Internal Combustion Engine (Mathematical Problem-1)

## A single cylinder, two stroke petrol engine develops 4 KW indicated power. Find the average speed of the piston, if the mean effective pressure is 6.5 bar and piston diameter is 100 mm. 

Solution:

Given,

           Indicated power I.P = 4 KW

           Mean effective pressure P_m = 6.5 bar

           Piston diameter D_P = 100 mm = 0.1 m

Let,

           L = Length of stroke in meters

           N = Speed of the engine in r.p.m

:: Number of working strokes per minute,

                              n= N (Engine works on two stroke cycle)

We know that area of piston,

                              A = π/4 x (0.1)² 
                                  = 7.855 x  10^-3 m²

So, Indicated power (I.P),

                        => I.P = (100 x P_m x L x A x n)/60

                        =>  4 = (100 x 6.5 x L x 7.855x10^-3 x N)/60

                        => 4 = 0.0851 LN

                        => LN = 47

So, Average speed of the piston,

                        = 2 x LN

                        = 2 x 47 

                        = 94 m/sec 

:: Average speed of the piston = 94 m/sec