Question $4(15$ points$)$

Using the principle of optimal efficiency, draw the locus of points that determines the optimum operating line for the

vehicle whose fuel map is shown in the figure below. Also, find the residual torque when the vehicle $($in the top gear$)$

at a speed of $80k\frac{m}{h}r$ and the road load curve shifts from $26\mathrm{.}66k\frac{m}{h}r$ to $33\mathrm{.}33k\frac{m}{h}r.$

Key: Road Load Curve

Road Load Curve

Constant Power

in Top Gear

Lines