BMEP at maximum power is the effective way to measure the engine performance of any given type with the other of the same type. It produces the break power output when average pressure is imposed on a pistol from top to bottom in each stoke. This online calculator is used to find the Brake Mean Effective Pressure (BMEP) at max power by selecting the engine and providing the values for Torque, Number of Cylinders, Bore and Stroke.
A 3 cylindric two stroke engine has a maximum power of 30 kW, with 3 bore and stroke as 5. What is its brake mean effective pressure?
Displacement = ( n x 3.14 ) / ( 4 x Bore2 x Stroke )
= (3 x 3.14) / (4 x 3^2 x 5)
Nmax = 15/(2*5)
BMEP = ((30 x 1 x 10^3 ) / 0.0523) x 1.5
= ((30 * 1000)/0.0523) * 1.5
= (573613.7667304015296367) * 1.5
Therefore, BMEP of the two stroke engine is 859872.6115 Pa
Brake Mean Effective Pressure is a function of temperature of gases in the cylinder. To produce more heat, temperature has to be increased by burning more fuel. From the above calculator, BMEP at maximum power will be lower than torque because when providing the values for torque, revolution per minute (rpm) are at maximum for the engine and the loss of friction will also be maximum