Question

A turbo-charged four-stroke direct injection diesel engine has a displacement volume of 0.0259 m³ (25.9 litres). The engine has an output of 950 kW at 2200 rpm. The mean effective pressure in MPa is closest to
1. 2
2. 1
3. 0.2
4. 0.1

Answer 1

Correct Answer - Option 1 : 2

Concept: 

Indicated Power for four-stroke engine is given by,

\(I.P.~=~\frac{P_mLAN}{60,000× 2}\)

where Pm = mean effective pressure in N/m2, L = stroke length in m, A = Area of cross-section of the cylinder in m2, N = rpm of the engine crankshaft

\(η_m~=~\frac{B.P.}{I.P.}\)

where ηm = mechanical efficiency, B.P. = brake power, I.P. = Indicated power

Calculation:

Given:

Volume = Area × Length = AL = 0.0259 m3  (25.9 litres)

IP = 950 kW, N = 2200 rpm, Four stroke

\(IP=\frac{P_mLAn}{60}=\frac{P_mLAN}{2×60}\)

\(950=\frac{P_m×0.0259×2200}{2×60}=2000\;kPa=2\;MPa\)