Internal combustion engine - Essay Example

ADVANTAGES AND DISADVANTAGES OF TWO STROKE CYCLE ENGINE An Essay Submitted by YOU YOUR ACADEMIC ORGANISATION HERE APPROPRIATE HERE OTHER RELEVANT COURSE INFO HEREADVANTAGES AND DISADVANTAGES OF TWO STROKE CYCLE ENGINE Two stroke cycle engine requires two strokes of the piston on take one revolution of the crank shaft to complete the cycle. Section and exhaust strokes are successfully eliminated in two stroke cycle engine . Compared to four stroke cycle engine, two stroke cycle engine has some advantages and disadvantages.

AdvantagesThe power developed by the two stroke cycle engine is twice than that of the four stroke engine for the same engine speed and cycle volume, since two stroke cycle engine gives one working stroke for each revolution of crankshaft, while in four stroke cycle engine gives one working stroke for every two revolution of the crank shaft. For the same power, a two stroke cycle engine is more compact and lighter than a four stroke cycle engine.Two stroke cycle engine is more suitable for motor cycles, auto cycles and scooters.

It has one working stroke for every revolution of the crank shaft, Hence more turning moment on the crank in two stroke cycle and require lighter fly wheel. It has high mechanical efficiency due to the absence of cams and camshaft and rockers etc.A two stroke cycle engine is simpler in construction and mechanism .it has no valve and valve mechanism in it. The port is easy to design and they are covered by the movement of the piston itself.It gives less torsional oscillations.It requires fewer spare parts due to its simple design.

It can be easily reversed if it is of valve type.There is a saving in work required to overcome the friction of inlet and exhaust port.DisadvantagesThe thermodynamic efficiency of two stroke cycle engine is less than four stroke cycle engine because the compression ratio of two stroke cycle engine is less than that of four stroke cycle engine.Fuel consumption of the two stroke engine is more because some of the fresh charge is mixed with burnt fuel and will escape through exhaust port. Which in turn reduction of overall efficiency.

Since the ports remains open during up word stroke, the actual compression starts only after both inlet and exhaust ports have been closed. So actual compression ratio and the thermal efficiency of the two stroke cycle engine is less than that of four stroke engine of the same dimension.In two stroke cycle engines the number of power strokes per minutes are twice the power strokes of four stroke cycle engine. So the capacity of cooling system used must be higher. The cooling of the engine also presents difficulty as quantity of heat remover per minutes is large.

The piston gets over heated due to firing in each revolution and oil cooling of the piston is necessary.Two stroke cycle engine consumes more lubricating oil because of high operating temperature.The exhaust is more noisy due to sudden release of the burnt gases.The fresh charge is polluted by the burnt gases due to incomplete scavenging.There is greater wear and tear of moving part, hence it gives loud noise.ConclusionIn two stroke cycle engine some of the fresh charge is mixed with burnt fuel and exhaust through the exhaust port which causes high fuel consumption.

So two stroke cycle engine is not widely used except in the case where size is compact for example light vehicles, scooters, out board motor, motor cycle etc .Large two stroke cycle engine are generally CI engines. Two stroke CI engines are better for slow and moderate speeds.ReferenceGupta, H.N (2006), Fundamentals of internal combustion engine, Prentice Hall of Privet Limited, New Delhi: 365-367