Current TRL: 4 (11/1/21)

“In it’s current form the decision has been taken to pass the brake subsystem off to the club. There is a detailed testing plan in place that will begin when the car is able to be a rolling chassis. The senior team will continue to assist the club with all questions and problems as they relate to the braking system.”

Braking System

Front Left Upright with Wheel Bearing, Hub, Rotor, and Caliper

The braking system currently mounted on the car includes slotted/4 pin mounting style rotors and AP Racing calipers. The rotors mount to our uprights using 4 motorcycle-styled floating disk mounts, while the calipers include a dual bolt mount design that fastens directly to the outer upright. The brake line is then run between the calipers and the master cylinder located behind the brake pedal. Pictured above is a fully constrained upright with braking components.

 

The main design goal for the braking team is to create a system powerful enough to lock all four wheels while under full power. This design was generated using Matlab code that can be located under the braking subsystem in Google Drive. Given our part sizing, and force applied to the brake pedal, our system can handle 200N of force applied, and in turn, will stop the rotation of each wheel given our estimated vehicle weight.

Main Documents

Literature Review

The braking system of a car is perhaps the most important safety feature of any automobile on the road and especially the race track. This system, given its importance for safety, is also a complex system tying in both fluid behavior and mechanical behavior. For that reason, before work could begin on the braking system it was first important to properly educate the brake team on the fundamentals of brake design and usage.

This literature review will point to multiple sources of information regarding the testing, design, and implementation of a braking system. The most important understanding from this literature review is the transfer of energy from the brake pedal through to the brake disc. It is this act that allows the braking system to work. Through modeling and testing, Lafayette hopes to fine-tune an already proven braking system to be optimized for this chassis. 

Full Literature Review

Components:

Brake Caliper

Brake Technical Drawings
Technical Drawings for Brake Caliper

  • The brake caliper is perhaps the most important part of the braking system. When the driver applies braking force to the pedal, that force is transmitted through the brake lines to the caliper. This pressure will cause the caliper to be too close around the brake disc. It is the force and the subsequent frictional force that comes in that allows the car to slow down

Brake Disc 

  • Brake Disc Drawings from 2018

    • It is noted that in 2018 brake discs were designed specifically for this car. The documentation to show this is minimal other than files pertaining to the drawing and creation of these files in the 2018 Google Drive folder.
  • The brake disk is a relatively simple but very important piece of the car. The disc has a force applied to it by the caliper. Again, it is this force that slows a car down. Brake discs have many different material types depending on their requirements for life expectancy and performance. In our case, life expectancy is not important at all, while the ability of the brake disc to produce the maximum amount of frictional force possible is very important. These design constraints will be considered when reviewing the design of the brake disc from 2018.

Brake Pedal

The custom-designed pedal tray is specific to this chassis. The brake pedal is managed by the braking subsystem and is comprised of three major parts.

  1. The actual pedal
    1. This system is a simple piece of metal designed in such a way to assist the driver in increasing brake forces by the way of geometrically increasing the torque the driver is able to apply to the system.
  2. The Rod  Piston assembly
    1. This system is what allows force on the pedal to be transferred to the master cylinders. When brake pressure is applied to the pedal, the rod is pressed into the piston dramatically increasing the pressure within both the piston and the attached master cylinders.
  3. The master cylinders
    1. This system is what allows the increased piston pressure to be transferred to the brake lines. This system acts as a reservoir in the hydro-mechanical system and allows for the changing pressure in the piston to be applied within the brake lines. This increase in pressure within the lines is what allows for the calipers to move and subsequently apply force onto the brake disc.

Subsystem TRL Chart (Link to Tests)

TRL What does this look like? Expected Completion Date
9 Brakes have been used in competition with success in lock up exercise being a priority for this subsystem May 2-5, 2022
8 Brakes have passed “Final Testing” Feb 2022 (Snow dependent)
7 Brakes have passed “High-Speed Straight Line Test” Feb 2022 (Snow dependent)
6 Brakes have passed “Low-Speed Test” Feb 2022 (Snow dependent)
5 Brakes have passed “Push Test” 09/29/21
4 Brakes have passed “Static Test” 09/15/21
3 Model is developed enough to prove theory and specific brake parts have been chosen CURRENT
2 A model is being developed to help choose parts COMPLETE
1 Brake are in selection process COMPLETE

 

Additional  Documentation