AUTOMOBILE ENGINEERING

Hello friend's in this post we will talk about pressure - volume diagram of four - stroke, otto cycle engine Fig. 3.8 shows theoretical p-v diagram of a four-stroke Otto cycle engine. During the suction stroke, the charge is admitted in the cylinder increasing the volume from 1 to 2, at the atmospheric pressure. Cylinder volume is the sum of clearance volume and stroke volume. During the compression stroke, the charge is compressed from 2 to 3. Volume decreases to clearance volume and pressure rises. The compressed charge is ignited at constant volume, which increases the pressure as represented by 3- 4 line. During the working stroke the volume increases and pressure decreases as represented by 4-5line. At 5, the exhaust valve opens and exhaust takes place at constant decreases the pressure suddenly as represented by 5-2 line. Finally the piston moves onward rushing out the exhaust gases at atmospheric pressure as represented by 2-1 line. The volume again decreases to clearance vo

Hello friend's in this post we will talk about valve timing diagram of a four stroke, otto cycle engine It has already been explained in the operation of four stroke, Otto cycle engine that the inlet valve opens during the suction stroke and the exhaust valve opens during the exhaust stroke. The exact moment at winch each of the valves opens and closes with reference to the position of piston and crank can be shown graphically in a diagram. This diagram is known as valve timing diagram. Theoretically, the inlet valve opens exactly at the beginning of suction stroke and closes at the end of the stroke. Both the valves remain closed during compression and power strokes. The exhaust valve opens exactly at the beginning of exhaust stroke and closes at the end of stroke. The theoretical valve timing diagram for a four-stroke Otto cycle engine is shown in Fig. 3.3. The opening and closing of valves with reference to the position of piston and crank shaft during the four strok

Hello friend's so in this post we will talk about four strock engines. The modern petrol ( gasoline ) engines operate on Otto ( constant volume ) cycle . This cycle was introduced in practical form by a German scientist Otto in 1876 , although it was described by a French scientist Beande Roches in 1862. In a four - stroke Otto cycle , spark ignition engine , the four strokes are as follows : 1. Suction stroke  During suction stroke , the piston is moved downward by the crankshaft , which is revolved either by the momentum of the flywheel or by the power generated by the electric starting motor . The inlet valve remains open and the exhaust valve is closed during this stroke . The downward movement of the piston sucks air - fuel mixture in the cylinder from the carburettor through the open inlet valve . Here the fuel is petrol mixed with air , broken up into a mist and partially vaporized in the carburettor .  2. Compression stroke   During compression stroke , the p