(i) Basic cycle: Petrol Engine work on Otto cycle whereas Diesel Engine work on diesel cycles.
(ii) Induction of fuel: During the suction stroke in petrol engine, the air fuel mixture is sucked in the cylinder while in diesel engine only air is sucked into the cylinder during its suction stroke.
(iii) Compression Ratio: In petrol engine the compression ratio in the range of 5:1 to 8:1 while in diesel engine it is in the range of 15:1 to 20:1.
(iv) Thermal efficiency: For same compression ratio, the thermal efficiency of diesel engine is lower than that of petrol engine.
(v) Ignition: In petrol engine the charge (A/F mixture) is ignited by the spark plug after the compression of mixture while in diesel engine combustion of fuel due to its high temperature of compressed air.
Two Stroke Engine
In two stroke engine all the four operation i.e. suction, compression, ignition and exhaust are completed in one revolution of the crank shaft.
Four Stroke Engine
In four stroke engine all the four operation are completed in two revolutions of crank shaft.
Application of 2-stroke Engines
2 stroke engine are generally used where low cost, compactness and light weight are the major considerations.
