This figure shows the effect of variation of engine load on brake thermal efficiency .It is evident from the figure that brake thermal efficiency increases with the increase in load . As the load increases, engine produces higher brake power.As brake power increases , brake thermal efficiency also increases .At the same time ,if EGR is applied ,brake thermal efficiency decreases for the same load .When EGR is applied,engine requires a higher F/A ratio than that without EGR for combustion .So as EGR is applied,brake thermal efficiency decreases for the same load.