Transmission Tuning | Differential Design | Composites Manufacturing
As a leader on the Drivetrain Engineering team, I made significant improvements to the transmission and differential subsystems of the race car. I also worked closely with our composites manufacturing partner to design and fabricate a carbon fiber + kevlar racing seat and body panels.
The previous BAJA team members had made uninformed modifications to the CVT, leaving the car yearning for improvement. I began by benchmarking acceleration times from 0-100 feet and then analyzing the transmission according to its kinematics and kinetics. We found that the stiffness of the contra-spring needed to be increased in order to achieve the power band illustrated above. Once these modifications were made, I developed an Arduino based digital tachometer that used hall effect sensors to validate our improvements.
The cars acceleration time increased by 18%, placing the car within the top 10 finishers in 2016.
Our team needed a way to reduce understeer and increase the ability to handle extreme terrain. We chose to design a custom, selectable locking open differential system. Components that could be sourced were purchased and modified. Custom components were conceived, designed, and fabricated in-house.
I used online resources, phone calls with suppliers, and decision matrices to source modifiable components. I then created 3D CAD designs in SolidWorks of the axle cup shaft and bearing housing. I made 2D drawings for our professional machinist using these 3D models, who then machined the individual components.
The day the entire differential stack up fit together perfectly was one of the most rewarding moments of my engineering career. I successfully took the project from concept to completion on a tight timeline and within budgetary constraints, reducing weight and increasing vehicle performance versatility.
Strength to weight ratio was crucial for our team this year. I was in charge of creating composite body panels and a composite racing seat for the car.
I used a 3D CAD model and cardboard prototypes to design body panels for the welded frame. I then cut and bent sheet metal to create forms for the composite to cure on. For the seat, an existing fiberglass mold was used.
The final seat and body panels resulted in a 2% overall vehicle weight reduction (~8 lbs) and stood up to the rigorous competition environment.
Our car dramatically outperformed teams with 4x our size and 20x our budget at the BAJA SAE California competition in Spring 2017. We placed 18th in a 100 car field and were thrilled with the work ethic and craftsmanship that went into this car. This was truly the culmination of the best technical experience of my life to date.