As the Program Manager for Saturn, you are asked to prepare a low-cost version of the...

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As the Program Manager for Saturn, you are asked to prepare a low-cost version of the Saturn SL2 to be sold in mountainous third-world countries. To save money one of your cost reduction strategies is to replace the standard 5-speed manual transmission with a 4-speed manual transmission. Top gear is direct drive. Below is data for a 1994 Saturn SL2 equipped with a 1.9L DOHC engine. Engine WOT Data: N (rpm) 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 1052 1058 1094 1089 1063 1001 bmep 743 887 970 1047 1094 1073 (kPa) Chassis Data: Coefficient of Drag: 0.345 Vehicle Height: 67.6 in (1.717 m) Vehicle Width: 52.5 in (1.333 m) Atm Cond: Pair=1-atm Tair=294K Curb Weight: 2405 lbf (1091 kgf). Assume that this is the actual weight! Neglect any driver weight for this calculation. Corporate Specifications Include: Minimum Top speed of 140 kph. Remember, you still want to maximize low speed performance, because of the mountainous conditions. A minimum speed of 20 kph must be maintained on a 25% grade. Available Rear Axle Choices: 4.12, 3.73, 3.55, or 2.95 Available tire sizes: 29 cm, 30 cm, 31 cm rolling radius (Assume all have a coefficient of rolling resistance: 0.012) 1. Determine the transmission ratios, rear axle ratio and tire size for maximum hill climb capability with a 4-speed transmission (fourth gear is direct drive- no overdrive in order to keep the costs down). Please add some text explaining the rationale behind your choices!!!!!! Do NOT just say I chose the largest final drive because it needs to go off-road. Remember, it is the N/V ratio which dictates your ability to go off-road, the final drive is simply one component which makes up the N/V ratio. That is, the hardware is chosen to achieve the desired N/V ratio- not the other way around! Axle Ratio Tire Rolling Radius 1st Gear Ratio 2nd Gear Ratio 3rd Gear Ratio 4th Gear Ratio 2. After the gear selection is complete make a plot of Road Load Power (level road and at grade) and Available Tractive (Powertrain) Power (at WOT) as a function of vehicle speed. The plot should have the Tractive Power available in each of the gears from engine speeds ranging from 500-6000 rpm. 3. What is the actual top speed of your vehicle assuming no losses in the drivetrain? 4. What gear(s) can be used to maintain the speed on the grade? Is there any reserve power available? 5. ***Explain the rationale for each of your selections. Use the engineering knowledge from this class in addition to "conventional wisdom." 6. *** Also, remember, as you make changes, you must go back and look at their effect on earlier choices. For example, if you calculated a desired axle ratio of 3.25, but had to select 3.3 (closest choice available), you must look at the effect of this new choice on the desired N/V ratio or the selection of other components! As the Program Manager for Saturn, you are asked to prepare a low-cost version of the Saturn SL2 to be sold in mountainous third-world countries. To save money one of your cost reduction strategies is to replace the standard 5-speed manual transmission with a 4-speed manual transmission. Top gear is direct drive. Below is data for a 1994 Saturn SL2 equipped with a 1.9L DOHC engine. Engine WOT Data: N (rpm) 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 1052 1058 1094 1089 1063 1001 bmep 743 887 970 1047 1094 1073 (kPa) Chassis Data: Coefficient of Drag: 0.345 Vehicle Height: 67.6 in (1.717 m) Vehicle Width: 52.5 in (1.333 m) Atm Cond: Pair=1-atm Tair=294K Curb Weight: 2405 lbf (1091 kgf). Assume that this is the actual weight! Neglect any driver weight for this calculation. Corporate Specifications Include: Minimum Top speed of 140 kph. Remember, you still want to maximize low speed performance, because of the mountainous conditions. A minimum speed of 20 kph must be maintained on a 25% grade. Available Rear Axle Choices: 4.12, 3.73, 3.55, or 2.95 Available tire sizes: 29 cm, 30 cm, 31 cm rolling radius (Assume all have a coefficient of rolling resistance: 0.012) 1. Determine the transmission ratios, rear axle ratio and tire size for maximum hill climb capability with a 4-speed transmission (fourth gear is direct drive- no overdrive in order to keep the costs down). Please add some text explaining the rationale behind your choices!!!!!! Do NOT just say I chose the largest final drive because it needs to go off-road. Remember, it is the N/V ratio which dictates your ability to go off-road, the final drive is simply one component which makes up the N/V ratio. That is, the hardware is chosen to achieve the desired N/V ratio- not the other way around! Axle Ratio Tire Rolling Radius 1st Gear Ratio 2nd Gear Ratio 3rd Gear Ratio 4th Gear Ratio 2. After the gear selection is complete make a plot of Road Load Power (level road and at grade) and Available Tractive (Powertrain) Power (at WOT) as a function of vehicle speed. The plot should have the Tractive Power available in each of the gears from engine speeds ranging from 500-6000 rpm. 3. What is the actual top speed of your vehicle assuming no losses in the drivetrain? 4. What gear(s) can be used to maintain the speed on the grade? Is there any reserve power available? 5. ***Explain the rationale for each of your selections. Use the engineering knowledge from this class in addition to "conventional wisdom." 6. *** Also, remember, as you make changes, you must go back and look at their effect on earlier choices. For example, if you calculated a desired axle ratio of 3.25, but had to select 3.3 (closest choice available), you must look at the effect of this new choice on the desired N/V ratio or the selection of other components!