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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.

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.

This paper starts with an analysis of design configurations of the drivelines with different power-dividing units (PDUs) of main dump truck manufacturing companies. As it follows from the analysis, improvements of articulated truck energy efficiency and reduction of fuel consumption by optimizing the power distribution to the drive wheels are still open issues. The problem is that a variety of operating and terrain conditions of dump trucks requires different wheel power distributions that cannot be provided by one set of PDUs employed in a truck. The central PDU in the transfer case was identified as the most important PDU among the five PDUs, which plays a crucial role in the power distribution between the front axle and the rear tandem of a 6×6 articulated dump truck. The paper formulates a constraint optimization problem to minimize the tire slippage power losses by optimizing the power distribution between the drive wheels.

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.

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.

We characterize the cyclic behavior of an AM30 extruded magnesium alloy. The micromechanisms of cyclic damage were studied by means of strain controlled experiments in both the extruded and transverse directions. A scanning electron microscope (SEM) analysis of the microstructure revealed that second phase particles were present in the Mg alloy that nucleated the cracks. However, crack initiation sites were observed to occur due to profuse twinning. Low cycle fatigue parameters were determined, and a microstructure-sensitive MultiStage Fatigue (MSF) model, which is able to capture mechanical and microstructure properties, was implemented to predict fatigue behavior and failure.

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.

A multi-coordinate FRF-based inverse substructuring approach is proposed to partition a vehicle system into two or more substructures, which are coupled at discrete interface points. The joint and free substructure dynamic characteristics are then extracted from the coupled system response spectra. Depending on the actual form of the structural coupling terms, three forms of the coupling matrix are assumed here. The most general one constitutes the non-diagonal form, and the other two simpler cases are the block-diagonal and purely diagonal representations that can be used to simplify testing process and overcome computational problems. The paper is focused on the investigation of the durability of these three formulations when the input FRFs are noise contaminated. A finite element model of a simplified vehicle system is used as the case study.

A spectral-based substructuring approach applying linear frequency response functions (FRF) is proposed for improving the accuracy of simulating the dynamics of coupled systems. The method also applies a least square singular value decomposition (SVD) scheme to overcome the inherent computational deficiency in the basic substructuring formulation. The computational problem is caused by the magnification of measurement errors during any one of the matrix inversion calculations required for this method. The primary objective of applying this approach is to examine the possibility of analyzing higher frequency response that is normally not possible using conventional modeling technique such as the direct finite and boundary element, and lumped parameter techniques. In this study, additional concepts are also evaluated to quantify the limitations and range of applicability of the proposed substructuring approach for simulating the vibration response of complex powertrain structures.

All modern automotive automatic transmissions require the use of a torque converter to allow for the transmission of torque from the engine to the drivetrain. Although they are commonly used throughout the automotive industry, there is little understanding of the internal flows within the torque converter. An experimental study has been conducted to reveal the internal flow characteristics within a production torque converter using Laser Doppler Velocimetry (LDV) under the operating conditions. LDV measurements were conducted on the planes between impeller blades, and the gap between the impeller and turbine blades. The study showed that the internal flow is highly complex and the difference in rotor speeds between the impeller and turbine compound the flow effects. Transmission oil flows in the planes at the impeller exit and gap region were affected by the turbine blade as it passed.

The Alabama Technology Network, Inc. (ATN) provides technical assistance, management assistance and training that complements workforce and economic development. The ATN center at the University of Alabama in Huntsville (UAH) has focused on lean manufacturing. This paper summarizes the principles of “lean”, presents three phases to implementing lean, and illustrates its application in a training simulation of a setup/changeover reduction. Finally, success stories show how UAH is helping many small and medium size manufacturers improve rapidly using lean techniques.

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.

The main objective of this study is to simulate the design and operational policies of the assembly shop of an automotive plant for planning purposes and to find possible improvements. The simulation study was used to answer the following questions: How does the sequence affect the daily throughput? What conveyor speeds are required to achieve a target output? How do the buffers between lines affect product flow and impact the line stoppage? What are the bottlenecks to the assembly lines in a given scenario? A simulation model was developed in accordance with the objective of this study. The model incorporates detailed workstation logic to accurately model downtime results through the use of a pull cord system. It is written with SIMAN. The discrete event feature of SIMAN does not adequately model the conveyor systems of the assembly shop. As a result, a few subroutines were added to the SIMAN modeling structures to mimic the operations of the assembly shop.

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 mathematical model is presented to help understand sheet metal deformation during forming. The particular purpose of this model is to predict the forming limit diagram (FLD). The present model is an extension of a previous analysis by Jones and Gillis (JG) in which the deformation is idealized into three phases: (I) homogeneous deformation up to maximum load; (II) deformation localization under constant load; (III) local necking with a precipitous drop in load. In phase III the neck geometry is described by a Bridgman type neck. The present model extends the JG theory which was applied to the right hand side of the FLD only. The main difference in treating the two different sides of the FLD lies in the assumptions regarding the width direction deformations. For biaxial stretching, the right hand side, the minor strain rate is assumed to be homogeneous throughout the process.