Tiêu đề Exp 2 Study of working of four stroke engine.pdf ✅

1 Experiment No. 2 Aim To study the working of four stroke Engine 1. Spark Ignition Engine (S.I) 2. Compression Ignition Engine (C.I) Working of Four Stroke Petrol Engine (S.I Engines) The cycle is completed in four strokes of the piston or in two revolutions of the crankshaft. One power stroke is obtained in every two revolutions of the crankshaft. 1. Suction Stroke: During this stroke piston moves from TDC to BDC; mixture of air and petrol is admitted through inlet valve into engine cylinder. The exhaust valve remains closed throughout the stroke. 2. Compression Stroke: In this stroke, the piston moves towards TDC. The air fuel mixture is compressed. Before the end of the compression stroke, the charge is ignited by the spark. The spark plug fitted in the cylinder head gives the spark. Both the inlet and exhaust valves remain closed during the stroke. 3. Power or Expansion Stroke: The ignited mixture at high temperature and pressure drives the piston downwards and we get work from the engine. The flywheel mounted on the engine shaft stores energy during this stroke and supplied it during the idle stroke. Both the valves remain closed during the start of this stroke but when the piston just reaches the BDC, the exhaust valve opens. 4. Exhaust Stroke: Here the gases from which the work has been collected become useless after the completion exhaust valve to the atmosphere. The piston moves from BDC to TDC and exhaust gases are driven out of the engine cylinder.
2 I.V. - Inlet valve, E.V. - Exhaust valve, C.R. - Connecting rod, C – Crank, S.P. - Spark plug.
3 Working of Four Stroke Diesel Engine 1. Suction Stroke: During this stroke air is admitted through inlet valve into the engine cylinder. The exhaust valve remains closed throughout the stroke. 2. Compression stroke: In this stroke, air is compressed. Before the end of the compression stroke, fuel is injected into the combustion chamber. The fuel gets ignited by high temperature of compressed air. Both the valves remain closed during this stroke. 3. Power or Expansion Stroke: The ignited mixture of air and fuel at high temperature and pressure drives the piston downwards. The piston, through gudgeon pin, connecting rod, crank pin and crank, converts reciprocating motion of piston into rotary motion of the crank shaft. Both valves remain closed during this stroke. 4. Exhaust Stroke: This is the last stroke in which the products of combustion are removed from the engine cylinder through exhaust valve.
4 Result Thus we have studied Combustion process of 4 stroke S.I and C.I engines.