Ben Marson
Mechanical Engineering
Theatrical Design
Senior Capstone Project
Project Statement
The current CVT in the Baja vehicle is outsourced and not fully understood by the Baja Team Members; there is room for performance improvement
Need
To design, analyze, and test a new CVT Primary that interfaces with the current system and improves performance
Goals
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Increase car’s top speed by 1 mph while maintaining acceleration times
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Reduce system temperatures after 60 minutes of driving by 10%
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Develop a more thorough understanding of CVT system
What is a C.V.T.?
Primary (Power from motor shaft)

Rubber belt
Secondary (Power to gear box)



engine
The CVT replaces a conventional gear transmission by using centripetal force to continuously change the gear ratio between the primary and secondary units. This allows the car to receive high torque from the engine when accelerating and high speed when the engine reaches max rpm.
How it works: As the driver supplies more gas to the engine, the primary rotates at a faster rate. Due the faster rotational speed, weights within the primary unit have more centrifugal force and press against the walls of the primary. Ramps against the walls redirect this force from an outward direction to an axial direction. This axial force moves a plate (called a sheave) inward, pinching the belt and rotating it. As the driver applies even more gas and the engine supplies more rotational speed, the sheave moves inward even more. The belt rides up on the sheave, changing the gear ratio of the system. The secondary unit acts oppositely to the primary; the sheaves on the secondary open as the engine gains speed.

Final Design

sheaves
hollow central shaft
spring
primary housing
ramps
fly weights
weight arm
spring cap
spring housing
primary cap






The team developed a 3D model of the primary CVT and developed drawings for all of the parts. The parts will be fabricated in the Spring of 2019.
The Design Process
Data Acquisition
In order to design an efficient system, ideal for the Baja car, tests were conducted to determine ideal performance and areas that could be improved. To do this, the team developed a computer that can sit in the chassis of the car and record rpm data in real time.




Anaylsis
Finite Element Analysis (FEA)




Project Management
system level diagram

procurement plan

Gantt chart


