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Technical Paper

Using Modal Techniques to Guide Acoustic Signature Analysis

1978-02-01
780106
The use of signature analysis to determine the acceptability of parts in a production line quality control situation is highly desirable. Specifically, the use of acoustic signature analysis is attractive due to the relaxed constraints in terms of fixturing the part in preparation for analysis. This study discusses techniques presently being investigated which rely on knowledge of the modal coefficients to direct the area of investigation.
Technical Paper

Survey of Excitation Techniques Applicable to the Testing of Automotive Structures

1977-02-01
770029
With the implementation of digital signal processing, frequency response measurements are not limited to swept sine testing. With the discrete Fourier Transform, any physically realizable signal can be used for excitation. The best technique depends on the application, available equipment, the presence of measurement noise, the linearity of the test object, and the time available in which to execute the test. In this paper a number of excitation techniques have been described. All of these techniques have advantages and disadvantages which have been described in the text of this paper.
Technical Paper

Future Applications of Ergonomics

1984-02-01
840039
Growth in service industries and increasing automation in manufacturing industries is gradually influencing the role of ergonomics. The purpose of this paper is to identify some of the new and developing areas which need an ergonomist's attention and to define and discuss specific problems within these areas.
Technical Paper

Optimizing Valve Rotational Speed Using Taguchi Techniques

2010-04-12
2010-01-1096
As fuel economy regulations increase and customer preference shifts to smaller, higher power density engines it is more important to effectively cool certain areas of the cylinder head and valvetrain. In order to maximize valvetrain life and increase engine performance it is critical to maintain a near uniform valve seat temperature to enable proper sealing. As cylinder head bridges narrow, and the temperature increases, the water jacket may not be sufficient. An alternative method to ensuring equal temperature distribution across the valve is to promote low speed valve rotation. This will not only aid, cooling the valve seat, as well as cooling and cleaning the valves' seating surface. This paper describes the development and testing of a valve rotation study, utilizing the Taguchi approach in order to determine the most robust design. A test stand was utilized to examine the valve rotation in which the cam was driven directly using a DC motor.
Technical Paper

The Consequences of Average Curve Generation: Implications for Biomechanics Data

2010-11-03
2010-22-0001
One method of understanding the general mechanical response of a complex system such as a vehicle, a human surrogate, a bridge, a boat, a plane, etc., is to subject it to an input, such as an impact, and obtain the response time-histories. The responses can be accelerations, velocities, strains, etc. In general, when experiments of this type are run the responses are contaminated by sample-to-sample variation, test-to-test variability, random noise, instrumentation noise, and noise from unknown sources. One common method of addressing the noise in the system to obtain the underlying response is to run multiple tests on different samples that represent the same system and add them together obtaining an average. This functionally reduces the random noise. However, if the fundamental response of each sample is not the same, then it is not altogether clear what the average represents. It may not capture the underlying physics.
Technical Paper

Noise Contribution Analysis at Suspension Interfaces Using Different Force Identification Techniques

2011-05-17
2011-01-1600
Road-tire induced vibrations are in many vehicles determining the interior noise levels in (semi-) constant speed driving. The understanding of the noise contributions of different connections of the suspension systems to the vehicle is essential in improvement of the isolation capabilities of the suspension- and body-structure. To identify these noise contributions, both the forces acting at the suspension-to-body connections points and the vibro-acoustic transfers from the connection points to the interior microphones are required. In this paper different approaches to identify the forces are compared for their applicability to road noise analysis. First step for the force identification is the full vehicle operational measurement in which target responses (interior noise) and indicator responses (accelerations or other) are measured.
Technical Paper

Characterization of a Ported Shroud Compressor using PIV Measurements

2010-04-12
2010-01-1225
Operational ranges of compressors are limited when running at low mass flow. In particular, large pressure fluctuations occur when reaching surge that can cause rapid deterioration of the bearing system and considerably increase the level of noise. In order to extent the operability of their turbochargers, Honeywell equipped its compressor housings with ported shrouds located at the inlet. The ported shroud has been demonstrated to allow a larger range of operability with minor negative impact on the compressor efficiency. In a collaborative work between Honeywell and the University of Cincinnati, a turbocharger bench facility was designed and tested. The size of the compressor was typical for a turbocharger used on diesel engines. The goal of the experimental study was to develop better understanding of the flow dynamic in the compressor housing that affects stall and surge for different operating conditions.
Technical Paper

Design and Control of Transmission Systems using Physical Model Simulation

2010-04-12
2010-01-0898
Physical modeling has been used by the industry to improve development time and produce a quality product. In this paper, we will describe two methods used in system control to take advantage of the physical model. One method describes a complete transmission physical model with a full system control utilizing co-simulation techniques. Data will be presented, and comparison to vehicle data will be conducted and verified. The second method will illustrate how to utilize the physical model to improve system design and modification. In this method, vehicle data will be used as inputs to the model, the model output will be verified against vehicle output data. The two methods are excellent tools for the Design For Six Sigma process (DFSS design).
Technical Paper

A Practical Failure Limit for Sheared Edge Stretching of Automotive Body Panels

2010-04-12
2010-01-0986
Edge cracking is one of the major formability concerns in advanced high strength steel (AHSS) stamping. Although finite element analysis (FEA) together with the Forming Limit Diagram has been widely used, it has not effectively predicted edge cracking. Primary problems in developing a methodology to insure that parts are safe from edge cracking are the lack of an effective failure criterion and a simple and accurate measurement method that is not only usable in both die tryout and production but also can be verified by finite element analysis. The intent of this study is to develop a methodology to ensure that parts with internal cutouts, such as a body side panel can be produced without edge cracking. During tryout and production, edge cracking has traditionally been detected by visual examination, but this approach is not adequate for ensuring freedom from edge cracking.
Technical Paper

Digital Image Correlation System Application - Measuring Deformation and Load of Convertible Top Fabric

2010-04-12
2010-01-0954
Strain gages have been widely used for measuring strain or deformation. They are very reliable and accurate. However, for application on fabric material, strain gages have their limitations. In this paper, digital image correlation (DIC) is used to measure the deformation around the rear window on a convertible top. The test needed to be non destructive, the vehicle and convertible top could not be damaged. The deformation or strain measured on the fabric was used to estimate the force experienced at the interface between the glass and the fabric during an opening/closing application. A speckle pattern was created on the convertible fabric where deformation was to be measured with washable paint. The image of the measured area was first recorded. The convertible top was then latched down and the fabric was stretched. A second image was recorded again. Based on the two images, the deformation/strain between the two conditions was measured.
Technical Paper

Determination of Vehicle Resistance Curve in Engine Cooling System Design

2010-04-12
2010-01-0933
A process to create a vehicle resistance curve based on airflow predictions using Computational Fluid Dynamics (CFD) simulation technique is presented. 1-dimensional engine cooling system simulation tool KULI is used to compute the coefficients of vehicle resistance curve. A full factorial Design of Experiment (DOE) established the relationship between the coefficients and the sum of absolute difference between KULI and CFD predictions. The NLPQL optimization routine is used to accurately predict the coefficients so that sum of absolute difference between KULI and CFD predictions is minimized.
Technical Paper

Standardization Proposal for “Automotive-Grade AVRCP” with Respect to In-Car use of Bluetooth Devices.

2010-04-12
2010-01-0689
With regard to the use of portable consumer electronic devices in an automobile, Bluetooth has become a widely accepted method for short range wireless communication between a vehicle and a portable device. One Bluetooth connectivity protocol for this use case is Audio/Visual Remote Control Profile (AVRCP). Currently, AVRCP specifies mandatory commands for both target devices (cellular phones and audio players), as well as for control devices like an audio head unit. However, there is no requirement that control devices and target devices implement the same commands, nor is there a requirement that supported commands utilize information that would be useful in improving the driver's experience (i.e. metadata). This paper will describe the impact of this reality from the perspective of the automotive consumer, and propose an “automotive grade” AVRCP that could provide a more consistent consumer experience in the automotive market.
Technical Paper

Stall Development in a Ported Shroud Compressor using PIV Measurements and Large Eddy Simulation

2010-04-12
2010-01-0184
Surge is a phenomenon that limits the operational range of the compressor at low mass flow rates. The objective of this research is to study effective operational range for a ported shroud compressor. The size of the compressor is typical for a turbocharger used on diesel engines. To be able to extend the operational range, the surge characteristics have to be assessed. This is done by performing measurement of the flow at the inlet to the compressor wheel and pressure fluctuations at the inlet and outlet of the compressor housing. Detailed numerical computations of the flow in the entire compressor section under similar operating conditions have also been carried out. The experimental work includes Particle Imaging Velocimetry (PIV) measurements of the instantaneous and mean velocity field at the inlet. At surge, low frequency pulsations are detected that seem to result from back flow already observed in stall.
Technical Paper

Fatigue Based Damage Analysis with Correlation to Customer Duty Cycle Using Design Reliability and Confidence

2010-04-12
2010-01-0200
This paper will define the process for correlating fatigue based customer duty cycle with laboratory bench test data. The process includes the development of the Median and Design Load-Life curve equations. The Median Load-Life curve is a best fit linear regression; whereas, the Design Load-Life curve incorporates component specific reliability and confidence targets. To account for the statistical distribution of fatigue life, due to sample size, the one-side lower-bound tolerance limit method ( Lieberman, 1958 ) will be utilized. This paper will include a correlation between the predicted design fatigue life and the actual product life.
Technical Paper

Evaluation of the Hybrid III 10-year-Old Dummy Chest Response in the Sled Test Environment

2010-04-12
2010-01-0137
Ten sled tests were conducted with a Hybrid III 10-year-old dummy under a 3-point belt only restraint condition to evaluate its performance. The results of the Hybrid III 10-year-old in these tests indicate that there are artifactural noise spikes observable in the transducer responses. A number of metal-to-metal contacts in the shoulder area were identified as one of the sources for the chest acceleration spikes. Noise spikes were also observed in the response from multiple body regions; however, the source of the spikes could not be determined. Compared to the other Hybrid III dummies, non-characteristic dummy chest deflection responses were also observed. This limited analysis indicates that the Hybrid III 10-year-old dummy requires additional development work to eliminate the metal-to-metal contacts in the shoulder area and to understand and correct the other sources of the noise spikes. More investigation is needed to determine if the chest deflection response is appropriate.
Technical Paper

Monotonic and Fatigue Behavior of Magnesium Extrusion Alloy AM30: An International Benchmark Test in the “Magnesium Front End Research and Development Project”

2010-04-12
2010-01-0407
Magnesium alloys are the lightest structural metal and recently attention has been focused on using them for structural automotive components. Fatigue and durability studies are essential in the design of these load-bearing components. In 2006, a large multinational research effort, Magnesium Front End Research & Development (MFERD), was launched involving researchers from Canada, China and the US. The MFERD project is intended to investigate the applicability of Mg alloys as lightweight materials for automotive body structures. The participating institutions in fatigue and durability studies were the University of Waterloo and Ryerson University from Canada, Institute of Metal Research (IMR) from China, and Mississippi State University, Westmorland, General Motors Corporation, Ford Motor Company and Chrysler Group LLC from the United States.
Technical Paper

Design Improvements of Urea SCR Mixing for Medium-Duty Trucks

2013-04-08
2013-01-1074
To meet the 2010 diesel engine emission regulations, an aftertreatment system was developed to reduce HC, CO, NOx and soot. In NOx reduction, a baseline SCR module was designed to include urea injector, mixing decomposition tube and SCR catalysts. However, it was found that the baseline decomposition tube had unacceptable urea mixing performance and severe deposit issues largely because of poor hardware design. The purpose of this article is to describe necessary development work to improve the baseline system to achieve desired mixing targets. To this end, an emissions Flow Lab and computational fluid dynamics were used as the main tools to evaluate urea mixing solutions. Given the complicated urea spray transport and limited packaging space, intensive efforts were taken to develop pre-injector pipe geometry, post-injector cone geometry, single mixer design modifications, and dual mixer design options.
Technical Paper

Alternative to Hydrogen/Helium as Flame Ionization Detector Fuel

2013-04-08
2013-01-1045
Flame ionization detector (FID) analyzers used in emission testing to measure total hydrocarbon emissions have been operating for the last forty years on a fuel mixture of 40% H₂ and 60% helium. These mixtures were selected based on research studies reported in the literature indicating that this particular mixed fuel combination gave the best sensitivity and relative response of the different hydrocarbons present in vehicle exhaust with respect to propane, the calibration gas. During the past few years, it was announced that there is a worldwide shortage of helium which triggered the automotive industry to look for alternatives for helium to be used in FID fuels. Helium which is produced as a byproduct from natural gas fields is non-renewable, expensive, and extremely rare on the earth. Current supply cannot keep up with demand. There are only few natural gas fields producing helium and unless new natural gas fields are found, current helium amounts will continue to dwindle.
Technical Paper

Prediction of HVAC System Aero/Acoustic Noise Generation and Propagation using CFD

2013-04-08
2013-01-0856
With the advent of quieter powertrain and improved cabin acoustic sealing, there is an increased focus on noise generated in the HVAC unit and climate control ducting system. With improved insulation from exterior noise sources such as wind & road noise, HVAC noise is more perceptible by the occupants and is a key quality indicator for new generation vehicles. This has increased the use of simulations tools to predict HVAC noise during the virtual development phase of new vehicle programs. With packaging space being premium under the instrument panel, changes to address noise issues are expensive and often impractical. The current methodology includes the best practices in simulation accumulated from prior aero acoustics validation studies on fans, ducts, flaps and plenum volume discharge. The paper details the acoustic noise generation and propagation in the near field downstream of an automotive HVAC unit in conjunction with ducting system.
Technical Paper

The Impact of Vehicle Front End Design on AC Performance

2013-04-08
2013-01-0859
Vehicle front end air flow management affects many aspects of vehicle aero/thermal performances. The HVAC system capacity is greatly driven by the airflow and the air temperature received at the condenser. In this paper, front end design practices are investigated using computer simulation and full vehicle test to evaluate their effects on AC system performance. A full vehicle 3D CFD model is developed and used to predict the airflow and temperature in underhood and around the vehicle body, and specifically the conditions entering the condenser. The condenser inlet airflow and temperature profiles from 3D CFD model are then used as inputs for the 1D AC system model. The 1D AC system model, which includes condenser, compressor, evaporator and TXV (Thermal eXpansion Valve), is developed to observe the critical AC performance indicators such as panel out air temperature and compressor head pressure.
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