Function- In the bore of cylinder the fresh charge of air-fuel mixture is ignited, compressed by piston and expanded to give power to piston.
2. CYLINDER HEAD- It closes in the top of the cylinder, forming the combustion chamber. The head can also be a place to mount the valves, spark plugs, and fuel injectors. EX: Overhead Cam- valve train configurations place the engine camshaft within the cylinder heads, above the combustion chambers, and drive the valves or lifters in a more direct manner compared to overhead valves (OHV) and pushrods.
Function-It carries inlet and exhaust valve. Fresh charge is admitted through inlet valve and burnt gases are exhausted from exhaust valve. In case of petrol engine, a spark plug and in case of diesel engine, an injector is also mounted on cylinder head.
3. CONNECTING ROD- The load on the piston due to combustion of fuel in the combustion chamber is transmitted to crankshaft through the connecting rod.
EX: Compound Rods- Many-cylinder multi-bank engines such as a V12 layout have little space available for many connecting rod journals on a limited length of crankshaft. Function-It changes the reciprocating motion of piston into rotary motion at crankshaft. This way connecting rod transmits the power produced at piston to crankshaft.
4. SPARK PLUG- A device inserted in the head of an internal-combustion engine cylinder that ignites the fuel mixture by means of an electric spark. EX: Surface-discharge spark plug- A piston engine has a part of the combustion chamber that is always out of reach of the piston; and this zone is where the conventional spark plug...