BMEP Calculator (Brake Mean Effective Pressure Calculator)

The BMEP calculator helps in finding the BMEP (Brake Mean Effective Pressure) of an engine, which is a useful metric to compare the performance of different engines of similar types. Here, we will see what BMEP is, how to calculate the BMEP of an engine and also learn more about the BMEP formula that's used to calculate this value.

Knowing what BMEP is, is pretty important, since the Brake Mean Effective Pressure value gives you a sense of how efficient your engine is.

BMEP stands for Brake Mean Effective Pressure. Our BMEP calculator measures the average pressure applied across the pistons to produce torque at the crankshaft. We can use this performance metric to compare different engines.

It's also interesting to note that the engine efficiency also depends on the amount of air-fuel that is handled by the carburetor, and the carburetor CFM metric provides a measure of that volume.

The formula used to calculate BMEP is as follows:

where,

• n - Number of revolutions per power stroke;
• T - Torque; and
• D - Displacement (volume) of the engine.

It is to be noted that the value of n is standard -

• n = 1 for a two-stroke engine; and
• n = 2 for a four-stroke engine.

If you're curious, you may even try converting torque to horsepower, or use a power converter to convert the horsepower value into various other units.

Let's say we have a 4-stroke engine with a volume (displacement) of 2000 cc and an indicated torque of 160 Nm. This is how we calculate the BMEP of the engine -

1. In the BMEP calculator, set the type of the engine to 4-stroke. Once this is selected, n is automatically set to 2. For other custom-made or experimental engines with more revolutions per power stroke, choose the Other stroke engine value option to enter a custom n.
2. Set the torque value as $160 \ \mathrm{Nm}$.
3. Set the displacement value as $2000 \ \mathrm{cc}$.
4. Voila! The BMEP calculator gives a result of $1,005.3 \ \mathrm{kPa}$.

Conversely, if we know the BMEP value, we can convert BMEP to torque by using the same formula and rearranging it to solve for torque. Converting BMEP to torque is especially useful since torque is an important metric that represents the load that the engine can handle.

Additionally, if you're curious about how horsepower can help in comparing engine efficiencies, you may try calculating the horsepower of different engines! You may also be interested in knowing about the various factors that affect the piston speed and the piston force using our piston speed calculator and piston force calculator.