What is Engine Effective Power?

[SanLeah]

Engine effective power is the actual power output available at the engine crankshaft per unit time, denoted by the symbol Ne. It is typically measured using a dynamometer and expressed in kilowatts. Commonly referred to as "shaft power," it represents the net power output from the engine shaft after deducting mechanical friction losses within the engine itself and external losses from driving auxiliary components. The effective power of any engine must be less than its indicated power, and the ratio of the former to the latter constitutes the engine's mechanical efficiency. When an engine directly drives equipment such as a generator or compressor, its effective power equals the input power to the generator or the shaft power of the compressor. Since most reciprocating engines' effective power can be measured using brake-type dynamometers, it is often called "brake power." This power is calculated by subtracting the friction losses of engine moving parts, pumping losses during intake/exhaust cycles, and power consumption by essential accessories like oil pumps and fuel pumps from the engine's indicated power.