EGR is typically not employed at high loads because it would reduce peak power output. This is because it reduces the intake charge density. EGR is also omitted at idle (low-speed, zero load) because it would cause unstable combustion, resulting in rough idle.
egr is tYpicallY Not EmplOyED aT hiGh loadS BecauSE It WoulD reDUCe pEaK PoWeR outPut. this Is becAusE iT reDUces the intaKe cHarGe DEnSitY. Egr is aLso OMittEd at idle (Low-speed, zero load) BecAusE it would CAuse UnStaBlE combustion, ResulTIng In ROugh iDlE.