In a typical two stroke (petrol) engine, the valves are replaced by ports in the cylinder wall, and closed / unclosed by the motion of the piston.
Piston rising, vacuum under draws (fuel) mix into the crankcase through the carburettor.
Piston falling, inlet port closes, pressure forces mix up through transfer ports into combustion chamber.
Rises and fires at TDC, then falls to uncover exhaust port.
valves are use in four stroke engine, and ports are use in two stroke engine.
suction stroke and exhaust strokes are the two strokes involved in 2 stroke engine....
In my point of view two stroke engine is the best engine ,because in two stroke engine there are only two stages or two stroke .In which one stage complete the two process frist is suction & second one is compression ,in these two process completes in one stage. The best advantage of this engine is the in every cycle there is a power stroke due to which the engine performance is very good . But the biggest disadvantage is the fuel consumption . Which after some time reduced by the resarcheres.
In the two stroke petrol engine as you know suction,compression,ignition,expansion and exhaust is completed in only two stroke and one revolution of crank wheel more over diesel ignites at very high pressure which is not the same in case of petrol........if petrol is also ignited under pressure it explodes producing a big thumping sound.called KNOCKINGthis may reduce the power output and also lead to breakdown of the engine. For the above reason two stroke engine cannot compress air and ignite the fuel like diesel engine.
if you see the difference between valves
valve timing diagram of two stroke engine
to get more aire flow though the block.
In a two-stroke reed valve engine the reed valve is used to seal the fuel air mixture in the crankcase.
Intake valve and exhaust valve.
valves are use in four stroke engine, and ports are use in two stroke engine.
A two stroke engine has half the strokes of an otto (or four stroke) engine, therefore it takes two crankshaft roatations to complete a cycle on a four stroke engine and only one revolution in a two stroke engine. There are several types of two stroke engines, the different types have to do with how the receive the air/fuel mixture, also you have two stroke diesel engines.
An IC engine comes in all sizes and shapes so the weights and dimensions of the valve system will differ. Most are a two-stroke or two-cycle engine.
Some two stroke engines have 4 valves, Detroit Diesel 71 series and 53 series engines for example. Most small 2 stroke engines have no "Valves" at all in the sense of the "POP" valve used in four stroke engines. Some people feel these engine has one valve because the piston acts as the valve covering the ports cut into the cylinder walls.
Explain the advantages of four-stroke engine over two-stroke engine
in my opinion a two stroke engine is a better quality engine as compared to a four stroke engine!
Detroit diesel engine is an example of two stroke engine
two stroke