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Technical Paper

Virtual Switches and Indicators in Automotive Displays

2020-04-14
2020-01-1362
Over the last decade, graphical and touch displays have become commonplace in automobile cockpits. Such displays have been used mainly for convenience functions such as navigation, radio, driver information, and vehicle settings. Automakers are now using these displays to generate “virtual” indicators that replace regulated and/or safety-critical physical indicators, such as gear position indication or the Malfunction Indicator Light [MIL]. Automakers are also replacing physical switches and controls, such as heating, ventilation, and air conditioning [HVAC] controls, with “virtual” controls rendered on the cockpit touch-screen. Many of these indicators and controls have regulatory and/or functional safety requirements that have been met using such methods as redundant terminals in a safety-critical switch, or by monitoring the electrical State-of-Health [SOH] of discrete LED indicators.
Technical Paper

Characterization of Seat Lateral Support as a Mechanical Behavior

2020-04-14
2020-01-0870
Seat lateral support is often talked about as a design parameter, but usually in terms of psychological perception. There are many difficulties in quantifying lateral support mechanically to the engineering teams: Anthropometric variation causes different people to interact with the seat in different places and at different angles, BPD studies are usually planar and don’t distinguish between horizontal support and vertical resistance to sinking in, most mechanical test systems are typically single-DOF and can’t apply vertical and horizontal loads concurrently, and there is scant literature describing the actual lateral loads occupants. In this study, we characterize the actual lateral loading on example seating (both driver and passenger, as passenger experience will become more important as autonomous vehicles evolve) from various sized/ shaped occupants according to dynamic pressure distribution.
Technical Paper

Evaluation of High Resistance Connection in Automotive Application

2020-04-14
2020-01-0926
A high resistance / poor connection in an electric circuit has been reported to cause a temperature increase exceeding normal operational range at the connection. Some studies have reported glowing condition at the poor connection. The 2017 edition of NFPA 921 states that the wattage of well-developed heating connections in wiring can be up to 30-40 W with currents of 15-20 A. Heating connections of lower wattage have also been noted at currents as low as about 1 A. The NFPA 921 data appears to be referenced from studies on residential electrical systems. This study is to determine the temperature and power loss in a typical automotive electrical connection with a simulated high resistance under different load conditions
Technical Paper

Loads simplification on multi input axle systems

2020-04-14
2020-01-1056
The time domain is currently the most widely chosen option in fatigue testing in order to fully represent random events occurring in multiple simultaneous input channels. In vehicles for example, time domain tests can represent the same conditions of the road, by applying the same loads at the hard points of the vehicle along a time history. The main drawback of this methodology is the extensive testing duration and hardware cost. Time domain based fatigue tests are composed of a complex hardware, that requires servo motors to work, in order to induce the specific amount of load at a specific time window. These tests are time consuming, since they require the same length duration of the event they are reproducing, times the required repetitions.
Technical Paper

Customer Perception of Road Induced Structural Feel

2020-04-14
2020-01-1080
A vehicle program’s timing and viability can be affected by subjective assessments made by engineering teams predicting customer perceptions of many different attributes. In this paper we explore the relationship of those assessments to match customer perceptions for the attribute of structural feel. The eventual goal of work like this is to develop an objective metric that could be used by the product development organization. The first step in developing a metric is to assess whether road induced structural feel can be sensed by the customer. An internal drive clinic was an effective approach for obtaining customer perception of structural feel. Vehicles which spanned excellent structural feel to poor structural feel were chosen as part of the experimental design. The participants, which comprised three groups (panelists, experts, and executives) were able to rank order the vehicles’ structural feel performance essentially the same and in the order determined a priori.
Technical Paper

Purge Pump Rotor Dynamics subjected to Ball Bearing Inner and Outer Race Wear Defects

2020-04-14
2020-01-0403
The purge pump is used to pull evaporative gases from canister and send to engine for combustion in Turbocharger engines. The purge pump with impeller at one end and electric motor at the other end is supported by the ball bearing assembly. A bearing kinematic model to predict forcing function due to defect in ball bearing arrangement coupled with bearing dynamic model of rotor because of rotating component is proposed in this paper to get accumulated effect on transmitted force to the purge pump casing. Rotor dynamic of purge pump rotor components only produces certain order forcing responses which can be simulated into the multibody software environment knowing the ball bearing geometry parameters hence providing stiffness parameter for rotor system.
Technical Paper

Conjugate Heat Transfer CFD Analysis of an Oil Cooled Automotive Electrical Motor

2020-04-14
2020-01-0168
This study brings to forefront the analysis capability of CFD for the oil-cooling of an Electric-Motor (E-Motor) powering an automobile. With the rapid increase in electrically powered vehicle, there is an increasing need in the CFD modeling community to perform virtual simulations of the E-Motors to determine the viability of the designs and their performance capabilities. The thermal predictions are extremely vital as they have tremendous impact on the design, spacing and sizes of these motors. In this paper, with the Simerics, Inc. software, Simerics-MP+®, a complete three dimensional CFD with conjugate heat transfer CHT model of an Electric Motor, including all the important parts like the windings, rotor and stator laminate, endrings etc. is created. The multiphase Volume of Fluid (VOF) approach is used to model the oil flow inside this motor.
Technical Paper

Random Vibration Fatigue Life Assessment of Transmission Control Module (TCM) Bracket Considering the Mean Stress Effect

2020-04-14
2020-01-0194
Random loads are experienced by many engineering systems/components such as the housing and the brackets mounted on the chassis of an automobile, wind blowing on the wind turbine blades, Printed Circuit Board (PCB) used in battery electric vehicles, fuel cell stacks mounted on housing of a fuel cell etc. In automotive systems, random load is caused due to unevenness of the road surface. As these loads are varying in nature, it could lead to the fatigue failure of systems experiencing such loads. To ensure structural integrity, they are designed considering random loads and commercially used FE software packages have the capabilities available to evaluate random vibration fatigue. While above mentioned systems undergo random loads during operation, there are other loads/stresses also acting on them such as assembly loads (bolt preload), residual stresses due to casting, static loads i.e. load due to belt or chain drive etc.
Technical Paper

Minimizing Disturbance Detection Time in Hydraulic Systems

2020-04-14
2020-01-0263
In a hydraulic system, parameter variation, contamination, and/or operating conditions can lead to instabilities in the pressure response. The resultant erratic pressure profile produces reduced performance that can lead to hardware damage. Specifically, in a transmission control system, the inability to track pressure commands can result in various types of slip and disturbances to the driveline. Therefore, it is advantageous to identify such pressure events and take remedial actions. The challenge is to detect the condition in the least amount of time while minimizing false alarms. In this study, cross and auto-correlation techniques are evaluated for the detection of pressure disturbances. The performance of the detectors is measured in terms of speed of detection and robustness to: 1) measurement noise, and 2) disturbance parameter uncertainty (frequency and amplitude).
Technical Paper

Large Scale Multi-Disciplinary Optimization and Long-Term Drive Cycle Simulation

2020-04-14
2020-01-1049
Market demands for increased fuel economy and reduced emissions are placing higher aerodynamic and thermal analysis demands on vehicle designers and engineers. These analyses are usually carried out by different engineering groups in different parts of the design cycle. Design changes required to improve vehicle aerodynamics often come at the price of part thermal performance and vice versa. These design changes are frequently a fix for performance issues at a single performance point such as peak power, peak torque, or highway cruise. In this paper, the motivation for a holistic approach in the form of multi-disciplinary optimization (MDO) early in the design process is presented. Using a Response-surface Informed Transient Thermal Model (RITThM) a vehicles thermal performance through a drive cycle is predicted and correlated to physical testing for validation.
Technical Paper

Analytical Evaluation of Engine and Vehicle Hardware Effects on Vehicle Response

2019-04-02
2019-01-1283
As the proliferation of downsized boosted engines continues, it becomes increasingly important to understand how engine and vehicle hardware impact vehicle transient response. Several different methodologies can be used to understand hardware impacts, such as vehicle testing, 0-D vehicle models, and constant engine speed load steps. The next evolution of predicting vehicle transient response is to transition to a system level vehicle analysis by coupling a detailed engine model, utilizing crank angle resolved calculations, with a simple vehicle model. This allows for the evaluation of engine and vehicle hardware effects on vehicle acceleration and the rate of change of vehicle acceleration, or jerk, and the tradeoffs that can be made between the hardware in early program development. By comparing this system level vehicle model to the different methodologies, it can be shown that a system level vehicle analysis allows for higher fidelity evaluations of vehicle transient response.
Technical Paper

Determining the Greenhouse Gas Emissions Benefit of an Adaptive Cruise Control System Using Real-World Driving Data

2019-04-02
2019-01-0310
Adaptive cruise control is an advanced vehicle technology that is unique in its ability to govern vehicle behavior for extended periods of distance and time. As opposed to standard cruise control, adaptive cruise control can remain active through moderate to heavy traffic congestion, and can more effectively reduce greenhouse gas emissions. Its ability to reduce greenhouse gas emissions is derived primarily from two physical phenomena: platooning and controlled acceleration. Platooning refers to reductions in aerodynamic drag resulting from opportunistic following distances from the vehicle ahead, and controlled acceleration refers to the ability of adaptive cruise control to accelerate the vehicle in an energy efficient manner. This research calculates the measured greenhouse gas emissions benefit of adaptive cruise control on a fleet of 51 vehicles over 62 days and 199,300 miles.
Technical Paper

A Mechanism-Based Thermomechanical Fatigue Life Assessment Method for High Temperature Engine Components with Gradient Effect Approximation

2019-04-02
2019-01-0536
High temperature components in internal combustion engines and exhaust systems must withstand severe mechanical and thermal cyclic loads throughout their lifetime. The combination of thermal transients and mechanical load cycling results in a complex evolution of damage, leading to thermomechanical fatigue (TMF) of the material. Analytical tools are increasingly employed by designers and engineers for component durability assessment well before any hardware testing. The DTMF model for TMF life prediction, which assumes that micro-crack growth is the dominant damage mechanism, is capable of providing reliable predictions for a wide range of high-temperature components and materials in internal combustion engines. Thus far, the DTMF model has employed a local approach where surface stresses, strains, and temperatures are used to compute damage for estimating the number of cycles for a small initial defect or micro-crack to reach a critical length.
Technical Paper

Development of an Alternative Predictive Model for Gasoline Vehicle Particulate Matter and Particulate Number

2019-04-02
2019-01-1184
The Particulate Matter Index (PMI) is a helpful tool which provides an indication of a fuel’s sooting tendency. Currently, the index is being used by various laboratories and OEMs as a metric to understand the gasoline fuels impact on both sooting found on engine hardware and vehicle out emissions. This paper will explore a new method that could be used to give indication of the sooting tendency of the gasoline range fuels, called the Particulate Evaluation Index (PEI), and provide the detailed equation in its initial form. In addition, the PEI will be shown to have a good correlation agreement to PMI. The paper will then give a detailed explanation of the data used to develop it. Initial vehicle PM/PN data will also be presented that shows correlations of the indices to the vehicle response.
Technical Paper

Combined Drag and Cooling Optimization of a Car Vehicle with an Adjoint-Based Approach

2018-04-03
2018-01-0721
The main objective of this work is to present an adjoint-based methodology to address combined optimization of drag force and cooling flow rate of an industrial vehicle. In order to cope with cooling effect, the volumetric flow rate is treated through a newly introduced cost function and the corresponding adjoint source term is derived. Also an alternative strategy is presented to tackle aerodynamic vehicle design improvement that relies on a so-called indirect force computation. The overall optimization is treated as a Multi-Objective problem and an original approach, called Optimize Both Favor One (OBFO), is introduced that allows selective emphasis on one or another objective without resorting to artificial cost function balancing. Finally, comparative results are presented to demonstrate the merit of the proposed methodology.
Technical Paper

Initial Comparisons of Friction Stir Spot Welding and Self Piercing Riveting of Ultra-Thin Steel Sheet

2018-04-03
2018-01-1236
Due to the limitations on resistance spot welding of ultra-thin steel sheet (thicknesses below 0.5 mm) in high-volume automotive manufacturing, a comparison of friction stir spot welding and self-piercing riveting was performed to determine which process may be more amenable to enabling assembly of ultra-thin steel sheet. Statistical comparisons between mechanical properties of lap-shear tensile and T-peel were made in sheet thickness below 0.5 mm and for dissimilar thickness combinations. An evaluation of energy to fracture, fracture mechanisms, and joint consistency is presented.
Technical Paper

Modified Experimental Approach to Investigate Coefficient of Friction and Wear under Lubricated Fretting Condition by Utilizing SRV Test Machine

2018-04-03
2018-01-0835
Fretting is an important phenomenon that happens in many mechanical parts. It is the main reason in deadly failures in automobiles, airliners, and turbine engines. The damage is noticed between two surfaces clamped together by bolts or rivets that are nominally at rest, but have a small amplitude oscillation because of vibration or local cyclic loading. Fretting damage can be divided into two types. The first type is the fretting fatigue damage where a crack would initiate and propagate at specific location at the interface of the mating surfaces. Cracks usually initiate in the material with lower strength because of the local cyclic loading conditions which eventually lead to full failure. The second type is the fretting wear damage because of external vibration. Researchers have investigated this phenomenon by theoretical modeling and experimental approaches. Although a lot of research has been done on fretting damage, some of the parameters have not been well studied.
Technical Paper

Learning Gasoline Direct Injector Dynamics Using Artificial Neural Networks

2018-04-03
2018-01-0863
In today’s race for improved fuel economy and lower emissions from gasoline engines, precise metering of delivered fuel is essential. Gasoline Direct Injection fuel systems provide the means for improved combustion efficiency through mixture preparation and better atomization. These improvements can be achieved from both increasing fuel pressure and using multiple injection events, which significantly reduce the required energizing time per injection, and in a number of cases, force the injector to operate at less than full stroke. When the injector operates in this condition, the influence of variation in injector dynamics account for a large percentage of the delivered fuel and require compensation to ensure accurate fuel delivery. Injector dynamics such as opening delay and closing time are influenced by operating conditions such as fuel pressure, energizing time, and temperature.
Technical Paper

Crash-induced Loads in Liftgate Latching Systems

2018-04-03
2018-01-1333
Automotive liftgate latches have been subject to regulation for minimum strength and inertial resistance requirements since the late 1990’s in the US and globally since the early 2000’s, possibly due to liftgate ejections stemming from the first generation Chrysler minivans which employed latches that were not originally designed with this hazard in mind. Side door latches have been regulated since the 1960’s, and the regulation of liftgate, or back door latches, have been based largely on side door requirements, with the exception of the orthogonal test requirement that is liftgate specific. Based on benchmarking tests of liftgate latches, most global OEM’s design their latches to exceed the minimum regulatory requirements. Presumably, this is based on the need to keep doors closed during crashes and specifically to do so when subjected to industry standard tests.
Technical Paper

Effect of Intake Valve Profile Modulation on Passenger Car Fuel Consumption

2018-04-03
2018-01-0379
Variable valve actuation is a focus to improve fuel efficiency for passenger car engines. Various means to implement early and late intake valve closing (E/LIVC) at lower load operating conditions is investigated. The study uses GT Power to simulate on E/LIVC on a 2.5 L gasoline engine, in-line four cylinder, four valve per cylinder engine to evaluate different ways to achieve Atkinson cycle performance. EIVC and LIVC are proven methods to reduce the compression-to-expansion ratio of the engine at part load and medium load operation. Among the LIVC strategies, two non-traditional intake valve lift profiles are investigated to understand their impact on reduction of fuel consumption at low engine loads. Both the non-traditional lift profiles retain the same maximum lift as a normal intake valve profile (Otto-cycle) unlike a traditional LIVC profile (Atkinson cycle) which needs higher maximum lift.
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