Question

A single cylinder spark ignition 4-stroke engine has a 100 mm bore and 100 mm stroke that run with 20 Nm, at 3000 rpm. The brake mean effective pressure (BMEP) is_________ bar.

• A. 3.2

Answer 1

The correct option is A 3.2

$BP=\frac{2\pi NT}{60\times 100}=2\times 3.14\times 3000\times \frac{20}{(60\times 1000)}=6.28kW$

$BMEP=\frac{BP\times 2\times 60}{Vs\times N\times K\times 100}\left(bar\right)$

$\text{Swept volume,}Vs=\frac{\pi \times {0.1}^2\times 0.1}{4}=0.000785m^3$

$EMEP=6.28\times 2\times \frac{60}{(0.000785\times 3000\times 1\times 100)}=3.2bar$