Search Results

In this work, a discrete,time-based, delay-compensated, adaptive PID control algorithm for air fuel ratio control in an SI engine is presented. The controller operates using feedback from a wide-ranging Universal Exhaust Gas Oxygen (UEGO) sensor situated in the exhaust manifold. Time delay compensation is used to address the difficulties traditionally associated with the relatively long and time-varying time delay in the gas transport process and UEGO sensor response. The delay compensation is performed by computing a correction to the current control move based on the current delay and the corresponding values of the past control moves. The current delay is determined from the measured engine speed and load using a two dimensional map. In order to achieve good servo operation during target changes without compromising regulator performance a two degree of freedom controller design has been developed by adding a pre-filter to the air fuel ratio target.

In a continuing effort to include real-world emissions in regulatory testing, the USEPA has included air conditioning operation as part of the Supplemental Federal Test Procedure (SFTP). Known as the SC03, these tests require automobile manufacturers to construct and maintain expensive environmental chambers. However, the regulations make allowances for a simulation test, if one can be shown to demonstrate correlation with the SFTP results. We present the results from an experiment on a 1998 Ford sedan, which simulates the heat load of a full environmental chamber. Moreover, the test procedure is simpler and more cost effective. The process essentially involves heating the condenser of the air conditioning system by using the heat of the engine, rather than heating the entire vehicle. The results indicate that if the head pressure is used as a feedback signal to the radiator fan, the load generated by a full environmental chamber can be duplicated.

This paper proposes a method to make diagnostic/prognostic judgment about the health of a tire, in term of its wear, using existing on-board sensor signals. The approach focuses on using an estimate of the effective rolling radius (ERR) for individual tires as one of the main diagnostic/prognostic means and it determines if a tire has significant wear and how long it can be safely driven before tire rotation or tire replacement are required. The ERR is determined from the combination of wheel speed sensor (WSS), Global Positioning sensor (GPS), the other motion sensor signals, together with the radius kinematic model of a rolling tire. The ERR estimation fits the relevant signals to a linear model and utilizes the relationship revealed in the magic formula tire model. The ERR can then be related to multiple sources of uncertainties such as the tire inflation pressure, tire loading changes, and tire wear.

An obliquely incident X-ray radiography was developed to measure the greatest depths, orientations and locations of corrosion pits in automobile metallic plates. This technique can also be used on-site for components in use. The corrosion depth profile and the greatest depth can be calculated with the established relations. A 3-D rotational microscope and surface profiler were utilized to evaluate the sensitivities and accuracies of the technique for aluminum and steel plates, respectively.

This paper provides an overview of the effects of blending ethanol with gasoline for use in spark ignition engines. The overview is written from the perspective of considering a future ethanol-gasoline blend for use in vehicles that have been designed to accommodate such a fuel. Therefore discussion of the effects of ethanol-gasoline blends on older legacy vehicles is not included. As background, highlights of future emissions regulations are discussed. The effects on fuel properties of blending ethanol and gasoline are described. The substantial increase in knock resistance and full load performance associated with the addition of ethanol to gasoline is illustrated with example data. Aspects of fuel efficiency enabled by increased ethanol content are reviewed, including downsizing and downspeeding opportunities, increased compression ratio, fundamental effects associated with ethanol combustion, and reduced enrichment requirement at high speed/high load conditions.

Low Temperature Combustion (LTC) engines are promising to improve powertrain fuel economy and reduce NOx and soot emissions by improving the in-cylinder combustion process. However, the narrow operating range of LTC engines limits the use of these engines in conventional powertrains. The engine’s limited operating range can be improved by taking advantage of electrification in the powertrain. In this study, a multi-mode LTC-SI engine is integrated with a parallel hybrid electric configuration, where the engine operation modes include Homogeneous Charge Compression Ignition (HCCI), Reactivity Controlled Compression Ignition (RCCI), and conventional Spark Ignition (SI). The powertrain controller is designed to enable switching among different modes, with minimum fuel penalty for transient engine operations.

In recent years, implementation of dual phase (DP) Advanced High Strength Steels (AHSS) and Ultra High Strength Steels (UHSS) is increasing in automotive components due to their superior structural performance and vehicle weight reduction capabilities. However, these materials are often sensitive to trimmed edge cracking if stretching along sheared edge occurs in such processes as stretch flanging. Tool wear is another major issue in the trimming of UHSS because of higher contact pressures at the interface between cutting tools and sheet metal blank caused by UHSS’s higher flow stresses and the presence of a hard martensitic in the microstructure. The objective of the present paper is to discuss the methodology of analyzing die wear for trimming operations of UHSS components and illustrate it with some examples of tool wear analysis for trimming 1.5mm thick DP980 steel.

A normalized analytical vehicle fuel consumption model is developed based on an input/output description of engine fuel consumption and transmission losses. Engine properties and fuel consumption are expressed in mean effective pressure (mep) units, while vehicle road load, acceleration and grade are expressed in acceleration units. The engine model concentrates on the low rpm operation. The fuel mep is approximately independent of speed and is a linear function of load, as long as the engine is not knock limited. A linear, two-constant engine model then covers the speed/load range of interest. The model constants are a function of well-known engine properties. Examples are discussed for naturally aspirated and turbocharged SI engines and for Diesel engines. A similar model is developed for the transmission where the offset reflects the spin and pump losses, and the slope is the gear efficiency.

Advanced High Strength Steels such as Dual Phase 600 (DP600) are gaining popularity in automotive body structure applications. Given their higher strength, the efficacy of Advanced High Strength Steels for intrusion resistance applications is relatively well accepted. On the other hand, use of Advanced High Strength Steels for energy absorption applications needs to be studied and understood on a case-by-case basis. Based on stress-strain characteristics, one would expect DP600 as a material to have better energy absorbing characteristics than conventional High Strength Steel such as HSLA350 (High Strength Low Alloy Steel) that has comparable yield strength. However, as the energy absorption at the component and system level, in addition to material properties, depends on geometry, as well as manufacturing and assembly related factors, a study was conducted to compare the component level energy absorption characteristics of DP600 and HSLA350 parts.

The chain link and sprocket tooth impact during a meshing has been identified as the most significant noise source in a chain drive system. This paper first presents the theoretical derivation of the chain drive natural frequencies and mode shapes using the equations of motion from a stationary undamped chain drive system. The theoretical derivation shows the existence of three types of chain resonances, namely the transverse strand resonance, the longitudinal chain sprocket coupled resonance and the longitudinal chain stress wave type resonance. The chain-sprocket meshing noise is amplified when the chain sprocket meshing frequency corresponds to any one of the above mentioned chain drive system resonances. These theoretical results are then validated by a chain drive system CAE model using ABAQUS to identify the chain drive system resonances.

The front bumper of a current production vehicle, which is made of hot-stamped 15B21 aluminized steel, was studied for mass and cost reductions using the Advanced High Strength Stainless Steel product NITRONIC® 30 (UNS Designation S20400) manufactured by AK Steel Corporation. This grade of stainless steel offers a combination of high ductility and strength, which was utilized to significantly modify the design of the bumper beam to incorporate geometry changes that improved its stiffness and strength. The structural performance of the bumper assembly was evaluated using LS-Dyna-based CAE simulations of the IIHS 40% Offset Full-Vehicle Impact at 40 mph with a deformable barrier, and the IIHS Full Width Centerline 6 mph Low-Speed Impact. Optimization of the bumper beam shape and gauge was performed using a combination of manual design iterations and a multi-objective optimization methodology using LS-Opt.

With interest in improving vehicle quality and customer satisfaction, Ford Motor Company initiated an effort aimed at improving dent resistance of closure panels. An investigation of various means of product improvement led to the recognition of dual phase steels, due to their inherent formability and strain hardening attributes, as the most appropriate steel panel for outer panel applications. Ispat Inland's new Electro-galvanized dual phase steel DI-FORM 500 (henceforth referred to by the generic designation, DP500), which meets 500 MPa minimum tensile strength, was specifically designed to meet automotive exposed quality standards. This paper compares the dent resistance performance of automotive door assemblies manufactured with both Bake Hardenable 210 (BH210) and DP500 door outer panels. Results indicate the achievement of significantly improved outer panel dent resistance through the use of the DP500 product.

This work presents an application of two sub-models relative to chemical-kinetics-based turbulent pre-mixed combustion modeling approach on the simulation of burn rate and emissions of spark ignition engines. In present paper, the justification of turbulent pre-mixed combustion modeling directly based on chemical kinetics plus a turbulence model is given briefly. Two sub-models relative to this kind of pre-mixed combustion modeling approach are described generally, including a practical PRF (primary reference fuel) chemical kinetic mechanism which can correctly capture the laminar flame speed under a wide range of Ford SI (spark ignition) engines/operating conditions, and an advanced spark plug ignition model which has been developed by Ford recently.

This work presents turbulent premixed combustion modeling in spark ignition engines using G-equation based turbulent combustion model. In present study, a turbulent flame speed expression proposed and validated in recent years by two co-authors of this paper is applied to the combustion simulation of spark ignition engines. This turbulent flame speed expression has no adjustable parameters and its constants are closely tied to the physics of scalar mixing at small scales. Based on this flame speed expression, a minor modification is introduced in this paper considering the fact that the turbulent flame speed changes to laminar flame speed if there is no turbulence. This modified turbulent flame speed expression is implemented into Ford in-house CFD code MESIM (multi-dimensional engine simulation), and is validated extensively.

Because of the need to safely vent exhaust gases, most engine dynamometer facilities are not well suited to measuring engine exhaust orifice noise. Depending on the location of the dyno facility within the building, the exhaust system may need to be extended in order to properly vent the exhaust fumes. This additional ducting changes the acoustic modes of the exhaust system which will change the measured orifice noise. Duct additions downstream of the original orifice location also alter the termination impedance such that in-duct pressure measurements with and without the extended exhaust system can vary significantly. In order to minimize the effect of the building's exhaust system on the desired engine exhaust system measurements, the present approach terminates the engine exhaust into a large enclosed volume or surge tank before venting the gases into the building's ventilation system.

MIG (Metal Inert Gas or Gas Metal Arc welding) and spot welding are the most common way of joining steel components in automotive body, and frame structures. The main design benefits of MIG welding are however the ability to join the parts with single side access and the reduction or elimination of flanges. Different finite element based methodologies exist for predicting the durability of welds. These methodologies are being used in the automotive industry to resolve potential and current durability issues in spot and MIG welded steel components and also to reduce expensive testing practices. However, the analysis results highly depend on the finite element modeling and the accuracy of weld data. This paper briefly describes some of the lessons learned while applying the weld life prediction technology for MIG and spot welds in automotive steel structural components.

The automotive refrigerant systems can occasionally exhibit a transient hoot/whistle type noise under certain operating conditions. High pressure/velocity refrigerant flow through an evaporator core can readily excite the inherent acoustical and/or structural modes, resulting in audible transient tones. This condition if present can be experienced while driving away from a short stop and can last 2 to 10 seconds. The ambient conditions suitable for creating this noise are - moderate/high air-conditioning (A/C) load during days at 85-95° F temperatures with high humidity. Possible noise generating mechanisms have been discussed in earlier publications and our findings during this study indicate that they are excited by the high velocity superheated refrigerant vapor flow through the evaporator core plates. Examples of this transient noise and its spectral characteristics are presented to characterize this refrigerant system induced issue.

To reach safety, emissions, and cost objectives, manufacturers of automotive body structural components shape thin gauge, high strength steel tube using a series of manufacturing steps that often include bending, preforming and hydroforming. Challenging grades and bend severity require a sensitive optimization of the tubular bending process. To this end, it is necessary to achieve an understanding of efficient measurement methods capable of capturing small differences in bending formability. In preparation for an optimization of a 90o bend using Dual Phase 780 (DP780) and High Strength Low Alloy (HSLA350) thin walled tube, the measurement techniques of three formability characteristics: thinning, strain, and final geometry were statistically evaluated. In addition, the difference in the bending behaviour of the two grades was evaluated.

To reach safety, emissions, and cost objectives, manufacturers of automotive body structural and chassis components shape thin gauge, high strength steel tube with a bending, pre-forming and hydroforming process. Challenging grades and bend severity require a careful optimization of the bending procedure. A joint project between Ford and ArcelorMittal Tubular Products investigated suitable bending parameters for severe bends using commercially available thin-walled DP780 and HSLA350 tubes. This paper summarizes the measurement methods found to be capable of capturing small differences in bending formability and details the influence of bender variables such as boost, pressure die, center-line bend radius and bend angle on the wrinkling, thinning and springback of these tubes. As a result of this work, recommendations were made as to effective bender set-ups for these tubes.

Mechanical shock tests for lithium metal and lithium-ion batteries often require that each cell or battery pack be subjected to multiple shocks in the positive and negative directions, of three mutually perpendicular orientations. This paper focuses on the no-disassembly requirement of those testing conditions and on the CAE methodology specifically developed to perform this assessment. Ford Motor Company developed a CAE analysis method to simulate this type of test and assess the possibility of cell dislodging. This CAE method helps identify and diagnose potential failure modes, thus guiding the Design Team in developing a strategy to meet the required performance under shock test loads. The final CAE-driven design focuses on the structural requirement and optimization, and leads to cost savings without compromising cell or pack mechanical performance.