What is the indicated power for four stroke petrol engines?

The indicated power of an engine is the power that is developed within the cylinders. It is calculated by multiplying the mean effective pressure (MEP) by the engine displacement and the number of revolutions per minute (RPM). The MEP is a measure of the average pressure exerted on the piston during the power stroke. It is calculated by dividing the work done by the piston during one power stroke by the displacement of the piston. The indicated power is a useful measure of the engine's efficiency because it takes into account the actual work that is being done by the engine.

For four-stroke petrol engines, the indicated power can be calculated using the following formula:

$$IP = \frac{MEP \times D \times N}{60}$$

Where:

* IP = Indicated power in kilowatts (kW)

* MEP = Mean effective pressure in megapascals (MPa)

* D = Displacement of the engine in cubic centimeters (cm³)

* N = Engine speed in revolutions per minute (RPM)

The MEP for a four-stroke petrol engine can be estimated using the following formula:

$$MEP = \frac{(P_1 - P_2)\times(1+1/n)}{n}$$

Where:

* P₁ = Maximum cylinder pressure in megapascals (MPa)

* P₂ = Backpressure in megapascals (MPa)

* n = Compression ratio

The indicated power is an important parameter for designing and optimizing engines. It can be used to compare different engine designs and to determine the best operating conditions for the engine.