Engine management system is used for managing the ignition and airfuel requirements of an engine. In the case of a four stroke multicyUnder petrol engine, each cylinder has a piston performing all the four stroke (suction, compression, working or expansion and exhaust strokes) and the piston rod of each piston connected to a common crankshaft, and their power stroke at different times resulting in continuous power for rotation of the crankshaft.
The power and speed of an engine are functions of ignition timing and air fuel mixture. Henc, by controlling the the ignition timing and air fuel mixture it is possible to control the speed and power of the engine. In modern cars the ignition timing, opening and closing of valves at appropriate time, quality of air fuel mixture are controlled by microprocessor with the help of sensors. Fig. 1.16 illustrates the basic concept of engine management
In modern washing machine mechanical system is replaced by digital device i.e., a micro controller and the sequence of instruction i.e. program embedded in the microcontroller. The amount of detergent, amount of water, pH value are all sensed by the sensor and these sensed quantities or signals are input to the microcontroller. Based on the input and the software embedded, the corresponding output of the micro controller to carry out the different sequence of operations. The sequence of contrail can be varied by varying the software embedded at the manufacturing level of the washing machine. Figure 1.15 illustrates the block diagram of a microcontrolled based automatic washing machine.