Engine Performance Basic Electronics and Computer Systems
Computers can be called CPU central processing unit controls all electronic system ECM engine control module controls engine systems PCM powertrain control module controls engine & transmission only TCM transmission control module controls transmission & traction BCM body control module controls body systemsGenerally for our learning purposes, we’ll group them all as one
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.
Let’s at INPUTS first• 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.
Switches something turned on or offeither by a person, or a device switches are either normally open or normally closedthey 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
SwitchesPSP Power Steering Pressure SwitchOD Overdrive SwitchCP Clutch Pedal Position SwitchIGN Ignition Switch
PNP Park Neutral SwitchBLS Brake Light SwitchACC A/C Clutch SwitchTS Temperature Switch
Sensors provide feedback information (instead of on / off)• Each sensor has a specific job. ✓confirms position or action ✓reports voltage changes• All sensors are either reference voltage sensors or voltage generating sensors.
Various SensorsCTS Coolant Temperature SensorATS Air Temperature SensorTPS Throttle Position SensorISC Idle Speed Control SensorCRK Crankshaft Position Sensor
CAM Camshaft Position SensorMAP Manifold Absolute Pressure Sensor KNOCK Sensor E G R Position Sensor MAF Mass Air Flow Sensor
Oxygen Sensors One Wire Two Wire Three Wire Four Wire
Remember this statement ? • All sensors are either reference voltage sensors or voltage generating sensors.Notice..... they all have to do with voltage They must either create their own voltage or respond to the battery voltage
Let’s Talk About Reference Voltage Sensors “use of a source of information inReference means order to ascertain something” 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 voltsA weak battery will supply less
A good charging alternator can supply 13.5 - 14.5 voltsA bad alternator can supply voltage above 14.5 volts or no volts at all leaving you with battery voltage that is decreasing
Since we are “measuring” or “referencing” somethingthere must be a point where that measurement is always the same A car simply won’t run if the voltage drops below 6 Volts
So............to solve this problem The computer sends a constant 5 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 point to measure from “reference” 5 For all of the sensorsvolts that need to measure or “reference” voltage
Reference Voltage Sensors• Computer sends a constant voltage to the sensor. • The sensor reacts and sends a voltage signal back to t • Reference voltage is normally 5 to 9 volts. • Most are variable resistors or potentiometers.
So......... inputs can be Switches On or Off 5Reference voltage feedback sensors volts OR Voltage Generating Sensors they make their own voltage signal
Voltage Generating Sensors• Produce an input voltage for the control system • Speed sensors • Knock sensors • Hall-effect switches • Oxygen sensors
How do they produce voltage ? ? • Use magnetic induction. Magnetic Pulse Generators• Also called permanent magnet generators.
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Current running thru a wire wound around a solid core
Hall-Effect Switch• Performs the same function as a PM generator
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Let’s at OUTPUTS next Actuators • Solenoids, • Switches, • Relays, lly • Motors. ica as • Electromechanical devices. b
What is a solenoid ? A coil of wire, wound tightly around a metallic core, which produces a magnetic fieldwhen an electric current is passed through it. They can create a controlled magnetic field and can be used as electromagnets
QuickTime™ and a GIF decompressor are needed to see this picture.Simplified ControlBeing a pulsed device with minimal components optimizessolenoids for digital control. This results in faster cycling andhigher reliability with fewer interfaces. Uncompromising Reliability Solenoids provide repeatable, predictable performance with a specified life of up to 100 million cycles.
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Starter solenoid Throttle solenoid Variable Valve solenoidTrans shift solenoid Fuel injector solenoid Idle air control solenoidFuel Solenoid EGR solenoid Door lock solenoid
An electric motor is an electromechanical device that converts electrical energy into mechanical energy QuickTime™ and a QuickTime™ and a GIF decompressor Animation decompressor are needed to see this picture. are needed to see this picture.