75 Questions
What is the strategy of tracking time variations between the voltage drops for each injection called?
Injector response time
What does a response time of 5 ms mean for the next injection event?
The ECU energizes the injector 5 ms earlier
What could cause individual injector response times to lengthen?
Different resistances
What could wide variations in injector response time at a steady engine rpm indicate?
Electrical problem
What method does the ECM use to calculate response times based on the poppet valve?
Detecting when the poppet valve closes
What does the ECM do when the poppet valve closes?
Creates a voltage drop
What is the major difference between the Detroit Diesel N3 and E3 injectors?
N3 uses a single compact electromagnetic solenoid while E3 uses two
What allows the Detroit Diesel N3 injector to supply a single pilot injection event?
Low-mass nozzle control valve (NCV)
What triggers faster acting, more powerful hydraulic forces in the Detroit Diesel N3 injector?
Solenoid
What is the function of the pump section in both the N3 and E3 unit injectors?
Consists of a camshaft-operated plunger operating inside a barrel
What is the purpose of the control valve section in the N3 and E3 unit injectors?
N3 has one control valve, while E3 has two
What is the main purpose of Emissions standards for EUI design?
Prevent the formation of emissions in an engine's cylinders
What is the maximum spray-in pressure that the N3 injector can reach?
35,000 psi
What technology does the Delphi E3 injector use to change injection pressure?
Dual-control valve, four-wire, two-solenoid design
What was one of the benefits of the Delphi E3 injector over other EUIs?
Programmable, variable-pressure nozzle opening and closing
What was the durability of the Delphi E3 injector in miles?
621,000 miles
What are the two valves used by the Delphi E3 injector to regulate injection pressure, timing, and metering events?
Normally closed NCV and normally open SCV
What happens during the filling stage of the injector operation?
Injector plunger draws fuel from the cylinder head fuel rail
What occurs during the pressurization stage of the injector operation?
Injector plunger moves downward
What happens during the injection stage of the injector operation?
Fuel pressure is applied to the bottom of the nozzle valve
What occurs at the end of injection stage of the injector operation?
Fuel is trapped below the injector plunger
What enables the N3 injector to provide faster injection events?
Electrically operated hydraulic control valves
What technology was used for HD on-road engines until 2017?
Unit injectors
What design feature of the Delphi E3 injector allows for high-speed, dual-valve operation?
Dual-control valve
What was the year when Electronic Unit Injectors (EUI) were first introduced in Detroit Diesel Series 92 engines?
1984
What is the main advantage of Electronic Unit Injectors (EUI) in terms of power output and emissions?
Capable of higher injection and spray-in pressure
What is a notable feature of overhead cam-driven Electronic Unit Injectors (EUIs) in terms of efficiency?
Minimizing injection lag and enhancing engine performance
What is the maximum injection pressure that the newest EUIs, such as the Delphi E3 electronic unit injector, can achieve?
35,000-38,000 psi
What is a service advantage offered by Electronic Unit Injectors (EUIs)?
Adjustment-free design
What components are included in the construction of Electronic Unit Injectors (EUIs)?
Spring-loaded plunger and barrel assembly, poppet valve or spill control valve, electric solenoid or cartridge valve, fuel inlet, and nozzle valve with multiple orifice holes
What regulates the injection timing and quantity of fuel in Electronic Unit Injectors (EUIs)?
An electrical signal from the Electronic Control Module (ECM)
How does the Electronic Control Module (ECM) ensure constant fueling to engine speed?
By adjusting the timing of actuating the solenoid as speed increases
What are the main stages of operation for Electronic Unit Injectors (EUIs)?
Suction stroke, main injection, and residual stroke
What is a notable characteristic of Electronic Unit Injectors (EUIs) in terms of reliability?
Less likely to be involved in a runaway engine
What is the purpose of adjustment of the injector plunger travel?
To ensure proper functioning and eliminate lash between the rocker lever and the injector tappet
What do Electronic Control Units (ECUs) use to determine injection timing and fuel quantity?
Operating algorithms, fuel timing maps, and calibration files
What is the purpose of the PWM strategy in ECU?
To mitigate injection lag by shaping the current flow during initial energization
What diagnostic strategy is used to check for defective wiring and poor connections in EUI injectors?
Pull test
What can cause injector fault codes such as Voltage High, Voltage Low, Current High, and Current Low?
Open or resistive solenoid windings, short-circuits, and loose or intermittent wiring problems
What is the purpose of the peak-and-hold-low strategy in solenoid energization?
To increase solenoid reliability and performance over extended operation periods
What is the function of the unique output signals produced by the ECU?
To drive the injector solenoids using pulse width modulated (PWM) current
What can cause significant differences between calculated and actual injection timing, especially at high engine speeds?
Variations in voltage levels and inductive reactance/resistance
What is the purpose of adjustment procedures for EUI plunger travel?
To ensure proper functioning and address low-power complaints
What do Electronic Control Units (ECUs) use to shape the current flow during initial energization to mitigate injection lag?
PWM strategy
What is the purpose of the ECU monitoring voltage and using series resistors?
To predict the current passing through the solenoid windings and identify electrical circuit problems
What is the purpose of the BIP detection circuit in Electronic Control Modules (ECMs) for EUIs?
To calculate response times based on the poppet valve closing
What could wide variations in injector response time at a steady engine rpm indicate?
Defective wiring and poor connections
What is the main advantage of using EUIs with electromagnetic solenoids?
Capable of pilot injections
What triggers the faster acting, more powerful hydraulic forces in the Detroit Diesel N3 injector?
Solenoid
What method does the ECM use to determine injection timing and fuel quantity in EUIs?
Tracking time variations between voltage drops for each injection
What is the purpose of adjustment procedures for EUI plunger travel?
To correct the start of delivery for the next injection event
What was one of the benefits of the Detroit Diesel N3 injector over other EUIs?
Capability of supplying a single pilot injection event
What is the purpose of the peak-and-hold-low strategy in solenoid energization?
To increase solenoid reliability and performance over extended operation periods
What diagnostic strategy is used to check for defective wiring and poor connections in EUI injectors?
A pull test to check for defective wiring and poor connections
What is the function of the unique output signals produced by the ECU?
To regulate the injection timing and fuel quantity
What technology does the Delphi E3 injector use to change injection pressure?
Dual-valve operation
What is the purpose of adjustment procedures for EUI plunger travel?
To ensure proper functioning and eliminate lash between the rocker lever and the injector tappet
What occurs during the filling stage of the injector operation?
Fuel is pressurized in the injector body
What do Electronic Control Units (ECUs) use to shape the current flow during initial energization to mitigate injection lag?
Current ramping
What is the function of the electric solenoid or cartridge valve in Electronic Unit Injectors (EUIs)?
It controls the fuel passageway during the main injection stage.
What is the purpose of the poppet valve or spill control valve in Electronic Unit Injectors (EUIs)?
To control the amount of fuel injected into the combustion chamber.
What is the main advantage of Electronic Unit Injectors (EUIs) in terms of serviceability?
Adjustment-free design and faster repair times due to integration of functions into a single component.
What technology enables the newest EUIs, such as the Delphi E3 electronic unit injector, to achieve efficient fuel atomization and distribution for cleaner engine combustion?
High injection pressures of 35,000-38,000 psi.
What is the function of the Electronic Control Module (ECM) in regulating injection timing and quantity of fuel in Electronic Unit Injectors (EUIs)?
It uses electrical signal time and plunger velocity dependent on engine speed to control fuel delivery.
What is the construction feature of Electronic Unit Injectors (EUIs) that includes a fuel inlet and a nozzle valve with multiple orifice holes?
Fuel inlet and nozzle valve with multiple orifice holes.
What is a notable characteristic of Electronic Unit Injectors (EUIs) in terms of reliability?
They are less likely to be involved in a runaway engine.
What is the function of the normally closed NCV and normally open SCV in the Delphi E3 injector?
Regulate injection pressure, timing, and metering events
What is the purpose of the double-pulse design in the N3 injector?
Close the nozzle at the end of the injection event
What is the significance of the Delphi E3 injector's ability to electronically change injection pressure from 5000 to 37,000 psi?
Enhanced flexibility in adapting to different engine requirements
What occurs during the filling stage of the injector operation?
Injector plunger draws fuel from the cylinder head fuel rail
What does the deenergized SCV coil allow at the end of injection?
A beveled washer-like spring to open the spill control valve
What is the main advantage of the Delphi E3 injector over other EUIs?
Programmable, variable-pressure nozzle opening and closing
What is the primary function of the electrically operated hydraulic control valves in the N3 injector?
Allow for faster injection events
What is the role of the unique output signals produced by the ECU in the context of injector technology?
Regulate injection pressure, timing, and metering events
What is the purpose of the spill control valve at the end of injection in the Delphi E3 injector?
Permit fuel trapped below the injector plunger to pass to a fuel return circuit
Study Notes
Diesel Engine Electronic Unit Injector (EUI) Adjustment and Electronic Signal Processing
- In the event of an injector failure, only one fuel injection can occur due to the poppet valve being open or closed.
- Adjustment of the injector plunger travel is crucial to ensure proper functioning, and there should be no lash between the rocker lever and the injector tappet.
- Adjustment procedures for EUI plunger travel vary between manufacturers and are performed at specific intervals or when indicated by low-power complaints.
- Electronic Control Units (ECUs) collect and process data using operating algorithms, fuel timing maps, and calibration files to determine injection timing and fuel quantity.
- The ECU produces unique output signals, notably the pulse width modulated (PWM) current, which drives the injector solenoids.
- Variations in voltage levels and inductive reactance/resistance can cause significant differences between calculated and actual injection timing, especially at high engine speeds.
- To address timing errors, the PWM strategy employs current ramping, which shapes the current flow during initial energization to mitigate injection lag.
- The peak-and-hold-low strategy of solenoid energization is used to increase solenoid reliability and performance over extended operation periods.
- The ECU monitors voltage and uses series resistors to predict the current passing through the solenoid windings, identifying open, shorted, and resistive electrical circuits.
- Fault codes, such as Voltage High, Voltage Low, Current High, and Current Low, are generated to indicate electrical problems in the injector circuit.
- Issues that could cause injector fault codes include open or resistive solenoid windings, short-circuits, and loose or intermittent wiring problems.
- A pull test is a diagnostic strategy used to check for defective wiring and poor connections, and most EUI injectors share a common ground wire with one or more other injectors.
Electronic Unit Injectors in Diesel Engines
- Electronic Unit Injectors (EUI) were introduced in 1984 in Detroit Diesel Series 92 engines to improve fuel economy and comply with greenhouse gas emissions legislation.
- EUIs are capable of higher injection and spray-in pressure, reduced injection lag, and increased delivery volumes for higher power output, resulting in lower emissions.
- EUIs are centrally located in the cylinder head and are driven by the engine camshaft with a wider and dedicated injector lobe to build injection pressure to higher levels.
- Overhead cam-driven EUIs are known for their efficiency in hydraulic and mechanical fuel system arrangements, minimizing injection lag and enhancing engine performance.
- The newest EUIs, such as the Delphi E3 electronic unit injector, can achieve injection pressures of 35,000-38,000 psi, resulting in efficient fuel atomization and distribution for cleaner engine combustion.
- EUIs offer service advantages such as adjustment-free design, serviceability in any shop, and faster repair times due to their integration of pressurization, timing, metering, and atomization functions into a single component.
- The construction of EUIs includes a spring-loaded plunger and barrel assembly, a poppet valve or spill control valve, an electric solenoid or cartridge valve, a fuel inlet, and a nozzle valve with multiple orifice holes.
- EUIs rely on an electrical signal from the Electronic Control Module (ECM) to regulate injection timing and quantity of fuel, with the quantity of fuel delivered being a function of both electrical signal time and plunger velocity dependent on engine speed.
- The ECM ensures constant fueling to engine speed to prevent over-fueling and adjusts the timing of actuating the solenoid as speed increases to control the amount of fuel injected into the combustion chamber.
- EUIs operate through suction stroke, main injection, and residual stroke, with the solenoid valve controlling the fuel passageway and the pressurized fuel traveling through a drilled passageway into the fuel annulus surrounding the injector nozzle tip.
- EUIs are less likely to be involved in a runaway engine, making them a reliable and efficient component in diesel engines.
Diesel Fuel Injector Technology Overview
- The N3 injector features a hydraulically balanced nozzle valve that is opened and closed with pressurized fuel, and its compact, electrically operated hydraulic control valves allow for faster injection events.
- The N3 injector can reach spray-in pressures of up to 35,000 psi, and its unique double-pulse design enables high-pressure fuel to close the nozzle at the end of the injection event.
- The Delphi E3 injector, introduced for 2002 EGR equipped, diesel engines, uses a dual-control valve, four-wire, two-solenoid design that can electronically change injection pressure from 5000 to 37,000 psi.
- The Delphi E3 injector has features that enable it to provide superior rate-shaping abilities compared to other unit injectors, and it was one of two remaining fuel injection systems in use for HD on-road engines until 2017, when only common rail systems were used.
- Benefits of the Delphi E3 injector over other EUIs include high-speed, dual-valve operation, programmable, variable-pressure nozzle opening and closing, ultra-high-injector pressure, lightweight, compact design, and 621,000 mile (1,000,000 km) durability.
- The Delphi E3 injector uses two valves, a normally closed NCV and a normally open SCV, to regulate injection pressure, timing, and metering events, and its operation involves a filling stage, pressurization stage, injection stage, and end of injection stage.
- During the filling stage, the injector plunger moves upward and draws fuel from the cylinder head fuel rail, and if the injector is not energized, it results in a waste stage of plunger movement.
- In the pressurization stage, the injector plunger is moved downward, and no pressurization can take place until the SCV closes, trapping fuel beneath the plunger and increasing fuel pressure.
- During the injection stage, fuel pressure is applied to the bottom of the nozzle valve, and when the NCV is energized, it opens and allows pressurized fuel to spray into the combustion chamber.
- At the end of injection, the deenergized SCV coil allows a beveled washer-like spring to open the spill control valve, permitting fuel trapped below the injector plunger to pass to a fuel return circuit, and the NCV is de-energized to allow fuel pressure to rebuild and hydraulically close the valve.
Test your knowledge of Diesel Engine Electronic Unit Injector (EUI) Adjustment and Electronic Signal Processing with this quiz. Explore topics such as injector plunger travel adjustment, ECU operation, PWM current, injection timing, and troubleshooting injector electrical issues.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
