IndexIC engineOperating principle of four-stroke gasoline enginesIntake stroke:Compression stroke:Working or expansion stroke:Exhaust stroke:Operating principles of gasoline engine 2 Stroke IC Engine Objectives: Explain the simple working of the engine Describe working of four stroke engine and explain the purpose of each stroke Describe the two stroke engine and explain the principle of two stroke operation Advantages and Disadvantages of Two and Four Stroke Engines Principle of Operation of four-stroke petrol enginesThere are four strokes which are as follows:Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original Essay Intake Strokes Compression Stroke Expansions or Work or Power Stroke Exhaust Stroke Intake Stroke: The intake stroke begins with the piston at the top dead center position. During this stroke the piston moves downwards via the crankshaft. The inlet valve is open and the exhaust valve is closed. The partial vacuum created by the downward movement of the piston draws fresh charge (mixture of air and gasoline) from the carburetor through the intake valve. The stroke is completed during the half revolution (180O) of the crankshaft, which means that at the end of the intake stroke, the piston reaches the bottom center position of the head. Compression stroke: During this stroke the intake and exhaust valves are closed and the piston returns from the bottom dead center position. When the piston rises, the charge is compressed. During compression the pressure and temperature increase. This increase in temperature and pressure depends on the compression ratio (in petrol engines the compression ratio generally varies between 6:1 and 9:1). Just before the completion of the compression stroke, the charge is ignited by an electric spark, produced on the spark plug.Working or Expansion Stroke: The ignition of the compressed charge. Just before the completion of the compression stroke, a rapid hidden increase in temperature and pressure occurs in the cylinder. During this stroke the intake and exhaust values ​​remain closed. The expansion of gases due to the heat of combustion exerts pressure on the piston due to which the piston moves downwards, doing useful work. Relief stroke: The relief value is opened and the input value remains closed. The piston moves upwards (from its BDC position) with the help of the energy stored in the flywheel during the working stroke. The upward movement of the piston discharges the burned gases through the exhaust value. At the end of the exhaust stroke, the piston reaches its TDC position and begins the next cycle. Working Principles of 2 Stroke Petrol EngineThe working principle of 2 Stroke Petrol Engine is discussed below: 1st stroke: To start with let's assume that the piston is in the BDC position. The arrangement of the ports is such that the piston performs two jobs simultaneously. As the piston begins to rise from its BDC position, it closes the transfer port and exhaust port. The charge (mixture of air and petrol) which is already present in the cylinder, following the previous operation of the engine, is compressed, at the same time as the upward movement creates the depression of the piston in the engine crankcase (which is gas-tight) . As soon as the front door is discovered; the new gearbox sucked into the crankcase. Charging continues until the crankcase and space in the cylinder under the piston are filled with charge. At the end of the third stroke, the piston reaches the TDC position. 2nd race: just before.