M.S.

An attempt was made to reduce fuel costs of a diesel-electric locomotive by operating the locomotive in a periodic manner, as opposed to operating at a constant velocity. The periodic operation consisted of accelerating the locomotive in a high throttle position and then deccelerating at a low throttle position. An SD40 Locomotive was modeled to test the periodic operation. The periodic operation was actually found to offer no improvement in fuel performance over that of constant velocity operation. A modification to the diesel engine that takes advantage of the periodic operation is suggested that will give a better fuel performance. The modification to the engine would not be possible with constant velocity operation. With the modification, the periodic operation was found to save fuel over the constant velocity operation. A controller was then designed to implement the periodic operation. The key component of the controller is an observer to determine unknown hill forces. The controller was found to work successfully. / M.S.

Existing traffic models are widely used in multiple frameworks, most prominently, microscopic vehicle-scale occurring on the scale of seconds and macroscopic city-scale flow patterns that develop over the scale of hours. Research works and practical applications usually employ either one or the other framework, and there is little overlap in the respective research communities. This dissertation develops mathematical techniques to bridge the two scales. The particular case of bridging the micro and macro scales of models in the stable traffic regime has been extensively studied, however what has been often overlooked is the unstable regime. Thus, of particular importance are models that can capture dynamic instabilities and traveling traffic waves called phantom jams. Such models are particularly challenging to analyze, as many papers on PDE models explicitly exclude the unstable situation. This thesis (i) outlines the mathematical foundations of microscopic and macroscopic models of interest, (ii) establishes a principled procedure of generating macroscopic flow quantities from microscopic models in the unstable regime, (iii) presents a study addressing the averaging of scales and the understanding of macroscopic manifestations of microscopic car-following traffic waves based on a framework of systematic hierarchy of tests that isolate the car-following dynamics, (iv) explains the corresponding effective traffic state and non-equilibrium wave structures that rise in the fundamental diagram, (v) and derives and validates vehicle type specific simple fuel consumption rate models that are accurate, computationally fast, and have desirable physics-like properties. The insights gained from this study has many applications. One of them presented here is the relevance of dampening traffic waves in the presence of sparse control and in light of the energy demand of traffic at the vehicle-scale, waves-scale, and city scale. / Mathematics

Diesel engine and generator sets (gensets) have been extensively used for standby and remote power generation over the past hundred years. Due to their use for standby power, these diesel gensets are designed to operate in conjunction with the grid, which relates to a fixed speed operation with a 60 Hz AC output. For operation in remote conditions, such as military and disaster relief applications, this fixed speed operation results in limiting the power output available from the engine, as well as the overall efficiency of the system. The removal of this grid connectivity requirement could result in an increase in system efficiency. At a given load, the engine operates more efficiently at lower speeds, which corresponds to an increase in the system efficiency. This low speed operation also results in lower power output. Knowledge of the load is important in order to determine the most efficient operating point for fixed speed operations. Operating at a higher power output for a given speed also results in higher system efficiency. The addition of a battery pack will allow for a higher apparent load, resulting in higher operating efficiency. The addition of a battery pack will also allow for energy storage, which allows for a higher operating efficiency, as well as "engine off time". A controlled series capacitor converter should be used to ensure that the maximum power is transferred from the genset to the battery/load. Knowledge of the load and equipment available should be used in order to determine the ideal dispatch strategy. Overall, operation at the grid frequency limits the efficiency of the overall system for remote operations where grid frequency is not required. The simulated genset had an efficiency of 24% for a 3 kW when operated at 1800 RPM, and increase from the 17% efficiency at it normal operating speed of 3600 RPM. This corresponded to a fuel savings of 3 gallons over 24 hours of continuous operation. When a battery is incorporated into the system, the efficiency of the system will increase for a given output load. For example, the simulated genset has an efficiency of 15% for a 1 kW load, which increases to 24% when a battery is added and charged at 2 kW. / Master of Science / Diesel engine and generator sets (gensets) have been extensively used for emergency and remote power generation over the past hundred years. Due to their use for emergency power, these diesel gensets are designed to operate in the same way as the grid. This results in a fixed speed operation in order to achieve 60 Hz. For operation in remote conditions, such as military and disaster relief applications, this fixed speed operation results in limiting the power output available from the engine, as well as the overall efficiency of the system. Increasing the efficiency of the diesel engine will increase the overall system efficiency, which is the relationship between the energy into the engine as compared to the energy produced. At a given load, or energy output requirement, the engine will operate more efficiently at lower speeds. This low speed operation, however, will result in a lower power output. Therefore, knowledge of the load is important in order to determine the most efficient operating point for a diesel engine, and the genset as a system. Operating at a higher power output for a given speed also results in higher system efficiency. The addition of a battery pack will allow for a higher apparent load, or the load seen by the engine, resulting in higher operating efficiency for the engine. The addition of a battery pack will also allow for energy storage, which allows for “engine off time”, or time which the system can provide power silently. Analysis should be conducted to ensure that the maximum power is transferred from the genset to the battery/load. Knowledge of the load and all equipment available should be used in order to determine the ideal charging and discharging strategy for the battery and system. Overall, operation at the grid frequency limits the efficiency of the overall system for remote operations where grid frequency is not required. A simulation was conducted to illustrate this concept. The simulated genset would save approximately 3 gallons of fuel over a 24 hour operating time when run at of speed of 1800 RPM, as opposed to its normal operating speed of 3600 RPM. When a battery is incorporated into the system, an additional gallon of fuel can be saved over a 24 hour period.

This thesis presents a performance assessment of flight operations in the North Atlantic Organized Track System (OTS) using the Global Oceanic Model. The main contributions of the study are: a) improvements to the logic of the Global Oceanic Model; b) prediction of benefits among various aircraft separation minima and operational policies to assign flights to tracks in the OTS system; and c) forecast of OTS traffic over North Atlantic from 2020 to 2040. The preliminary results show that a concept of operation with longitudinal separation minima of 15 nm and information of the flight cost matrix provides average fuel savings of 93 kilograms per flight using 2020 traffic. The fuel savings increase to 170 kilograms per flight using traffic levels expected in the year 2040. A new operational track assignment routine is developed and it could save around 40 kilograms per flight compared with the current concept of operations. The study results show a shortage of capacity of the Organized Track System in the future. The analysis shows that the OTS configuration used today and in 2020 is unable to accommodate the traffic projected in 2040. The analysis concludes that more tracks will be needed to maintain an acceptable level of service. / MS / The North Atlantic Organized Track System (OTS) are directional tracks for aircraft to fly between North America and Europe. This thesis presents a performance assessment of flight operations in the North Atlantic using a computer simulation model -- Global Oceanic Model. The main contributions of the study are: a) improvements to the logic of the Global Oceanic Model; b) prediction of benefits among various aircraft separation minima and operational policies to assign flights to tracks in the OTS system; and c) forecast of OTS traffic over Atlantic from 2020 to 2040. The preliminary results show that the predicted average fuel savings in the year 2020 are 93 kilograms per flight when aircraft are separated 15 nm longitudinally and assigned to tracks based on the flight cost matrix. The average fuel savings increase to 170 kilograms per flight using traffic levels expected in the year 2040. Additionally, a new operational track assignment routine is developed and it could save around 40 kilograms per flight compared with the current concept of operations. In conclusion, the Organized Track System configuration used today may be unable to accommodate the traffic projected in the year 2040. The shortage of capacity of the OTS indicates that more tracks will be needed to maintain an acceptable level of service.

In the traffic engineering field today, much attention is being given to the area of intersection control. The intersection has long been recognized as the most critical element in our highway system. Accidents, delay, wasted fuel and congestion are greatest at intersections. The variable having the greatest effect on traffic flow at an intersection or in a network of intersections is the traffic signal timing. In recent years, several computer programs have been developed to aid the traffic engineer in signal timing. This thesis examines the effect of the signal timing plans generated by one of the more widely used programs, TRANSYT 7, on the energy consumption of two signalized networks. Also examined are the relationships of delay and stops to fuel consumption. The TRANSYT 7 program was used to generate signal timing plans over a range of cycle lengths and stop penalties. The TRANSYT 7 signal timing plans were entered into NETSIM, a microscopic traffic simulation program, to determine their effect on fuel consumption in the two study networks. / Master of Science

Consecutive traffic signals produce vehicle stops and acceleration/deceleration maneuvers on arterial roads, which may increase vehicle fuel consumption levels significantly. Eco-cooperative adaptive cruise control (Eco-CACC) systems can improve vehicle energy efficiency using connected vehicle (CV) technology. In this thesis, an Eco-CACC system is proposed to compute a fuel-optimized vehicle trajectory while traversing multiple signalized intersections. The proposed system utilizes signal phasing and timing (SPaT) information together with real-time vehicle dynamics data to compute the optimal acceleration/deceleration levels and cruise speeds for connected-technology-equipped vehicles while approaching and leaving signalized intersections, while considering vehicle queues upstream of the intersections. The INTEGRATION microscopic traffic simulation software was used to conduct a comprehensive sensitivity analysis of a set of variables, including different levels of CV market penetration rates (MPRs), demand levels, phase splits, offsets, and distances between intersections to assess the benefits of the proposed algorithm. Based on the analysis, fuel consumption saving increase with an increase in MPRs and a decrease in the cycle length. At a 100% equipped-vehicle MPR, the fuel consumption is reduced by as much as 13.8% relative to the base no Eco-CACC control. The results demonstrate an existence of optimal values for demand levels and the distance between intersections to reach the maximum fuel consumption reduction. Moreover, if the offset is near the optimal values for that specific approach, the benefits from the algorithm are reduced. The algorithm is limited to under-saturated conditions, so the algorithm should be enhanced to deal with over-saturated conditions. / Master of Science / Consecutive traffic signals produce vehicle stops and acceleration/deceleration maneuvers on arterial roads, increasing vehicle fuel consumption levels. Drivers approaching signals are unaware of the signal status and may accelerate/decelerate aggressively to respond to traffic signal indications and thus increasing their fuel consumption. Research has been conducted to provide the driver with an optimal speed recommendations to reduce fuel consumption. Connected vehicle (CV) technology can be used to create a communication between the vehicle and traffic signals to provide information about the traffic light status and how many vehicles are waiting in the queue. In this thesis, an Eco-cooperative adaptive cruise control (Eco-CACC) system is proposed, which is a system that uses signal information to provide speed advice to the driver. This speed advice will not make the vehicle stop at any intersection, and this will reduce fuel consumption levels. The INTEGRATION software was used to test the effectiveness of the system in many scenarios. These scenarios include how many vehicles are equipped with this system, how many vehicles are in the system, the length of the green interval of the traffic signal, and distance between intersections. If we equip all vehicles with the system, the savings in fuel consumption can reach up to 13.8%. The system is designed for a network that is not extremely congested (over-saturated), implying that queues dissipate in a single traffic light cycle. The system needs to be further developed to deal with over-saturated conditions.

Traffic signal cycle lengths are traditionally optimized to minimize vehicle delay at intersections using the Webster formulation. This thesis includes two studies that develop new formulations to compute the optimum cycle length of isolated intersections, considering measures of effectiveness such as vehicle delay, fuel consumption and tailpipe emissions. Additionally, both studies validate the Webster model against simulated data. The microscopic simulation software, INTEGRATION, was used to simulate two-phase and four-phase isolated intersections over a range of cycle lengths, traffic demand levels, and signal timing lost times. Intersection delay, fuel consumption levels, and emissions of hydrocarbon (HC), carbon monoxide (CO), oxides of nitrogen (NOx), and carbon dioxide (CO2) were derived from the simulation software. The cycle lengths that minimized the various measures of effectiveness were then used to develop the proposed formulations. The first research effort entailed recalibrating the Webster model to the simulated data to develop a new delay, fuel consumption, and emissions formulation. However, an additional intercept was incorporated to the new formulations to enhance the Webster model. The second research effort entailed updating the proposed model against four study intersections. To account for the stochastic and random nature of traffic, the simulations were then run with twenty random seeds per scenario. Both efforts noted its estimated cycle lengths to minimize fuel consumption and emissions were longer than cycle lengths optimized for vehicle delay only. Secondly, the simulation results manifested an overestimation in optimum cycle lengths derived from the Webster model for high vehicle demands. / Master of Science / Traffic signal timings are traditionally designed to reduce vehicle congestion at an intersection. This thesis is based on two studies that develop new formulations to compute the most efficient signal cycle lengths of intersections, considering vehicle fuel consumption and tailpipe emissions. Additionally, both studies validate the Webster model, a model that is traditionally used in traffic signal design. Simulations were run to determine the intersection delay, fuel consumption levels, and emissions of hydrocarbon (HC), carbon monoxide (CO), oxides of nitrogen (NO_x), and carbon dioxide (CO₂) of the study intersections. To account for the random nature of traffic, each simulation scenario was run twenty different times. The cycle lengths that minimized the noted simulation outputs were then used to develop the proposed formulations. The new formulations demonstrated its estimated cycle lengths to minimize fuel consumption and emissions were longer than cycle lengths designed to minimize vehicle congestion. Secondly, the simulation results manifested an overestimation in optimum cycle lengths derived from the Webster model for high vehicle traffic.

Yes / In all industrial petrochemical plants and refineries, the furnace is the source of heat resulting from fuel combustion with air. The model-based furnace simulation is considered one of the efficient methods help to reduce the energy loss and maintain fixed refinery revenues, conserving energy, and finally reducing external fuel consumption and total fuel cost. In this paper, a model-based simulation is carried out for a natural air draught industrial scale furnace related to Liquified Petroleum Gas (LPG) production plant in Libya to thoroughly investigate the most responsible factors in lowering the furnace butane exit temperature, which is supposed to be two degrees Fahrenheit higher than inlet temperature. Therefore, to resolve this industrial problem, Aspen Hysys V10, coupling with EDR (exchanger design and rating) is used to carry out rigorous model-based simulation. This is specifically used to assess the impact of heat loss from inside the firebox to the surrounding medium and heat loss from the furnace stack and walls, besides the effect of excess air on the furnace efficiency. Furthermore, this research intends to verify whether the operating conditions, such as furnace tubes inlet flow rate, temperature and pumping pressure, are conforming to the upstream process design specifications or need to be adjusted. The results confirm that increasing furnace outlet temperature two degrees Fahrenheit from off specification 190 °F instead of 184 °F is successfully achieved by decreasing upstream stream flowrate 25% below the operating value and cutback excess air gradually until 20%. Also, the results clarify the necessity of increasing the flue gas temperature by 7% over design condition, to gain a significant reduction of heat loss of 31.6% and reach as low as 35.5 MBtu/hr. This improvement is achieved using optimum operating conditions of an excess air of 20%, and flue gas oxygen content of 3.3% delivered to stack. Accordingly, the furnace efficiency has been increased by 18% to hit 58.9%. Furthermore, the heat loss from the furnace walls can be also reduced by 68% from 5.41 MBtu/hr to 1.7 MBtu/hr by increasing the refractory wall thickness to 6 in., which entails an increase in the furnace efficiency by 3.66% to reach 58.96%. Decreasing the heat loss fraction through the refractory wall, pip doors, expansion windows and refractory hair cracks would also increase the efficiency by 21% to reach a high of 59.7%. Accordingly, a significant reduction in daily fuel consumption is observed, which costs 1.7 M$ per year. The outcomes of this research clearly show the potential of reducing the operation and maintenance costs significantly.

published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management