Matching Items (3)
Filtering by

Clear all filters

137210-Thumbnail Image.png
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

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
135503-Thumbnail Image.png
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

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
132111-Thumbnail Image.png
Description
An understanding of aerodynamics is crucial for automobile performance and efficiency. There are many types of “add-on” aerodynamic devices for cars including wings, splitters, and vortex generators. While these have been studied extensively, rear spoilers have not, and their effects are not as widely known. A Computational Fluid Dynamics (CFD)

An understanding of aerodynamics is crucial for automobile performance and efficiency. There are many types of “add-on” aerodynamic devices for cars including wings, splitters, and vortex generators. While these have been studied extensively, rear spoilers have not, and their effects are not as widely known. A Computational Fluid Dynamics (CFD) and wind tunnel study was performed to study the effects of spoilers on vehicle aerodynamics and performance. Vehicle aerodynamics is geometry dependent, meaning what applies to one car may or may not apply on another. So, the Scion FRS was chosen as the test vehicle because it is has the “classic” sports car configuration with a long hood, short rear, and 2+2 passenger cabin while also being widely sold with a plethora of aftermarket aerodynamic modifications available. Due to computing and licensing restrictions, only a 2D CFD simulation was performed in ANSYS Fluent 19.1. A surface model of the centerline of the car was created in SolidWorks and imported into ANSYS, where the domain was created. A mesh convergence study was run to determine the optimum mesh size, and Realizable k-epsilon was the chosen physics model. The wind tunnel lacked equipment to record quantifiable data, so the wind tunnel was utilized for flow visualization on a 1/24 scale car model to compare with the CFD.

0° spoilers reduced the wake area behind the car, decreasing pressure drag but also decreasing underbody flow, causing a reduction in drag and downforce. Angled spoilers increased the wake area behind the car, increasing pressure drag but also increasing underbody flow, causing an increase in drag and downforce. Longer spoilers increased these effects compared to shorter spoilers, and short spoilers at different angles did not create significantly different effects. 0° spoilers would be best suited for cases that prioritize fuel economy or straight-line acceleration and speed due to the drag reduction, while angled spoilers would be best suited for cars requiring downforce. The angle and length of spoiler would depend on the downforce needed, which is dependent on the track.
ContributorsNie, Alexander (Author) / Wells, Valana (Thesis director) / Huang, Huei-Ping (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2019-12