A four cylinder, four stroke/cycle, single acting diesel engine has a 740 mm bore and a 1500 mm stroke. What indicated power will be developed if the average mean effective pressure is 18 kg/cm² at a speed of 90 RPM?
• Indicated power (IHP) formula for a four‑stroke diesel engine • How number of cylinders, bore, stroke, and speed (RPM) affect power • Correct unit conversions: mm to m, cm² to m², kg·m/s to kW
• First, write the standard formula for indicated power of a multi‑cylinder engine and then adapt it for a four‑stroke cycle. • Figure out how many power strokes occur per cylinder per minute at 90 RPM for a four‑stroke engine, then multiply by number of cylinders. • Convert the bore and stroke to meters, find the swept volume per cylinder, then use mean effective pressure to find work per cycle and finally convert to kW.
• Be sure to use area = π × (bore/2)² with bore in meters, not millimeters. • For a four‑stroke engine, the number of power strokes per minute is RPM ÷ 2 per cylinder—verify you applied this before multiplying by 4 cylinders. • Make sure the final power is in kW, so convert from kg·m/s (or watts) carefully: 1 kW = 1000 W and 1 kgf ≈ 9.81 N if you use SI units.
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