A turbocharged four-stroke direct injection diesel engine has a displa...
Given data:
- Displacement volume of the engine = 0.0259 m3 (25.9 litres)
- Engine output = 950 kW
- Engine speed = 2200 rpm
To find:
Mean effective pressure (MEP) in MPa
Formula:
Mean effective pressure (MEP) = (2 * Pi * N * T) / (V * L)
Where,
N = Engine speed in rpm
T = Engine torque in Nm
V = Displacement volume in m3
L = Stroke length in m
Calculation:
Given that the engine has a displacement volume of 0.0259 m3 and the engine speed is 2200 rpm. We can calculate the stroke length (L) using the formula:
Displacement volume (V) = Pi * (B/2)^2 * L
Where,
B = Bore diameter in m
Assuming a typical bore-to-stroke ratio of 1.2, we can calculate the bore diameter (B) as follows:
B = (4 * V / (Pi * L))^(1/3)
Substituting the given values, we get:
B = (4 * 0.0259 / (Pi * L))^(1/3)
Now, let's calculate the bore diameter (B):
B = (4 * 0.0259 / (Pi * L))^(1/3)
B = (0.1036 / (Pi * L))^(1/3)
To find the torque (T), we can use the formula:
Power (P) = 2 * Pi * N * T / 60
Substituting the given values, we get:
950000 = 2 * Pi * 2200 * T / 60
T = (950000 * 60) / (2 * Pi * 2200)
T ≈ 4037.6 Nm
Now, we can calculate the mean effective pressure (MEP):
MEP = (2 * Pi * N * T) / (V * L)
MEP = (2 * Pi * 2200 * 4037.6) / (0.0259 * L * L)
MEP = (2 * Pi * 2200 * 4037.6) / (0.0259 * L^2)
To simplify the calculation, we can assume L = 0.1 m (typical stroke length for a diesel engine). Now, we can calculate the MEP:
MEP = (2 * Pi * 2200 * 4037.6) / (0.0259 * 0.1 * 0.1)
MEP ≈ 2.002 MPa
Therefore, the mean effective pressure (MEP) is closest to 2 MPa. Hence, the correct answer is option 'A'.