IP = (PLAN) / 60
Where:
* IP is the indicated power (in kW or hp)
* P is the mean effective pressure (in kPa or psi)
* L is the stroke length (in meters or inches)
* A is the area of the piston (in square meters or square inches)
* N is the engine speed (in revolutions per minute - RPM)
Explanation:
* Mean Effective Pressure (MEP): This is the average pressure acting on the piston during the power stroke. It is a measure of the engine's efficiency.
* Stroke Length: This is the distance the piston travels from top dead center (TDC) to bottom dead center (BDC).
* Piston Area: This is the area of the piston face.
* Engine Speed: This is the number of revolutions the crankshaft makes per minute.
Derivation:
The formula is derived from the basic work-energy principle. The work done by the engine is equal to the force acting on the piston multiplied by the distance it travels. The force is equal to the pressure acting on the piston times its area. The distance is equal to the stroke length.
Note:
* This formula calculates the indicated power, which is the power produced inside the engine cylinders.
* The actual power delivered to the crankshaft (brake power) is less than the indicated power due to friction losses in the engine.
* The mean effective pressure (MEP) is a variable that depends on factors such as the engine design, operating conditions, and fuel-air mixture.
Example:
Consider a four-stroke petrol engine with the following parameters:
* MEP = 800 kPa
* Stroke Length = 0.1 m
* Piston Area = 0.02 m²
* Engine Speed = 3000 RPM
The indicated power can be calculated as:
IP = (800 kPa * 0.1 m * 0.02 m² * 3000 RPM) / 60
IP = 80 kW
