Electronically Controlled Fuel Injection Systems Flashcards
What is the purpose of the ECM cooling plate?
Allow fuel to flow through the ECM and cool it
What is the purpose of the fuel transfer system?
Supply the electronically controlled injector with clean, cooled, de-aerated fuel at the correct pressure and temperature
Electronic Unit injectors
Pressure built by the camshaft rocker pushing down on the top of injector. The ECM then decides how long to open the injector, and when it needs to be opened.
the three main sensors monitored to control EUI injection processes are?
Throttle position
Intake manifold pressure
Engine speed and timing
EUI injection process is broken down into what for stages?
Pre-injection
Injection
End of injection
Fill
EUI pre injection
The cam lobe starts to force the fuel injector plunger downward, the solenoid is de-energized, poppet valve is open and fuel is forced out of injector by the plunger into the fuel supply passage
EUI injection
Solenoid is energized, poppet valve closed, nozzle opens at around 4500 PSI, fuel is injected. S
EUI end of injection
Solenoid is de-energized and poppet valve opens by spring pressure
EUI fill
The injector plunger moves upward and the injector is filled with transfer pressure
Calibration code number
Identifies fuel delivery variations that exist between each fuel injector
HEUI system operation is dependent on the interaction between what sub-systems?
Electronic control
Fuel transfer
Hydraulic actuation
HEUI injectors
HUEI injectors
Are hydraulically actuated to create injection pressure and deliver fuel to each of engines combustion chambers
HUEI hydraulic actuation pressure varies from?
870 - 3500 PSI
HUEI actuation pressure is controlled by what?
Injection actuation pressure control valve, ECM, And the injection actuation pressure sensor.
What is size ratio of intensifier piston?
Top is 6-7 times larger then plunger
HUEI injection operation consists of what 5 stages?
Pre-injection pilot injection delay period main injection end of injection
The HPCR system consists of what components?
High pressure pump Rail pressure control valve Rail pressure sensor Common fuel rail Pressure limiting valves High pressure lines Injectors
HPCR high pressure pump builds pressure of what?
Module says 4000 - 26000 PSI
HPCR pressure limiting valve will open if rail pressure reaches what?
2000 - 3000 PSI over the normal operating pressure
What is the purpose of a flow limiting valve?
Shut off fuel flow to the injector when it exceeds about 1.5 times the normal flow rate
Energizing the solenoid in a HPCR injector creates what?
A pressure differential in the injector that allows the high pressure pushing up to over come the spring and low pressure on top of intermediate valve, the nozzle opens and fuel enters combustion chamber
Electronic unit injector are actuated by?
A mechanical injector drive mechanism
What is the purpose of the poppet valve in the electronic unit injector?
Controls fuel flow through the injector to begin and end injection
The amount of fuel injected by an electronic unit injector is typically expressed as pulse width. Pulse width can be measured in?
Degrees of crankshaft rotation
Percentage of fuel
mm of fuel
A HUEI fuel injection system involves a high pressure engine oil hydraulic system and a _____ pressure diesel fuel system.
Low
HEUI injectors are controlled by the ECM to determine?
BOI
EOI
Fuel metering
What are the 5 stages of the HEUI fuel injection process?
Pre-injection Pilot injection Delay period Main injection End of injection
To begin the injection process in a HEUI injector, the poppet valve must be _________ by the injector solenoid
Opened
T/F The HEUI fuel injector is filled with diesel fuel during the end of injection stage?
True
What component does the high pressure oil act on inside of the HEUI injector?
Intensifier piston assembly
The HPCR fuel system utilizes a radial piston pump that provides high pressure:
Fuel for the injection process
In a HPRC fuel injector, what keeps the injector needle valve closed between injections?
A spring and the high pressure fuel on top the intermediate valve
What the purpose of using the extremely high pressure that are found in the HPCR system.
Better atomization of the fuel
What is the purpose of a pilot injection?
Pilot injection develops a flame front in the cylinder before the main fuel charge is injected which helps reduce overall engine noise and emissions
What are the main components of the EUP fuel system(6)?
Engine control unit Vehicle control unit Sensors, switches and wiring Fuel transfer system Camshaft actuated electronic pumps Injection lines and nozzles
To begin injection, the EUP solenoid is energized and this _____ the poppet valve:
Closes
What component does the high pressure oil act on inside act on inside the HEUI injector
The intensifier piston assembly
T/F In a HPCR system, when the engine is shutdown, there will be no pressure in the common rail and the injection lines?
False. In most systems there will be about 1000 PSI residual pressure
T/F In the HPCR fuel system, to begin the injection process, the injector control valve must be opened.
True
In a HPCR fuel injector, what keeps the injector needle valve closed between injections?
A spring and the high pressure fuel on top of the intermediate valve
What is fuel pressure during HEUI pilot injection?
About 4500 PSI
on a system with a multi-plunger injection pump, the fuel injection nozzles atomize and distribute the fuel in the combustion chamber. What type of injection nozzle is this?
hydraulic nozzle
What does “TRAMP” mean in a fuel system.
T = timing R = rate A = atomization M = metering P = penetration
electronic unit type injectors are actuated by?
mechanical drive mecanism
