The off-roading industry is perpetually increasing engine performance, and a byproduct of that is increased heat output and higher stress on components. Constant velocity transmissions (CVT) in utility terrain vehicles (UTV) are a great example of where this occurs; the drive belt that converts engine torque into drive torque within the transmission frequently overheats and can fail if it surpasses a temperature threshold (approximately 200 ℉). A CVT drive belt failure is extremely dangerous as it can cause the secondary clutch to seize, causing the driver to lose all control of the vehicle at very high speeds, and renders the vehicle inoperable. In some cases, onsite repairs are not possible and the occupants are left stranded far from civilization. In addition to the hazard that a belt failure poses to the occupants, it also often causes costly damage to other critical components
Team VCool intends to design a cooling system for the CVT transmission in a UTV that would allow for longer use of the vehicle and more stress on the engine while avoiding a drive belt failure. This solution would promote the safety and well-being of off road enthusiasts, while allowing racing teams to put more stress on their engines without worrying about a belt failure making them more competitive. Some of the design requirements outlined in Team 16’s PDS are: the design must reduce the temperature rise time of the CVT drive belt by at least 10%, display the belt temperature and control output status to the user, and be compatible with multiple UTV brands.
Proof of Concept
VCool CVT cooling technology will be competing in the UTV aftermarket industry. There are two main categories that VCool will be competing with, belt temperature monitors and clutch replacements. Belt temperature monitors are a relatively inexpensive way to monitor the temperature on the CVT drive belt however they do nothing to cool the belt. Clutch replacements increase the size of the CVT allowing for different gear ratios and larger belts. These kits are expensive and require the replacement of the entire CVT assembly. VCool has identified a gap in this market for a product that can inexpensively prolong belt life. The team proposes that by actively cooling the intake air of the CVT when the belt gets above the threshold temperature the belt temperature rise time can be reduced by 10%. VCool will begin by proving the technology by partnering with UTV racing teams where overheating belts are a major problem. Once the product is well established with racing UTVs VCool will market add the performance UTV enthusiast to its target demographic and eventually pursuing licensing agreements with original equipment manufacturers.
Team 16’s challenge was to reduce the temperature of the air entering a continuously variable transmission (CVT) housing utility terrain vehicles (UTV). To evaluate and test our concept, a simple test apparatus was designed and constructed (Fig 1). The test apparatus was designed to mimic, as closely as possible, an air intake system. The test apparatus was comprised of two different diameters of pipe, a heat source, and blower fan (specific details of the internals and technical components have been omitted). The heater and air velocities were controlled during the experiment, and a complete data panel was collected for all temperatures. For the Proof of Concept to be considered a success, Team 16 needed to realize a significant drop in temperature in the system after the introduction of isopropyl alcohol (IPA) to the system through the smaller intake end of the test apparatus (Fig 2). For each test sequence completed, Team 16 realized a significant drop in temperature as recorded by the aluminum test sample located in the test apparatus (Fig. 3). Details of the aluminum test sample are in Fig. 4. The temperature drop provided a positive result the Proof of Concept initial design was successful, as was forecasted from our design selection process.
Upon completion of this preliminary proof of concept testing, Team 16 has effectively proven that they have a real-world concept for the reduction of heat for an air intake system application and testing provides support for Team 16’s concept to provide a real-world solution to heat related issues. Using our proof of concept test apparatus, we were able to realize a significant drop in temperature confirming that our engineering solution works.
Fig. 1: Testing apparatus for Proof of Concept modeling.
Fig. 2: Overview of the complete test apparatus.
Fig. 3: Detail of the chamber where the heater, thermocouples, and housing are suspended on the inside of the ABS pipe to collect data on the thermal effects of adding isopropyl alcohol (IPA) to the system.
Fig. 4: Drawing of PoC aluminum test sample with cavities for three thermocouples and heating element.
The final design of VCool’s product will reduce the temperature rise time of continuously variable transmissions (CVTs) on performance utility terrain vehicles (UTVs). Effectively cooling the CVT transmission decreases the risk for belt failure when operating the UTV. This is vital to maintain the safety of the operators of the vehicle as belt failures can cause the wheels to lock at any speed and send belt shrapnel flying causing damage other vehicle functions.
This design utilizes the convective cooling properties of atomized isopropyl alcohol. This alcohol will be introduced via injectors mounted in a centrifugal filter. This whole system will replace the stock CVT pre-filter and will mount to existing holes. An alcohol tank mounted in the rear of the vehicle with an in-tank fuel pump will pressurize the alcohol to a fuel rail and and arduino controller will control the pulse time of the injectors.
A small LCD display will be mounted on the driver side A-pillar and will provide the user with temperature read out of the CVT as well as system activity. A LED bar graph will alert the operator if and when the transmission is reaching critical belt failure temperature. This screen will be display system conditions and temperature from an infrared temperature mounted on the CVT transmission.
Fig. 1: The display carrier attached to the A-pillar mounting clamp. This will house the digital display in the front of the vehicle, and will be communicated with via arduino.
Fig. 2: The centrifugal filter mounted on the intake manifold for the CVT. The purpose of this part is to separate dust from the intake air stream, which could potentially cause the formation of an alcohol-mud slurry.
Fig. 3: Wiring diagram of the Arduino controller.
Fig. 4: An exploded view of the isopropyl alcohol holding tank assembly, which will be mounted near the rear of the vehicle. The pump will be housed inside of the tank.
Testing and Results
Meet the Team
Parker Burnell came to UNR from the Silicon Valley in California and will use his hands-on experience gained from a challenging instrumentation summer internship to assist Team 16 with sub-system integration as well as other tasks that he has developed during his academic career including: control system tuning, sensor selection, and control/power wiring. Parker boasts an incredible attention to detail and has used his task-oriented personality and analytical techniques to design a balsa wood bridge capable of withstanding over 300 pounds of force (during a Statics course). After earning his Bachelor of Science Degree in the Spring of 2018, Parker plans to pursue the professional world of engineering in the Reno/Tahoe area.
Growing up in El Dorado Hills, California, Lucas Dodson has developed a respect for the outdoors. Lucas has worked for the California Department of Transportation on large paving projects in Truckee, CA. During this project, Lucas was tasked with overseeing the grinding and paving of wheel ruts on highway 80. In his academic career, he has improved upon his problem-solving techniques. Outside of school, Lucas has been featured in big name off-roading magazines for the documentation of trips both himself and others have gone on. Lucas has been involved with the off-roading community for the past 6 years and has provided media coverage of many events. He will use his off-roading knowledge and fabrication experience to aid in the testing and design of the prototype. His goals are to graduate with a BS and begin working in a profession he enjoys.
Andrew Kapczynski a native to Northern Nevada, is a senior mechanical engineering student at the University with an emphasis on manufacturing. He is also a UTV field specialist and Team 16’s leader. During his 12 years in the U.S. Air Force, he earned associates degrees in Aerospace Ground Equipment and Aircraft Metals Technology. Using these degrees, he learned to professionally maintain, troubleshoot, and repair power generation systems, hydraulics, HVAC, pneumatics, turbine, and reciprocating engines. He is also a seasoned in design, repair, and fabricate components with strong skills in computer aided design, finite element analysis, welding, heat treating, and machining using precision tools and precision measuring equipment. Following graduation, Andrew plans to commission in the Air Force and seek employment locally in his field of expertise.
Bill Perez is a native Nevadan who lives in Carson City. A nontraditional student, Bill has returned to the University to complete a degree in Mechanical Engineering. Bill has almost 20 years of extensive experience working in the aerospace fastener industry where he was recently involved in the development of a rapid deployment repair kit for use on one of the most advanced fighter programs in the world. Bill will utilize his expertise in the development of design processes to help the team avoid pitfalls and adopt best practices. As a design engineer, Bill has extensive CAD experience working with AutoCAD, Inventor, and SolidWorks. His skills include machining, prototyping, materials, testing, metal, and composite fabrication. Currently, Bill is focused on successfully completing his education and graduating with his degree in Mechanical Engineering. After graduation, Bill plans to continue with the company where he now works.
Nate Volat is from northern California and will utilize his experience in fabrication to streamline the prototyping process. He has AWS qualifications in FCAW, GMAW, and GTAW as well as extensive experience in machining and fabrication. His expertise at 3D modeling with experience in Autodesk Inventor, Fusion 360, as well as SolidWorks will make him an invaluable asset to the team. Nate is employed as a machinist where he makes parts for the automotive and firearm industries as well as the Tesla factory. As a quality control manager, he has used applied analytical techniques to identify and solve metrology challenges including statistical quality assurance. Nate intends to continue in the manufacturing industry.