Sequence of Operations in a Cycle

Sequence of Operations in a Cycle Points : Sequence of Operations in a Cycle, Suction Stroke, Compression Stroke, Expansion or Working Stroke, Exhaust Stroke Strictly speaking, when an engine is working continuously, we may consider a cycle starting from any stroke. We know that when the engine returns back to the stroke where it started we say that one cycle has been completed. But in this chapter, we shall consider the following sequence of operations in a cycle, which is widely used. 1. Suction Stroke In this stroke the fuel vapor, in correct proportion, is supplied to the engine. 2. Compression Stroke In this stroke, the fuel vapour is compressed in the engine cylinder. 3. Expansion or Working Stroke In this stroke, the fuel vapour is fired just before the compression is complete. It results in the sudden rise of pressure, due to expansion of the combustion products in the engine cylinder. This sudden rise of the pressure pushes the piston with a great force, and rotates the crankshaft. The crankshaft, in turn, drives the machine connected to it. 4. Exhaust Stroke In this stroke, the burnt gases (or combustion products) are exhausted from the engine cylinder, so as to make space available for the fresh, fuel vapour.