Question

An ideal four stroke Otto cycle engine has 6 cylinders and a displacement of 4 Liters. It has a compression ratio of 8.5:1. If the mean effective pressure is 4000 kPa when operating at 3000 rpm, what will be the indicated power and what is the required heat transfer to the engine from a combusting fuel?

Answer 1

we know that

indicated power of an engine (I.P.)

I.P. =

where,

k = number of cylinder= 6

V =Length * Area = stroke volume = 4 liters = 0.004 m³

r = compression ratio = 8.5:1

p_m = mean effective pressure = 4000 kPa = 40 bar

N = speed = 3000 rpm

K = number of cylinders = 6

now,

1) indicated power of an engine (I.P.)

I.P. =

n=N/2 for four strokes, and n=N for two-strokes

so here

put all the given values

I.P. =

I.P. = 2400 KW

2) required heat transfer to the engine from a combusting fuel

required heat transfer to the engine from a combusting fuel = Heat equivalent to I.P.

Heat equivalent to I.P. = I.P. * 3600 kJ/h

                                     = 2400 * 3600

                                     = 8640 MJ/h

heat required for 6 cylinder engine = 8640 MJ/h