190203e Advanced Mechanical Fuel Injection Systems

Question 0

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

Answer 0

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

Question 1

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

Answer 1

Barrel and plunger

Question 2

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

Answer 2

Injection

Question 3

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

Answer 3

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

Question 4

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

Answer 4

This is called “loading”

Question 5

Where would you commonly find timing marks for positioning the engine

Answer 5

On the flywheel or the damper

Question 6

List three effects of incorrect fuel injection pump timing

Answer 6

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

Question 7

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

Answer 7

Remove valve cover and insure both valves are closed

Question 8

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

Answer 8

In order to remove geartrain lash that could affect timing accuracy

Question 9

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

Answer 9

Remove the timing pins to prevent damage

Question 10

What effect does a cracked AFRC diaphragm have an engine

Answer 10

Reduced power output

Question 11

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

Answer 11

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

Question 12

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

Answer 12

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

Question 13

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

Answer 13

False. Cam ring lobes push the plungers together

Question 14

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

Answer 14

The amount of fuel that enters the pumping element changes

Question 15

As pump speed increases what is used to advance the timing

Answer 15

Fuel transfer pressure

Question 16

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

Answer 16

Nope. Personal injury and mechanical damage will occur

Question 18

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

Answer 18

Nozzle body, nozzle assembly and nozzle retaining ring

Question 18

What are two basic types of hydraulically operated fuel injection nozzles

Answer 18

Multi hole and pintle

Question 19

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

Answer 19

The engine shuts down or fails to start

Question 20

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

Answer 20

Spring pressure

Question 21

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

Answer 21

True

Question 22

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

Answer 22

Water, dirt and high heat loads

Question 23

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

Answer 23

True

Question 24

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

Answer 24

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

Question 25

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

Answer 25

You must clean around the injector and fittings to avoid contamination

Question 26

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

Answer 26

If checking for high-pressure use a piece of cardboard

Question 27

List the three basic functions of a governor

Answer 27

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

Question 28

Define the term low idle speed

Answer 28

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

Question 29

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

Answer 29

False injectors should slide in easily and not be forced

Question 30

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

Answer 30

True

Question 31

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

Answer 31

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

Question 32

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

Answer 32

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

Question 33

What are two governor classifications typically used in mobile equipment

Answer 33

Limiting speed and variable speed

Question 34

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

Answer 34

True

Question 35

Pintle fuel injection nozzles are ________ hole design

Answer 35

Single

Question 36

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

Answer 36

Ture they both open at (1400-2500 psi)

Question 38

What should be done after each fuel line is removed?

Answer 38

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

Question 39

What should NOT be done to the fuel line

Answer 39

Should NOT attempt to straighten or bend lines

Question 40

Purpose of fuel injection line clamps?

Answer 40

Eliminate vibration and prevent damage from chafing

Question 41

Why should injection lines be equal in length?

Answer 41

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

Question 42

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

Answer 42

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

Question 43

What will the governor regulate?

Answer 43

RPM and power output

Question 44

What does the governor continually regulate?

Answer 44

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

Question 45

In most engines where are the fuel injector assemblies mounted

Answer 45

They are mounted in machined openings in the cylinder head

Question 46

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

Answer 46

1) pressure tight seal from the combustion chamber | 2) transfers heat from the injector to the cylinder head

Question 47

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

Answer 47

- erodes the calibrated holes | - destroys the sealing surface between needle valve and nozzle body

Question 48

As transfer pump rotor speed increases what else increases?

Answer 48

Volume and pressure increase proportionately

Question 49

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

Answer 49

4 PSI

Question 50

A restricted return line can cause what?

Answer 50

Engine shutdown or failure to start

Question 51

How many lobes does cam ring have?

Answer 51

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

Question 52

What's the function of the metering valve?

Answer 52

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

Question 53

Identify two governor classifications used in mobile equipment.

Answer 53

limiting speed | variable speed

Question 54

List five functions of a fuel injection system.

Answer 54

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

Question 55

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

Answer 55

eccentric on the engines camshaft or the fuel injection pump camshaft

Question 56

Define "penetration" in regards to a fuel injection pump?

Answer 56

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

Question 57

What does "metering" mean in a fuel injection system?

Answer 57

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

Question 58

What does "atomization" mean?

Answer 58

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

Question 59

Identify two basic type of hydraulically operated injection nozzels

Answer 59

mulihole | pintle

Question 60

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

Answer 60

nozzle nozzle body nozzle retaining nut

Question 61

List three basic functions of a governor.

Answer 61

control low idle control high idle maintain a constant speed