Matching Items (3)
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- All Subjects: SAE
- Creators: Huang, Huei-Ping
- Member of: Barrett, The Honors College Thesis/Creative Project Collection
Description
The exhaust system is an integral part of any internal combustion engine. A well- designed exhaust system efficiently removes exhaust gasses expelled from the cylinders. If tuned for performance purposes, the exhaust system can also exhibit scavenging and supercharging characteristics. This project reviews the major components of an exhaust system and discusses the proper design techniques necessary to utilize the performance boosting potential of a tuned exhaust system for a four-stroke engine. These design considerations are then applied to Arizona State University's Formula SAE vehicle by comparing the existing system to a properly tuned system. An inexpensive testing method, developed specifically for this project, is used to test the effectiveness of the current design. The results of the test determined that the current design is ineffective at scavenging neighboring pipes of exhaust gasses and should be redesigned for better performance.
ContributorsKnutsen, Jeffrey Scott (Author) / Huang, Huei-Ping (Thesis director) / Steele, Bruce (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2014-05
Description
Formula SAE is a student design competition where students design and fabricate a formula-style racecar to race in a series of events against schools from around the world. It gives students of all majors the ability to use classroom theory and knowledge in a real world application. The general guidelines for the prototype racecars is for the students to use four-stroke, Otto cycle piston engines with a displacement of no greater than 610cc. A 20mm air restrictor downstream the throttle limits the power of the engines to under 100 horsepower. A 178-page rulebook outlines the remaining restrictions as they apply to the various vehicle systems: vehicle dynamics, driver interface, aerodynamics, and engine. Vehicle dynamics is simply the study of the forces which affect wheeled vehicles in motion. Its primary components are the chassis and suspension system. Driver interface controls everything that the driver interacts with including steering wheel, seat, pedals, and shifter. Aerodynamics refers to the outside skin of the vehicle which controls the amount of drag and downforce on the vehicle. Finally, the engine consists of the air intake, engine block, cooling system, and the exhaust. The exhaust is one of the most important pieces of an engine that is often overlooked in racecar design. The purpose of the exhaust is to control the removal of the combusted air-fuel mixture from the engine cylinders. The exhaust as well as the intake is important because they govern the flow into and out of the engine's cylinders (Heywood 231). They are especially important in racecar design because they have a great impact on the power produced by an engine. The higher the airflow through the cylinders, the larger amount of fuel that can be burned and consequently, the greater amount of power the engine can produce. In the exhaust system, higher airflow is governed by several factors. A good exhaust design gives and engine a higher volumetric efficiency through the exhaust scavenging effect. Volumetric efficiency is also affected by frictional losses. In addition, the system should ideally be lightweight, and easily manufacturable. Arizona State University's Formula SAE racecar uses a Honda F4i Engine from a CBR 600 motorcycle. It is a four cylinder Otto cycle engine with a 600cc displacement. An ideal or tuned exhaust system for this car would maximize the negative gauge pressure during valve overlap at the ideal operating rpm. Based on the typical track layout for the Formula SAE design series, an ideal exhaust system would be optimized for 7500 rpm and work well in the range
ContributorsButterfield, Brandon Michael (Author) / Huang, Huei-Ping (Thesis director) / Trimble, Steven (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Materials Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
This study explores the relationship between three physics-based predictive models defined by Castruccio et al. (2013), and four different distinct experimental morphologies of lava flows produced in a series of laboratory simulations where polyethylene glycol 600 (PEG) was pumped into an inclined chilled bath of water. The length of the experimental flow was recorded over time to create an experimental model to later be compared to the physics-based predictive models. The experimental morphologies are pillowed, rifted, folded, and leveed flows which can be characterized by a dimensionless parameter š¯›¹, which scales natural lava flows to experimental lava flows and is a ratio of timescales, the characteristic timescale of thermal flux from the vent and the characteristic timescale of crust formation caused by surface cooling (Fink and Griffiths 1990). The three physics-based models are presented such that the downslope gravitational acceleration drives the flow, while either the Newtonian viscosity of the flow, the Yield Strength of the core (YS), or the Yield Strength of the growing crust (YSC) is the primary retarding factor in flow propagation. This study concluded that low š¯›¹-value flows (low flux, low temperature, extensive crust formation) are better captured by the YSC model. And although the Newtonian model did not perfectly capture the behavior of any experimental flows in this study, high š¯›¹-value flows (high flux, high temperature, little crust formation) that formed levees exhibited the most Newtonian behavior.
ContributorsCourtney, Cara Alexandra (Author) / Clarke, Amanda B. (Thesis director) / Huang, Huei-Ping (Committee member) / Williams, David A. (Committee member) / School of Sustainability (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05