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Technical Paper

Duct Shape Optimization Using Multi-Objective and Geometrically Constrained Adjoint Solver

2019-04-02
2019-01-0823
In the recent years, adjoint optimization has gained popularity in the automotive industry with its growing applications. Since its inclusion in the mainstream commercial CFD solvers and its continuously added capabilities over the years, its productive usage became readily available to many engineers who were previously limited to interfacing the customized adjoint source code with CFD solvers. The purpose of this work is to demonstrate using an adjoint solver a method to optimize duct shape that meets multiple design objectives simultaneously. To overcome one of the biggest challenges in the duct design, i.e. the severe packaging constraints, the method here uses geometrically constrained adjoint to ensure that the optimum shape always fits into the user-defined packaging space. In this work, adjoint solver and surface sensitivity calculations are used to develop the optimization method.
Technical Paper

SAE J3168: A Joint Aerospace-Automotive Recommended Practice for Reliability Physics Analysis of Electrical, Electronic and Electromechanical Components

2019-04-02
2019-01-1252
This paper describes a joint SAE automotive and aerospace Recommended Practice SAE J3168 now in development to standardize a process for Reliability Physics Analysis. This is a science-based approach to implement Physics-of-Failure research in conducting durability simulations in a Computer Aided Engineering Environment. It is used to calculate failure mechanism susceptibilities and estimate the likelihood of failure and the expected durability life of Electrical, Electronic and Electromechanical components and equipment, due to stresses such as mechanical shock, vibration, temperature cycling, etc. Reliability Physics Analysis is based on the material science principle of stress driven damage accumulation in materials. The process enables the identification of potential failure risks early in the design phase so that such risks can be designed out in order to efficiently design high reliable and robustness into electronic products.
Technical Paper

Copper Effect on the Ultrasonic Fatigue Life of A356 Aluminum Alloy Under Variable Humidity Levels

2018-04-03
2018-01-1411
Ultrasonic fatigue tests (testing frequency around 20kHz) have been conducted on A356 aluminum alloys with different copper contents and AS7GU aluminum alloy. Tests were performed in dry air and submerged in water conditions. The effect of copper content was investigated and it was concluded that copper content plays an important role influencing the humidity effect on A356 aluminum alloy ultrasonic fatigue lives. Also, for the same copper content, copper in solute solution or in precipitate have different humidity sensitivities.
Technical Paper

Development of Wireless Message for Vehicle-to-Infrastructure Safety Applications

2018-04-03
2018-01-0027
This paper summarizes the development of a wireless message from infrastructure-to-vehicle (I2V) for safety applications based on Dedicated Short-Range Communications (DSRC) under a cooperative agreement between the Crash Avoidance Metrics Partners LLC (CAMP) and the Federal Highway Administration (FHWA). During the development of the Curve Speed Warning (CSW) and Reduced Speed Zone Warning with Lane Closure (RSZW/LC) safety applications [1], the Basic Information Message (BIM) was developed to wirelessly transmit infrastructure-centric information. The Traveler Information Message (TIM) structure, as described in the SAE J2735, provides a mechanism for the infrastructure to issue and display in-vehicle signage of various types of advisory and road sign information. This approach, though effective in communicating traffic advisories, is limited by the type of information that can be broadcast from infrastructures.
Technical Paper

Accelerated Corrosion Testing of Automotive Evaporators and Condensers

2018-04-03
2018-01-0062
There is an ongoing effort in the industry to develop an accelerated corrosion test for automotive heat exchangers. This has become even more important as automakers are focusing on corrosion durability of 15 years in the field versus current target of 10 years. To this end an acid immersion test was developed and reported in a previous paper for condensers (1). This paper extends those results to evaporators and establishes the efficacy of the test using these results and those reported in the literature. The paper also discusses variability in corrosion test results as observed in tests such as ASTM G85:A3 Acidified Synthetic Sea Water Test (SWAAT), and its relation to field durability.
Technical Paper

Calculating System Failure Rates Using Field Return Data. Application of SAE-J3083 for Functional Safety and Beyond

2018-04-03
2018-01-1074
In early design activities (typically before the hardware is built), a reliability prediction is often required for the electronic components and systems in order to assess their future reliability and in many cases to meet customer specifications. These specifications may include the allocated reliability for a particular electronic unit and in the cases of functional safety products to meet the ASIL (Automotive Safety and Integrity Level) requirement specified by the functional safety standard ISO 26262. The standard allows for the use of “statistics based on field returns or tests” as a valid alternative to the handbook-based reliability prediction. This paper presents a newly developed SAE-J3083 standard “Reliability Prediction for Automotive Electronics Based on Field Return Data”, which covers the types of the required data, ways to collect it, and the methodology of how to process this data to calculate the failure rates and meet the expected safety goals.
Technical Paper

A Packaging Layout to Mitigate Crosstalk for SiC Devices

2018-04-03
2018-01-0462
SiC devices have inherent fast switching capabilities due to their superior material properties, and are considered potential candidates to replace Si devices for traction inverters in electrified vehicles in future. However, due to the comparatively low gate threshold voltage, SiC devices may encounter oscillatory false triggering especially during fast switching. This paper analyzed the causes of false triggering, and also studied the impact of a critical parasitic parameter - common source inductance. It is shown that crosstalk is the main cause for the false triggering in the case and some positive common source inductance help to mitigate the crosstalk issue. A packaging layout method is proposed to create the positive common source inductance through layout of control terminals / busbars, and/or the use of control terminal bonded wires at different height.
Technical Paper

New FR Lower Spring Pad Design to Avoid Squeak Noise During Suspension Travel

2017-11-07
2017-36-0238
During a B-Car durability validation route, it was observed a squeak noise coming from front suspension structure. In the teardown, it was verified metal to metal contact between coil spring and damper spring plate and squeeze-out of spring pad. To reproduce the vehicle failure, it was developed in laboratory a fixture and test to reflect a B-Car McPherson suspension motion, to reproduce the failure and validate a proposal. After root cause understanding, the challenge was to design a new spring pad to avoid squeeze-out keeping the coil spring lower pigtail unchanged. It was tested some prototype parts also in vehicle to approve the design proposal.
Technical Paper

Methodology for Determination and Optimization of Bolted Joints

2017-11-07
2017-36-0294
In order to optimize the development of bolted joints used to components attachments in the Sidemember of commercial vehicles, the joints development has become relevant to better definition of the fasteners size, eliminating overweight and avoiding under or super-sized. This paper presents a development sequential approach of bolted joints applied on commercial vehicles ensuring the correct specifications usage of the fasteners and the joint to keep their clamp force. The evaluations were conducted based on theoretical and practical aspects applied on products and in the definition of all elements contained in a joint. The calculation methodology was developed based on standardized bolts and forces generated through the reactions of the components required for each vehicle family.
Technical Paper

Development of a Commercial Truck Parabolic Leaf Spring Using CAE Simulation with Correlated Experimental Stress Analysis Results

2017-11-07
2017-36-0126
The development costs that new design requires are subject to everyday discussions and saving opportunities are mandatory. Using CAE to predict design changes can avoid excessive costs with prototypes parts, considering the high reliability those current mathematical models can provide. This paper presents the methodology used during the development of a parabolic leaf spring for the rear suspension of a commercial truck, considering mainly the parabolic profiles and stress distribution on the leaves, calculated using CAE software (ANSYS) and experimental tests to measure the actual stress on each leaf, certifying the correlation between computational calculations and real stress on the parts during bench and vehicle evaluations.
Technical Paper

A Method for Rapid Durability Test Development

2017-03-28
2017-01-0199
Designing a durability test for an automatic transmission that appropriately reflects customer usage during the lifetime of the vehicle is a formidable task; while the transmission and its components must survive severe usage, overdesigning components leads to unnecessary weight, increased fuel consumption and increased emissions. Damage to transmission components is a function of many parameters including customer driving habits and vehicle and transmission characteristics such as weight, powertrain calibration, and gear ratios. Additionally, in some cases durability tests are required to verify only a subset of the total parameter space, for example, verifying only component modifications. Lastly, the ideal durability test is designed to impose the worst case loading conditions for the maximum number of internal components, be as short as practicable to reduce testing time, with minimal variability between tests in order to optimize test equipment and personnel resources.
Technical Paper

Evolution of Engine Air Induction System Hydrocarbon Traps

2017-03-28
2017-01-1014
Engine air induction systems hydrocarbon trap (HC trap) designs to limit evaporative fuel emissions, have evolved over time. This paper discusses a range of HC traps that have evolved in engine air induction systems. (AIS) The early zeolite flow through HC trap utilized an exhaust catalyst technology internal stainless steel furnace brazed substrate coated with zeolite media. This HC trap was installed in the AIS clean air tube. This design was heavy, complicated, and expensive but met the urgency of the implementation of the new evaporative emissions regulation. The latest Ford Motor Company HC trap is a simple plastic tray containing activated carbon with breathable non-woven polyester cover. This design has been made common across multiple vehicle lines with planned production annual volume in the millions. The cost of the latest HC trap bypass design is approximately 5% of the original stainless steel zeolite flow through HC trap.
Technical Paper

Vehicle Deep Data: A Case Study in Robust Scalable Data Collection

2017-03-28
2017-01-1651
Onboard, embedded cellular modems are enabling a range of new connectivity features in vehicles and rich, real-time data set transmissions from a vehicle’s internal network up to a cloud database are of particular interest. However, there is far too much information in a vehicle’s electrical state for every vehicle to upload all of its data in real-time. We are thus concerned with which data is uploaded and how that data is processed, structured, stored, and reported. Existing onboard data processing algorithms (e.g. for DTC detection) are hardcoded into critical vehicle firmware, limited in scope and cannot be reconfigured on the fly. Since many use cases for vehicle data analytics are still unknown, we require a system which is capable of efficiently processing and reporting vehicle deep data in real-time, such that data reporting can be switched on/off during normal vehicle operation, and that processing/reporting can be reconfigured remotely.
Technical Paper

Impact of Pre-Study Exploration on System Usability Scale and Task Success Rates for Automotive Interfaces

2017-03-28
2017-01-1385
Measurement of usability with the System Usability Scale (SUS) is successfully applied to products in many industries. The benefit of any measurement scale, however, is limited by the repeatability of the associated testing process. For SUS, these factors can include sample size, study protocol, previous experience, and pre study exposure to the system being tested. Differences in user exposure can influence the usability assessment of interfaces which could affect the validity of SUS scores.
Technical Paper

Human-Centered Measurement Scales in Automotive Product Development

2017-03-28
2017-01-1381
There is a strong business case for automotive companies to improve by understanding what consumers want, like and dislike. Various aspects of ergonomics such as reach, visibility, usability, feel are dependent on measuring consumer’s ability, opinions and satisfaction. Rating scales (such as adjective, continuous, logarithmic, etc.) are used to measure these complex attitudes. It is essential the correct rating scale and appropriate analysis methods are used to capture these attitudes. Previous psychology research has been conducted on the performance of different rating scales. This ratings scale research focused on scales and their reliability and validity for various applications. This paper will summarize past research, discuss the use of rating scales specific to vehicle ergonomics, and analyze the results of an automotive interface study that correlates the seven-point adjective rating scale to the system usability score (SUS).
Technical Paper

MyFord Dock Development

2017-03-28
2017-01-1694
Demand for enhanced infotainment systems with features like navigation, real-time traffic, music streaming service, mirroring and others is increasing, forcing automakers to develop solutions that fulfill customer needs. However, many of those systems are too expensive to be fitted to an entry-level vehicle leaving a gap in the market that fails customer’s expectation. This gap is usually filled by a smartphone which may have all the features the customer wants but in many cases it cannot be properly fitted in the vehicle due to lack of specific storage space. This paper describes how the engineering team developed an innovative, flexible and effective solution that holds a smartphone in an ergonomic location.
Journal Article

Development of a Fork-Join Dynamic Scheduling Middle-Layer for Automotive Powertrain Control Software

2017-03-28
2017-01-1620
Multicore microcontrollers are rapidly making their way into the automotive industry. We have adopted the Cilk approach (MIT 1994) to develop a pure ANSI C Fork-Join dynamic scheduling runtime middle-layer with a work-stealing scheduler targeted for automotive multicore embedded systems. This middle-layer could be running on top of any AUTOSAR compliant multicore RTOS. We recently have successfully integrated our runtime layer into parts of legacy Ford powertrain software at Ford Motor Company. We have used the 3-core AURIX multicore chip from Infineon and the multicore RTA-OS. For testing purposes, we have forked some parallelizable functions inside two periodic tasks in Ford legacy powertrain software to be dynamically scheduled and executed on the available cores. Our preliminary evaluation showed 1.3–1.4x speedups for these two forked tasks.
Journal Article

Evaluation of Prog-Die Wear Properties on Bare DP1180 Steel

2017-03-28
2017-01-0310
The die wear up to 80,800 hits on a prog-die setup for bare DP1180 steel was investigated in real production condition. In total, 31 die inserts with the combination of 11 die materials and 9 coatings were evaluated. The analytical results of die service life for each insert were provided by examining the evolution of surface wear on inserts and formed parts. The moments of appearance of die defects, propagation of die defects, and catastrophic failure were determined. Moreover, the surface roughness of the formed parts for each die insert was characterized using Wyko NT110 machine. The objectives of the current study are to evaluate the die durability of various tooling materials and coatings for flange operations on bare DP 1180 steel and update OEM tooling standards based on the experimental results. The current study provides the guidance for the die material and coating selections in large volume production for next generation AHSSs.
Technical Paper

Frequency FE-Based Weld Fatigue Life Prediction of Dynamic Systems

2017-03-28
2017-01-0355
In most aspects of mechanical design related to a motor vehicle there are two ways to treat dynamic fatigue problems. These are the time domain and the frequency domain approaches. Time domain approaches are the most common and most widely used especially in the automotive industries and accordingly it is the method of choice for the fatigue calculation of welded structures. In previous papers the frequency approach has been successful applied showing a good correlation with the life and damage estimated using a time based approach; in this paper the same comparative process has been applied but now extended specifically to welded structures. Both the frequency domain approach and time domain approach are used for numerically predicting the fatigue life of the seam welds of a thin sheet powertrain installation bracketry of a commercial truck submitted to variable amplitude loading. Predicted results are then compared with bench tests results, and their accuracy are rated.
Journal Article

The Effects of CO, C2H4, and H2O on the NOx Storage Performance of Low Temperature NOx Adsorbers for Diesel Applications

2017-03-28
2017-01-0942
Model low temperature NOx adsorbers (LTNA) consisting of Pd on a ceria/zirconia washcoat on monoliths were evaluated for low temperature NOx storage under lean conditions to assess their potential for adsorbing the cold-start NOx emissions on a diesel engine during the period before the urea/SCR system becomes operational. A reactor-based transient test was performed with and without C2H4, CO/H2, and H2O to assess the effects of these species on the NOx storage performance. In the absence of C2H4 or CO/H2, H2O severely suppressed the NOx storage of these model LTNAs at temperatures below 100°C, presumably by blocking the storage sites. When C2H4 was included in the feedgas, H2O still suppressed the NOx storage below 100°C. However, the C2H4 significantly increased the NOx storage efficiency above 100°C, attributable to the formation of alkyl nitrites or alkyl nitrates on the catalyst.
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