Energy Systems Engineering MEng Projects

With the expanding market for battery electric vehicles, new opportunities in brake sizing and added focus to vehicle range continue to gain importance in the automotive industry. By considering hybrid and electric vehicle’s ability to decelerate using regenerative braking brake hardware can be optimized and reduced while new opportunities for aerodynamic features that would otherwise be detrimental to brake performance can be pursued. By understanding how regen braking, aerodynamic drag and brake cooling interact with each other and quantifying their respective impact to vehicle performance. An optimized solution to maximize vehicle range and reduce mass was provided and recommended in this paper. The resulting outcome of the paper indicates a total vehicle range improvement of 1.5% can be achieved.

In the consumer space, bulk data collection and analysis has been around for quite some time. In the report entitled “Automotive Quality Development Using Connected Customer Bulk Data Analysis” our team’s goal was to explore how the analysis of bulk customer vehicle data can lower warranty and increase customer satisfaction. On average, automotive OEMs spend $9 billion per year on warranty so even small improvements in this area can lead to substantial savings for the manufacturers. Through the use of two major case studies, or team evaluated a process to mitigate warranty in two major categories; customer complaints and warranty spills which make up roughly 35% of total warranty, or $3.15 billion. During the duration of this project, our team has identified areas in which this process can be improved for future users, as well as a business unit within General Motors that can own and refine it. Once rolled out to the proper internal engineering users it is estimated that this process can conservatively mitigate one percent, or $100 million, of customer warranty.

This project examined using an existing fuel saving technology to its full potential by modifying it to facilitate engine torque control during the inertia phase of an upshift. As fuel economy and emissions standards become stricter for automotive manufacturers, the addition of new fuel economy improving technologies that push the boundaries of current operation become necessary for a vehicle to achieve its fuel economy targets. Our goals for this project were to; first, develop a calibration strategy for controlling the technology during upshifts, and second, to determine the benefit of this strategy in terms of fuel savings and cost savings to the company. In order to assess the effectiveness of the Modified Torque Reduction Strategy (MTRS), we created various implementations of the strategy and tested them along with several baseline cases. Each implementation of the MTRS showed potential for reducing fuel consumption during upshifts. The reduction in fuel consumption observed in this project represents a significant potential cost savings for the company.

Accurate estimation of battery state of charge and energy remaining is required for good UAV control. Over the course of four months, an electro-thermal model of an electric UAV’s battery system was developed in order to simulate in-flight battery performance. The model was implemented in MATLAB/Simulink and interfaces with the flight controls model. It simulates both the electrical and thermal behavior of the battery as well as the interaction between the two (i.e., more electrical power demand results in faster heating of the battery). Due to the short timeframe for this demo project and limited budget, all data used for the model was from publicly available sources. Methods were developed to extract and process this data in order to implement the Simulink model. The model was validated against the manufacturer’s datasheet. An example flight power profile was then used to show the trends between battery temperature and battery performance.

The development of this model is crucial for the success of the prototype UAV project. It is integral to verifying the propulsion and contingency logic in the flight control software prior to first flight. Additionally, its development saves significant schedule on the project by parallelizing the development of the battery and the flight control software, only requiring a couple of weeks for integration rather than several months of serial development. Long-term, the strategy and lessons learned from this project can be carried on in future electric vehicle projects to help ensure continued success of these missions.

Military ground vehicle technology and doctrine are evolving, requiring more energy onboard and the ability to operate silently. Current technologies are struggling to meet these new demands, providing an opportunity for emerging technology, such as the hydrogen fuel cell. There are several challenges presented by this technology that need to be overcome, the most pressing being hydrogen storage. Vehicle simulations were performed in Siemens LMS Amesim and hydrogen storage material and physical models were used to determine the best method for storing hydrogen onboard ground vehicles. It was found that cryo-compressed hydrogen is the best near-term solution for hydrogen storage onboard military ground vehicles. Cryo-compressed offers 160% more hydrogen per unit mass and three times the hydrogen per unit volume without compromises to refueling time or operation. Two other technologies that emerged as candidates, pending continued development, are metal organic frameworks and aluminum hydride.

The purpose of this report was to analyze my carbon footprint for the year of 2019. In doing so, I assessed the largest contributors to my footprint, examined the weaknesses in current publicly available online carbon footprint calculators, and identified areas of improvement needed in current carbon research. Through this research I quantified the largest contributor to my carbon footprint and made suggestions for emissions reduction. However, this analysis also highlighted the broad range in carbon emission factor data available. Depending on the emission factor used my carbon footprint could range from 9.6 to 34.1 mtCO₂-eq. Different reports find different emission factors for the same product. The data on how other non-good purchases, such as insurance or doctor visits, is out of date and only looks at dollar equivalent. This range in carbon footprint is also seen in the output from the online carbon footprint calculators, with estimates ranging from 11.8 – 28.1 mtCO₂-eq even though all input data was controlled. Overall, the uncertainty in carbon emission factor data is large and more research needs to be done to allow users to accurately understand their contribution to emissions, and thus reduce their total carbon emissions.

Companies want to hire the best candidates to enable optimum performance, but that is not a simple or straightforward task. In order to develop trends to enable an instructional design company to better evaluate designer performance during the interview process and predict outcomes of future projects, interview and performance data was gathered and assessed. Eight Candidate Application Scoring Rubrics were obtained and evaluated. To assess current performance of the same employees, a questionnaire was developed and provided to directors. Skills including communication, collaboration, pedagogy, learning architect skills, remote work skills, and project management skills were rated in this questionnaire. Based on trends developed from the limited data set, it is recommended that collaboration and project management skill evaluation during interviews be used to ensure better future performance. On the other hand, learning architect skills assessed in hiring interviews are not indicative of future performance. Based on given assumptions, this practice can save over $89,000 per year.

This project details the efforts undertaken during my internship at NASA Johnson Space Center to investigate guidelines on designing a safe high power and high performing battery that is resistant to thermal runaway. The objectives included determining if the flame arresting feature of the battery enclosure prevented sparks or flames from exiting the enclosure through the vents and also to prevent cell-to-cell propagation during thermal runaway. I helped to facilitate the testing of the battery module’s flame arresting features by performing nine test runs in which nine 18650 lithium-ion batteries were triggered into thermal runaway; this involved assembling all the individual components of the battery module, observing the test, gathering and analyzing the data and performing a destructive physical assessment after each test. The test runs concluded that the flame arresting feature did work and that cell-to-cell propagation did not occur during thermal runaway.

The automotive industry has had a large rise in electrified vehicles in recent years. As the number of electrified vehicles continues to grow, the risk of electro-magnetic interference (EMI) within the vehicle systems has also risen. For the drive unit controls hardware team, this risk of EMI has direct impact on the performance of the transmission range sensor (TRS). The goal of this project is to develop the resources and understanding available to the controls hardware team for considering EMI in the design of a TRS. This project focuses on three development aspects of the EMI impact on a TRS device including analysis capabilities available to predict EMI, hardware testing on a TRS to map the EMI exposure, and research into protection techniques which can mitigate risk caused by EMI. The work in these areas found that there are limited analysis capabilities currently available to the controls hardware team for reliably predicting the EMI environment. However, hardware testing of a specific TRS found that the EMI exposure in that application is acceptable and would not have significant impact on the TRS performance. As the hardware testing results proved to be acceptable, there is no recommendation of further protection techniques for the TRS evaluated in this project.

The findings from this project have improved the understanding of EMI exposure on TRS devices which will lead to a reduction in late design changes caused by EMI issues. This reduction in late design changes will in turn reduce cost and timing impacts caused by late changes. It is recommended that development work continue on understanding the EMI impact in the drive unit environment. Further testing on hardware in additional drive unit configurations will increase the amount of data available and improve the ability to provide robust TRS designs in future applications.

Renewable energy is intermittent and thus we need energy storage. Demand response is a good source of balancing load and generation. However, previous experiments have found that using building temperature setpoint control for load shifting can increase building energy consumption, resulting in a low effective efficiency. This research seeks to find the reason for this inefficiency through experiments conducted at the University of Michigan. We make three hypotheses: 1) More cycling events result in higher efficiency. 2) Shorter time period events have higher efficiency. 3) Temperature setpoint neutral events are not equivalent to energy neutral event. While analyzing the data we discovered that our previous Round Trip Efficiency (RTE) metric does not take into account the change in average temperature to the building and thus does not give us a full picture of the efficiency. We must change how we calculate efficiency by considering average temperature impacts and this will allow us to analyze the data more effectively. For hypothesis 3 we need more tests to verify the hypothesis though we may be able to combine previous experimental data with the experimental data obtained this year to increase the number of events in our data set.

Vehicle level performance requirements were revisited for level 4 and 5 autonomous systems that automatically accelerate and brake with the flow of traffic on expressways. The first is providing a methodology for peak braking capability of an autonomous vehicle from an expressway cruising speed. The second is providing a methodology for vehicle jerk requirement at expressway cruising speeds to ensure driver comfort. For this report, objective measurements were found using a model which compared the following distance, speeds, and deceleration profiles between a leading and following vehicle in an emergency braking scenario, and subjective evaluations were performed in a Cadillac CT6 with SuperCruise and Full Speed Range Adaptive Cruise Control. If too high a maximum vehicle deceleration capability requirement is chosen, optimizations in other trade off areas such as tire durability could be underspecified. If too low-performance maximum vehicle deceleration capability is chosen, vehicle could be unsafe for the various expressway driving scenarios an autonomous vehicle would encounter, as well as vehicles may cut in front of the vehicle on the expressway compromising ride and violating safety requirements. To optimize maximum vehicle deceleration capability while providing a safe and smooth ride to passengers, requirements must set constraints for the design of various subsystems in both hardware and software. Subjective and objective measurements were combined into a methodology to calculate a Minimum Safety TTC based on maximum vehicle deceleration, and a comfort jerk requirement.

This project’s purpose is to replace the coal-based generated electricity that is currently supplied to the Lou Walker Senior Center (LWSC), located in Lithonia, GA, with electricity that is provided by a photovoltaic (PV) system designed for the LWSC. The PV system will reduce the amount of coal generated CO₂ emissions and other greenhouse gases that contribute to metro-Atlanta’s non-attainment of the EPA Clean Air Act standards.

First, PV technologies are selected from a range of available technologies using the Contingent Valuation Method as a selection criteria. Electrical and physical data that are specific to the selected technologies are then used to design the LWSC PV system. The LWSC roof-mounted PV system that is needed to meet the 1,248,903 kWh/yr. energy demand of the LWSC must consist of 2,025 roof-mounted solar modules. The available LWSC south-facing roof area will only accommodate 936 of the 2,025 modules that are required. The LWSC PV system consists of 936 solar modules and will only meet 45% of the LWSC energy requirement. The PV system if implemented as designed, based on limited south-facing roof area will result in a 12% annual increase in current energy expenses, or $415,000 in added cost to the LWSC, over the 25-year expected life of the PV system. The realized CO₂ emissions reduction from implementing the PV system is 55%. The recommendation is to not implement the LWSC PV system, based on increased annual and long term costs.