shaping the future engine management systems and calibration
TRANSCRIPT
Shaping the Future
Engine Management Systems and Calibration
Engine Management Systems
The basic role of an Engine Management System is to provide precise control of engine operation by managing fuel supply, ignition, and the quantity of air inducted into the engine
At the heart of every Engine Management System is an electronic control module (ECM), which is an on-board computer incorporating a digital microprocessor.
The ECM is linked to the engine by means of sensors installed on the engine (to read data about the operating conditions of the engine), and actuators such as ignition coils, stepper motors, relays, etc as the means for effecting control on engine operation.
The modern EMS also has to provide a comprehensive level of self-diagnosis in the case of faulty components or engine operation. This is referred to as On-Board Diagnostics (OBD).
Engine Management Systems
Engine Control Module (ECM)
Sensors
Actuators
Engine Management Systems Early EMS
ECMFuel Tank
Fuel Pump
Distributor Based Spark
Ignition Port Fuel Injector
Cold Start Injector
Idle Speed By-Pass
Gate – Air Mass Flow Meter
Throttle Position Sensor
Bosch L-Jetronic
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Engine Management Systems
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Engine Management Systems
Bosch Motronic MED EMS (Direct Petrol Injection)
Engine Management Systems
Wide Band – Linear Lambda Sensor
Typical Functions of an EMS
Spark Advance Control (with or without Waste Spark)Knock Control through Adaptive Spark AdvanceIdle Speed ControlIndependent Cylinder Fuel Injection (inc Multi Strike)Exhaust Gas Recirculation ControlAdaptation for Alternative FuelsCharcoal Canister Purge ControlCam Phasing and Valve LiftVariable Geometry Turbocharging and Intake SystemsFull Diagnostics (compliance with OBD legislation) Cylinder Disablement for torque controlEngine Temperature Management
Main Components of an EMS
Electronic Control Module (ECM)Crankshaft Speed SensorCamshaft Position SensorFuel PumpFuel InjectorsFuel Pressure RegulatorAir Mass Flow Meter Manifold Absolute Pressure SensorThrottle Position SensorThrottle Actuator Exhaust Gas Recirculation ValveIdle Speed Air By-Pass ValveExhaust Gas Oxygen Sensor Ignition CoilSpark Plug
Sensors and Actuators
Sensors - Speed & Position
Variable Reluctance Crankshaft Speed Sensor
Hall Effect Camshaft Position Sensor
A voltage is generated transversely (between points E and F) to the direction of current flow (A to B) if a magnetic field is applied perpendicularly to the conductor. (usually a
semiconductor)
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Air Mass Flow Meter
Sensors – Mass Air Flow
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Oxygen or Lambda Sensor
Sensors – Oxygen Sensor
Engine Control Module (ECM)
Delphi MT80 Control Module
EMS Control Overview Fundamentally the Engine Management System (EMS) attempts to control the highly complex thermodynamic functions that define the continuously varying engine operating conditions, by providing the right quantities of air, fuel, timing of ignition, exhaust gas recirculation etc.
A theoretical approach to this problem would be to incorporate a complex set of mathematical models or algorithms that define every possible condition. The EMS would then only have to run these models in real time to correctly supply the desired fuel, air, egr and ignition advance.
Algorithms used in the EMS are models that describe the operation of a particular function for given values of input data but also use some previously determined empirical data (maps)
An EMS will have a wide range of relatively simple models (also known as strategies) for specific control functions
Engine Speed Engine Load(Throttle Position or Manifold Absolute Pressure)
Fuel Injection Quantity (milligrams) or Pulse Width (millisecs)
EMS Control Overview
Data from Sensors
Instructions to Actuators
Structured 2-D and 3-D Maps or “Look Up Tables” (Maps) and algorithms (“Strategy”)
EMS Control Overview
Spark Advance Control (with or without Waste Spark)Knock Control through Adaptive Spark AdvanceIdle Speed ControlIndependent Cylinder Fuel Injection (inc Multi Strike)Exhaust Gas Recirculation ControlAdaptation for Alternative FuelsCharcoal Canister Purge ControlCam Phasing and Valve LiftVariable Geometry Turbocharging and Intake SystemsFull Diagnostics (compliance with OBD legislation) Cylinder Disablement for torque controlEngine Temperature Management
EMS Control Strategies
EMS Strategy ExampleIdle Speed Control
Idle speed variation is caused by; Changes in auxiliary power take off requirements, for example air
compressors and alternators. Combustion performance variability (eg COV of IMEP) Driver input – “blipping the throttle”
The task of the idle speed control system is to primarily manage the step torque demands of the auxiliary systems through air flow
control and ensure that the idle speed is kept as low as possible
EMS Strategy ExampleIdle Speed Control
Dynamic Control LoopsEnergy conversion
Intake manifoldTorque balance
InputsEngine SpeedEngine Load
(Man Abs Press)
OutputsAir mass flow
modulator
Plant Model(algorithms & maps)
EMS Strategy ExampleIdle Speed Control Dynamic Control Loops
Energy conversionIntake manifoldTorque balance
InputsEngine SpeedEngine Load
(Man Abs Press)
OutputsAir mass flow
modulator
Plant Model(algorithms & maps)
Intake air flow rate Engine Torque
Engine Speed
Engine Friction Load
Man Press
Air Manifold Pressure
EMS Strategy ExampleIdle Speed Control
Manifold Pressure
Engine Speed
Manifold Air Mass Outflow Estimation (Map)
Manifold Air Mass Inflow dpm /dt = (1/) dmin/dt – dm*out/dt
Integrator
EMS Strategy ExampleIdle Speed Control
Combustion Torque Pulse per Cylinder
(Map)
Torque Delay due to cylinder firing order (dead time & lag)
2J (dn/dt) = Tcomb - Tload
Man Press
Engine Speed Engine
SpeedIntegrator
EMS Strategy ExampleIdle Speed Control Dynamic Control Loops
Energy conversionIntake manifoldTorque balance
InputsEngine SpeedEngine Load
(Man Abs Press)
OutputsAir mass flow
modulator
Plant Model(algorithms & maps)
Air Mass Flow
Modulator Proportional & Integral Controllers
Engine Calibration
Term coined in late 1980s
The precise measurement and optimisation of the characteristics of an engine and drive train in all possible vehicle model variants
A Calibration Engineer instigates the measurement of the engine characteristics and subsequently decides which are the optimum
The Engineer includes the optimum values within the engine EMS
Calibration
“The process of determining the calibre
of a gun”
Typical Calibration Programme
Initial calibrations based on previous experienceTesting of prototype engines on an engine dynamometerCalibration transferred to vehicle for refinementSuccessive approximationsHomologationFinal Calibration ValidationSold to production+90 days support
2 to
3 Y
ears
“Tools of the Trade” Engine Test Cell Vehicle Chassis Dynamometer Linear AFR sensor Measurement & Calibration (Interface) System Automated Calibration System Cold and Hot chambers
(and/or equivalent ambients) Emissions Lab Test Track Analysis tools
ExcelMatlab SimulinkModel Based Calibration toolbox
Measurement & Calibration System
ECU Description Data
ECU Program Data
Calibration Data
Auto Calibration System
Measurement and Calibration
System
ECU
Engine Actuators
Sensors
Master Slave
Low Level Commands, Data and On-Line Values
Commands, Data and On-Line Values
Serial Communication Serial Link (CAN or K-Line)
RS 232
e.g. ATI Vision e.g. AVL CAMEO
MCS Calibration Tool – ATI Vision
MCS Calibration Tool – ATI Vision
Engine Speed
Thro
ttle
Pos
ition
Lambda
MCS Calibration Tool – ATI Vision
Automated Calibration – AVL Cameo
Optimises Engine Testing using Design of Experiments Models to gather data for EMS Maps
Thank You for Listening