WorksheetsCommon Rail Fuel Injection
Total questions: 33
Worksheet time: 17mins
Fill in the blank: ________ is the most recent development in high-pressure injection systems.
Common rail fuel injection
Distributor pump system
Unit injector system
Mechanical fuel injection
What is the maximum fuel pressure that new technology allows to be managed in common rail fuel systems?
37,500 psi
25,000 psi
15,000 psi
10,000 psi
What are two benefits of new technology in common rail fuel systems?
Increased emissions and reduced fuel efficiency
Almost no emissions and increased fuel efficiency
Reduced control of injectors
Lower fuel pressures
What are the advantages of Common Rail Fuel Systems?
Low-injection pressures and slow-acting injectors
High-injection pressures, fast-acting injectors, and electronic controls
Manual controls and low-emission gasoline engines
None of the above
In common rail fuel systems, fuel is pressurized regardless of engine speed for optimal fuel efficiency and low emissions.
True
False
Higher Pressurization Systems in development could reach more than ______ psi.
45,000
10,000
25,000
60,000
Fill in the blank: CR injectors use ________ design, allowing electrical solenoid to trigger servo valve and provide a short duration injection.
servo-hydraulic
mechanical
pneumatic
piezoelectric
How many injections per combustion cycle could first generation CR injectors produce?
1 or 2
2 or 3
4 or 5
Up to 8
Fundamentals of Common Rail Fuel Systems Multiple Injection Events True or False: The newer versions of CR injectors can deliver up to 8 injections per combustion cycle.
True
False
Fill in the blank: CR injectors change injection discharge volume during each injection event to suit ______ and ______ conditions.
speed; load
temperature; humidity
pressure; altitude
voltage; resistance
Fill in the blank: Common rail system components are __________ across a wide range of engine platforms.
interchangeable
unique
obsolete
incompatible
Fill in the blank: In a high-pressure common rail fuel system, the tube or rail stores ________ fuel at levels for current speeds/loads through steel lines.
pressurized
cold
unfiltered
low-pressure
Fill in the blank: In a high-pressure common rail fuel system, ________ actuators control timing and metering during injection events.
Electrical
Hydraulic
Mechanical
Pneumatic
Fill in the blank: An engine-driven high-pressure fuel pump supplies the rail, also known as the ________.
accumulator
injector
reservoir
distributor
Fill in the blank: ________ control of fuel system is a defining feature of high-pressure common rail systems.
Microprocessor
Manual
Hydraulic
Mechanical
Which of the following is a defining feature of high-pressure common rail fuel systems?
Pressure regulator
Carburetor
Air filter
Oil pump
Fill in the blank: High-pressure common rail fuel systems are characterized by having ________ fuel lines.
short
long
wide
flexible
Common design requirements for injectors in common rail fuel systems include: ________ for optimal fuel atomization.
Very high injection pressure
Low fuel temperature
Wide nozzle opening
Slow injection rate
Common design requirements for injectors in common rail fuel systems include: Flexible timing of ________.
multiple injections
fuel pressure
engine speed
coolant temperature
How many main types of injectors are mentioned in the Types of Common Rail Fuel Systems?
Three main types of injectors
Two main types of injectors
Four main types of injectors
Five main types of injectors
Fill in the blank: Hundreds of ________ wafers form the actuator mechanism in Piezoelectric Electric Actuators.
piezoceramic
silicon
aluminum
polymer
Piezoelectric Electric Actuators: What happens to the material when electrical current is applied?
It slowly changes shape
It instantly changes shape
It does not change shape
It changes color
What causes an instantaneous change in the injector control valve in Piezoelectric Electric Actuators?
Increasing fuel pressure
Changing polarity of signal to injector
Decreasing temperature
Increasing voltage
What is a characteristic of Piezoelectric Electric Actuators in common rail fuel systems?
Slower response and fewer injections per combustion cycle
Faster response and more frequent injections per combustion cycle
No response and no injections per combustion cycle
Same response and same number of injections per combustion cycle
What type of nozzle valves are used in CRS1 and CRS2 systems?
Mechanically Balanced
Hydraulically Balanced
Electrically Balanced
Pneumatically Balanced
Servo actuators use ________ to move a control valve, which can be a ball or mushroom type.
electromagnetism
hydraulics
pneumatics
mechanical force
Fill in the blank: The first step to an injection event is that ______ is actuated by an electrical signal from the control module.
Magnetic solenoid
Fuel injector nozzle
Throttle body
Pressure regulator
What happens during the beginning of injection in a common rail fuel system?
Fuel is drained from the top of the control rod; needle valve lifts because high pressure acts on its bottom surface.
Fuel is injected directly into the combustion chamber without any pressure change.
The control rod is pushed down by low pressure, causing the needle valve to close.
Fuel is recirculated back to the tank without entering the injector.
What happens to piezoceramic material when an electrical signal is applied?
It melts
It changes shape
It emits light
It remains unchanged
What does an electrical signal do in Piezo CRS3 Operation?
It actuates a control valve which allows needle valve to move
It closes the control valve
It increases fuel pressure
It stops the engine
At rest with the engine running, the control valve in Piezo CRS3 Operation is held closed by ________.
high-pressure fuel
low-pressure oil
electrical current
vacuum pressure
What happens when an electrical signal is applied to the piezoelectric material in Piezo CRS3 Operation?
It contracts and closes the drain passage
It expands and opens the drain passage, causing needle valve to lift
It stops the fuel flow
It increases engine speed
What happens when the piezo actuator is energized in Siemens CR Injectors? Fill in the blank: The mushroom valve is ______ from its seat.
lifted
pressed
rotated
sealed
