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Journal Article

Evaluation of DAMAGE Algorithm in Frontal Crashes

2024-04-17
2023-22-0006
With the current trend of including the evaluation of the risk of brain injuries in vehicle crashes due to rotational kinematics of the head, two injury criteria have been introduced since 2013 – BrIC and DAMAGE. BrIC was developed by NHTSA in 2013 and was suggested for inclusion in the US NCAP for frontal and side crashes. DAMAGE has been developed by UVa under the sponsorship of JAMA and JARI and has been accepted tentatively by the EuroNCAP. Although BrIC in US crash testing is known and reported, DAMAGE in tests of the US fleet is relatively unknown. The current paper will report on DAMAGE in NCAP-like tests and potential future frontal crash tests involving substantial rotation about the three axes of occupant heads. Distribution of DAMAGE of three-point belted occupants without airbags will also be discussed. Prediction of brain injury risks from the tests have been compared to the risks in the real world.
Technical Paper

CAATS - Automotive Wind Tunnel Test Techniques

2024-04-09
2024-01-2543
This paper contributes to the Committee on Commonized Aerodynamics Automotive Testing Standards (CAATS) initiative, established by the late Gary Elfstrom. It is collaboratively compiled by automotive wind tunnel users and operators within the Subsonic Aerodynamic Testing Association (SATA). Its specific focus lies in automotive wind tunnel test techniques, encompassing both those relevant to passenger car and race car development. It is part of the comprehensive CAATS series, which addresses not only test techniques but also wind tunnel calibration, uncertainty analysis, and wind tunnel correction methods. The core objective of this paper is to furnish comprehensive guidelines for wind tunnel testing and associated techniques. It begins by elucidating the initial wind tunnel setup and vehicle arrangement within it.
Technical Paper

A Comparative Study of Recurrent Neural Network Architectures for Battery Voltage Prediction

2021-09-21
2021-01-1252
Electrification is the well-accepted solution to address carbon emissions and modernize vehicle controls. Batteries play a critical in the journey of electrification and modernization with battery voltage prediction as the foundation for safe and efficient operation. Due to its strong dependency on prior information, battery voltage was estimated with recurrent neural network methods in the recent literatures exploring a variety of deep learning techniques to estimate battery behaviors. In these studies, standard recurrent neural networks, gated recurrent units, and long-short term memory are popular neural network architectures under review. However, in most cases, each neural network architecture is individually assessed and therefore the knowledge about comparative study among three neural network architecture is limited. In addition, many literatures only studied either the dynamic voltage response or the voltage relaxation.
Journal Article

Brake Particulate Matter Emissions Measurements for Six Light-Duty Vehicles Using Inertia Dynamometer Testing

2020-10-05
2020-01-1637
Emissions of particulate matter, or PM, due to brake wear, are not well quantified in current air pollutant emission inventories. Current emission factor models need to be updated to reflect new technologies and materials and to incorporate the effects of changing driving habits and speeds. While emission regulations drive technical innovations that are significantly reducing PM emissions in vehicle exhaust, non-exhaust automotive emissions remain unregulated. Current emission factor models need to be updated to reflect the changes caused by new technologies, materials, and speed-dependent vehicle usage. Most research regarding brake emissions relies on a laboratory setting. Laboratory testing has allowed researchers, application engineers, data modeling engineers, and environmental agencies to generate large datasets for multiple vehicle configurations and friction couple designs.
Technical Paper

A reduced order turbocharging process model for manifold pressure control with EGR

2019-12-19
2019-01-2212
A mean value turbocharged engine model is useful in terms of accuracy and convenience for fuel economy strategies or engine controller development. Turbocharging process is a feedback system with a positive gain, i.e. increasing exhaust work leads to increasing a cycle work. The gain of the feedback system is determined mainly by exhaust work ratio in a cycle and inertia of the turbine. The work ratio was investigated based on engine test with EGR. A turbocharging process model was obtained using the work ratio in a cycle and theoretical equations. The model is applied to investigate manifold absolute pressure response with EGR.
Technical Paper

An Analysis on Cycle-by-cycle Variation and Trace-knock using a Turbulent Combustion Model Considering a Flame Propagation Mechanism

2019-12-19
2019-01-2207
Gasoline engines have the trace-knock phenomena induced by the fast combustion which happens a few times during 100 cycles. And that constrains the thermal efficiency improvement due to limiting the ignition timing advance. So the authors have been dedicating a trace-knock simulation so that we could obtain any pieces of information associated with trace-knock characteristics. This simulation consists of a turbulent combustion model, a cycle-by-cycle variation model and a chemical calculation subprogram. In the combustion model, a combustion zone is considered in order to obtain proper turbulent combustion speed through wide range of engine speed. From a cycle-by-cycle variation analysis of an actual gasoline engine, some trace-knock features were detected, and they were involved in the cycle-by-cycle variation model. And a reduced elementary reaction model of gasoline PRF (primary reference fuel) was customized to the knocking prediction, and it was used in the chemical calculation.
Technical Paper

The Mechanism of Hissing Noise in the Automotive Cabin and Countermeasures for its Reduction

2019-06-05
2019-01-1474
The automotive refrigerant system can occasionally exhibit an excessive noise out of air-conditioner (A/C) vents during vehicle’s developments. If the vehicle has been parked for long hours in summer and the A/C system is turned on, sometimes hissing noise is induced by the refrigerant flow. In order to understand the mechanism, a lot of bench and vehicle tests were conducted. However, there is still not enough to understand the physical behavior in detail. Therefore, for the first step, the visualization method to capture the behavior of multi-phased refrigerant flow jet inside the pipe was proposed with a high-speed camera, some light devices and acrylic test piece. In addition, image analysis to quantify the flow regime from a series of observed snapshots. Using proposed method, the correlation study between flow and noise was performed at A/C bench test. As a result, different flow features such as the velocity can be observed in the occurrence of the noise or not.
Technical Paper

Limitations of Sector Mesh Geometry and Initial Conditions to Model Flow and Mixture Formation in Direct-Injection Diesel Engines

2019-04-02
2019-01-0204
Sector mesh modeling is the dominant computational approach for combustion system design optimization. The aim of this work is to quantify the errors descending from the sector mesh approach through three geometric modeling approaches to an optical diesel engine. A full engine geometry mesh is created, including valves and intake and exhaust ports and runners, and a full-cycle flow simulation is performed until fired TDC. Next, an axisymmetric sector cylinder mesh is initialized with homogeneous bulk in-cylinder initial conditions initialized from the full-cycle simulation. Finally, a 360-degree azimuthal mesh of the cylinder is initialized with flow and thermodynamics fields at IVC mapped from the full engine geometry using a conservative interpolation approach. A study of the in-cylinder flow features until TDC showed that the geometric features on the cylinder head (valve tilt and protrusion into the combustion chamber, valve recesses) have a large impact on flow complexity.
Technical Paper

Composite Lightweight Automotive Suspension System (CLASS)

2019-04-02
2019-01-1122
The Composite Lightweight Automotive Suspension System is a composite rear suspension knuckle/tieblade consisting of UD prepreg (epoxy resin), SMC (vinylester resin) carbon fibre and a steel insert to reduce the weight of the component by 35% and reduce Co2. The compression moulding manufacturing process and CAE optimisation are unique and ground-breaking for this product and are designed to allow high volume manufacture of approx. 30,000 vehicles per year. The manufacturing techniques employed allow for multi-material construction within a five minute cycle time to make the process viable for volume manufacture. The complexities of the design lie in the areas of manufacturing, CAE prediction and highly specialised design methods. It is a well-known fact that the performance of a composite part is primarily determined by the way it is manufactured.
Technical Paper

Model-Based Software Development: Functional Safety Compliance via Built-In Tool Intelligence

2019-04-02
2019-01-1041
Today’s automobiles are among the most sophisticated machines on the planet. Much of the functionality of modern automobiles emanates from embedded software features that control electronic, mechanical or pneumatic devices. Over the past few decades the number of software features and the associated code has grown exponentially and the respective embedded software systems have reached a level of complexity which is increasingly difficult to manage. As a consequence, recalls due to software defects have become a major concern and today constitute about 50% of the overall warranty cost [1]. Since the operation of automobiles has severe public safety implications, the development of embedded automotive software has become subject to stringent functional safety standards (ISO 26262) and compliance with these standards has become a major hurdle in the development of automotive software.
Journal Article

A Resonant Capacitive Coupling WPT-Based Method to Power and Monitor Seat Belt Buckle Switch Status in Removable and Interchangeable Seats

2019-04-02
2019-01-0465
In this study, we present an intelligent and wireless subsystem for powering and communicating with three sets of seat belt buckle sensors that are each installed on removable and interchangeable automobile seating. As automobile intelligence systems advance, a logical step is for the driver’s dashboard to display seat belt buckle indicators for rear seating in addition to the front seating. The problem encountered is that removable and interchangeable automobile seating outfitted with wired power and data links are inherently less reliable than rigidly fixed seating, as there is a risk of damage to the detachable power and data connectors throughout end-user seating removal/re-installation cycles.
Technical Paper

Multi Attribute Balancing of NVH, Vehicle Energy Management and Drivability at Early Design Stage Using 1D System Simulation Model

2019-01-09
2019-26-0178
Improving fuel efficiency often affects NVH performance. Modifying a vehicle’s design in the latter stages of development to improve NVH performance is often costly. Therefore, to optimize the cost performance, a Multi-Attribute Balancing (MAB) approach should be employed in the early design phases. This paper proposes a solution based on a unified 1D system simulation model across different vehicle performance areas. In the scope of this paper the following attributes are studied: Fuel economy, Booming, Idle, Engine start and Drivability. The challenges to be solved by 1D simulation are the vehicle performance predictions, taking into account the computation time and accuracy. Early phase studies require a large number of scenarios to evaluate multiple possible parameter combinations employing a multi-attribute approach with a systematic tool to ease setup and evaluation according to the determined performance metrics.
Technical Paper

Characterization of Gaseous Emissions from Blended Plug-In Hybrid Electric Vehicles during High-Power Cold-Starts

2018-04-03
2018-01-0428
There is a distinct difference between plug-in hybrid electric vehicles in the market today. One key distinction that can be made is to classify a plug-in hybrid electric vehicle (PHEV) according to its operational behavior in charge depleting (CD) mode. Some PHEVs are capable of using the electric-only propulsion system to achieve all-electric operation for all driving conditions in CD mode, including full power performance. In contrast, some PHEVs, henceforth termed “blended PHEVs”, cannot satisfy the power requirements of all driving conditions with the electric-only propulsion system and occasionally utilize blended CD operation whereby it is necessary to blend the use of the internal combustion (IC) engine with the use of the electric motor(s) to help power the vehicle.
Technical Paper

Age-Specific Injury Risk Curves for Distributed, Anterior Thoracic Loading of Various Sizes of Adults Based on Sternal Deflections

2016-11-07
2016-22-0001
Injury Risk Curves are developed from cadaver data for sternal deflections produced by anterior, distributed chest loads for a 25, 45, 55, 65 and 75 year-old Small Female, Mid-Size Male and Large Male based on the variations of bone strengths with age. These curves show that the risk of AIS ≥ 3 thoracic injury increases with the age of the person. This observation is consistent with NASS data of frontal accidents which shows that older unbelted drivers have a higher risk of AIS ≥ 3 chest injury than younger drivers.
Technical Paper

Thoracic Injury Risk Curves for Rib Deflections of the SID-IIs Build Level D

2016-11-07
2016-22-0016
Injury risk curves for SID-IIs thorax and abdomen rib deflections proposed for future NCAP side impact evaluations were developed from tests conducted with the SID-IIs FRG. Since the floating rib guide is known to reduce the magnitude of the peak rib deflections, injury risk curves developed from SID-IIs FRG data are not appropriate for use with SID-IIs build level D. PMHS injury data from three series of sled tests and one series of whole-body drop tests are paired with thoracic rib deflections from equivalent tests with SID-IIs build level D. Where possible, the rib deflections of SID-IIs build level D were scaled to adjust for differences in impact velocity between the PMHS and SID-IIs tests. Injury risk curves developed by the Mertz-Weber modified median rank method are presented and compared to risk curves developed by other parametric and non-parametric methods.
Technical Paper

Biomechanical and Scaling Basis for Frontal and Side Impact Injury Assessment Reference Values

2016-11-07
2016-22-0018
In 1983, General Motors Corporation (GM) petitioned the National Highway Traffic Safety Administration (NHTSA) to allow the use of the biofidelic Hybrid III midsize adult male dummy as an alternate test device for FMVSS 208 compliance testing of frontal impact, passive restraint systems. To support their petition, GM made public to the international automotive community the limit values that they imposed on the Hybrid III measurements, which were called Injury Assessment Reference Values (IARVs). During the past 20 years, these IARVs have been updated based on relevant biomechanical studies that have been published and scaled to provide IARVs for the Hybrid III and CRABI families of frontal impact dummies. Limit values have also been developed for the biofidelic side impact dummies, BioSID, ES-2 and SID-IIs.
Technical Paper

Disc Brake Pad Corrosion Adhesion: Test-to-Field Issue Correlation, and Exploration of Friction Physical Properties Influence to Adhesion Break-Away Force

2016-09-18
2016-01-1926
Brake pad to rotor adhesion following exposure to corrosive environments, commonly referred to as “stiction”, continues to present braking engineers with challenges in predicting issues in early phases of development and in resolution once the condition has been identified. The goal of this study took on two parts - first to explore trends in field stiction data and how testing methods can be adapted to better replicate the vehicle issue at the component level, and second to explore the impacts of various brake pad physical properties variation on stiction propensity via a controlled design of experiments. Part one will involve comparison of various production hardware configurations on component level stiction tests with different levels of prior braking experience to evaluate conditioning effects on stiction breakaway force.
Journal Article

CVJ and Knuckle Design Optimization to Protect Inboard Wheel Bearing Seals from Splash

2016-09-18
2016-01-1956
For higher mileage vehicles, noise from contaminant ingress is one of the largest durability issues for wheel bearings. The mileage that wheel bearing sealing issues increase can vary due to multiple factors, such as the level of corrosion for the vehicle and the mating components around the wheel bearing. In general, sealing issues increase after 20,000 to 30,000 km. Protecting the seals from splash is a key step in extending bearing life. Benchmarking has shown a variety of different brake corner designs to protect the bearing from splash. This report examines the effect of factors from different designs, such as the radial gap between constant velocity joint (CVJ) slinger and the knuckle, knuckle labyrinth height and varying slinger designs to minimize the amount of splash to the bearing inboard seal. This report reviews some of the bearing seal failure modes caused by splash.
Journal Article

Vehicle Level Brake Drag Target Setting for EPA Fuel Economy Certification

2016-09-18
2016-01-1925
The strong focus on reducing brake drag, driven by a historic ramp-up in global fuel economy and carbon emissions standards, has led to renewed research on brake caliper drag behaviors and how to measure them. However, with the increased knowledge of the range of drag behaviors that a caliper can exhibit comes a particularly vexing problem - how should this complex range of behaviors be represented in the overall road load of the vehicle? What conditions are encountered during coastdown and fuel economy testing, and how should brake drag be measured and represented in these conditions? With the Environmental Protection Agency (amongst other regulating agencies around the world) conducting audit testing, and the requirement that published road load values be repeatable within a specified range during these audits, the importance of answering these questions accurately is elevated. This paper studies these questions, and even offers methodology for addressing them.
Technical Paper

Laboratory Testing of a Continuous Emissions Monitor for Trace Level Sulfur Dioxide

2016-04-05
2016-01-0986
The measurement of SO2 levels in vehicle exhaust can provide important information in understanding the relative contribution of sulfur and sulfate from fuel vs. oil source to PM. For this study, a differential optical absorption spectrometer (DOAS) that can measure SO2 down to 20 ppbV in real-time was built and evaluated. The DOAS consisted of an extractive sampling train, a cylindrical sampling cell with a single-path design to minimize cell volume, a spectrometer, and a deuterium lamp light source with a UVC range of ∼200-230 nanometer (nm). Laboratory tests showed detection limits were approximately in the range of 12 to 15 ppbV and showed good linearity over SO2 concentration ranges of 20 to 953 ppbV. Interference tests showed some interference by NO and by NH3, at levels of 300 ppmV and 16.6 ppmV, respectively.
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