Question

A compression ignition engine when tested gave an indicator card having area 3250mm^2 and length 73mm. The calibration factor was 0.2 bar/mm. The mechanical efficiency of the engine is 80%. Calculate the IMEP and the BMEP

Answer 1

Answer:

BMEP = 8.904 bar

IMEP =  11.13 bar

Explanation:

given data

area A = 3250 mm²

length L = 73 mm

calibration factor = 0.2 bar/mm

mechanical efficiency = 80 %

to find out

IMEP and the BMEP

solution

first we calculate the BMEP break mean efficiency pressure tat is express as

BMEP = $\frac{A}{L}$

here A is area and L is length

so BMEP is

BMEP = $\frac{3250}{73}$ = 44.52 mm

BMEP = 44.52 × 0.2 bar = 8.904 bar

and

we know mechanical efficiency is

mechanical efficiency = $\frac{BMEP}{IMEP}$

so put here value we get IMEP

IMEP = $\frac{8.904}{0.80}$

IMEP =  11.13 bar