DIRECTIONS:Calculatethe master cylinder requirements of the car defined below. Do all of your workNEATLYon a separate sheet of paper. Show all work, calculations, formulas, units.Put your final answers in the blanks for each questionand staple your worksheet to these pages.
CHASSIS–2011 Toyota Prius Hatchback
Wheel Base 106.3”Curb Weight 3042lbs.
Vertical CG 21” above the groundWeight Distribution (static)60/40front/rearLoadon front (braking)80%
TIRES
Front & RearP195/16R15, 12.2” loaded radiusTire Coefficient of Friction Dry Road = 1.2Wet Road = 0.4(at normal operating temp.)
BRAKES
Driver Leg Force (desired) 100lbs. maximumPedal Assembly M.A. 3.5:1Single Master Cylinder 22.22 mmdiameterFront Brake Rotor 255 mmdiameter (104 mm effective radius)Front Rotor Weight 19.1lbs. eachRear Brake Drum200 mm insidediameterRear DrumWeight 16.0lbs. eachFront Calipers 1Piston, 54 mmDiameterRear Wheel Cylinder20.64 mmDiameterPad Coefficient of Friction 0.44(at normal brake operating temperature)Power Brake Booster Ratio2.3:1
CALCULATE THE FOLLOWING: All conditions are under maximum braking conditions on dry pavementunless defined differently. Be sure to use and show the correct units.
1) Temperature rise of brakes during a complete stop from 90MPH___________________3pts.
2) Loadon the front tiresduringmaximumbraking________________3pts.
3) Front Brake Torqueper wheel________________3pts.
4) It is raining. What is the loadon the front wheels under maximum braking effort?3pts.________________
5) Draw a sketch of the brake pedal assembly described above. The assembly is a hanging1stclass lever. In your drawing show the pivot points, MC location and distances to give you the proper mechanical advantage.Keep your dimensions reasonable for a car driven by adult humans.3pts.
6) Assume this vehicle is being driven in a bizarre hybrid race, with top speeds of 100mph on the straightaways and frequentbraking to 30 or 45 mph.in the turns.Is this an adequate brake design to handle 250 miles? What special considerations for the braking system (if any) would you recommend be consideredprior to using this vehicle in this application? 4 pts.
7) For the brake pedal setup shown, assume the frontbrakemaster cylinderhas a diameter of 20mm. The fixed calipers are doublepiston, 51 mmdiameter. You want a total front brake clamping force of 4200 lb. With the master cylinder pushrodforce shown, is it possible to adjust the center pivot location to provide that force? If so, what would the distance be from the center pivot to the front m/c rod?Don’t worry about the dimensions of mechanical components on the adjuster bar. Show your work neatlyand completely.6pts.3651.25”1821821.25”
The owner of the Dodge Ram pickup shown wants to get into high-speed off-road racing, and wants to switch from cast iron to carbon-ceramic rotors. He desires the ability to absorb50% more kinetic energy with the new brakesfor the same temperature rise. How much will each new front rotor weigh to accomplish this? 5 ptsCHASSIS–2009 Dodge Ram 2500 SXT 4x4 Quad CabWheel Base 160.5”Weight 8800lbs. (at standard GVWR)Vertical CG 35.3” above the groundWeight Distribution (static)60/40 front/rearWeight on front (braking)80%TIRESB.F. Goodrich Comp T/A –R1Front 245 –70 R17 LT, 15.3” loaded radiusRear 245 –70 R17 LT, 15.3” loaded radiusTire Coefficient of FrictionDry Road = 1.2Wet Road = 0.4(at normal operating temp.) BRAKESDriver Leg Force (desired) 100lbs. maximumPedal Assembly M.A. 4.3:1 Single Master Cylinder 1.063” diameterFront Brake Rotor 13.9” diameter (5.75”effective radius)Front Rotor Weight 32.95lbs. eachRear Brake Rotor13.9” diameterRear RotorWeight 31.75lbs. eachFront Calipers 2Pistons, 1.25” DiameterRear Calipers2 Pistons, 1.125” DiameterPad Coefficient of Friction 0.42(at normal brake operating temperature)Power Brake Booster Ratio2:1
i found number 1 to be 150 degrees of temp rise i also found number 5 just am unsure how to solve others help appreciated
