Rear Driven Snowmobile for CSC

The goal of the project is to design an effective and fully functional rear driven track for the Clean Snowmobile Challenge Team. This design is to be implemented on the snowmobile for use during the 2020 SAE Clean Snowmobile Competition.



=Problem Definition= Conventional snowmobiles have tracks that are driven from the front causing the top of the tack to be pulled in tension and the bottom of the track to be pushed in compression. The portion of the track in contact with the snow, being in compression, causes losses in efficiency and decreased handling. The clean snowmobile team anticipates to see drastic improvements in the following competition events: Acceleration, handling, and endurance.

Background
Currently, there are not any rear driven snowmobiles on the market. This is mainly due to manufacturers wanting to reduce sled weight and simplify designs. Aftermarket rear driven snowmobile prototypes have been made in the past, however, their application is mainly for drag racing snowmobiles. The past CSC projects that have attempted this type of design are detailed below.

2011-2012 This Senior Design Project was the first attempt by the UICSC team at implementing a rear drive snowmobile skid. The design this team created involved a gear and chain system that ran down the center of the tunnel. Having the chain in this configuration meant the team had to redesign the suspension, and complete a finite element analysis. Once the system was fabricated and testing could be done, the team found that their chain would brake too often/quickly; they concluded that they were lacking a chain tensioner.



2014-2015 During this school year another senior design team took a second crack at tackling the rear driven snowmobile. Following findings by the previous group, and adapting the built skid from the 2011 project they added a chain tensioner. However, due to part received delays the system was not completed not implemented on the sled for competition.

Due to a change in SAE competition rules a chain and gear system would need to be fully shielded and an oil bath and lubrication system would need to be implemented. The amount of modification and weight adage to do this leads our team to explore other avenues of research.

2015 A masters student, Matthew Kologi, looked into this design problem as a part of completing his masters degree. He performed conceptual and ideological experiments in detail to explore the theoretical efficiencies that could be gained from implementing a rear driven skid. In his analysis, he explored a drive shaft and pinion gear system. In his road load models he found that once a cruise speed is reached there is little resistance to maintain the cruise speed. Being a conceptual design exploration there isn't any information detailing how such a system would fair on snow.



Deliverables
Our team's goal is to design, fabricate, and test a rear driven snowmobile. The implementation of this system is hoped to improve competition activities where handling, fuel efficiency, and overall sled performance is necessary. The system should maintain the full functionality of a stock snowmobile. Minimal weight addition is desirable. Any designs involving the electronic transmission of power from the engine, clutch, and/or crankshaft must be submitted to the SAE competition proprietors prior to the competition for approval. Other deliverables include:

* Two people should be able to swap out stock and designed skids with relative ease. * Detailed 3D model & engineering drawing package. * Must withstand the power (120hp), torque (100ft-lbs), and track speed (100mph) of the UICSC snowmobile * In-depth Engineering Analysis for the re-designed suspension system.

Specifications

 * SAE Clean Snowmobile Challenge Requirements

Meet sound requirements for National Parks

=Design Considerations= Preliminary Designs:


 * Hydro-static power transmission implemented motorcycles
 * Pump
 * Motor
 * Dimensional Drawing
 * Synchronous Belts and Pulleys
 * McMaster
 * Pulleys
 * Belts
 * BB Man
 * BB Man - Belt Drive Calculator
 * AutomationDirect
 * Electronic Power Transference Components


 * Alternator


 * Power Bank


 * Speed Controller


 * Motors
 * DC/Sservo
 * Induction Motor

=Final Design= Final CAD Model Designs by Sub-Assembly:

Final CAD Model Designs of Driving Axle's: Full Assembly without the tunnel Displayed on our final design of the Rear Driven Snowmobile. Full Assembly with the tunnel Displayed on our final design of the Rear Driven Snowmobile.

=Team Members=

=Additional Documentation=

Team Contract

Product Requirements Document

Project Schedule

Project Budget

Calculation Spreadsheet

Meeting Minutes





Exta Info/ Worksheets

Stock Sled Parts