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Significant effort has been put toward developing future-generation biofuels aimed at either spark-ignition or compression-ignition engines. Butyl-Acetate (BA), C6H12O2, is one such fuel that may be viable as a soot reduction drop-in blend candidate without significant impact on performance or efficiency. Though BA does have a low CN (≈ 20) and heating value (27 MJ/kg), it offers promise as a drop in blend-candidate with pump diesel due to its improved cold weather performance, high flash point, and potential for high volume renewable production capacity. This work investigated the impacts of 5% by volume blend of BA and standard pump diesel (DF2) on overall performance and with a particular focus on soot behavior. Tests were completed at 13 operating points spanning the operating map including full power. Results show a significant reduction in soot without significant impact on NOx emissions and minimal impact on thermal efficiency.

Dual-fuel engines employ precisely metered amounts of a high reactivity fuel (HRF) such as diesel at high injection pressures to burn a low reactivity fuel (LRF) such as natural gas, which is typically fumigated into the intake manifold. Dual fuel engines have demonstrated the ability to achieve extremely low engine-out oxides of nitrogen (NOx) emissions compared to conventional diesel combustion at the expense of unburned hydrocarbon (HC) and carbon monoxide (CO) emissions. At low engine loads, due to low in-cylinder temperatures, oxidation of HC and CO is very challenging. This results in both compromised combustion and fuel conversion efficiencies.

This research examines the interdependence of the control strategies of a high-pressure exhaust gas recirculation (HP-EGR) and a variable geometry turbocharger (VGT) on a medium-duty diesel engine in transient load operation. The effect on fuel economy, particulate and NO production were investigated through multiple tests of synchronously controlled VGT and EGR positions. An optimal steady-state strategy of the above determinants was defined as a function of the VGT’s boost pressure and EGR percent mass. The optimal steady-state strategy was then used to investigate the interdependence of the VGT and HP-EGR in transient load acceptence events which occurred over a range of 2 to 10 seconds. The faster transients increased deviations of boost and EGR levels from steady-state calibration values which consequently led to corresponding fuel consumption and particulate matter emission increases.

This work investigates the potential improvements in vehicle fuel economy possible by optimizing gear shift strategies to leverage a novel boosting device, an electrically assisted variable speed supercharger (EAVS), also referred to as a power split supercharger (PSS). Realistic gear shift strategies, resembling those commercially available, have been implemented to control upshift and downshift points based on torque request and engine speed. Using a baseline strategy from a turbocharged application of a MY2015 Ford Escape, a vehicle gas mileage of 34.4 mpg was achieved for the FTP75 drive cycle before considering the best efficiency regions of the supercharged engine.

This paper presents a system intended to optimize the balance between performance and efficiency of a vehicle completing a course. For example, the Formula SAE competition includes an endurance event where 100 points are based on fuel efficiency, and 275 points are based on performance. While lap simulation programs are typically used to decrease lap times by modifying the car’s design parameters, our goal is a lap simulation tool that can also be used to maximize the fuel efficiency while maintaining a prescribed performance level. In the FSAE event, if the fuel consumption can be reduced enough while maintaining a comparable lap time, the overall score can increase dramatically. The simulation presented will optimize gear shifts points, maximum throttle position, fuel mixture, and perform a lift and coast procedure to achieve the highest score for endurance and efficiency combined.

Lightweight metals such as Al and Mg alloys have been increasingly used for reducing mass in both structural and non-structural applications in transportation industries. Joining these lightweight materials using traditional fusion welding techniques is a critical challenge for achieving optimum mechanical performance, due to degradation of the constituent materials properties during the process. Friction stir welding (FSW), a solid-state joining technique, has emerged as a promising method for joining these lightweight materials. In particular, high joining efficiency has been achieved for FSW of various Al alloys and Mg alloys separately. Recent work on FSW of dissimilar lightweight materials also show encouraging results based on quasi-static shear performance. However, coach-peel performance of such joints has not been sufficiently examined.

Friction stir linear welding (FSLW) is widely used in joining lightweight materials including aluminum alloys and magnesium alloys. However, fatigue life prediction method for FSLW is not well developed yet for vehicle structure applications. This paper is tried to use two different methods for the prediction of fatigue life of FSLW in vehicle structures. FSLW is represented with 2-D shell elements for the structural stress approach and is represented with TIE contact for the maximum principal stress approach in finite element (FE) models. S-N curves were developed from coupon specimen test results for both the approaches. These S-N curves were used to predict fatigue life of FSLW of a front shock tower structure that was constructed by joining AM60 to AZ31 and AM60 to AM30. The fatigue life prediction results were then correlated with test results of the front shock tower structures.

Engine and drivetrain simulation has become an integral part of the automotive industry. By creating a virtual representation of a physical system, engineers can design controllers and optimize components without producing a prototype, thus reducing design costs. Among the numerous simulation approaches, 1D physics-based models are frequently implemented due to balanced performance between accuracy and computational speed. Several 1D physics-based simulation software packages currently exist but cannot be directly implemented in MALAB/Simulink. To leverage MATLAB/Simulink's powerful controller design and simulation capabilities, a 1D physics-based engine simulation tool is currently being developed at The University of Alabama. Previously presented work allowed the user to connect engine components in a physically representative manner within the Simulink environment using a standard block connection scheme and embedded MATLAB functions.

Natural luminosity (NL) and chemiluminescence (CL) imaging diagnostics are employed to investigate fuel-property effects on mixing-controlled combustion, using select research fuels-a #2 ultra-low sulfur emissions-certification diesel fuel (CF) and four of the Fuels for Advanced Combustion Engines (FACE) diesel fuels (F1, F2, F6, and F8)-that varied in cetane number (CN), distillation characteristics, and aromatic content. The experiments were performed in a single-cylinder heavy-duty optical compression-ignition (CI) engine at two injection pressures, three dilution levels, and constant start-of-combustion timing. If the experimental results are analyzed only in the context of the FACE fuel design parameters, CN had the largest effect on emissions and efficiency.

Currently, several 1D physics-based high-fidelity engine simulation software packages exist and provide reasonably accurate predictions of engine performance. However, most of the current high-fidelity engine simulation packages are developed in conventional programming languages and cannot be directly implemented in today's predominant MATLAB/Simulink simulation environment. In an effort to develop a MATLAB/Simulink-based engine simulation package, a high-fidelity 1D physics-based engine simulation model is currently being developed at The University of Alabama. The proposed model library includes various functional blocks capable of being connected in a logical manner to form a full engine system. Some of the functional blocks include a 1D unsteady flow section, cylinder valve, throttle, flow junction, cylinder, and engine dynamics. In this paper, preliminary simulation results are presented as well as descriptions of the functional blocks.

Recently [1, 2, 3 and 4], the novel Advanced (injection) Low Pilot-Ignited Natural Gas (ALPING) low-temperature combustion (LTC) concept was demonstrated to yield very low NOx emissions (<0.2 g/kWh) with high fuel conversion efficiencies (>40%). In the ALPING-LTC concept, very small diesel pilot sprays (contributing ∼2-3 percent of total fuel energy) are injected early in the compression stroke (60°BTDC) to ignite lean, homogeneous natural gas-air mixtures. To simulate ALPING-LTC, a phenomenological thermodynamic model was developed. The cylinder contents were divided into an unburned zone containing fresh natural gas-air mixture, several packets containing diesel and entrained natural gas-air mixture, a flame zone, and a burned zone. The simulation explicitly accounted for pilot injection, spray entrainment, diesel ignition (with the Shell autoignition model), spray combustion of diesel and entrained natural gas, and premixed turbulent combustion of the natural gas-air mixture.

Liquid coolants are commonly used as thermal transport media to increase efficiency and flexibility in aerospace vehicle design. The introduction of gas bubbles into the coolant can have negative consequences, including: loss of centrifugal pump prime, irregular sensor readings, and blockage of coolant flow to remote systems. One solution to mitigate these problems is the development of a passive gas removal device, or gas trap, installed in the flight cooling system. In this study, a new hydrophilic, composite membrane has been developed for passage of the coolant fluid and retention of gas bubbles. The trapped bubbles are subsequently vented from the system by a thin, hydrophobic, microporous membrane. The original design for this work employed a homogeneous membrane that was susceptible to fouling and pore plugging.

Aerospace applications with requirements for large capacity heat removal (launch vehicles, platforms, payloads, etc.) typically use a liquid coolant as a thermal transport media to increase efficiency and flexibility in vehicle design. An issue with these systems, however, is susceptibility to the presence of non-condensable gas (NCG) or air. The presence of air in a coolant loop can have one or more negative consequences. It can cause loss of centrifugal pump prime, interfere with sensor readings, inhibit heat transfer, and block coolant flow to remote systems. Hardware ground processing to remove this air is also cumbersome and time consuming which drives up these recurring costs. Current systems for maintaining the system free of air are tailored and have demonstrated only moderate success.

The flow inside of an internal combustion engine is highly complex and varies greatly among different engine types. For a long time IC engine researchers have tried to classify the major mean flow patterns and turbulence characteristics using different measurement techniques. During the last three decades tumble and swirl numbers have gained increasing popularity in mean flow quantification while turbulent kinetic energy has been used for the measurement of turbulence in the cylinder. In this paper, simultaneous 3-D LDV measurements of the in-cylinder flows of the three different engines are summarized for the quantification of the flow characteristics. The ensemble averaged velocity, tumble and swirl motions, and turbulence kinetic energy during the intake and compression strokes were examined from the measured velocity data (approximately 2,000 points for each case) by the 3-D LDV system.

The problem of supplying JIT assembly workstations from a central depot with a goal of minimizing inventory and vehicle requirements is the focus of this paper. To minimize work-in-process inventory, the quantity of component parts delivered to each workstation must be just enough to satisfy production until the next delivery of components. To minimize vehicle requirements, there should be no vehicle idle time. The problem is modeled as a vehicle routing problem with a nonlinear capacity constraint. A heuristic solution procedure is outlined and a relaxed formulation is given to provide a lower bound on the number of vehicles required.

A simulation methodology for dynamic modeling of geared rotor systems such as superchargers was used for determining the housing vibration response. The approach provides an ability to make quick parametric design modifications to the model for evaluation of relative noise response with the assumption that the averaged housing vibration level correlates approximately to the noise radiating from the surface. The housing in some cases was modeled as a lumped mass representation for efficiency, and when higher accuracy of housing modes was needed, a detailed flexible Finite Element Analysis (FEA) representation was used. The interesting features of the methodology were the use of constraint equations to model the gear mesh response per unit Transmission Error (TE) input, along with summarizing the component kinetic and strain energy for each mode and the mesh compliance for fast evaluation of opportunities for noise reduction.

A nominal 520 kW (thermal) air-conditioning system based on the seasonal storage of cold water in an aquifer has cooled a University of Alabama building since 1983. During cold weather, ambient, 18° C water is pumped from warm supply wells, chilled to about 6° C in a cooling tower, and reinjected into separate cold storage wells. In warm weather, water is withdrawn from the cold wells and pumped through building heat exchangers for air conditioning. Presented here are results of 6 years of study [sponsored by the U.S. Department of Energy through Pacific Northwest Laboratory] of the first successful U.S. application of this technology. This system yields high energy efficiency, with measured annual average COP of about 5 (SEER = 17 Btu/Wh), and energy recovery efficiency ranging from 40 to 85%, shifts utility loads from summer to winter, and no chlorofluorocarbon (CFC) release.

A dual-fuel conversion for the 3406-B Caterpillar marine diesel engine has been developed. The purpose of this conversion is to use lower priced natural gas as a fuel, thus providing substantial cost savings for large fuel consumers. The conversion applies dual-fuel technology to the smaller high-speed direct-injected diesel engine. Parameters are identified which allow a dual-fuel conversion to operate with similar performance as a diesel engine while simultaneously maintaining parameters that promote engine life. Test data is presented comparing various characteristics of both dual-fuel and diesel operation. Details of the conversion system are given. Data is presented showing fuel consumption, conditions leading to engine knock, conditions promoting methane flame propagation, and air-fuel ratios required for efficient combustion.