Engine power definitions — power developed inside the cylinder What is the term for the power calculated from the pressure–volume work inside an engine cylinder before mechanical losses?

Introduction / Context:
Engine performance analysis distinguishes between gross work in the cylinder and net output at the crankshaft. Understanding these terms is vital for interpreting test results and diagnosing losses.

Given Data / Assumptions:

• Pressure in cylinder measured (conceptually) via indicator diagrams or transducers.
• Mechanical losses (friction, pumping, accessory drives) exist between cylinder and output shaft.

Concept / Approach:
Indicated power (IP) is derived from the integrated P–V work of the working cycle multiplied by engine speed and number of cylinders. Brake power (BP) is the usable output measured at the crankshaft or dynamometer. Friction power (FP) is the difference: FP = IP − BP.

Step-by-Step Solution:
Define IP as the gross power developed by gases on the piston.Recognise BP as measured output after mechanical losses.Therefore, the power developed inside the cylinder is indicated power.

Verification / Alternative check:
From the relation, FP = IP − BP and Mechanical efficiency = BP / IP, it follows that IP represents in-cylinder work rate.

Why Other Options Are Wrong:

• Brake power: output after losses, not in-cylinder development.
• Frictional power: a loss term, not a developed power.

Common Pitfalls:
Assuming dynamometer power equals combustion work; it is lower due to friction, oil pump, water pump, valve train, and sealing losses.

Final Answer:
indicated power