Powertrain Projects

My contribution: system integration, weight reduction, component design, manufacturing, and assembly.

I enabled the integration of the Suspension and Drivetrain systems by designing and manufacturing a new toe-link mounting bracket; I diagnosed and resolved a system integration mishap by modifying the design of a part interfacing both systems; and I designed an improved mounting solution for the brake light and modified HV Enclosure mounting tabs to enable serviceability and finalize system integration process with the chassis.

Skills developed:

  • Cross-system integration

  • Component design

  • Metal machining

  • System troubleshooting

Software utilized:

  • SolidWorks (CAD, FEA)

  • OptimumKinematics

  • Fusion 360 (CAM)

Tools put to use:

  • CNC mills (Haas Mini-Mill)

  • Waterjet (Ward A-0612)

  • 3D-printers

  • Hand tools

To accommodate a change in suspension geometry and decrease component mass, I was looking to change the design of the toe-link bracket. The previous design was unnecessarily heavy and over-engineered; I wanted to simplify the design to both cut down on the weight and reduce the manufacturing effort and time.

Conveniently, the Drivetrain System was also looking to cut down on weight by reducing the thickness of the drivetrain mounting plate. This gave me an opportunity to adjust the mounting for the toe-link bracket as well; I was able to shift it more towards the center of the vehicle, which allowed the drivetrain system to cut down on extra material to the left of the red line, saving about one pound total (a symmetric cut was made on the right side as well).

Toe Link Brackets

Given that the toe-link bracket is unlikely to experience significant loading conditions (as determined using OptimumKinematics), the factor of safety at the maximum expected loading was determined to be 6.7 using SolidWorks FEA tool. While it is a high FOS, I decided to avoid further cutting the material off of the bracket since the weight target had already been reached and because of the uncertainty in precision of the estimation of the maximum loading conditions the part would experience on a racetrack.

Initially, I designed the toe-link bracket to be manufactured primarily using the waterjet, with the holes being the only features that had to be milled out. However, at the time of manufacturing, the waterjet was under maintenance; I therefore made a CAM in Fusion 360 to be able to manufacture the bracket on a CNC mill instead. I then manufactured the bracket on a Haas Mini Mill.

The change in design decreased the weight of the bracket by a significant amount. On this picture, the left bracket is the old bracket used on the previous car; it weighs 0.9 pounds. The right bracket is the new toe-link bracket, weighing 0.1 pounds. With the change in weight between the two designs being 0.8 pounds, I was able to reduce the overall weight by 1.6 pounds since there are two toe-link brackets on the car.

And here it is, the toe-link bracket on the fully assembled vehicle.

This year, the rear suspension increased in trackwidth while the drivetrain design remained roughly the same in lateral dimensions. Because of it, the half shafts that were used on the drivetrain last year were on the edge of the tripod adapter at their maximum travel; thus, were the half-shaft to slide to that position, only half of the tripod bearing would remain engaged on one side of a half-shaft.

Half-Shafts

To resolve this, I modified the cap in the half-shaft that was interfacing with the cap on the hub, thereby limiting the half-shaft travel. I then 3D-printed the caps and assembled the half-shafts with the new caps. That effectively limited the distance the half-shaft was able to slide laterally and thus resolved the issue.

Brake Light Mount

As a side project, I designed a mount for the brake light that interfaces with both the drivetrain plate and the tabs that the dampers are mounted onto; this allowed for use of the shortest possible screws while still leaving sufficient space to route the wiring to the brake light and connect it to the rest of the low voltage system. The previous mounting for the brake light was not rigid enough, and this solution with four contact points provided a much more rigid mounting.

While I was completing the Structural Equivalency Spreadsheet for the year 2025 vehicle, I noted that the tab design for the high voltage enclosure did not account for clearances needed to fit the tools needed to fasten the tabs securely. To accommodate for the serviceability of the enclosure, I modified the tab design and put my rapid prototyping skills to practice in order to verify my modifications.

High Voltage Enclosure Mounting