MEL432Microprocessor Applications InManufacturingControl Systems in AutomobilesSubmitted By:Rohit Gothwal(2010ME20796)Himanshu Kumar(2010ME20775)Anil Kumar (2010ME20764)Dileep Kr. Meena(2010ME20773)
ECU:The Brain of your vehicle• ECU stands for electronic control unit.• It is a generic term for any embedded system that controlsone or more of the electrical system or subsystems in a motorvehicle.• A modern ECU contains a 32-bit, 40-MHz processor.
• It collect data from different sensors, it knows everything fromthe coolant temperature to the amount of oxygen in the exhaust.• With this data, it performs many calculations and decides thebest spark timing and determining how long the fuel injector isopen.• The code in an average ECU takes up less than 1MB of memory.• It uses closed-loop control, a control scheme that monitorsoutputs of a system to control the inputs to a system, managingthe emissions and fuel economy of the engine.
ECU COMPONENTSTh-e processor is packaged in a module with hundreds ofcomponents on a multi-layer circuit board. Some of thecomponents in the ECU that support the processor are: Analog-to-digital converters - These devices read theoutputs of the sensors in the car, such as the oxygen sensor.The output of an oxygen sensor is an analog voltage. Theprocessor only understands digital numbers, so the analog-to-digital converter changes this voltage into a 10-bit digitalnumber. High-level digital outputs - On many modern cars, the ECUfires the spark plugs, opens and closes the fuel injectors andturns the cooling fan on and off. All of these tasks requiredigital outputs. A digital output is either on or off, there isno in-between.
• Digital-to-analog converters - Sometimes the ECU has to provide ananalog voltage output to drive some engine components. Since theprocessor on the ECU is a digital device, it needs a component thatcan convert the digital number into an analog voltage.• Signal conditioners - A signal conditioner is a circuit that adjusts thelevel of the signals coming in or out. For instance, if we applied asignal conditioner that multiplied the voltage coming from the oxygensensor (0V to 1.1V) by 4, wed get a 0V to 4.4V signal.• Communication chips - These chips implement the variouscommunications standards that are used on cars. This communicationstandard allows for communication speeds of up to 500 kilobits persecond (Kbps).This speed is becoming necessary because somemodules communicate data onto the bus hundreds of times persecond.
OBJECTIVES Power output Fuel efficiency Emissions performance Engine tuning Driveability and smooth operation
Strict emission standards require precise fuel delivery. Computers used to calculate fuel needs. EFIS is very precise, reliable & cost effective. EFI provide correct A/F ratio for all loads, speeds, & temperature ranges.
Overview What is Knock Sensor Micro Controller application in Knock Sensor
What is knocking? What are Knocks?? - high frequencyvibrations caused by detonation, orthe premature burning of fuelinside an engines cylinders
How can it be prevented? Why do we care?? - Knocks can robpower from the engine and worst,destroy the engine itself. How can we prevent knocking?? –lower compression ratio, higheroctane fuel, change driving habitsor……MICRO-CONTROLLERS
The Sensor Knock Sensors generate a voltagewhen vibration is applied to themutilizing the piezoelectric effect Generated voltage is proportionalto the acceleration Due to the vibration, a counterweight inside the sensor is applyingpressure on the piezo element, thispressure creates an electric chargein the piezo element which is theoutput signal of the sensor. Tuned to engine knock frequency(typically 6-8kHz)
Location of Knock Sensor The knock sensor is located onthe engine block, cylinderhead, or the intake manifold. This is because the function ofthis sensor is to sensevibrations an engine creates. The ECU uses this signal toalter the ignition timing andprevent detonation. It will compare thisinformation with its presettables to identify an engineknock.
Knock Sensor Circuit Once signs of detonation are detected (i.e. knocking), the knock sensorsends a voltage signal to the engine management computer which retardsthe spark timing slightly to avoid detonation.
Benefits Vehicle engines work more efficiently and produce more power whenoperating near the detonation limit. Although simple, knock sensors allow optimum engine performance andprotect the engine from potential damage caused by detonation.
Other applications Rain sensors Anti collision system ABS- Anti lock Braking System