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Electronic Fuel Systems > 190204b > Flashcards

190204b Flashcards

0
Q

What pump takes low pressure fuel & raises it to injection pressure ?

.

A

“The high pressure pump” -
A multi-plunger radial piston style pump.

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1
Q

List five features electronically controlled fuel systems that can be provided by fuel systems in this module

A

Limiting or variable speed governor control. Multiple horsepower ratings. Starting aid control intake heaters either start. Coldstart and warm up mode. Machine speed limiting.Cruise control truck applications. Throttle control for excess three system operation such as PTO. Integration with other computer controlled systems such as ABS, traction control, electronic transmission control. Self diagnostics.personal computer interface for system testing and programming

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2
Q

What type of pump is a “high pressure pump” ? .

A

Multi-plunger radial piston

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3
Q

HPCR - stands for what ? .

A

High pressure common rail

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4
Q

Approximate cracking pressure of the HPCR is what ?

                         .
A

2000 - 3000 psi

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5
Q

High pressure fuel lines are made of ? .

A

Heavy wall seamless tubing

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6
Q

What does the acronym HEUI stand for?

A

Hydraulic Electronic Control Injection

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7
Q

On a HEUI injector, what does the solenoid do?

A

it controls the injection process by energizing and de-energizing thru ECM output

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8
Q

How many times larger is the larger is the intensifier piston compared to the plunger? What is the purpose of this?

A

6-7 times larger. The reason for the ratio is to provide a force multiplication and receive higher injection pressures.

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9
Q

True or False? On a HEUI injector, during pre-injection the injector is full and ready for injection

A

TRUE

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10
Q

How does engine oil affect a HEUI injector?

A

Pressurized engine oil enters the injector when the solenoid is energized, acting on the intensifier piston. When fuel reaches pressure, the injector begins injection.

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11
Q

What is the approximate opening pressure of a HEUI injector?

A

4500 psi

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12
Q

What is “pilot injection”?

A

This gives the pilot fuel time to burn and develop a flame front in the cylinder (also referred to as delay period)

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13
Q

The amount of fuel delivered in an injection is determined by how long the injector solenoid is “ON”

A

True.

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14
Q

“Rate shaping” of injection timing, done by the ECM, offers what benefits?

A

Increased engine performance and Lower exhaust emissions

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15
Q

The popped valve Co controls what?

A

It controls fuel flow through the injector from Boi to eoi

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16
Q

What conditions may effect fuelling and timing maybe affected by input from what devices

A

Coolant temp sensor.
air temp sensor.
Air pressure sensor
and fuel temp sensor

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17
Q

True/False? Horsepower ratings, governor ability, cold start and warm up modes, cruise control, and starting aid control are able to be controlled by the ECM.

A

True

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18
Q

Electronic unit injectors are actuated by?

A

a mechanical injector drive mechanism

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19
Q

What is the purpose of the fuel transfer system on a EUI injection system?

A

The transfer system on an EUI injection system supplies the EUI’s with fuel at the correct volume and pressure.

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20
Q

An ECM cooling plate is used to?

A

Protect the electronic components from excessive heat

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21
Q

What is the purpose of the poppet valve on an EUI?

A

The poppet valve controls fuel flow through the injector to begin and end injection

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22
Q

In the EUI system, the ECM does what to initiate the injection process?

A

energizes the solenoid to begin the injection process.

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23
Q 
Pulse width (the amount of fuel injected by the EUI) can be measured in:
A) mm of fuel
B) percentage of fuel
C) degrees of crankshaft rotation
D) all of the above
A

D

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24
Q

What is the purpose of an Electronic Fuel Injector calibration code?

A

It identifies fuel delivery variations that exist between each fuel injector and enables the ECM to electronically meter the fluid delivered by each injector to obtain the same horsepower output from all the cylinders.

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25
Q

True or False? The HEUI injection system involves a high pressure engine oil hydraulic system and a low pressure diesel fuel system.

26
Q

True or False? Hydraulically actuated fuel injectors cannot be controlled electronically.

A

False. The are controlled by the ECM

27
Q

List the five stages of the HEUI fuel injection process.

A
  1. Pre injection
  2. Pilot injection
  3. Delay period
  4. Main injection
  5. End of injection
28
Q

The hydraulic pressure on the HEUI system is controlled by the ECM and the…?

A

IAP (Injection Actuation Pressure) control valve

29
Q

True or False? The HEUI injector is filled with diesel fuel during the end of injection stage.

30
Q

What position is the poppet valve be in on a HEUI injector to begin the injection process?

31
Q

What component does the high pressure oil act on inside the HEUI injector?

A

The intensifier piston assembly

32
Q

If 2000 psi of actuation oil pressure was applied to a HEUI injector, what would be the resulting fuel injection pressure?

A

12,000 - 14,000 psi

33
Q

What happens to the actuation oil inside the HEUI injector upon completion of injection?

A

The oil is expelled through a drain hole to the crankcase

34
Q

In an HPCR fuel system, fuel output pressure to the injectors is controlled by what?

A

The rail pressure control valve

35
Q

What is the purpose of a pilot injection?

A

The pilot injection develops a flame front in the cylinder before the main fuel charge is injected which helps reduce overall engine noise and emissions.

36
Q

What keeps the injector needle valve closed between injections on a HPCR injector?

A

A spring as well as high pressure fuel acting on the top of the intermediate valve

37
Q

The HPCR system utilizes a radial piston pump that provides high pressure… ?

A

Fuel - used for the injection process

38
Q

True or False? In the HPCR, when the engine is shut down, there will be no fuel pressure in the common rail or injector lines

A

False - in most systems the common rail holds approx. 1000 psi with engine off

39
Q

What is the purpose of the flow limiting valve on a HPCR system?

A

It prevents overfuelling of a cylinder in the event of an injector failure (IE. needle on injector stuck open)

40
Q

Tue or False? In an HPCR system, to begin the injection process, the injector control valve must be opened.

41
Q

List the main components of a EUP system

A
  1. engine control unit
  2. vehicle control unit
  3. sensors, switches and wiring harnesses
  4. fuel transfer system
  5. camshaft actuated electronic unit pumps
  6. injection lines and nozzles
42
Q

The EUP injectors are connected to the high pressure pumps through what?

A

External lines and jumper tubes

43
Q

The EUP system high pressure fuel pump is actuated by what?

A

A camshaft lobe

44
Q

To begin injection, the EUP solenoid is energized and does what to the poppet valve?

45
Q

True or False? An EUP fuel injector is electronically controlled to determine the BOI and EOI

46
Q

How does the ECU and the vehicle control unit communicate to one another during engine operation?

A

They communicate through a high speed multiplex communications network which simplifies the vehicles wiring structure.

47
Q

What are the 4 common types of electronically controlled fuel systems?

A
  • electronic unit injector (EUI)
  • hydraulic electronic unit injector (HEUI)
  • high pressure common rail (HPCR)
  • electronic unit pump (EUP)
48
Q

Components in an electronic fuel injection system typically include?

A
  • ECM
  • sensors and switches
  • engone accessory solenoids and relays
  • electronic unit injectors
  • wiring harnesses and data links
49
Q

What is the purpose of a transfer pump?

A

Provide instant flow of fuel to injectors

50
Q

Electronically controlled injectors should be supplied with what kind of fuel?

A

Clean, cooled de-aerated fuel at the correct volume and pressure

51
Q

Transfer pressure is usually what pressure?

A

65 PSI or 448 kPa

52
Q

How is an ECM cooled?

A

Diesel fuel flowing through a cooling plate.

53
Q

How are EUI injectors actuated?

A

Mechanically by the engine’s camshaft through a fuel injector drivetrain.

54
Q

What are the main components of an EUI?

A

Cartridge valve, tappet, plunger, barrel, nozzle assembly

55
Q

True or false

Dose the HPCR share the same principles and the HEUI

56
Q

What are two input sensors monitored by the ECU

A 
Engine speed
Fuel temperature 
Oil pressure
Coolant temperature
Boost pressure
Ambient air pressure.   Intake manifold temp
57
Q

What is the approximately transfer fuel pressure in a HPCR

58
Q

True or false

Can residual fuel pressure stay in a HPCR over a long period of time

59
Q

Fuel transfer system consist of

A 
Fuel tank 
Transfer pump
Fuel filters 
Fuel lines
ECM cooling plate
60
Q

What style of high pressure pump is in the HPRC

A

Multi-plunger radial piston

61
Q

Pressure limiting valve safety valve is set approximately to what pressure

A

2000 to 3000 psi

62
Q

One thing that should never be done to injector lines

A

Bend it straighten

Electronic Fuel Systems (5 decks)

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