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EMS-D All Chapters Studied > Week 2, Chapter 62 - Gasoline Fuel Systems > Flashcards

Week 2, Chapter 62 - Gasoline Fuel Systems Flashcards

1
Q

What kind of injection system is more prevalent today?

A

Multipoint Fuel Injection (MPFI)

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2
Q

What kind of injection system places the fuel injectors in the cylinder head near the spark plugs?

A

Gasoline Direct Injection (GDI)

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3
Q

What is needed to determine the proper quantity of fuel to be injected?

A

The PCM/ECM

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4
Q

Fuel needs to be ___________ as it enters the cylinder

A

Vaporized

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5
Q

___________ of fuel helps it mix with air better

A

Atomization

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6
Q

Modern gasoline-powered vehicles use _____ systems

A

EFI (Electronic Fuel Injection)

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7
Q

Pressure differential is central to _____ fuel systems

A

All

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8
Q

What are some sub-systems of modern fuel injection systems?

A
  • Fuel supply system
  • Air supply system
  • Fuel metering system
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9
Q

It is highly explosive to mix air with what?

A

Gasoline Vapor

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10
Q

What generally occurs in lower pressure fuel systems, or in systems that have too low of fuel pressure?

A

Vapor lock

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11
Q

Gasoline must be enhanced with different additives such as…

A

Detergents

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12
Q

What helps to keep the fuel system clean?

A

Detergents

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13
Q

What two methods are used to measure the octane rating of fuel?

A
  1. Research Octane Number (RON)
  2. Motor Octane Number (MON)
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14
Q

Higher octane does NOT mean…

A

Higher energy output

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15
Q

Engines perform best when used with octane rating recommended by the…

A

Engine Manufacturer

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16
Q

Carburetion works off pressures ______ atmospheric pressure

A

Below (Vacuum)

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17
Q

Fuel injection works off pressures _______ atmospheric pressure

A

Above

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18
Q

_______ is now boosted with additives of ethanol, aromatic hydrocarbons, and ether chemicals

A

Octane

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19
Q

_________ is a violent collision of flame fronts in the cylinder, caused by uncontrolled combustion

A

Detonation

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20
Q

What occurs before normal ignition?

A

Pre-ignition

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21
Q

What occurs after normal ignition?

A

Detonation

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22
Q

Many engine management systems use _________ to detect detonation

A

Knock sensors

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23
Q

What is a running-on or dieseling engine?

A

An engine that keeps running after it is switched off

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24
Q

What happens when a hot spot in the cylinder ignites the mixture before the spark plug?

A

Pre-ignition

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25
Q

What happens when a hot spot in the cylinder ignites the mixture after the spark plug causing a second flame front?

A

Detonation

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26
Q

What kind of unit is a fuel injector?

A

Solenoid

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27
Q

What is the shelf life of gasoline?

A

6 months

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28
Q

What can be caused by a high idling speed, an overheated engine, too many carbon deposits in the chamber, or use of a gasoline with an octane rating that is too low?

A

Dieseling

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29
Q

Fuel-injected vehicles do not experience dieseling unless…

A

There is a leaking injector when the ignition is turned off

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30
Q

What kind of air-fuel mixture has more air than fuel?

A

Lean

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31
Q

What kind of air-fuel mixture has less air than fuel?

A

Rich

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32
Q

A slightly _____ air-fuel mixture gives good fuel economy and low exhaust emissions

A

Lean

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33
Q

A slightly ______ mixture can produce more power, but the extra fuel it uses steps up fuel consumption and greatly increases emissions

A

Rich

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34
Q

Extremely ______ mixture can foul spark plugs and increase carbon deposits in the combustion chamber and exhaust

A

Rich

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35
Q

What describes the chemically correct air-fuel ratio necessary to achieve complete combustion of the fuel and air?

A

Stoichiometric Ratio

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36
Q

What is the stoichiometric air-fuel ratio?

A

14.7 lb of air to 1 lb of fuel

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37
Q

What sensor is used to indicate the amount of oxygen in the exhaust to help the PCM maintain the stoichiometric ratio?

A

Exhaust Gas Oxygen Sensor

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38
Q

Atmospheric pressure _________ with altitude

A

Reduces

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39
Q

A pressure gauge indicates only pressure __________ atmospheric pressure

A

Above

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40
Q

Gauge Pressure + Atmospheric Pressure =

A

Absolute Pressure

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41
Q

Pressure below atmospheric pressure is called __________

A

Vacuum

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42
Q

At wide-open throttle, the vacuum is much less and the pressure in the manifold does what?

A

Rises to atmospheric pressure

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43
Q

A vacuum gauge can be calibrated in inches of mercury in a scale reading from what?

A

0” to 30”

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44
Q

Some engine management systems use a ____________ or the MAP sensor KOEO to determine atmospheric pressure

A

Barometric Pressure Sensor

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45
Q

What is the primary reservoir of the onboard fuel supply?

A

Fuel Tank

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46
Q

Modern emission controls prevent tanks from…

A

being vented directly to the atmosphere

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47
Q

A liquid-vapor separator prevents liquid fuel from…

A

Reaching the charcoal

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48
Q

Fuel filler neck can incorporate the use of a ____________________

A

Blowback Ball Valve

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49
Q

Fuel filler neck can also contain a ________________ in the event of a roll-over to prevent fuel spillage

A

Roll-over check ball

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50
Q

Modern vehicles are required by the EPA to have a non-vented _________

A

Gas cap

51
Q

A ______________ is an electromagnetically operated switch that basically activates the fuel pump

A

Fuel Pump Relay

52
Q

The current operating the fuel pump relay winding is typically controlled by…

A

The PCM

53
Q

In most cases, the PCM _______ the winding when it wants the fuel pump to operate

A

grounds

54
Q

Where is the fuel pump typically located?

A

Fuel tank

55
Q

Electric fuel pumps can be the __________ type or ___________ type

A

low-pressure; high-pressure

56
Q

A fuel pressure regulator maintains fuel pressure between the…

A

Pump and the injectors

57
Q

Speed of the fuel pump is varied to maintain the correct pressure using…

A

Fuel pump control module and PWM

58
Q

A pressure check valve in the pump does what?

A

Maintains the fuel pressure in the system after engine shutdown

59
Q

What kind of pump chambers do electric fuel pumps use?

A
  • Roller cell pump
  • Peripheral pump
  • Side channel pump
60
Q

What component sends constant electrical signals to the gas gauge located in the driver information center or to the BCM

A

Fuel Tank Sending Unit

61
Q

What is the fuel tank sending unit?

A

A variable resistor that is attached to a float mechanism

62
Q

As the fuel level changes (in a fuel tank sending unit), so does the…

A

Resistance

63
Q

On today’s EFI vehicles, the sending unit is incorporated with the ____________

A

Fuel Pump

64
Q

What are the three steps in the Fuel Tank Sending Unit assembly?

A
  1. Pick up fuel from the bottom of the tank by way of the fuel pump
  2. Strain the fuel and pressurize it
  3. Report the level of fuel in the tank
65
Q

What is the first line of defense of a fuel assembly and is incorporated into the end of the fuel pickup?

A

Filter Sock

66
Q

What is the purpose of fuel lines?

A

To carry fuel from the tank to the engine

67
Q

What 3 components are connected by the evaporative emission system lines?

A
  1. Fuel tank
  2. Charcoal canister
  3. Intake manifold
68
Q

What component typically consists of a pleated paper filter housed in a sealed container?

A

Fuel Filter

69
Q

What is the primary function of the fuel filter?

A

To prevent contaminants from reaching the injectors

70
Q

Where are fuel filters typically found?

A

On the frame rail, near the tank, or in the tank

71
Q

The __________________ can also serve as a mounting place for the fuel pressure regulator usually located on the outlet side of the fuel rail

A

Fuel Rail

72
Q

What are fuel rails usually sealed by?

A
  • Flared ends
  • high-pressure O-rings
  • banjo fittings
73
Q

What is the first thing you should do if you suspect an electrical issue?

A

Check the fuse

74
Q

___________ is important. __________ is critical for performance.

A

Pressure; Volume

75
Q

Some vehicles have a ___________________ which uses a one-way valve to hold pressure in the system while the pressure tester is connected and disconnected to the fuel rail

A

Schrader Valve

76
Q

What should you do before handling a high pressure GDI (or any) fuel system?

A

Relieve pressure before removing components

77
Q

All sealing components are _________ on the high-pressure side of GDI systems

A

One-time use

78
Q

The EFI pressure regulation system can be a _______________, also known as a returnless type

A

Circulation type

79
Q

In a _______________________, fuel is drawn from the tank by a fuel pump and delivered to solenoid-operated injectors

A

Circulation system

80
Q

On most modern circulation/returnless systems, the pressure is controlled by the ________________ and the pump only delivers the amount of fuel being injected

A

Speed of the pump

81
Q

On slightly older systems, a __________________ mounted on the fuel rail, incorporates a diaphragm-operated valve

A

Fuel pressure regulator

82
Q

The fuel pressure regulator inlet is connected to the fuel rail and an outlet does what?

A

Lets fuel return to the thank

83
Q

A _____________ and ____________ determines the exposed opening of the outlet and the amount of fuel that can return

A

Control diaphragm; pressure spring

84
Q

The strength of the ____________ determines fuel pressure in the fuel rail

A

Pressure spring

85
Q

A typical fuel pressure regulator uses _________________ to maintain a constant pressure drop across the fuel injector

A

Intake manifold vacuum

86
Q

No hot fuel is returned to the tank in a returnless system. This results in less ___________________

A

Evaporative emissions

87
Q

On some GDI systems there is a solenoid on the high-pressure mechanical pump that allows fuel to return to the tank. This is often referred to as the __________

A

Spill valve

88
Q

What component has a spring-loaded, electric-solenoid spray nozzle?

A

Fuel injector

89
Q

The fuel injector nozzle can be a…

A
  • Rotating disc style
  • Pintle style
  • Ball-valve style
90
Q

The response time to lift the injector needle to the fully open position is about ___________

A

1 Millisecond

91
Q

Also known as single-point injection or central-point injection

A

Throttle body injection

92
Q

In TBI system, fuel is sprayed into the top center of the throttle body and then _________ with the incoming filtered air

A

Atomized

93
Q

What injection system includes these points…
- Simplest type of EFI system
- Require only one or two injectors
- Central injector is normally triggered on every ignition pulse
- Fuel pressure and flow is provided by an electric fuel pump
- Operate between 15 and 20 PSI

A

Throttle Body Injection (TBI) systems

94
Q

Commonly referred to as Multi-port Fuel Injection

A

Multipoint fuel injection

95
Q

What fuel system includes these points…
- A fuel injector is used for each cylinder
- Each injector is located in the intake manifold facing the intake port and valve in the cylinder head
- Each injector is connected to the fuel rail

A

Multipoint fuel injection system

96
Q

Most _______________ are supplied with constant battery voltage when the ignition key is in the Run or Crank position

A

Electronic Fuel Injectors

97
Q

Fuel pressure and flow is provided by a(n) _______ fuel pump

A

Electric

98
Q

Injectors can be triggered at the same time or in groups; this is known as ______________

A

Batch/gang firing

99
Q

Operates the injectors _____ per cycle

A

Twice

100
Q

What fuel injection system incudes these points…
- Grouping the injectors allows for a less powerful processor in the PCM and fewer drivers inside
- Fewer terminals coming out from the PCM and fewer wires in the harness
- This was a common system in the late 80’s and early 90’s

A

Simultaneous Fuel Injection

101
Q

In sequential fuel injection, injection occurs in the sequence of the ______________

A

Firing order

102
Q

In sequential Fuel Injection, each injector typically opens _____ in each cycle to deliver the fuel needed

A

Once

103
Q

In sequential fuel injection, the crankshaft position sensor informs the PCM the location of the _____________

A

1 Cylinder

104
Q

In sequential fuel injection, the camshaft position sensor informs the PCM for top dead center compression cylinder __

A

1

105
Q

In sequential fuel injection, if cam signal is lost, the PCM may go into _______________

A

Batch fire mode

106
Q

In GDI, since fuel is sprayed directly into the cylinder, the fuel itself has a ___________ effect

A

Cooling

107
Q

What are the 4 modes of operation of a GDI system?

A
  1. Stratified Charge
  2. Stoichiometric
  3. Full Power
  4. Catalyst Heating
108
Q

GDI systems are a ________ injection event

A

Multi-pulse

109
Q

GDI fuel systems can either be ____________ variety or ____________ variety

A

Low pressure; High pressure

110
Q

GDI low pressure systems operate with about _________ PSI

A

35-70

111
Q

GDI high pressure systems operate up to as much as _______ PSI

A

3,000

112
Q

It is critical to use gasoline with adequate ____________

A

Detergents

113
Q

To reduce ______________, use a high-quality motor oil specified for the vehicle and change the oil at the recommended intervals

A

Carbon Buildup

114
Q

Low-speed pre-ignition can be reduced by using quality ____ that is specified by the manufacturer

A

Oil

115
Q

The carburetor system is a ____________ fuel delivery system

A

supply-and-demand

116
Q

Traditionally, fuel pumps for a carburetor-type fuel system were a _________________ pump

A

Diaphragm-type

117
Q

Carbureted fuel systems have a ____________ where a float and needle valve control the fuel level

A

Float bowl

118
Q

In a _______________ system, the fuel pump is usually mounted on the cylinder head or the engine block

A

Mechanical Fuel Pump

119
Q

A mechanical fuel pump is _________ operated by an eccentric on the camshaft

A

Diaphragm

120
Q

When _____ fuel is needed, pressure builds up in the fuel line to the carburetor and in the pumping chamber

A

Less

121
Q

As the fuel circulates, it _____ the fuel pump and lines, reducing the chance of vapor lock

A

Cools

122
Q

In a low-pressure electric fuel pump, the magnetic field energizes an armature that does what?

A

Pulls down the diaphragm

123
Q

In low-pressure electric fuel pump system, the armature is released and the diaphragm spring forces up the diaphragm, which does what?

A

Forces fuel out of the pump

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