Subtopic: Calculation of power, torque, fuel consumption, heat load and power losses
Question Statement:
A four-cylinder, four-stroke diesel engine with bore of $100\text{ mm}$ and stroke of $100\text{ mm}$ runs at $2000\text{ rpm}$. The engine develops an indicated mean effective pressure of $650\text{ kPa}$. The indicated power developed by the engine in $\text{kW}$ is ________ (round off to 2 decimal places).
Answer Key:
34.03
Step-by-Step Solution & Explanation
Indicated Power formula for a multi-cylinder four-stroke engine:
$IP = \frac{p_{imep} \cdot L \cdot A \cdot n \cdot k}{60 \times 1000}$
Where:
• $p_{imep} = 650\text{ kPa} = 650 \times 10^3\text{ N/m}^2$
• Stroke $L = 100\text{ mm} = 0.10\text{ m}$
• Bore $D = 100\text{ mm} = 0.10\text{ m} \implies A = \frac{\pi}{4}(0.10)^2 = 0.007854\text{ m}^2$
• For 4-stroke engine, power strokes per minute $n = \frac{N}{2} = \frac{2000}{2} = 1000\text{ rpm}$
• Number of cylinders $k = 4$
$IP = \frac{(650 \times 10^3) \times 0.10 \times 0.007854 \times 1000 \times 4}{60 \times 1000} = \frac{2042.04}{60} = 34.03\text{ kW}$