248 ENGINE 273 MPFI AN OVERVIEW EMS (Engine Management System) Engine Management System (EMS) comprises of Electronic Control Unit (ECU), sensors, actuators and control algorithms that determine the performance of the Engine as a whole and as part of the vehicle. ECU (Electronic Control Unit) Electronic Control Unit (ECU) as a system consists of amicroprocessor with peripheral devices like ignition driver, ADCs device and I/O drivers. ECU read values from the sensors and uses the sensor readings to control the fuel injection and ignition systems. It is the ‘Brain’ of the Engine Management system, which controls all the actuators based on the processing of the Sensors inputs in conjunction with various control algorithms for the optimum working of the Engine/Vehicle. Being the most important component of the Engine management system, ECU apart from ensuring the optimum working of the Vehicle, also keeps an eye on the working of the sensors and actuators. When ever a malfunction/fault occurs in the component or the system the ECU alerts the user by glowing CKNL (Service Indicator). Apart from glowing the CKNL (Service Indicator), ECU also does the following: • Stores a DTC in its memory (indicates the faulty component/system). • Stores a context frame (list of parameters indicating the operating condition during the fault generation) in its memory. Sensors A sensor is a device that measures a physical quantity and converts it into an electrical voltage which can be read by an instrument or used by some controller for its purpose. Actuators An actuator causes an action (say injector open or close) based on command given by ECU.
RkJQdWJsaXNoZXIy MTIwNTUz