The idea for team 25’s capstone project came from a team member who commutes to and from work and school on his 2005 Kawasaki ZX-6R sport bike. On cool mornings with an ambient temperature below 50 degrees Fahrenheit he can feel an alarming decrease in the stability and traction of the motorcycle while accelerating through a turn until the tires get up to operating temperatures. However, unlike four wheel vehicles that have tires with flat contact surface profiles, Michelin Pilot Road 2 tires, a popular tire for street bike riders, has a contact patch while in the normal upright riding position of only 90mm on the front tire and 40mm on the rear tire [Cycletreads, website]. Naturally, rubber is harder when it’s cold, softening when the rubber is heated, but with a reduced tire surface contact patch the time for the internal tire air temperature to reach a safe operating temperature is increased. The dangers of riding before the rear tire is brought to safe operating temperature is that the bike has a tendency of sliding out from underneath the rider under the slightest acceleration while in a lean, causing a “cold tire” crash [Cycle World, website]. Team 25 wants to create a device that will divert the hot exhaust created by the bike during normal operation over the surface of the rear tire, decreasing the time it takes for the tires to warm up to a safe operating temperature.
Novice or professional riders can use the Hot Wheel heating system. Riders who use a sport bike as a daily commuter will improve their safety by increasing the amount of traction the drive wheel. Weather conditions, including rain, can quickly cool the drive tire of a motorcycle, greatly decreasing the traction of an already low traction condition, compromising the safety of the rider. The VEOH Valve system can help prevent the rapid cooling of the tire in these conditions. Professional riders can benefit from the increased traction by improving track lap times with better acceleration and braking from the sport bike. The main competition to the VEOH Valve are bag tire heaters. These heaters are fabric that are wrapped around the tire and have interior heaters that are controlled with a power supply. Most tire warmers are distributed to third party vendors, which then sell the product to individual customers directly. Racing teams that heavily utilize tire warming technology can purchase a bulk amount of tire warmers through a distributer. Both market paths are suitable for VEOH Valve distribution.
Proof of Concept
On cool mornings with an ambient temperature below 50℉ a motorcycle rider can feel an alarming decrease in the stability and traction of the motorcycle while accelerating through a turn until the tires get up to operating temperatures. Riding before the tire reaches a safe operating temperature, the bike has a tendency of sliding out from underneath the rider under the slightest acceleration while in a lean, causing a “cold tire” crash. In order to mitigate this effect, Team 25 proposes the creation of their Variable Exhaust Output Heating (VEOH) Valve. The VEOH Valve is a simple device, integrated with the existing exhaust system. When the rear tire of the motorcycle is below a safe operating temperature, the valve diverts the hot exhaust over the rear tire, heating it up without the need for cumbersome external jackets to be applied to the outside. Motorcycle exhaust can reach temperatures north of 700 ℉. According to Team 25’s calculations, even exhaust moving at extremely high speeds can transfer upwards of 20 W of heat, drastically decreasing the warm-up time. Utilizing infrared technology, the valve senses when the rear tire has reached a safe temperature, at which time the valve opens and typical exhaust function is restored.
The main purpose of the VEOH (Variable Exhaust Output Heating) Valve is to divert exhaust gases produced from regular bike operation to the rear tire for convective heating. An infrared thermocouple takes a temperature reading from the rear tire of the motorcycle. Based on this reading, the VEOH Valve is actuated by an Arduino motor, to either a closed or open position. This allows the VEOH Valve to open when the tire temperature is below operating standards, and to close once the tire has become warm enough to promote nominal traction. Consumers looking for a novel way to improve the capabilities of their motorcycle will find a reduced wait time until tire operating temperature is reached valuable. The current market leaders in motorcycle tire heating technology are removable heating blankets that are draped around the tires for a set amount of time. This prevents the competitor’s technology from being used while the motorcycle is in motion, which is a large disadvantage to the VEOH Valve, giving the new exhaust heating technique more value. The VEOH Valve requires the modification of the OEM exhaust pipe present on the motorcycle. A Y-splitter pipe is welded in place of a small section of the original exhaust system. One end of the Y-splitter pipe is fit into the original muffler, while the other end can either be sealed off with a flange or attached to the variable valve actuating system. The actuating valve is attached to a pent pipe which bends to orthogonally point down at the rear tire 3” above its surface. This allows for the bike suspension to be fully compressed without interruption from the additional pipe. A larger diameter pipe is welded onto a U-bar which is attached directly to the swing arm. This pipe acts like a shroud and reduces the amount of exhaust heat lost to the environment, while travelling with the motorcycle suspension system.
A section of the OEM exhaust pipe was removed, allowing space for the Y-split VEOH Valve pipe to be welded in line with the remainder of the pipe. The added exhaust exit port from the Y-split pipe can either be sealed with a gasket and flange, or expanded into the variable valve system, both systems are completely modular and can be removed with a socket wrench. When attaching the variable valve exhaust system, a gasket and the actuating valve are fastened over the Y-splitter exit piping. After the actuating valve, another gasket is held in place and then the custom-built extension pipe is attached via nut and machine screw. The end of the pipe extension sits approximately 3” above the tire and is pointed directly at the tire’s surface. This design choice was implemented because the total suspense travel of the swing arm is 2.5”, fixing the pipe 3” above the tire allows the rear tire to travel up and down freely without contacting the rear tire. To combat heating interference from external winds due to this large distance from pipe exit to tire surface, a shroud that was connected to the swingarm, which will allow for a smaller gap between the tire and the exhaust pipe exit was implemented. The shroud consists of circular tubing that was bent to the shape of a “U” with an additional pipe welded to the top of the U bar. The bar is fastened to the motorcycle’s rear swing arm, allowing the U bar to travel freely with the suspension. The pipe that has been attached to the U bar has a larger diameter than the extension pipe, so the smaller extension pipe is encased within the larger pipe. The shroud allows for the exhaust gasses to exit directly above the tire at a consistent height regardless of suspension movement. Additionally, an Arduino motor was programmed to communicate with an attached infrared thermocouple, to initialize whether the exhaust valve should open.
Testing and Results
Meet the Team
Jonathan Burns –Jonathan is a 25 year old senior mechanical engineering student at the University of Nevada, Reno. Born and raised in Las Vegas, Jonathan moved to Reno in 2013 and has never looked back. Jonathan currently interns at Southland Industries as a Project Engineer, where he will start full time after graduating in May 2018 with a BS in Mechanical Engineering and a Minor in Renewable Energy. Jonathan enjoys working in project management for a mechanical contractor because it forces him to use his analytical problem solving skills on a day to day basis.
Jake Oliver- Jake Oliver is a mechanical engineering student at the University of Nevada, Reno. He is 22 years old, born and raised in Reno, Nevada. Jake is planning on graduating in May 2018 with a Bachelor of Science degree in Mechanical Engineering. Jake is currently a Custom Solutions Intern at Hamilton Robotics where he has further advanced his engineering skills by designing, manufacturing, and assembling one off customer specific robotic liquid handling systems. He hopes to continue working for Hamilton after he graduates.
Donavon Martin – Donavon is a 22-year-old Mechanical Engineering student who plans on graduating in May 2018 with a Bachelors of Science in Mechanical Engineering. He was born and raised in Murrieta, California. He transferred to the University of Nevada, Reno in the Fall of 2015 and has enjoyed the learning experiences in the mechanical engineering program. Donavon enjoys the design and fabrication aspects of engineering and has been able to expand on those skills by working at California Expanded Metals Company (CEMCO) as an intern during his summers. He plans to go to work for CEMCO at their Los Angeles, California location upon graduating in May. Outside of school and work, Donavon enjoys sports and can often be found playing basketball at the fitness center on campus.
Connor Nielsen– Connor Nielsen was born in Orem, Utah and moved to Reno, Nevada in 2003. He is currently a 22-year-old and a senior mechanical engineering at the University of Nevada, Reno. Connor currently interns at Chromalloy Nevada in Carson City as an NPI Engineer with plans to be fully employed upon his graduation in spring of 2018. Chromalloy operates as a reparation center for gas turbine engine internal components for both commercial and military aircraft. NPI stands for “new product introduction,” and involves synthesizing a manufacturing operation for different components being introduced to the manufacturing facility. This procedure requires the analysis and computation Connor has learned from the engineering program at the university.
Paul Vazquez- Born in Reno, Paul grew up in Fallon, Nevada and in 2013 he returned to his birth city to pursue a degree in mechanical engineering. Paul is currently 22 years old, he is enrolled at the University of Nevada, Reno and plans to graduate in December of 2018. Paul enjoys the technical approach to problem solving that the his education at the university has taught him. Currently an intern for Advanced Materials and Devices, Paul appreciates the practical hands on experience that he gains from the job that broaden his engineering abilities. To relax with his spare time Paul enjoys playing hockey, playing the piano, and socializing with friends.