Components

     The basic parts of engine are shown in Fig. 3. 1.

 

 

 

    ．block - main supporting member of engine to hold all the other engine partsin place

 

    ．cylinder - a round hole machined in the block，which guides piston movement

 

    ．piston - a cylindrical component that transfers the energy of combustion to theconnecting rod

 

    ．rings - seal the small gap around the side of the piston, to keep combustionpressure and oil from leaking between the piston and the cylinder wall

 

    ．connecting rod - links the piston to the crankshaft

 

    ．crankshaft - changes the reciprocating movement of piston and rod into usefulrotary motion

 

    ．cylinder head - covers and seals the top of the cylinder, and also holds thevalves，rocker arms，and camshaft

 

    ．combustion chamber - a small cavity between the top of the piston and the bottomof the cylinder head，where the burning of the air-fuel mixture occurs

 

    ．valves - control the flow of air-fuel mixture into the combustion chamber andexhaust gases out of the combustion chamber, through opening and closing

 

    ．camshaft - controls the opening of the valves

 

    ．valve springs - keep the valves closed when they do not need to be openrocker arms一transfer camshaft action to the valves

 

    ．lifters or followers - ride on the camshaft and transfer motion to the other partsof the valve train

 

    ．flywheel - helps keep the crankshaft turning smoothly，and provides a large gearfor the starting motor