Main construction part of two stroke engine.

Bed plate and crankcase
Crankshaft and flywheel
Connecting rod
Piston
Liner
A-frame
Entablature
Cylinder block.
Engine structure includes fixed parts that hold the engine parts together and keep moving parts in alignment. These parts also resist the internal forces generated due to engine operation.
The structure offer rigidity and strength to
Ensure crankshaft stresses are minimum.
Main bearing are uniformly loaded to avoid excessive bending.
Maintain perfect alignment of piston and running gear.
Resist fatigue failure.
The structural element are made up of plane carbon normalised steel plates with carbon- 0.16% and UTS 430 to 500 N/ mm2.
Cylinder cover and mountings.

Cylinder cover seals the upper end of the cylinder space and also carries mountings necessary for Engine operations.
Cylinder cover also forms a gas tight seal and prevent the escape of gases from the combustion chamber.
It is subjected to gas forces during combustion. Thermal stresses and pressure fluctuation during entire cycle.
It is also subjected to bending stresses due to tightening of cylinder cover bolts.
Cylinder cover are cooled with the help of jacket water to withstand the firing pressure and cylinder heat.
High tensile strength and high fatigue strength material are used to withstand high pressure and temperature and also the pressure fluctuations in cylinder.
The cylinder cover inhouse mountings such as :
Safety valve

Fuel valve

Indicator cock

Starting air valve

Exhaust valve

Cylinder liner and piston

Cylinder liner

The cylinder liner is tightened against top of cylinder frame by cylinder cover.
It is arranged such that it is free to expand downwards when temperature increases during the running of Engine.
It has number of scavenge ports that is uncovered by piston when piston reaches bottom dead centre.
Cylinder liner are provided with bores circumferentially for injection of cylinder lube oil at regular interval.
The cylinder liner are centrifugally casted the material used is PEARLITIC GREY CAST IRON with 3 to 3.5% carbon.

Piston

Diesel engine pistons are made up of two parts the upper part is called CROWN and lower part is called SKIRT.
As the piston is subjected to high combustion heat it has to be cooled.
Cooling of piston is necessary for avoiding high metal temperature and also to maintain correct clearance between piston and liner
Piston rod is provided to connect the piston to the crosshead. Stuffing box is also provided to seperate scavenge space from crank case.
Piston crown and skirt are of cast steel and piston rod is of forged steel.
Crown houses piston ring of grey cast iron to seal the gases in combustion space.