Analysis of Spark Analysis of Spark Ignition Engine Ignition Engine

Management SystemManagement System

James BowerJames BowerJosh DukeJosh Duke

Casey FisherCasey Fisher

Engine Management SystemEngine Management System

Engine Management Engine Management System BasicsSystem Basics

Advantages of EFIAdvantages of EFI

Future TrendsFuture Trends

The Brains of the CarThe Brains of the Car

Electronic Control Unit or ECUElectronic Control Unit or ECUSmall computer connected directly to engineSmall computer connected directly to engine

Monitors engine parameters through the use of sensorsMonitors engine parameters through the use of sensors

Manages throttle control, ignition, fuel injection, and Manages throttle control, ignition, fuel injection, and powerpower

Fuel MappingFuel Mapping

Through the use of the ECU data and computer programs the engine Through the use of the ECU data and computer programs the engine can be mapped depending on speed and load of the engine.can be mapped depending on speed and load of the engine.Fuel and timing settings can be adjusted using these maps to Fuel and timing settings can be adjusted using these maps to achieve maximum performance from the engine.achieve maximum performance from the engine.

Crank SensorCrank Sensor

Determines speed of engineDetermines speed of engineConsists of toothed wheel Consists of toothed wheel and an inductive pickupand an inductive pickupSensor pulses and creates a Sensor pulses and creates a magnetic field magnetic field Depending on location of Depending on location of wheel, changes magnetic wheel, changes magnetic field strengthfield strengthFrom magnetic strength the From magnetic strength the ECU can tell the exact crank ECU can tell the exact crank position and speedposition and speed

Throttle Position SensorThrottle Position SensorDetermines the load on the engineDetermines the load on the engineTwo types:Two types:

1) Electronic accelerator pedal 1) Electronic accelerator pedal Senses force applied to pedal and opens throttle body Senses force applied to pedal and opens throttle body

accordingly accordingly 2) Direct linkage2) Direct linkage

Uses a linkage between pedal and throttleUses a linkage between pedal and throttle

Mass Airflow SensorMass Airflow Sensor

Current setup uses hot wire Current setup uses hot wire methodmethod

Heated wire placed in venturi Heated wire placed in venturi section and air flows over wire section and air flows over wire and coolsand cools

Measures current required to Measures current required to keep at a constant keep at a constant temperaturetemperature

ECU converts voltage drops ECU converts voltage drops into mass airflowinto mass airflow

Lambda Sensor (Oxygen Sensor)Lambda Sensor (Oxygen Sensor)

One of the most important components of the engine management system This device is extremely important in fuel conservation and emissions control The amount of oxygen present in the exhaust stream is a direct result of the air/fuel ratio

Oxygen Sensor - How it WorksOxygen Sensor - How it Works

Sensor consists of two Sensor consists of two electrodes, one exposed to air electrodes, one exposed to air and the other exposed to the and the other exposed to the exhaust gasesexhaust gasesDifference in partial pressures Difference in partial pressures of oxygen produces a voltageof oxygen produces a voltageThe ECU reads how much fuel The ECU reads how much fuel should be injected based on should be injected based on the voltage the voltage Rich mixtures contain little free Rich mixtures contain little free oxygenoxygenLean mixtures contain Lean mixtures contain considerable free oxygenconsiderable free oxygen

Temperature SensorTemperature Sensor

Temperatures measured Temperatures measured with a with a sensor known as a sensor known as a thermistorthermistorA thermistor is a resistor A thermistor is a resistor made of a semiconductor made of a semiconductor material whose electrical material whose electrical resistance changes with resistance changes with temperaturetemperature

Pressure SensorPressure Sensor

Used to monitor intake Used to monitor intake manifold and ambient manifold and ambient pressures pressures Measured by semi-Measured by semi-conducting silicon conducting silicon diaphragm that separates diaphragm that separates two chamberstwo chambersPressure change causes Pressure change causes diaphragm to flexdiaphragm to flexWhen diaphragm flexes When diaphragm flexes cause resistance of cause resistance of material to change material to change ECU monitors voltage ECU monitors voltage changechange

Knock SensorKnock SensorSensors alert ECU when Sensors alert ECU when vibrations are detected in vibrations are detected in the cylinder the cylinder Knock sensors contain a Knock sensors contain a piezoelectric crystalpiezoelectric crystalCrystal produces an Crystal produces an electric signal when electric signal when subjected to physical subjected to physical stress due to engine stress due to engine knock. knock. ECU responds by ECU responds by retarding or advancing retarding or advancing ignition time ignition time

EFI SystemsEFI Systems

AdvantagesAdvantagesImproved fuel distribution Improved fuel distribution

Engine power increases by average of 10 percent Engine power increases by average of 10 percent

Faster acceleration resulting from direct delivery of Faster acceleration resulting from direct delivery of fuel to the cylinderfuel to the cylinder

Leaner air/fuel ratiosLeaner air/fuel ratios better fuel economy better fuel economy reduced exhaust emissionsreduced exhaust emissions

Decreased engine knock Decreased engine knock

Elimination of inlet manifold backfiring and icing Elimination of inlet manifold backfiring and icing

EFI SystemsEFI Systems

DisadvantagesDisadvantagesCostCost

More vulnerable than carburetorsMore vulnerable than carburetors Require clean fuel and air to operate correctly Require clean fuel and air to operate correctly Dirt could cause significant damage to systemDirt could cause significant damage to system

Future TrendsFuture Trends

Replacement of mechanical and hydraulic linkages with Replacement of mechanical and hydraulic linkages with purely electrical systems purely electrical systems Electronically controlled valve systems Electronically controlled valve systems

Faster opening and closing timesFaster opening and closing times Minimal impact forcesMinimal impact forces Optimized fuel consumption and engine power Optimized fuel consumption and engine power

Implementation of direct fuel injectors Implementation of direct fuel injectors Increased fuel efficiency Increased fuel efficiency Reduced emissions Reduced emissions

Drive-by-wire chassis Drive-by-wire chassis Electronically controlled breaking, steering, and shiftingElectronically controlled breaking, steering, and shifting Shortened braking distanceShortened braking distance Improved vehicle stabilityImproved vehicle stability Lower maintenance costsLower maintenance costs Potential for remote diagnosis and maintenance Potential for remote diagnosis and maintenance

ConclusionConclusion

The electronic fuel management system of The electronic fuel management system of today’s engines is a revolutionary design today’s engines is a revolutionary design that works to maximize engine performance that works to maximize engine performance while reducing emissions. This new while reducing emissions. This new technology allows for changes in the engine technology allows for changes in the engine while it is running to achieve peak while it is running to achieve peak performance. These systems will only performance. These systems will only continue to improve as technology continue to improve as technology advances. advances.