Reports

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Reports, Abstracts, and Links

An Analysis of Advanced Vehicle Propulsion Systems - MIT 2.62 - 2010-05-10 - Report - Presentation

Transportation plays an immense role in society and represents a large fraction of total energy consumption worldwide. More importantly, oil is the fuel of choice for nearly all vehicle propulsion systems, a resource that may become limited in the near future. Further, there is significant opportunity to reduce $\rm CO_2$ emissions from the transportation sector via higher efficiency engines, the increased use of efficient mass transit, and also with the use of less carbon intensive fuels such as natural gas instead of oil. Many conventional vehicles have seen significant performance and efficiency gains over the last two decades as modern engine control systems, hybridization and lighter, more aerodynamic vehicle designs have become more prevalent. Though these vehicles are economical, they do not necessarily offer the highest potential efficiency available. Unconventional concepts such as a Stirling-Electric, PEM Fuel-Cell or Compressed Air Vehicle offer unique advantages in terms of efficiency, flexibility and fuel usage. However, each also has distinct disadvantages that must be addressed in order for mainstream commercialization. A review is presented of these advanced vehicle systems that assesses the basic underlying theory behind each concept, the main components of each, and examples of concepts that have already been built.

A model-based thermodynamic analysis was performed for two of the three advanced vehicle propulsion systems presented, namely, the fuel-cell powered vehicle with on-board $\rm H_2$ storage, and an external combustion Stirling engine coupled with an electric generator and battery system. The overall design philosophy follows that of the Chevrolet Volt plug-in hybrid vehicle due to its practicality and potential for excellent fuel economy. The models were developed and explained with thermodynamic theory, but were ultimately implemented within the vehicle simulation based on empirical data available for representative state of the art concepts, such as the MODII (Stirling) and the 2008 Toyota FCV (PEFMC). The analysis focused on the ``tank to wheel" efficiencies of each system as a function of distinct operating conditions, namely city and highway EPA drive cycles. Detailed vehicle simulation dynamics were used to calculate the required engine power as a function of time, and the resulting fuel consumption. Key thermodynamic aspects of each system were explored in order to explain the complex dependence of performance on operating conditions and concept design. Parametric studies were performed in order to assess the impact of both engine-battery control relationships, nominal vehicle operational strategies, and battery capacity on the fuel economy.

Typical gross tank to wheel fuel economies in miles per gallon gasoline equivalents highway (city) for the Stirling concept were comparable to modern hybrids 56(38), whereas the Fuel Cell concept performed significantly better 80(58) as expected. However, these figures are extremely dependent on the distance traveled (a unique characteristic of plug-in hybrids) as well as vehicle operational set-points and battery size. For trips less than 40 miles, both the Stirling concept and the Fuel Cell concept achieved fuel economies closer to 135 miles per gallon gasoline equivalent. Finally, conclusions were drawn regarding the performance of each system, the potential and relative merits of each concept, and possible technical barriers that could prevent widespread commercialization. The perennial comparison of the established thermo-mechanical heat engine versus the forward-looking electrochemical fuel cell has thus been set.
Purification of Water in Phaeton and Paulette, Haiti - MIT 2.500 - 2009-05-14 - Report - Presentation

Phaeton and Paulette, two small villages in the northeast part of the Haitian coastline, currently suffer from a lack of available freshwater for personal consumption. This paper looks at methods for improving the water supply through desalination techniques and rainwater collection. Mercy and Shairing, a nonprofit NGO, hopes to take recommendations and implement the best solution in these two villages. Unfortunately, both villages are subject to abject poverty and cost is the major limiting factor when considering possible improvements to the existing water infratstructure. Humidification-dehumidification (HDH) and reverse osmosis (RO) were the only two desalinations that appeared to be viable options for the area. HDH proved to be too expensive without locally available and inexpensive sources of energy. RO is quite cost competitive with existing supply ($0.017/bucket vs. existing $0.024/bucket) provided a financing plan can be arranged. Rainwater collection is a viable option for improving the existing water supply, but will not completely solve the problem. By renovating and expanding the existing 100 m^3 cistern, up to 462 m^3 of water can be collected each year. Basic treatment can be added to the cistern to improve the quality of the water. It is our recommendation that if the water quality problem is to be solved as completely as possible that a community-wide RO plant be implemented and the water be sold at cost to pay for the plant's maintenance and security.

This paper and presentation can also be found on MIT's OpenCourseWare (OCW) website: MIT OCW 2.500 - Desalination and Water Treatment, Spring 2009.
Flywheel Hybrid Drive System - UCLA MAE 162M - 2008-06-04 - Report - Presentation

As energy demands and fuel prices increase, there is a need for hybrid vehicles that can recover the energy lost during braking. The FlyHyDriSys, or Flywheel Hybrid Drive System, is a kinetic energy storage system that captures and stores a vehicle's energy during braking for use at a later time. Mechanical energy storage hybrids are superior to gas-electric hybrids since they do not require battery packs and operate at much higher efficiencies. As with gas-electric hybrids, mechanical energy storage is excellent for city fuel economy but does little to improve highway fuel economy.

The system has two main drive components: the engine and flywheel. The engine and transmission from the standard vehicle are kept intact. A flywheel, clutch, and transmission is added to complete the hybrid power train. A planetary gear set is used to combine the two power sources into a single drive output. The FlyHyDriSys was designed around the 2009 Nissan Murano and with the exception of the flywheel and planetary gear set, utilizes all stock Nissan parts.

An energy analysis performed on the new system found that the FlyHyDriSys had a system efficiency, defined as the ratio of the recovered energy to the initial energy prior to braking, of 49%. This resulted in a reduction of city and suburban fuel consumption of 33% and an EPA city mileage increase of 49%. For a typical driver, the fuel consumption improvements results in a savings of $750/yr and a reduction of CO2 emissions of 1440 kg CO2/yr. These fuel economy improvements are superior to any existing hybrid vehicles currently on the market.
Dumbbellator - UCLA MAE 162B - 2008-03-20 - Report - Presentation

The Dumbbellator is a combination of a drawbridge and slider crank system. Upon start of the competition, the drawbridge is lowered in place using a simple motorized spool and pulley mechanism. Then, the slider crank mechanism pushes the dumbbell from Platform A to Platform B. The Dumbbellator performed exceptionally well during competition and won first place with a system weight of 14.8 lbs and a transport time of 3.2 seconds.

This report covers all aspects of the Dumbbellator, from early design process, analysis, manufacturing and testing, and up through the competition itself. A complete breakdown of the required parts, system and component drawings, and an overview of the machining and testing processes are also included. Lastly, a discussion of the team's progress throughout the quarter and final thoughts are presented at the end of the report.
Solar Collector - UCLA MAE 136 - 2008-03-11 - Report - Presentation

Energy is an issue that has risen to the global stage as fossil fuel options are becoming more expensive and detrimental to planet as well as our own health. The time for innovation has never been as necessary as the present. Solar energy provides a clean, fossil fuel free resource that could greatly mitigate our energy problems today while simultaneously providing a stable foundation for the future.

Solar energy is plentiful in many parts of the world, particularly desert areas such as the Mojave Desert in California. There are currently many ways to gather solar radiation and convert it into a usable form of energy. However, the focus of this project will be to analyze the parabolic trough collector in detail by utilizing powerful mathematical modeling techniques and to evaluate the effects of numerous parameters.
Solar Power Plant Optimization - UCLA MAE 133A - 2007-12-05 - Report

Several power plant design proposals are to be investigated and optimized in order to determine which power plant has the greatest efficiency and the lowest running cost. Four power plants were considered: Brayton Power, Rankine Regeneration Power, Combined Power, Combined Power with Solar Collector. The Brayton power plant had an efficiency of 34.5% and had a fuel consumption rate of 2.24 kg CH4/s resulting in a cost of $0.089/kWh . The Rankine power plant had an efficiency of 42.3% and had a fuel consumption rate of 3.10 kg CH4/s resulting in a cost of $0.100/kWh. The Combined power plant had an efficiency of 48.1% and had a fuel consumption rate of 2.24kg CH4/s resulting in a cost of $0.064/kWh . The Combined power plant with a Solar collector had an effective efficiency of 48.1% and had a fuel consumption rate of 1.43kg CH4/s resulting in a cost of $0.041/kWh . Clearly, the combined cycle with the solar heater is the best option as it results in the lowest energy prices. By projecting the cost of fuel over the next ten years, the solar collector will save an estimated 165-275 million dollars. In addition to monetary savings, the solar collector also has positive environmental impacts since it cuts down on greenhouse emissions.
CAD Project - UCLA MAE 94 - 2006-12-01 - Report - Presentation - Animation

Designed and modeled a working steering system for a car using Autodesk Inventor.

Karan Mistry

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Reports, Abstracts, and Links