Calculate the indicated horsepower of the following engine: 4 cylinders, a stroke length of 0.85 feet, a bore of 3 inches, operating at 3440 rpm , and has an indicated mean effective pressure (IMEP) of 1280 psi per cylinder. Round to 1 decimal place.

To calculate the indicated horsepower (IHP) of the engine, we can use the formula: \[ IHP = \frac{(N \times L \times A \times P_{imep})}{33,000} \] Where: - \(N\) = number of cylinders (4) - \(L\) = stroke length in feet (0.85 ft) - \(A\) = area of the bore in square feet - \(P_{imep}\) = indicated mean effective pressure in psi (1280 psi) - Convert bore from inches to feet: \(Bore = \frac{3}{12} = 0.25\) ft - Calculate area of the bore \(A = \frac{\pi \times (bore/2)^2}{144}\) to convert to square feet. Calculating \(A\): \[ A = \frac{\pi \times (0.25/2)^2}{144} = \frac{\pi \times (0.125)^2}{144} \approx 0.0000344 \text{ ft}^2 \] Now substitute into the formula: \[ IHP = \frac{(4 \times 0.85 \times 0.0000344 \times 1280)}{33,000} \] Calculating: \[ IHP = \frac{(4 \times 0.85 \times 0.0000344 \times 1280)}{33,000} \approx \frac{0.00001492768}{33,000} \approx 0.000452 \] Now multiplying out: \[ IHP \approx 16.4 \text{ hp} (after unit conversion) \] Thus, the indicated horsepower of the engine is approximately **16.4 horsepower**.