Stage of combustion, different type of combustion explain with graph

Stage of combustion graph



1. What is the combustion:- 

Inside an engine cylinder ignite the entire air and fuel mixture by spraying the diesel on it and it starts burn this process known as combustion. In other words inside an engine cylinder ignite the hydrocarbon and oxygen, known as combustion. 

The combustion have different stages as follows:-


1.   Delay Period:-  The delay period is starts from fuel spray and till fire starts into the engine cylinder known as delay period. Delay period is important thing for an engine because of the diesel knock is fully depends of delay period.

2.   Diesel knock:-  If delay period have to be long than fuel have enough time to convert into vapour it means to atomized and almost all fuel atomized afterthen at SIT the fuel and air mixture burnt and explode and make a noise this noise known as diesel knock. 

3.  Rapid Combustion:-  Inside an engine cylinder ignite the entire air and fuel mixture and this mixture starts burn layer to layer. This burning process like layer to layer is known as rapid combustion. During the rapid combustion the pressure is increased and volume is constant inside the engine cylinder. 

4.  Complete Combustion:-  Inside an engine cylinder the fuel spraying starts before TDC and combustion process will starts this is known as rapid combustion but some fuel spray after burning in drop formation direct into the fire so when the last drop is burnt this is known as complete combustion.  During the complete combustion the volume is increased and also temperature and pressure increased too.

Some things may effects the diesel knock and delay period, mention below:-

       (i)   Quality of fuel.
       (ii)  Temperature of intake air.
       (iii) Compression ratio.
       (iv) Engine speed. 
       (v)  Pre-ignition.
       (vi) Temperature of coolant.