs

39
Q

What should NOT be done to the fuel line

A

Should NOT attempt to straighten or bend lines

40
Q

Purpose of fuel injection line clamps?

A

Eliminate vibration and prevent damage from chafing

41
Q

Why should injection lines be equal in length?

A

Ensures that an equal volume of fuel is in each line to prevent injection delay from cylinder to cylinder

42
Q

What can happen if you do not remove the copper washer from the fuel injector or cylinder head?

A

The injector position will change when you install the new copper washer.

43
Q

What will the governor regulate?

A

RPM and power output

44
Q

What does the governor continually regulate?

A

Engine RPM, reacts to RPM change, controls the fuel system to adjusts metering as required

45
Q

In most engines where are the fuel injector assemblies mounted

A

They are mounted in machined openings in the cylinder head

46
Q

The nozzle is seated on a soft metal washer list two factors that this provides

A

1) pressure tight seal from the combustion chamber

2) transfers heat from the injector to the cylinder head

47
Q

What can happen when a fuel injector nozzle is exposed to dirty fuel ?

A
  • erodes the calibrated holes

- destroys the sealing surface between needle valve and nozzle body

48
Q

As transfer pump rotor speed increases what else increases?

A

Volume and pressure increase proportionately

49
Q

A portion of transfer fuel fills the pump housing, where a return line check valve regulates pressure to approximately?

A

4 PSI

50
Q

A restricted return line can cause what?

A

Engine shutdown or failure to start

51
Q

How many lobes does cam ring have?

A

The pumping element revolves within a cam right that usually has the same number of lobes of the engine has cylinders

52
Q

What’s the function of the metering valve?

A

The metering valve controls the amount of fuel delivered to each fuel injector on the engine and is connected to the governor and throttle assembly

53
Q

Identify two governor classifications used in mobile equipment.

A

limiting speed

variable speed

54
Q

List five functions of a fuel injection system.

A
  1. inject fuel at correct time
  2. inject fuel at the correct rate
  3. atomized the fuel
  4. meter the fuel
  5. inject the fuel at high enough pressure for proper penetration
55
Q

Diaphragm and plunger type fuel transfer pumps are operated by an __________.

A

eccentric on the engines camshaft or the fuel injection pump camshaft

56
Q

Define “penetration” in regards to a fuel injection pump?

A

penetration refers to the ability of the fuel spray to reach all areas of the combustion chamber

57
Q

What does “metering” mean in a fuel injection system?

A

to supply exactly the right amount of fuel for all engine speeds and loads

58
Q

What does “atomization” mean?

A

to break the fuel up into tiny droplets small enough to vaporize readily with the heat of compression

59
Q

Identify two basic type of hydraulically operated injection nozzels

A

mulihole

pintle

60
Q

List three major components that make up a fuel injector assembly.

A

nozzle
nozzle body
nozzle retaining nut

61
Q

List three basic functions of a governor.

A

control low idle
control high idle
maintain a constant speed

Diesel Fuel Injection Systems (8 decks)

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