What is the term for the horsepower developed in the cylinders of a reciprocating engine?

The term for the horsepower developed in the cylinders of a reciprocating engine is indicated horsepower. This measurement is derived from the pressure in the cylinders during the power stroke of the engine and reflects the total power produced by the engine's combustion process without any losses due to friction or other inefficiencies.

Indicated horsepower is calculated based on the area of the cylinders, the stroke length, and the number of power strokes per minute, combined with the average pressure in the cylinders. It is an important metric as it provides insight into the engine’s potential power output.

In summary, indicated horsepower specifically measures what is produced within the engine cylinders and is a critical parameter for evaluating engine performance under ideal conditions, setting it apart from other terms like brake horsepower, which takes losses into account.