Electronic Fuel Fundamentals Flashcards
Actuator
An output device that receives signals from the ECM. It converts the signal into a particular action
What is an analog signal?
A waveform that has a continual change in amplitude
Digital signal
Is either on or off between two fixed voltages (commonly 0 to 5V with ECM circuits)
Parameter
A programmable feature, value or instruction that affects vehicle operation characteristics
Pulse width modulation
Occurs when a circuit is turned on and off. The width is the time that the circuit is turned on.
What are sensors?
Input devices that monitor pressures, temps, levels, or mechanical movements. Sometimes are sometimes referred to as transducers
Input devices that the operator controls are referred to as?
Function switches
What does the ECM input control consist of?
Converters and amplifiers that modify the sensor signal.
The process of converting analog signal to a digital signal is called?
Encoding
ECM microprocessor
Sometimes referred to as the central processing unit (CPU). It is the brain or control section. Makes output decisions by comparing inputs to stored values and then generates outputs.
What are the two memory systems that are most relevant?
RAM - random access memory
EEPROM - Electronically erasable programmable read only memory
Multiplexing
A method of connecting computer controlled systems and allowing them to communicate through a common network
The backbone
Is the method of connection for a network, such as wires or fibre optic cables, often referred to as the data bus. Common backbone is a twisted pair of wires that are shielded to prevent EMI
What is baud rate?
The speed of data transfer over the network, commonly measured in kilo baud per second (kbps)
What are the 3 basic functions of the warning/shut-down system?
Warn operator of an engine or system malfunctions
De-rate or shut-down the engine when damaging conditions exist
Generate fault codes to assist with system diagnosis
What are the 3 levels of engine protection that can be programmed into an ECM?
Warning only
Warning and de-rate
Warning, de-rate and shutdown
What are the sensor voltages used in most systems?
Starting from a 5V reference, return voltages from the sensors should be between 0.5V and 4.5V
Protocol is what?
The common language used between control modules
Engine manufacturer codes can be separated into what two sections?
Engine protection codes
System fault detection codes
FMI?
Failure mode identifier
SID
System identification
PID
Parameter identification
In temp sensor an open will result in what?
Sensor circuit voltage high
What took is used to hook up to engines?
DDL diagnostic data link
List five features of electronically controlled fuel systems?
- limited or variable speed governor controls
- multiple horsepower ratings
- starting aid control
- cold start and warm up mode
- machine speed limiting
- cruise control
- engine warning and shutdown systems
- self diagnostics
Flow limiting valves are typically calibrated to shut the of the fuel to the injector when it exceeds about _____ times normal flow rate.
1.5 times
Pressure limiting valve on a High Pressure Common Rail will open if the injection pressure in the rail exceed the normal max value by approximately ______ to _______.
2,000 psi to 3000 psi
Depending on the system, the high pressure pup takes fuel from the low pressure system and raises it to injection pressure, which will varies from ______ to ______.
4,000 psi to 26,000 psi
HEUI injectors are ________ actuated and _________ controlled.
hydraulically
electronically
Injection Actuation pressure will range from approximately _______ psi to ______ psi.
870 psi 3,500psi
HEUI systems operation is dependent on the interaction that occurs between four subsystems. The subsystems are?
electronic control
fuel transfer
hydraulic actuation
HEUI injectors
The injection process can be broken down to four stages which are?
pre injection
injection
end of injection
fill
The three main sensors monitored to control the injection process are?
throttle position
intake manifold pressure (turbo boost)
engine speed and timing
What two common data link connectors?
J1939 nine pin deutsch connector
J1708/j1587 six pin deutsch connector
