🔍 Key Concepts

• Mechanical efficiency definition and formula in diesel engines • Relationship between indicated power (in the cylinders) and brake power (at the crankshaft) • How to handle per‑cylinder power when the engine has multiple cylinders

💭 Think About

• First, decide which is larger in a real engine: indicated power or brake power, and why. • Figure out how to get the total indicated power for a 7‑cylinder engine when you are given the indicated power per cylinder. • Once you have total indicated power and brake power, think about how to form a ratio that represents the fraction of power delivered at the crankshaft compared to what’s developed in the cylinders.

✅ Before You Answer

• Confirm you are using the formula for mechanical efficiency (not thermal or overall efficiency). • Double‑check you converted the per‑cylinder indicated power to total indicated power before forming the ratio. • After you compute the efficiency, verify that the result is a realistic fraction for a large marine diesel engine (think about whether values like 0.18 or 0.83 make sense mechanically).