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Technical Paper

1D Model for Correcting the Rate of Injection Signal Based on Geometry and Temperature Influence

2017-03-28
2017-01-0819
The fuel consumption and emissions of diesel engines is strongly influenced by the injection rate pattern, which influences the in-cylinder mixing and combustion process. Knowing the exact injection rate is mandatory for an optimal diesel combustion development. The short injection time of no more than some milliseconds prevents a direct flow rate measurement. However, the injection rate is deduced from the pressure change caused by injecting into a fuel reservoir or pipe. In an ideal case, the pressure increase in a fuel pipe correlates with the flow rate. Unfortunately, real measurement devices show measurement inaccuracies and errors, caused by non-ideal geometrical shapes as well as variable fuel temperature and fuel properties along the measurement pipe. To analyze the thermal effect onto the measurement results, an available rate measurement device is extended with a flexible heating system as well as multiple pressure and temperature sensors.
Technical Paper

2005 Ford GT - Vehicle Aerodynamics - Updating a Legend

2004-03-08
2004-01-1254
This paper documents the processes and methods used by the Ford GT team to meet aerodynamic targets. Methods included Computational Fluid Dynamics (CFD) analysis, wind tunnel experiments (both full-size and scale model), and on-road experiments and measurements. The goal of the team was to enhance both the high-speed stability and track performance of the GT. As a result of the development process, significant front and rear downforce was achieved while meeting the overall drag target.
Technical Paper

2005 Ford GT Electrical & Electronics

2004-03-08
2004-01-1259
The Ford GT Program Team was allocated just 22 months from concept to production to complete the Electrical and Electronics systems of the Ford GT. This reduced vehicle program timing - unlike any other in Ford's history -- demanded that the team streamline the standard development process, which is typically 54 months. This aggressive schedule allowed only 12 weeks to design the entire electrical and electronic system architecture, route the wire harnesses, package the components, and manufacture and/or procure all components necessary for the first three-vehicle prototype build.
Technical Paper

A CFD Validation Study for Automotive Aerodynamics

2000-03-06
2000-01-0129
A study was conducted using Ford's nine standard CFD calibration models as described in SAE paper 940323. The models are identical from the B-pillar forward but have different back end configurations. These models were created for the purpose of evaluating the effect of back end geometry variations on aerodynamic lift and drag. Detailed experimental data is available for each model in the form of surface pressure data, surface flow visualization, and wake flow field measurements in addition to aerodynamic lift and drag values. This data is extremely useful in analyzing the accuracy of the numerical simulations. The objective of this study was to determine the capability of a digital physics based commercial CFD code, PowerFLOW ® to accurately simulate the physics of the flow field around the car-like benchmark shapes.
Technical Paper

A Comparison of Four Methods for Determining the Octane Index and K on a Modern Engine with Upstream, Port or Direct Injection

2017-03-28
2017-01-0666
Combustion in modern spark-ignition (SI) engines is increasingly knock-limited with the wide adoption of downsizing and turbocharging technologies. Fuel autoignition conditions are different in these engines compared to the standard Research Octane Number (RON) and Motor Octane Numbers (MON) tests. The Octane Index, OI = RON - K(RON-MON), has been proposed as a means to characterize the actual fuel anti-knock performance in modern engines. The K-factor, by definition equal to 0 and 1 for the RON and MON tests respectively, is intended to characterize the deviation of modern engine operation from these standard octane tests. Accurate knowledge of K is of central importance to the OI model; however, a single method for determining K has not been well accepted in the literature.
Technical Paper

A Computational Investigation of the Effects of Swirl Ratio and Injection Pressure on Mixture Preparation and Wall Heat Transfer in a Light-Duty Diesel Engine

2013-04-08
2013-01-1105
In a recent study, quantitative measurements were presented of in-cylinder spatial distributions of mixture equivalence ratio in a single-cylinder light-duty optical diesel engine, operated with a non-reactive mixture at conditions similar to an early injection low-temperature combustion mode. In the experiments a planar laser-induced fluorescence (PLIF) methodology was used to obtain local mixture equivalence ratio values based on a diesel fuel surrogate (75% n-heptane, 25% iso-octane), with a small fraction of toluene as fluorescing tracer (0.5% by mass). Significant changes in the mixture's structure and composition at the walls were observed due to increased charge motion at high swirl and injection pressure levels. This suggested a non-negligible impact on wall heat transfer and, ultimately, on efficiency and engine-out emissions.
Journal Article

A Frontal Impact Taxonomy for USA Field Data

2008-04-14
2008-01-0526
An eight-group taxonomy was created to classify real-world frontal crashes from the Crashworthiness Data System (CDS) component of the National Automotive Sampling System (NASS). Three steps were taken to develop the taxonomy: (1) frontal-impact towaway crashes were identified by examining 1985-2005 model year light passenger vehicles with Collision Deformation Classification (CDC) data from the 1995-2005 calendar years of NASS; (2) case reviews, engineering judgments, and categorization assessments were conducted on these data to produce the eight-group taxonomy; and (3) two subsets of the NASS dataset were analyzed to assess the consistency of the resulting taxonomic-group frequencies. “Full-engagement” and “Offset” crashes were the most frequent crash types, each contributing approximately 33% to the total. The group identified as “D, Y, Z No-Rail” was the most over-represented crash type for vehicles with at least one seriously-injured occupant.
Technical Paper

A Method of Predicting Brake Specific Fuel Consumption Maps

1999-03-01
1999-01-0556
A method of predicting brake specific fuel consumption characteristics from limited specifications of engine design has been investigated. For spark ignition engines operating on homogeneous mixtures, indicated specific fuel consumption based on gross indicated power is related to compression ratio and spark timing relative to optimum values. The influence of burn rate is approximately accounted for by the differences in spark timings required to correctly phase combustion. Data from engines of contemporary design shows that indicated specific fuel consumption can be defined as a generic function of relative spark timing, mixture air/fuel ratio and exhaust gas recirculation rate. The additional information required to generate brake specific performance maps is cylinder volumetric efficiency, rubbing friction, auxiliary loads, and exhaust back pressure characteristics.
Technical Paper

A Methodology of Real-World Fuel Consumption Estimation: Part 1. Drive Cycles

2018-04-03
2018-01-0644
To assess the fuel consumption of vehicles, three sets of input data are required; drive cycles, vehicle parameters, and environmental conditions. As the first part of a series of studies on real-world fuel consumption, this study focuses on the drive cycles. In principle, drive cycles should represent real-world usage. Some of them aim at a specific usage such as a city driving condition or an aggressive driving style. However, the definition of city or aggressive driving is very subjective and difficult to quantitatively correlate with the real-world usage. This study proposes a methodology to quantify the speed and dynamics of drive cycles, or vehicle speed traces in general, against the real-world usage. After reviewing parameter sets found in other studies, relative cubic speed (RCS) and positive kinetic energy (PKE) are selected to represent the speed and dynamics through energy flow balance at the wheels.
Technical Paper

A New Analysis Method for Accurate Accounting of IC Engine Pumping Work and Indicated Work

2004-03-08
2004-01-1262
In order to improve fuel economy, engine manufacturers are investigating various technologies that reduce pumping work in spark ignition engines. Current cylinder pressure analysis methods do not allow valid comparison of pumping work reduction strategies. Existing methods neglect valve timing effects which occur during the expansion and compression strokes, but are actually part of the gas exchange process. These additional pumping work contributions become more significant when evaluating non-standard valve timing concepts. This paper outlines a new analysis method for calculating the pumping work and indicated work of a 4-stroke internal combustion engine. Corrections to PMEP and IMEP are introduced which allow the valid comparison of pumping work and indicated efficiency between engines with different pumping work reduction strategies.
Journal Article

A Novel Approach to Create Dimensional Tolerance Requirements from Expert Knowledge

2017-03-28
2017-01-0241
Geometric Dimensioning and Tolerancing is used to describe the allowed feature variations regarding the product design. Tolerance specification is important in many stages of all phases on product development. The product development engineering need to define the symbols to use on the Feature Control Frame of every component. Since the component function has an increment on its complexity year over year, it is not trivial to define those symbols anymore. The determination of dimensional tolerance shall be preceded by careful specification of the types of tolerance and symbols that will be applied in controlled features. Poor tolerance specifications can increase the production cost, require late product changes or lead to legal issues.
Technical Paper

A Review of Human Physiological, Psychological & Human Biomechanical Factors on Perceived Thermal Comfort of Automotive Seats.

2017-03-28
2017-01-1388
Thermal comfort in automotive seating has been studied and discussed for a long time. The available research, because it is focused on the components, has not produced a model that provides insight into the human-seat system interaction. This work, which represents the beginning of an extensive research program, aims to establish the foundation for such a model. This paper will discuss the key physiological, psychological, and biomechanical factors related to perceptions of thermal comfort in automotive seats. The methodology to establish perceived thermal comfort requirements will also be presented and discussed.
Technical Paper

A Review of Modal Choice Models: Case Study for São Paulo

2017-11-07
2017-36-0279
The world urbanization is growing rapidly, bringing many challenges for people to move in dense metropolitan regions. Public transportation is not able to attend the whole demand, and individual transportation modes are struggling with traffic congestion and stringent regulations to reduce its attractiveness, such as the license plate restriction in São Paulo. On the other hand, enablers like smartphones mass penetration, GPS connected services and shared economy have opened space to a whole new range of possible solutions to improve people perception on urban mobility. This work aims to evaluate the modal choice behavior models and understand the success factor of current mobility solutions in the city of São Paulo. The data available through origin/destination researches will be used to validate the models used in this work.
Technical Paper

A Side Impact Taxonomy for USA Field Data

2018-04-03
2018-01-1331
An eleven-group taxonomy was created to classify real-world side crashes from the Crashworthiness Data System (CDS) component of the National Automotive Sampling System (NASS). Three steps were taken to develop the classification scheme: (1) side-impact towaway crashes were identified by examining 1987-2016 model year light passenger vehicles with Collision Deformation Classification (CDC) data from the 1997-2015 calendar years of NASS; (2) case reviews, engineering judgments, and categorization assessments were conducted on these data to produce the eleven-group taxonomy; and (3) taxonomic groups were reviewed relative to regulated crash test procedures. Two of the taxonomic groups were found to have the most frequent crash types, each contributing approximately 22% to the total, followed closely by a third taxonomic group contributing approximately 19%.
Technical Paper

A Technical Analysis of a Proposed Theory on Tire Tread Belt Separation-Induced Axle Tramp

2011-04-12
2011-01-0967
Recently, papers have been published purporting to study the effect of rear axle tramp during tread separation events, and its effect on vehicle handling [1, 2]. Based on analysis and physical testing, one paper [1] has put forth a mathematical model which the authors claim allows vehicle designers to select shock damping values during the development process of a vehicle in order to assure that a vehicle will not experience axle tramp during tread separations. In the course of their work, “lumpy” tires (tires with rubber blocks adhered to the tire's tread) were employed to excite the axle tramp resonance, even though this method has been shown not to duplicate the physical mechanisms behind an actual tread belt separation. This paper evaluates the theories postulated in [1] by first analyzing the equations behind the mathematical model presented. The model is then tested to see if it agrees with observed physical testing.
Technical Paper

A Testbed for the Mars Returned Sample Handling Facility

2001-07-09
2001-01-2412
Samples of Mars surface material will return to Earth in 2014. Prior to curation and distribution to the scientific community the returned samples will be isolated in a special facility until their biological safety has been assessed following protocols established by NASA’s Planetary Protection Office. The primary requirements for the pre-release handling of the Martian samples include protecting the samples from the Earth and protecting the Earth from the sample. A testbed will be established to support the design of such a facility and to test the planetary protection protocols. One design option that is being compared to the conventional Biological Safety Level 4 facility is a double walled differential pressure chamber with airlocks and automated equipment for analyzing samples and transferring them from one instrument to another.
Technical Paper

Accuracy of Powertrain Control Module (PCM) Event Data Recorders

2008-04-14
2008-01-0162
The primary purpose of this paper is to evaluate the accuracy of speed data recorded in the Ford PCM under steady state conditions. The authors drove 3 different test vehicles at 5 different steady state speeds from 48 to 113 kph (30 to 70 mph), making 6 runs at each speed. The authors collected PCM data after each run. For the first vehicle a GPS based Racelogic VBOX III was used to measure speed. For the second and third vehicle a purpose built speed trap with .0001 second resolution was used. The authors compare the readings and calculated differences and statistical limits. The secondary purpose is to deliberately create conditions that could result in errors of speed measured, document the conditions, and to quantify the error.
Technical Paper

Achievements and Exploitation of the AUTOSAR Development Partnership

2006-10-16
2006-21-0019
Reductions of hardware costs as well as implementations of new innovative functions are the main drivers of today's automotive electronics. Indeed more and more resources are spent on adapting existing solutions to different environments. At the same time, due to the increasing number of networked components, a level of complexity has been reached which is difficult to handle using traditional development processes. The automotive industry addresses this problem through a paradigm shift from a hardware-, component-driven to a requirement- and function-driven development process, and a stringent standardization of infrastructure elements. One central standardization initiative is the AUTomotive Open System ARchitecture (AUTOSAR). AUTOSAR was founded in 2003 by major OEMs and Tier1 suppliers and now includes a large number of automotive, electronics, semiconductor, hard- and software companies.
Technical Paper

Adaptive EGR Cooler Pressure Drop Estimation

2008-04-14
2008-01-0624
The pre EGR valve pressure is an important measurement for the Diesel engine air handling system. It is commonly used for the EGR flow calculation during engine transient operation. Due to the erosive exhaust gas, an EGR pressure sensor will eventually have gold corrosion resulting in drive-ability issues. Therefore, a software replacement for the EGR pressure sensor is desirable. However, when the EGR valve is on the cold side of the EGR cooler, the accuracy of the EGR pressure estimation deteriorates because of the variability of the pressure drop across the EGR cooler due to EGR cooler fouling. In this paper, an adaptive scheme is developed to improve the accuracy of pre EGR valve pressure estimation in the presence of EGR cooler fouling for diesel engines. The pressure drop across the EGR cooler is shown to be proportional to the velocity pressure of the EGR flow through the cooler.
Technical Paper

Advanced Development of the Direct Osmotic Concentration System

2008-06-29
2008-01-2145
Direct osmotic concentration (DOC) is an integrated membrane treatment process designed for the reclamation of spacecraft wastewater. The system includes forward osmosis (FO), membrane evaporation, reverse osmosis (RO) and an aqueous phase catalytic oxidation (APCO) post-treatment unit. This document describes progress in the third year of a four year project to advance hardware maturity of this technology to a level appropriate for human rated testing. The current status of construction and testing of the final deliverable is covered and preliminary calculations of equivalent system mass are funished.
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