Question

Problem 1 (50): A 3100 lb car has a 5-speed manual transmission with in = 3.22, 1,2 = 2.15, 1,4 = 1.05, 1,5 = 0.68. The final drive ratio 3.08. The air drag coefficient is 0.29 and the front projected area is 22 square feet. The rolling resistance coefficient is 0.02 and the tire radius is 11 inches. The mass factor is 1.0. The drive train efficiency is 0.93. The engine wide-open-throttle output is shown in the figure. a) Determine the engine output power in horse power when the vehicle is cruising at a constant speed of 65mph on a 2% slope in the 5th gear. (Note: One Horse Power=550 ft. Ibs/s) b) When the vehick speed is 40 mph, the driver makes a 3-4 upshift and the engine speed drops 695 RPM right after the shift. Determine the third gear ratio. c) Determine the steepest slope in percentage on which the vehicle can be driven at a constant speed of 65 mph in the 5th gear? d) The driver makes a 5-4 downshift when the vehicle is driven on a 2% slope at a speed of 65 mph, determine the maximum acceleration the vehicle can achieve right after the shift. 150 130 125 Torque 20 100 Torget 1 1101 Power Power 100 1000 2000 5000 6000 7000 3000 4000 Speed (RPM)

Answer 1

here, first I have listed all the given data and then have solved all the sub-questions step by step.

Note that little reasonable approximations are made during the calculations and I have mentioned them.

one should take good care to convert and maintain same units of all the parameters.

​​​​​​
engine speed, C = Ven. (d) 6-2.1 Uveh - 65 mph = 95.333 ft /s2 Gear is shifted to 4th, = Wentiratif 60 RPM. WA - 93.333 * 1.05*3.08 (5) Wy = 321.76 RPM 2T from given graph, at Wa = 3211076 Rpm We get T2 1 24 lb ft. SO Event TN- ůra + if = 124 +0.93 +3.08 12 354.09 lb Fren

Now, for accelerating scenerio, Even - Faero & troll + Faradt m. a ♡ Here, = 19). 588 6 (Faerot + Frollt grad) at 65 mph and 2% G From part (a) So Substitute in egn (V), 35.4.09 = 191.588+ 3100 ca 32017 - (a = 1.6864 fel seca
Hope you find this helpful.

Please upvote.