Week 1, Chapter 63 - Engine Management Systems Flashcards
What are the categories of the engine management system?
- Sensors (input devices)
- Control Modules (PCM, TCM, BCM, etc)
- Controlled Devices (Output Devices)
What are the two main types of electrical signals?
Analog
Digital
What are analog signals?
Signals that are continuously variable, typically changing in strength or time
What are digital signals?
Signals that are a direct on/off with no in-between transition
In a varying analog signal, what is used to control the strength of the output signal?
Variable Resistance (Potentiometers and Thermistors)
Duty Cycle uses _______________________ to control the strength of the output signal generated
Pulse Width Modulation
A cycle is the distance between repeat patterns in signals. Frequency is measured in cycles per second, or _______
Hertz
Changes rotary or linear motion into an electrical signal
Ex.
- Throttle Position Sensor
- EGR Position Sensor
- Radio Volume Control
Potentiometers
Changes resistance due to temperature change - include PTC and NTC types
Ex.
- Engine Coolant Temp
- Intake Air Temp
- Transmission Temp
- Exhaust Temp
- O2 Sensor Heater
- Etc
Thermistors
Produces voltage when pressure is applied to a quartz crystal
Ex.
- Knock Sensor
- Crash Sensor
- Anti-Theft Sensor
Piezo-electric
Change resistance when they are compressed or strained
Ex.
- Manifold Absolute Pressure
- Barometric Pressure Sensor
- Tire Pressure Sensor
- Oil Pressure
Piezo-Resistive
The resistance changes with changing light intensity
Ex.
- Ambient Light Sensor for Headlights
- Auto-Dimming Mirrors
Photo-Resistive
A semiconductor device that converts light into current
Ex.
- Optical Distributor
- Alarm Systems
- Infrared Remote Control Receiver
Photo-Diode
Creates voltage through the induction process
Ex.
- Crankshaft Position
- Camshaft Position
- Wheel Speed
PM Generator (VRS)
A transducer that switches its output voltage in response to a magnetic field
Ex.
- Crankshaft Position
- Camshaft Position
- Wheel Speed
- Etc
Hall Effect
Produces electricity due to an electrochemical reaction
Ex.
- Oxygen Sensor
Galvanic Battery
A device that changes one form of energy into another form of energy
Ex.
- TPS
- ECT
- IAT
- CKP
- CMP
- Essentially any sensor
Transducer
What creates a variable voltage signal that corresponds to a specific condition? (Has 3 wires: power, ground and signal)
Potentiometer
What gathers information on the throttle position and is operated by the rotation of the throttle shaft?
Throttle Position Sensor (TPS)
What is…
- used on vehicles with an electronic throttle control
- made up of two potentiometers that work opposite of each other
- the component that sends signals about the position, direction and speed of the throttle pedal
Accelerator Pedal Position Sensor
What changes resistance with the changes in temperature?
Thermistors
When temperature goes up, resistance goes down
NTC Thermistor
When temperature goes up, resistance goes up
PTC Thermistor
The Engine Coolant Temperature sensor (ECT) and Intake Air Temperature sensor (IAT) are examples of what kind of sensors?
Engine Temperature Sensors
What sends information on the speed and position of the crankshaft to the PCM? (Can be VRS, Hall Effect, or Optical)
Crankshaft Position Sensor
__________ Sensors….
- Sense the movement of a toothed disc on the crank pulley or the ring gear teeth on the flywheel
- Do not make physical contact
- Mounted on the crankcase housing
- consists of a stator with a central permanent magnet and soft iron core surrounded by an induction winding
Inductive-Type Sensors (VRS)
This sensor…
- measures the position of the crankshaft and engine speed
- Is stationary and mounted to the block
- Made up of hall-effect materials
Crankshaft Position Sensor (CKP)
This sensor…
- Sends constant data to computer to let it know when the #1 piston is on the compression stroke
- Identifies the position of the camshaft and valves
- Works in conjunction with the CKP and a Knock Sensor
Camshaft Position Sensor (CMP)
A hall-effect vane switch that provides camshaft position data to the ignition module and Ford ECC-IV processor
Ignition Pickup-Style Position Sensor
What is…
- A device that sends the vehicle speed information
- usually a magnetic pickup/reluctance sensor
- component that consists of an iron core wrapped with copper wiring while a reluctor wheel rotates around it and creates voltage
- component that creates DC wave pattern
Vehicle Speed Sensor (VSS)
What is positioned in the exhaust pipe and provides the engine management PCM with an electrical signal that relates to the amount of oxygen in the exhaust gas?
Oxygen Sensor
How much heat does an oxygen sensor need to reach to enter Closed Loop operation?
600 Degrees
What component compares the amount of oxygen in the exhaust gas to oxygen levels in the outside air?
Nernst Cell
In what kind of air supply system does the air required for combustion travel from the air filter, through the throttle valve, and into the common manifold (plenum chamber)?
Multiport Fuel Injection (MPFI)
What determines the mass of air than can be drawn into a cylinder?
Intake System Design
Length of ___________ influence torque ranges at different RPM
Intake Runners
In what two ways can volume of air be determined?
- Speed density calculation
- Direct measurement
What sensor directly measures the mass of filtered air entering the engine? (usually installed in the air intake hose leading to the thottle body assembly
Mass Airflow Sensor (MAF)
Whirlpools can be measured by what methods?
- Optical type
- Ultrasonic type
- pressure type
What measures manifold pressure changes and converts it into an electrical signal? (can also determine if the EGR valve is open or not)
Manifold Absolute Pressure Sensor
What sensor works in conjunction with the MAP sensor to provide coolant pressure difference information to the PCM and helps calibrate the fuel injection system?
Barometric Pressure Sensor
What sensor is mounted on the fuel rail and allows the PCM to monitor pressure so it can control the speed of the fuel pump?
Fuel Pressure Sensor
What sensor is used to monitor engine vibration and creates its own voltage using a piezo-electric crystal?
Knock Sensor
What provides a digital on/off signal to the PCM and can be use to indicate when devices are activated?
Switches
What is the “brain of the engine” called?
Powertrain Control Module (PCM)
What is a PCM in control of?
- Sensor input/output signal processing
- Data processing
- Memory and storage
- Output drivers
An input signal is sent to the PCM for processing, then an output signal is sent to what?
Controlled Devices
What is often used as an actuator to control other actuators when the computer must control a high-current load?
Relays
An electromechanical device in which valve or linkage is moved to do a mechanical job
Solenoid
Modules that have their own switching circuit and is usually controlled by the PCM
Control Modules
A component that operate many devices on a vehicle and can be controlled by the PCM
Electric Motor Actuators
Commonly referred to as drive-by-wire or throttle-by-wire, this component uses a pedal position sensor to calculate the drivers desired throttle position
Electronically Controlled Throttle (ECT)
Speed-density method and Mass airflow systems are examples of…
Engine Management System Control Strategies
The process of monitoring data over time and updating it in the PCM memory is called…
Feedback and looping
When an engine is first started, it starts in _____ loop
Open
The PCM will change injector pulse width based off ____ or _____ readings
rich; lean
The difference between the stored pulse width and the actual pulse width required to keep fuel mixture at the correct ratio is called…
Fuel Trim
_____________ turns the fuel injectors off when the vehicle is coasting above a certain RPM and speed with the throttle closed
Fuel Shutoff Mode
_____________ is activated if the PCM sees wide-open throttle usually 80% or higher readings when the ignition is first turned on or cranked
Clear Flood Mode
