Kn ppt aum221 1 1 intro basics
Transcript of Kn ppt aum221 1 1 intro basics
Computers can be called
central processing unit
powertrain control module
engine control module
body control module
transmission control module
controls body systems
controls transmission & traction
controls engine & transmission only
controls all electronic system
Generally for our learning purposes, we’ll group them all as one
C P U
E C M
P C M
T C M
B C M
controls engine systems
Computer Functions
• Input– Is a signal sent from an input device.
• Processing (logic)– The computer compares input information to programmed instructions.
• Storage– The programmed instructions are stored in the computer’s memory.
• Output– Is a command given by the computer to operate an output device.
at INPUTS firstLet’s
• All inputs have same basic function
detect a mechanical condition, position, chemical state
temperature, or electrical value
change it into an electrical signal to be used by a computer.
something turned on or offeither by a person, or a device
switches are either normally open or normally closed
they send an digital input signal to the pcm
some switches switch the ground side some switch the power side
if they switch power, it can be B+ or Reference Voltage
Switches
Switches
P S P Power Steering Pressure Switch
OD Overdrive Switch
CP Clutch Pedal Position Switch
I G N Ignition Switch
Sensors
• Each sensor has a specific job.
• All sensors are either
reference voltage sensors or
voltage generating sensors.
provide feedback information
✓confirms position or action
✓reports voltage changes
(instead of on / off)
Various Sensors
C T S Coolant Temperature Sensor
A T S Air Temperature Sensor
T P S Throttle Position Sensor
I S C Idle Speed Control Sensor
C R K Crankshaft Position Sensor
M A P Manifold Absolute Pressure Sensor
KNOCK Sensor
E G R Position Sensor
M A F Mass Air Flow Sensor
C A M Camshaft Position Sensor
• All sensors are either reference voltage sensors or voltage generating sensors.
Remember this statement ?
Notice..... they all have to do with voltage
They must either create their own voltageor respond to the battery voltage
Let’s Talk AboutReference Voltage Sensors
“use of a source of information in order to ascertain something”
Reference means
What are we “referencing . . . . and why ?
Remember this is
“Reference Voltage”
All we have to work with is the vehicles voltage
A good battery supplies 12.6 volts
A weak battery will supply less
A good charging alternator can supply 13.5 - 14.5 volts
A bad alternator can supplyvoltage above 14.5 volts
or no volts at allleaving you with
battery voltage that is decreasing
Since we are “measuring”or “referencing” something
there must be a point where that measurementis always the same
A car simply won’t runif the voltage drops below
6 Volts
So............to solve this problem
The computer sends a constant5 volts
to the sensor
That way it can’t be confused with any voltage generated by something other than
what the computer sends out
And it provides a constant pointto measure from
For all of the sensors that need to measureor “reference” voltage
“reference”
5volts
Reference Voltage Sensors
• Computer sends a constant voltage to the sensor.
• The sensor reacts and sends a voltage signal back to the computer.
• Reference voltage is normally 5 to 9 volts.
• Most are variable resistors or potentiometers.
So......... inputs can be
Switches
Reference voltage feedback sensors5
volts
On or Off
Voltage Generating Sensorsthey make their own voltage signal
OR
Voltage Generating Sensors
• Speed sensors
• Hall-effect switches
• Oxygen sensors
• Produce an input voltage for the control system
• Knock sensors
Magnetic Pulse Generators• Also called permanent magnet generators.
• Use magnetic induction.
How do they produce voltage ? ?
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at OUTPUTS nextLet’s
Actuators
• Solenoids, • Switches, • Relays, • Motors.
• Electromechanical devices.basically
What is a solenoid ?
A coil of wire, wound tightlyaround a metallic core,
which produces a magnetic fieldwhen an electric current is passed through it.
They can create a controlled magnetic fieldand can be used as electromagnets
Simplified ControlBeing a pulsed device with minimal components optimizes solenoids for digital control. This results in faster cycling and higher reliability with fewer interfaces.
Uncompromising ReliabilitySolenoids provide repeatable, predictable performance with a specified life of up to 100 million cycles.
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Starter solenoid
Trans shift solenoid Fuel injector solenoid
Idle air control solenoid
EGR solenoid
Door lock solenoid
Fuel Solenoid
Throttle solenoid
Variable Valve solenoid
Relays are remote control electrical switchesthat are controlled by another switch
Horn SwitchSwitch #1
Switch #2
Horn Circuit
A switchcontrolled by
A switch
An electric motor is an electromechanical device that converts
electrical energy into mechanical energy
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