MS, University of Cincinnati, 2006, Engineering : Mechanical Engineering

The task of tuning an engine from scratch can be very time consuming and difficult if the right equipment is not utilized. Several different types of dynamometers with feedback control systems exist that enable a tuner to simplify the process. However, most of these systems are designed for specific applications and engines. Typically, the proper equipment is determined based on the budget and requirements of the tuner. The most common engines for Formula SAE (FSAE) cars are usually motorcycle engines or something similar. Unlike the usual car engines, which have separate transmissions, these engines and transmissions are built together. A complete custom engine dynamometer stand and corresponding connection between the transmission output shaft and the dynamometer is necessary.

Committee: Dr. Randall Allemang (Advisor) Subjects: Engineering, Automotive

Master of Science in Engineering, Youngstown State University, 2025, Department of Mechanical, Industrial and Manufacturing Engineering

A continuously variable transmission (CVT) is a type of transmission used commonly in small engine racing such as snowmobiling, go-karting, or in Society of Automotive Engineers (SAE) Baja racing. These transmissions allow for a constantly varying gear ratio while driving, without requiring the driver to shift gears manually. The continually changing ratio adapts well to varying course conditions such as frequent stops and starts, turns, and jumps. CVTs must be properly installed and tuned to reach their highest level of performance, which is a common difficulty for these complex systems. A MATLAB code has been developed that characterizes the torque, horsepower, and shift profile of a Gaged GX9 CVT. This predictive model may be used to select a tune for a vehicle and evaluate its performance without requiring extensive test time on a track. Multiple setups of the primary and secondary were analyzed, including different primary and secondary springs, flyweights, and ramps. The numerical characterization of torque, horsepower, shift curve, and acceleration has been validated experimentally, through the use of an inertia dynamometer, Kohler CH440Pro 14HP engine, and DynoMiteTM analysis software. Theoretical comparison was completed using free body and kinetic diagrams of the forces acting in the system, which were entered into a MATLAB code.   A new inertia dynamometer system has been installed within Youngstown State University's (YSU) engine laboratory, providing a hands-on application of methods learned in the classroom for students. The new installation has been used by several student groups to date. An operator's manual for the system focusing on safety and proper machine operation has been developed to aid in correct usage of the dynamometer. The new installation and numerical modeling completed has also been used to develop a laboratory for mechanical engineering students in the Dynamic Systems Modeling (DSM) class. Within the lab students will learn t (open full item for complete abstract)

Committee: C. Virgil Solomon PhD (Advisor); Hazel Marie PhD (Committee Member); Fred Persi PhD (Committee Member) Subjects: Applied Mathematics; Automotive Engineering; Mechanical Engineering

Master of Science, University of Toledo, 2021, Exercise Science

Context: Hip muscle function is important for physical function. Two important components of muscle function are strength (peak force or torque); and power (rate of torque or force). Hip muscle power has not been investigated as much as strength. Hip muscle strength is often measured isometrically using hand-held dynamometers (HHD) which are inexpensive/portable. Hip muscle power is largely measured with linear transducers and isokinetic dynamometers (IKD) which are expensive and not portable. Objective: Investigate the reliability and validity of hip muscle strength and power measured by the belt-stabilized (BS-HHD) and tension (T-HHD) HHDs, and to compare the BS-HHD and T-HHD measures for hip muscle power and strength. Design: Repeated measure cohort study. Setting: University Laboratory. Participants: 16 healthy adults (sex: 4 male/12 female, age: 21.9±2.4 years, height: 1.70±0.10m, mass: 80.5±24.8kg. Intervention: Two days of MVIC trials using the IKD and HHD methods for hip abduction (ABD), extension (EXT), internal rotation (IR), and external rotation (ER). Main Outcomes Measure(s): Reliability, measured by intraclass correlation coefficients, and validity, measured by Pearson correlations. Results: For peak torque (PT), BS-HHD and T-HHD showed large reliability (ICC >.7) except for T-HHD for EXT (ICC=.09). For rate of torque development (RTD), BS-HHD revealed fair/good reliability for ABD/EXT (ICC=.5-.7) and good reliability for IR/ER (ICC=.7-1.0). All measures of T-HHD showed good reliability except for EXT (ICC<.7). In comparison to IKD, BS-HHD showed large validity (r=.7-.9) for all measures of PT, except for IR. PT, measured by T-HHD, also had large validity with the exception of EXT (r=0.5). For RTD, T-HHD had small to moderate correlations (r=.4-.6) and BS-HHD had small to moderate correlations with ABD/EXT having small correlations (r=.4) and IR/ER showing moderate correlations. Conclusion: HHD is a reliable and valid tool for assessing hip muscle st (open full item for complete abstract)

Committee: David Bazett-Jones PhD, AT, ATC, CSCS (Committee Chair); Neal Glaviano PhD, AT, ATC (Committee Member); Grant Norte PhD, AT, ATC (Committee Member) Subjects: Health Care; Sports Medicine

MS, University of Cincinnati, 2020, Engineering and Applied Science: Mechanical Engineering

With the absence of a combustion engine in an electric automobile, that behaves like a noise masking agent for the noise coming from the accessories, the wind and road noises become prominent. Learning about the vibration signatures of the electric motor is crucial to help mitigate these noise sources. Dynamometers are devices used to measure the power of rotating machinery. They help in understanding real-world problems in a lab environment. The dynamometer used for this thesis consists of an induction motor, a gearbox, and an alternator with an applied resistive electric load. Although the initial intent was to study the gearbox, the electric motor's acceleration data showed interesting orders with a negative slope, contrary to the generic orders with a positive slope. This prompted an investigation of the science behind the phenomena. There are four outcomes to this thesis: 1) to study the space and time harmonics of the electric motor, 2) to learn the effect of angular misalignment of the motor and the gearbox shafts, 3) to learn the effect of change in couplings from nitrile rubber (buna-n) to urethane, 4) to learn the effect of load on the dynamometer. All the experiments are studied in transient speeds, with buna-n coupling by default. In the electric motor, the slotting and pulse width modulation (PWM) harmonics are studied. To better understand the gearbox's noise characteristics, seven dominant orders are chosen, which helped distinguish the case results. Time variant discrete Fourier transform is used to track orders, and results are compared case by case. The misalignment in shafts caused an audible increase in the noise. This especially excited the lower natural frequencies and orders. There is a significant increase in the amplitude of these orders when the coupling changed from buna-n to urethane. Lastly, the application of load highlighted new harmonics and showed the highest amplitude spike comparatively.

Committee: Randall Allemang Ph.D. (Committee Chair); Aimee Frame Phd (Committee Member); Allyn Phillips Ph.D. (Committee Member) Subjects: Mechanical Engineering

Master of Science, The Ohio State University, 2020, Mechanical Engineering

The fuel economy label (window sticker) is used by every vehicle manufacturer in the United States to report fuel economy for two purposes. First, the values reported on the sticker are certified by the United States Environmental Protection Agency (EPA) and are used for certifying emissions regulations like the Corporate Average Fuel Economy (CAFE). Second, the fuel economy numbers are used by consumers to compare competing vehicles in the marketplace. These fuel economy numbers are generated through a process that involves standardized testing on a chassis dynamometer using standard drive cycles. As a result, the test requires an accurate replication of the resistive forces that a vehicle experiences in the real-world, which requires an accurate estimation of road load applied by the road and the surroundings opposing the vehicle motion. The estimation also depends on the type (aerodynamic shape, drivetrain configuration, etc.) of vehicle being tested. To get a description of road load that is as close as possible to reality, several noise factors and residuals need to be estimated as well, which forms the bulk of this thesis. Vehicle coastdown method is widely used to determine road load coefficients for testing vehicles on a chassis dynamometer for fuel economy certification. However, apart from being a time-consuming procedure for each variant in a mass production vehicle lineup, the repeatability of track coastdown testing procedure is sensitive to environmental conditions, the track surface condition as well as on the type of vehicle being tested (for example, SUVs, sedans, hybrid vehicles, manual transmissions, etc.). As a result, several attempts have been made to accurately model the coastdown road load parametrically. This thesis explores various ways in which such parametric models can be obtained and methods to minimize risks related to overfitting and collinearity of variables. Since, the vehicle's road load is dependent on several physical phenomen (open full item for complete abstract)

Committee: Giorgio Rizzoni (Advisor); Yann Guezennec (Committee Member); Adithya Jayakumar (Committee Member) Subjects: Automotive Engineering; Mechanical Engineering; Statistics

Master of Science in Engineering (MSEgr), Wright State University, 2013, Renewable and Clean Energy

Electric wheelchairs have a considerable impact on improving the quality of life for the millions of disabled persons around the world. These modern pieces of technology offer freedom and mobility for disabled persons to interact with the world outside of their homes. The goal of this project is to assist in advancements of conventional electric wheelchairs. This includes replacing the heavy, bulky, and inefficient lead acid batteries and worm gear drive systems with lithium-ion batteries and wheel hub motors in order to decrease weight and size, and increase efficiency. This master thesis research is focused on designing, fabricating, and testing an eddy current brake dynamometer that can effectively determine the efficiency of the newly implemented wheel hub motor system at operational speeds. The importance of measuring the efficiency of the wheel hub motors used is to verify that they have a sufficient efficiency that would increase running time, extend traveling distances, and increase reliability. Because of the low speeds and high torque required, geared wheel hub motors were used instead of brushless permanent magnet hub motors. In this research, SolidWorks was used for modeling and to create an engineering drawing packet. The components of the dynamometer were machined and fabricated with a lathe and a milling machine. MATLAB was utilized for the calculations. With the help of the dynamometer platform, it was determined that the wheel hub motors have a higher efficiency but only at higher speeds. Although the geared hub motors used compromise some efficiency in order to produce greater torque at low speeds, they are light weight with compact size and have a much lower cost making them ease for maneuverability and economically feasible for next generation wheelchairs.

Committee: Junghsen Lieh Ph.D. (Advisor); Hong Huang Ph.D. (Advisor); Ha-Rok Bae Ph.D (Committee Member) Subjects: Electrical Engineering; Energy; Mechanical Engineering

Master of Science (MS), Ohio University, 2008, Mechanical Engineering (Engineering and Technology)

There was a need to study drive train components (such as transmissions) in the Mechanical Engineering Automotive lab at Ohio University. The approach was to expand the capabilities of the existing chassis dynamometer into a complete drive train test system. The prototype Electric Bobcat Racecar was modified to serve as a platform for component testing by removing all non-essential parts from the chassis. Suitable mounts were designed for the motor, controller, and cooling system. A wireless telemetry strain gage system was selected to measure shaft torque at locations throughout the drive train and on the dynamometer shaft. A gantry crane was selected to safely load components into the test bed and the test bed onto the roller frame.Validation testing confirmed that the strain gage telemetry system gave values consistent with the values recorded by the calibrated dynamometer. Differential testing confirmed the capability of single component testing. Testing of two strain gages on the same shaft confirmed the potential repeatability of strain gages to be used as torque sensors.

Committee: Gregory G. Kremer Dr. (Advisor); Israel Urieli Dr. (Committee Member); Martin Kordesch Dr. (Committee Member); Robert Williams Dr. (Committee Member) Subjects: Mechanical Engineering

Master of Science (MS), Ohio University, 2002, Mechanical Engineering (Engineering)

Design and validation of a chassis dynamometer for present and future vehicle testing and design.

Committee: Gregory Kremer (Advisor) Subjects: Engineering, Mechanical