Spark ignition engine (I.C. Engine).pptx

A presentation on 4 stroke spark ignition engine
Content of this presentation are as follows -
What is I.C. Engine?
Basic parts of I.C. Engine
Working of 4-stroke Engine
1) Suction stroke
2) Compression stroke
3) Expansion stroke
4) Exhaust stroke
Advantages
Disadvantages

Thank You

1. Government engineering college, Bilaspur (C.G) DEPARTMENT OF MECHANICAL ENGINEERING A PRESENTATION ON 4 STROKE SI ENGINE Submitted by Girendra Kumar Submitted to Prof. A.R. Patnaik Assistant professor

2. topic What is I.C. Engine? Basic parts of I.C. Engine Working of 4-stroke Engine Advantages & Disadvantages

3. What is I.C. Engine? I.C. Engines means Internal Combustion Engines . I.C. engine is type of heat engine which converts the heat energy released during combustion of fuel into mechanical work. These engines are widely used as prime movers and also in road vehicles, locomotives, industrial applications. Examples: Petrol engines, Diesel engines and Gas engines.

4. Basic parts of I.C. Engine Cylinder Cylinder head Piston Piston Rings Spark plug Combustion chamber Inlet manifold

5. 8. Exhaust manifold 9. Inlet & Exhaust valve 10. Connecting rod 11. Crank shaft 12. Cam shaft 13. Fly wheel

6. Basic parts of I.C. Engine 1. Cylinder : It is the important part of this engine in which the piston moves up and down in order to develop power. 2. Cylinder head : It is fitted one end of the cylinder and act as a cover to close the cylinder It contains: Inlet valve & Outlet valve. Spark plug or injector. 3. Piston : It is considered as the heart of I.C engine. Whose main function is to transmit the force exerted by the burning of charge to the connecting rod. 4. Piston Ring : It fitted slots around the piston , provide a tight and seal between the piston and the cylinder wall thus preventing leakage of combustion gases. 5. Spark Plug : It is a component to initiate the combustion process in Spark Ignition (SI) engines and is usually located on the cylinder head.

7. f 6. Combustion chamber : The space enclosed in the upper part of the cylinder, by the cylinder head and the piston top during the combustion process is called the combustion chamber. 7. Inlet Manifold : The pipe which connects the intake system to the inlet valve of the engine and through which air or air-fuel mixture is drawn into the cylinder is called the inlet manifold. 8. Exhaust Manifold : The pipe which connects the exhaust system to the exhaust valve of the engine and through which the products of combustion scape into the atmosphere is called the exhaust manifold. 9. Inlet and Exhaust valve : Valves are commonly mushroom shaped poppet type. Inlet valve provided either on the cylinder head or on the side of the cylinder for regulating the charge coming into the cylinder. Exhaust valve is used for discharging the products of combustion from the cylinder.

8. 10 . Connecting rod : It is the link between the piston and crank shaft. Whose main function is to transmit force from the piston to the crank shaft. 11. Crank shaft :It is considered as the backbone of an I.C Engine. Whose function is to convert reciprocating motion of piston in to the rotary motion with the help of connecting rod. 12. Cam shaft :The shaft which has cams for the opening and closing of inlet & outlet valves. 13. Fly wheel : It is the big wheel mounted on the crankshaft whose function is to maintain speed at constant. The constant speed is done by storing excess energy during power stroke up to returning of other power stroke.

9. 4 Stroke Petrol Engine The four stroke engine was first demonstrated by Nikolaus Otto in 1876, hence it is also known as the Otto cycle. The technically correct term is actually four stroke cycle. The four stroke engine is probably the most common engine type nowadays. It powers almost all cars and trucks . The four strokes of the cycle are intake, compression, power, and exhaust. Each corresponds to one full stroke of the piston; therefore, the complete cycle requires two revolutions of the crankshaft to complete.

10. Working of 4-stroke Engine

11. Working of 4-stroke petrol Engine Suction stroke During the suction stroke of spark ignition engine, the piston moves down form top end of the cylinder to the bottom end of cylinder and simultaneously intake valve opens. Due to the movement of piston low pressure or vacuum generates inside the cylinder. Due to this vacuum and the gravity action air fuel mixture enter into the cylinder through the intake valve . The intake valve remains open until the piston reach the lower end of the cylinder. After it the intake valve closes and seals the upper end of the cylinder .

12. Compression stroke After the piston passes bottom end of the cylinder, it starts moving up. Both valves are closed and the cylinder is sealed. The piston moves upward. This movement of piston compresses the air fuel mixture into a small space between the top of the piston and cylinder head. The mixture is compressed into 1/8 or less of its original volume. This compression ratio decides the power of engine. At the end of compression stroke the piston is at top end of the cylinder.

13. Expansion (Power) stroke At the end of the compression stroke when the piston is at the top end of the cylinder an electric spark generated by the spark plug. The heat of the spark ignites the compressed air fuel mixture. The air fuel mixture then burn rapidly and produces high temperature up to 3300°C. This high temperature causes very high pressure, which pushes down. on the top of the piston. The connecting rod force to the carries this crankshaft, which turns to move the vehicle . At the end of power stroke the piston reach the bottom end of cylinder.

14. Exhaust stroke When the piston reaches the bottom end of cylinder on the power stroke, the exhaust valve opens . At this time due to the burn gases inside the cylinder, the pressure inside the cylinder is slightly high from atmospheric pressure. This pressure difference allows burn gases to escape through the exhaust port and the piston move through the top end of the cylinder. At the end of exhaust all burn gases escape and exhaust valve closed . Now again intake valve opens and this process keep on running until your vehicle remain in starting position.

15. Advantages i.c. engine Size of engine is very less compared to external combustion engines Power to weight ratio is high Very suitable for small power requirement applications Usually more portable than their counterpart external combustion engines Starting time is very less High efficiency than external combustion engine No chances of leakage of working fluids Requires less maintenance Lubricant consumption is less as compared to external combustion engines

16. Disadvantages of i.c. engine Variety of fuels that can be used is limited to very fine quality gaseous and liquid fuel Fuel used is very costly like gasoline or diesel Engine emissions are generally high compared to external combustion engine Not suitable of large scale power generation In case of reciprocating internal combustion noise is generated due to detonation of fuel

17. Thank you