Answer:
The brake mean effective pressure is [tex]BMEP = 398154.542Pa[/tex]
The indicated mean effective pressure is [tex]IMEP = 338431.36 Pa[/tex]
Explanation:
From the question we are told that
The number of cylinder is [tex]n = 9[/tex]
The bore diameter is [tex]b = 5.5 \ inches = \frac{5.5 * 2.54}{100} = 0.1397 \ m[/tex]
The stroke is [tex]s = 5.5 \ inches = \frac{5.5 * 2.54}{ 100} = 0.1397\ m[/tex]
The angular speed is [tex]w = 3500 rpm[/tex]
The break horsepower of engine is [tex]E = 600hp = 600 * 746 = 447.600 \ kW[/tex]
Let assume the mechanical effectiveness [tex]\eta mech[/tex] = 85%
The mechanical effectiveness of the engine is mathematically represented
[tex]\eta mech = \frac{[BMEP]}{[IMEP]} *100[/tex]
the brake mean effective pressure (BMEP) is mathematically represented as
[tex]B MEP =[ \frac{60 *10^{3} E }{s * a * n * w} ][/tex]
where a is the area of the engine piston which is mathematically as
[tex]a = \frac{\pi}{4} (b)^2[/tex]
Substituting values
[tex]a = \frac{\pi}{4} * (0.1397^2)[/tex]
[tex]= 0.01532 \ m^2[/tex]
Substituting values into the equation for BMEP
[tex]BMEP = \frac{60 *10^{3} * 447.600}{0.1397 * 0.01532 * 3500 * 9}[/tex]
[tex]BMEP = 398154.542Pa[/tex]
From the equation of [tex]\eta mech[/tex]
We have that
[tex]85 = \frac{[398154. 542]}{[IMEP]} *100[/tex]
[tex]0.85 = \frac{[398154. 542]}{[IMEP]}[/tex]
[tex]IMEP = 398154.52 * 0.85[/tex]
[tex]IMEP = 338431.36 Pa[/tex]
