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Technical Paper

Automotive HVAC Flow Noise Prediction Models

2001-04-30
2001-01-1498
Flow noise from automotive HVAC (Heating, Ventilating and Air Conditioning) systems is one of the major considerations of occupant comfort. The noise generated at high blower speed is a major contributor to the vehicle interior noise. This paper reviews automotive HVAC air rush noise prediction models for estimating register, buck (air handling subsystem) and vehicle noise levels. The vehicle noise prediction method correlates well with measured noise levels at driver right ear location: with a standard deviation of 1.31 dB where standard deviation is the difference between measured and predicted noise levels for a sample size of 10 vehicles.
Technical Paper

Fuel Economy Improvements through Improved Automatic Transmission Warmup - Stand Alone Oil to Air (OTA) Transmission Cooling Strategy with Thermostatic Cold Flow Bypass Valve

2001-05-14
2001-01-1760
The stand alone oil to air (OTA) transmission cooling strategy with thermostatic cold flow bypass valve has been shown to be an effective means of improving the warmup of an automatic transmission. Improving the system warmup rate of an automatic transmission significantly improves its efficiency by reducing losses resulting from extremely viscous transmission fluid and can allow for calibration changes that improve overall transmission performance. Improved transmission efficiency in turn allows for improved engine efficiency and performance. The improvements obtained from increased transmission and engine efficiency result in an overall increase in vehicle fuel economy. Fuel economy and consumption are important parameters considered by the vehicle manufacturer and the customer. Fuel economy can be considered as important as reliability and durability.
Technical Paper

R134A Suction Line Heat Exchanger in Different Configurations of Automotive Air-Conditioning Systems

2001-05-14
2001-01-1694
A suction line heat exchanger (SLHX) transfers heat from the condenser outlet to the suction gas. In a TXV (thermostatic expansion valve) system, the performance improvement with a 60 to 80 % effective SLHX is expected to be on the order of 8 to 10 % for capacity, and 5 to 7 % for COP for high outdoor air temperatures of 43ºC. In a FOT (fixed orifice tube) system, the performance improvement was calculated to be about 10 to 15 %. The calculated improvements have been verified experimentally within a few percent.
Technical Paper

Power Steering Pump with Enhanced Cold Start Priming

2001-04-30
2001-01-1422
The objective of the present work was to improve the cold start NVH performance of an automotive power steering pump under low temperature conditions. This objective was accomplished through the use experimental study and measurement. The satisfactory operation of a fixed displacement vane pump in cold temperatures depends on a number of factors including; (1) filling characteristics, (2) the inlet conditions to the pump, (3) the fluid, and (4) the ability of the vanes to maintain contact with the cam surface. In this investigation, factor (4) was chosen for investigation. A unique outlet orifice was designed and tested at three different operating ambient temperatures, -19 °C, -29 °C, and -40 °C. Maximum “noise” duration was measured as the maximum duration of fluid borne pump outlet pressure oscillations greater the 345 kPa peak-to-peak. The results show that noise duration can reduced by as much as 50% at -40 °C.
Technical Paper

Water Condensate Retention and “Wet” Fin Performance in Automotive Evaporators

2001-03-05
2001-01-1252
Water condensate retained inside an automotive evaporator has remained as one of the primary sources of unpleasant “odors”, which in turn can drive up the warranty cost for automotive manufacturers. The “wet” evaporator fin can also underperform due to the presence of condensate blocking the air passage. Moreover, condensate retention can be a potential factor of freezing up evaporators. Thus, an evaporator fin must be designed such that it can shed and drain water condensate as well as provide an excellent heat transfer capability. While the importance of water retention is well known, there seems lacking of a comprehensive way to evaluate the water retention characteristics of a particular product. In this work, attempts were made to answer four questions: (1) What is the mechanism that controls water condensate retention characteristics in an automotive evaporator? (2) Can different water retention evaluation methods reveal the same characteristics?
Technical Paper

Stability Control of Combination Vehicle

2001-03-05
2001-01-0138
This paper discusses the development of combination vehicle stability program (CVSP) at Visteon. It will describe why stability control is needed for combination vehicles and how the vehicle stability can be improved. We propose and evaluate controller structures and design methods for CVSP. These include driver's intent identification, combination vehicle status estimation and control, and fault detection / tolerance. In this paper, the braking and steering dynamics of car-trailer and tractor-semitrailer combinations, and the brake systems which should be used extensively to increase the stability of combination vehicles are presented. Also our development platform is introduced and the combination vehicle simulation results are presented. The definition of combination vehicles in this paper includes car-trailer and commercial tractor-semitrailer combinations since their vehicle dynamics are based on the same equations of motion.
Technical Paper

Optimizing the Effects of Body Attachment Stiffness on Steering Column In-Vehicle Modes

2001-03-05
2001-01-0041
This paper presents an unambiguous and intuitive method for identification of steering column resonant (SCR) mode of vibration. One simple but overlooked technique to determine the SCR mode in-vehicle is to provide local stiffnesses of the body locations where the Instrument Panel (IP) attaches, to the IP suppliers to be used in their design and development. This paper describes how this technique is useful in predicting the first few important in-vehicle steering column modes for different classes of vehicles, with examples presented in each class. The results obtained from such analyses are compared against those from direct in-buck simulations. This technique is not limited to its application in developing IP systems, but can easily be extended to include other systems such as seats, fuel tanks, etc. Also it is shown that a design optimization analysis may be performed using these attachment stiffnesses as design variables resulting in a system level solution.
Technical Paper

A Unique Approach to All-Wheel Drive Vehicle Dynamics Model Simulation and Correlation

2000-12-04
2000-01-3526
Experimental correlation is essential in the development of analytical simulation models. A methodology for correlating an All-Wheel Drive (AWD) minivan, created with ADAMS/Pre is presented in this paper. The paper is developed in three parts. Presented first are detailed component and system level, static and dynamic tests, including tire tests that were performed for inputs to the model. Then, the static correlation of the model, in particular, the front and rear suspension kinematics and compliance correlation are presented. Finally the dynamic correlation of the model, for the constant radius test and the swept steer test, is discussed. The paper concludes with some observations on AWD modeling.
Technical Paper

Development and Implementation of a Tool for Modeling Driveline Systems

2000-12-04
2000-01-3525
In order to facilitate the modeling of vehicle drivelines in ADAMS, an ADAMS/View driveline tool was developed with the aid of Mechanical Dynamics, Inc (MDI). Known as Visteon Axle & Driveline Simulation-Dynamics (VADSIM-DYNA) this tool is used to supply customers with driveline models for use in their full vehicle modeling as well as for predicting forces in the driveline. Of specific interest is a method for calculating the mesh point of a hypoid gear set using the geometry of the ring and pinion gears, and a custom force statement for calculation of the mesh point reactions at the center of gravity for both the pinion and ring gears. With the introduction of ADAMS/Driveline, The comapny has worked with MDI to implement VADSIM-DYNA into the base product. With the aid of VADSIM-DYNA the ability to provide customers with ADAMS models of driveline components and systems has been greatly enhanced.
Technical Paper

An Integrated System Life Cycle-Based Risk Management Methodology

2002-03-04
2002-01-0145
A new risk management method, the System Integrated Life Cycle Risk Management Methodology (SILC RMM), is based on systems engineering principles and is compatible with current standards. The SILC method, created by automotive engineers, addresses shortcomings with FMEA and other risk management (RM) methods, and integrates the FMEA and risk management functions into day-to-day engineering project activities. The SILC approach accommodates technology, cost, schedule, environmental and safety risks throughout the systems engineering project life cycle - from conception to recycle. It allows direct integration of RM information with system and project information for more efficient and effective utilization of resources and optimal overall risk management.
Technical Paper

Correlation Study of Exhaust Manifold - Lab Test Results vs Customer Fleet Results

2002-03-04
2002-01-1317
The purpose of this study is to develop specifically a correlation between Exhaust Manifold Cracking Laboratory Test results and 150,000 mile customer fleet usage test results. The study shows that the exhaust manifold design meets the reliability requirements of 10 years or 150,000 miles, given 90th percentile customer usage without an evidence of cracking or audible leaks. This correlation between the Lab Test and the customer Fleet results has been expressed as an acceleration factor. An acceleration factor is the ratio of how much quicker the engine dynamometer test ( i.e. Lab Test ) can accumulate the effect of customer usage over time versus the customers themselves. The acceleration factor is provided for useful life time period of 10 years or 150,000 miles. The recommended acceleration factor, determined in this study, is 38 to 1, comparing the engine dynamometer test ( i.e. Lab Test ) results to 150,000 mile modular truck customer fleet field results.
Technical Paper

Finite Element Study of a Composite Tube Under Impact Load

2002-03-04
2002-01-0723
Composite materials can be used effectively for structural applications where high strength-to-weight and stiffness-to-weight ratios are required. Although the design and analysis techniques for static, buckling and vibration loadings are fairly well established, methodologies for analysis of composite structures under impact loading are still a major research activity. This paper presents a nonlinear finite-element analysis method to analyze a composite structure subjected to axial impact load. The analysis was performed using MSC/DYTRAN FE code while pre and post processing were done using MSC/PATRAN program. In addition, a steel tube of the same geometry was analyzed for comparison purpose.
Technical Paper

DSS, The Driver Stability System of Visteon

2002-03-04
2002-01-0782
This paper introduces the Driver Stability System (DSS) at Visteon. DSS is a new active comfort / safety system for automobiles which controls the seat bolsters independently in real time to enhance the lateral support of the occupants. Under turning maneuvers, DSS reacts to the vehicle dynamics to provide an increased contact area between the occupants and their seats, allowing optimal occupant location with respect to such variables as steering wheel angle, lateral acceleration, yaw rate, and vehicle velocity. The lateral force compensation is directly coupled to the dynamic movement of vehicle chassis and the change of road profile. The system consists of the seat bolster assembly including DC motors, wheel speed sensors, steering wheel sensor, lateral accelerometer, yaw rate sensor, and electronic control unit (ECU). This paper also discusses the control concept of DSS and its realistic controller structure.
Technical Paper

Creating a Positive and Successful Experience for Black-Belt Candidates

2002-03-04
2002-01-0897
For a first-time Black-Belt, many factors will determine the difference between success and failure, satisfaction and frustration. While some factors are affected by company policy, many are still within the control of the Black-Belt. Black-Belts can improve their chance for success by recognizing the opportunities and pitfalls going into the process, setting achievable goals, carefully scoping projects, and being prepared to work around obstacles.
Journal Article

Assessment of Automatic Volume Leveling for Automotive Sound Systems

2013-04-08
2013-01-0162
This paper presents an assessment of competing algorithms for normalizing volume levels between tracks and/or sources in an automotive infotainment system. Portable media players such as smartphones and iPod® devices are extremely popular for listening to music collections or streaming content from the Internet. The lack of normalization is a source of dissatisfaction if the user experiences significant changes in audio level between tracks. Several commercially available algorithms exist to solve this problem. This research includes a double-blind listening test comparing an audio sample processed with the different leveling algorithms to an unprocessed reference. The listener preference rating is recorded and results indicate which algorithm is preferred.
Technical Paper

Radiated Noise Prediction of Air Induction Systems Using Filter Seal Modeling and Coupled Acoustic-Structural Simulation Techniques

2007-04-16
2007-01-0253
In this paper, an analytical procedure for prediction of shell radiated noise of air induction systems (AIS) due to engine acoustic excitation, without a prototype and physical measurement, is presented. A set of modeling and simulation techniques are introduced to address the challenges to the analytical radiated noise prediction of AIS products. A filter seal model is developed to simulate the unique nonlinear stiffness and damping properties of air cleaner boxes. A finite element model (FEM) of the AIS assembly is established by incorporating the AIS structure, the proposed filter seal model and its acoustic cavity model. The coupled acoustic-structural FEM of the AIS assembly is then employed to compute the velocity frequency response of the AIS structure with respect to the air-borne acoustic excitations.
Technical Paper

Key Aspects of Electronics Automotive Components Testing

2013-10-07
2013-36-0569
Electronics components are estimated to be between 9 to 15 % of a total vehicle cost, and this trend will remain strong for the next years. The amount of electronics content in a vehicle has grown steadily since 1970's, and as a result, development challenges such as testing and validation are a key aspect of its overall development costs. Testing costs can amount easily to US$ 500 k in medium complex automotive parts of a vehicle (e.g. instrument cluster) depending on a specific OEM customer demand, and this on top of limited regional laboratory capacity can also lead to increased testing time. The goal of this paper is to outline key aspects of electronics in vehicle components testing, including overall costs and timing, and propose a lean approach to optimize such costs & timing. The key aspects of such optimization include not only resources, but also laboratories and upfront OEM customer planning.
Technical Paper

Compressor Body Temperature and Lubrication

2013-04-08
2013-01-1501
The paper addresses compressor body temperature (crankcase) importance to the vehicle AC system long-term durability. Majority of OEM vehicle test evaluation is to see if AC system can pass compressor discharge temperature and discharge pressure targets. Most OEMs adopt 130°C max compressor discharge temperature and 2350 kpag head pressure as the target. From the field, although some of the compressor failure results from a high compression ratio, and compressor discharge temperature that are caused by the poor front end airflow, etc., high percentage compressor failed systems exhibit not too high compression ratio and compressor discharge temperature, but having the trace of high temperature in the shaft area, gasket area, etc. With introducing more and more variable swash plate compressor applications, OEMs start to see more and more compressor failures that are not related to a high compressor discharge temperature but the trace of high compressor body temperature.
Journal Article

A New Automotive Air Conditioning System Simulation Tool Developed in MATLAB/Simulink

2013-04-08
2013-01-0850
Accurate evaluation of vehicles' transient total power requirement helps achieving further improvements in vehicle fuel efficiency. When operated, the air-conditioning (A/C) system is the largest auxiliary load on a vehicle, therefore accurate evaluation of the load it places on the vehicle's engine and/or energy storage system is especially important. Vehicle simulation models, such as "Autonomie," have been used by OEMs to evaluate vehicles' energy performance. However, the load from the A/C system on the engine or on the energy storage system has not always been modeled in sufficient detail. A transient A/C simulation tool incorporated into vehicle simulation models would also provide a tool for developing more efficient A/C systems through a thorough consideration of the transient A/C system performance. The dynamic system simulation software MATLAB/Simulink® is frequently used by vehicle controls engineers to develop new and more efficient vehicle energy system controls.
Technical Paper

Test Strategy for Linux based Platforms using Open Source Tools

2016-04-05
2016-01-0053
Today open source software is widely used in different domains like Desktop systems, Consumer electronics (smart phones, TV, washing machines, camera, printers, smart watches), Automotive, Automation etc. With the increased involvement of the open source software in the different domains including the safety critical ones, there has been a requirement of the well-defined test strategy to test and verify such systems. Currently there are multiple open source tools and frameworks to choose from. The paper describes the various open source test strategies and tools available to qualify such systems, their features, maintenance, community support, advantages and disadvantages. Target audience would be the software engineers, program managers, using an open source stack for the product development.
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