Engine testing: To compute indicated power (I.P.) from mean effective pressure (m.e.p.), what additional engine data are required? Select the most appropriate set for a single-cylinder calculation.

Introduction:
Indicated power (I.P.) measures the power developed inside the engine cylinder based on pressure–volume work. It is central to performance analysis and efficiency calculations, distinct from brake power and friction power.

Given Data / Assumptions:

• Mean effective pressure p_m is known from an indicator diagram or pressure transducer.
• Single-cylinder engine with known geometry.
• Speed N in revolutions per minute (or power strokes per second) is available.

Concept / Approach:
The standard relation is I.P. = p_m * L * A * n, where L is stroke length, A is piston area, and n is the number of power strokes per second. For a four-stroke single-cylinder engine, n = N / 2 (in rev/s); for a two-stroke, n = N. Thus, in practical terms, you need bore (or piston diameter, to get A), stroke length L, and rotational speed N to convert p_m to power.

Step-by-Step Solution:
1) Compute piston area A = (π/4) * D^2 using piston diameter D.2) Use given stroke length L.3) Determine power strokes per second from speed N and cycle type.4) Evaluate I.P.: I.P. = p_m * L * A * n (units consistent; divide by 60 if N is in rpm).

Verification / Alternative check:
Cross-check with brake power and mechanical efficiency: η_mech = B.P. / I.P.

Why Other Options Are Wrong:
Options with calorific value and specific fuel consumption relate to fuel and brake power/thermal efficiency, not directly to indicated power from m.e.p.

Torque appears in brake power, not indicated power determination from p_m.

Common Pitfalls:
Mismatching units (Pa vs bar), forgetting cycle factor (2-stroke vs 4-stroke), or using rpm directly without converting to strokes per second.

Final Answer:
piston diameter, length of stroke and speed of rotation