Question

o reduce the drag coefficient and thus to improve the fuel efficiency, the frontal area of a car is to be reduced. Determine the amount of fuel and money saved per year as a result of reducing the frontal area from 18 to 14 ft2. Assume the car is driven 12,000 mi a year at an average speed of 55 mi/h. Take the density and price of gasoline to be 50 lbm/ft3 and $3.10/gal, respectively; the density of air to be 0.075 lbm/ft3, the heating value of gasoline to be 20,000 Btu/lbm; and the overall efficiency of the engine to be 30 percent. Take the drag coefficient as CD in progress 0 3 weeks 2021-08-30T02:06:07+00:00 1 Answers 0 views 0 ## Answers ( ) 1. Complete question To reduce the drag coefficient and thus to improve the fuel efficiency, the frontal area of a car is to be reduced. Determine the amount of fuel and money saved per year as a result of reducing the frontal area from 18 to 14 ft2. Assume the car is driven 12,000 mi a year at an average speed of 55 mi/h. Take the density and price of gasoline to be 50 lbm/ft3 and$3.10/gal, respectively; the density of air to be 0.075 lbm/ft3, the heating value of gasoline to be 20,000 Btu/lbm; and the overall efficiency of the engine to be 30 percent. Take the drag coefficient as CD=0.3 for a passenger car.

$57 Explanation: From the question we are told that Initial area of frontal area Final area of frontal area Distance covered a year Average speed a year Density Price Density of air Heating value of gasoline Efficiency Drag coefficient  Generally the equation for drag force is mathematically given as   where Generally the equation for work done W is mathematically given as where    Generally the equation for overall efficiency is mathematically given as where     Generally the equation for reduction fee with change in frontal area is mathematically given as Where   if   Therefore if   Generally the equation for reduction of fuel is mathematically given as where  Fuel reduction price by reducing front area is 22.22% Money saved per year is$57