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Technical Paper

Use of Plastic Trim Fasteners for Automotive Trimming Applications

2017-03-28
2017-01-1304
For many years, the use of in-mold fasteners has been avoided for various reasons including: not fully understanding the load cases in the part, the fear of quality issues occurring, the need for servicing, or the lack of understanding the complexity of all failure modes. The most common solution has been the use of secondary operations to provide attachments, such as, screws, metal clips, heat staking, sonic welding or other methods which are ultimately a waste in the process and an increase in manufacturing costs. The purpose of this paper is to take the reader through the design process followed to design an in-molded attachment clip on plastic parts. The paper explores the design process for in-molded attachment clips beginning with a design concept idea, followed by basic concept testing using a desktop 3D printer, optimizing the design with physical tests and CAE analysis, and finally producing high resolution 3D prototypes for validation and tuning.
Journal Article

Uncertainty Analysis of Model Based Diesel Particulate Filter Diagnostics

2008-10-07
2008-01-2648
This paper analyzes the potential benefit of a model based DPF leakage monitor over a conventional DPF leakage monitor that checks pressure drop after a complete regeneration. We analyze the most important noise factors involved in both approaches and demonstrate that the model based leakage monitor does not improve on the conventional leakage monitor in accuracy. It does improve on completion frequency, but at the expense of a great modeling effort.
Technical Paper

Threshold Monitoring of Urea SCR Systems

2006-10-31
2006-01-3548
To meet stringent 2010 NOx emissions, many manufacturers are expected to deploy urea selective catalytic reduction systems. Indications from ARB are that a threshold monitor must be developed to monitor their performance. The most capable monitoring technology at this time relies on NOx sensors. This paper assesses the capability of the NOx sensor as an SCR monitoring device. To this end, the NOx sensor must be able to distinguish between a marginal and a threshold catalyst with enough separation to allow for variability. We present the noise factors associated with the NOx conversion of the SCR system, and analyze what NOx sensor accuracy we need to preserve separation in the face of those noise factors. It is shown that a 1.75 threshold monitor is not feasible with current NOx sensor technology. We analyze the benefit of a partial volume monitor, and show there is no advantage unless the slope error of the NOx sensor is drastically reduced from current levels.
Technical Paper

The effects of contamination on commercial trucks rear suspension springs durability

2020-01-13
2019-36-0083
On current competitive scenario for road load transportation in Brazilian market, the operational costs should be reduced as much as possible. The suspension system commonly used on road commercial trucks is based on leaf spring use and Hotchkiss concept for axle locating devices. The use of leaf springs without bolt attachment eyelets are still common for rear suspension systems. When using the leaf spring with direct contact to the brackets, wear plates are placed between them to work as wear elements due to the friction between the parts. The friction will cause wear on the parts, and the wear plate is designed to suffer the damages of this friction instead of the leaf spring, being the cheapest element and can be easily replaced. When the system works on a severe contamination environment with high levels of grit and dirt, the degradation of the parts are accelerated.
Technical Paper

Reducing High Frequency Driveshaft Radiated Noise by Polymer Liners

2005-11-01
2005-01-3554
In automotive industry inserting cardboard liners or foam in the dirveshaft to prevent them from functioning as a path or amplifier to high frequency gear whine excitation is a common practice. Due to limited damping capability, these liners, however, have limited effectiveness and may not prevent or effectively reduce the shaft radiated noise. This paper addresses the feasibility and performance of polymers as an alternative lining material and technique. Through experimental investigations it has been shown that the polymer liners in reducing the driveshaft radiated noise are more effective than the cardboard liners.
Technical Paper

Redesign of an Exhaust Manifold Outlet Fastener Using Robust Design Techniques

2000-03-06
2000-01-0917
An L16 orthogonal array parameter Design of Experiment (DOE) evaluated six design parameters of the mating thread interface between the exhaust manifold outlet flange and jointing stainless steel fastener. The objective of this study was to identify optimal parameters for the redesign the thread interface by ensuring 100% seating of the fastener into the manifold flange (here after referred to as stud seating). Since the current fastener and manifold outlet flange interface threads do not always achieve the design objectives, due in part to a form of abrasive wear, consideration was given to develop a testing strategy that would quantify the amount of remaining thread engagement for a given stud length. This testing strategy ensured that the control parameters considered in this experiment would reveal main effects and interactions between the stud and tapped hole threads thus providing the necessary parameters for the redesign on the joint threads.
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

Light Truck Stabilizer Bar Attachment Non-linear Fatigue Analysis

1998-11-16
982833
The stabilizer bar attachments problem can not be simply analyzed by using linear FEA methodology. The large deformation in the bushing, the elastic-plastic material property in the bushing retainer bracket, and the contact between different parts all add complexity to the problem and result in the need for an analysis method using a non-linear code, such as ABAQUS. The material properties of the bushing were experimentally determined and applied to the CAE model. It was found that using strains to estimate the fatigue life was more accurate and reliable than using stress. Many modeling techniques used in this analysis were able to improve analysis efficiency.
Technical Paper

LNT+SCR Catalyst Systems Optimized for NOx Conversion on Diesel Applications

2011-04-12
2011-01-0305
A laboratory study was performed to assess the effectiveness of LNT+SCR systems for NOx control in lean exhaust. The effects of the catalyst system length and the spatial configuration of the LNT & SCR catalysts were evaluated for their effects on the NOx conversion, NH₃ yield, N₂O yield, and HC conversion. It was found that multi-zone catalyst architectures with four or eight alternating LNT and SCR catalyst zones had equivalent gross NOx conversion, lower NH₃ and N₂O yield, and significantly higher net conversion of NOx to N₂ than an all-LNT design or a standard LNT+SCR configuration, where all of the SCR volume is placed downstream of the LNT. The lower NH₃ emissions of the two multi-zone designs relative to the standard LNT+SCR design were attributed to the improved balance of NOx and NH₃ in the SCR zones.
Technical Paper

Improve Frame Assembly Flexibility with Low Investment

2017-11-07
2017-36-0132
Commercial vehicles are being developed for long decades in Brazil creating a deep background on manufacturing process. With the current scenario a variety of different vehicles specifications (weight capacity, load distribution, torque, size, etc.) are being required by the market. Joints with bolts and nuts are the engineering solution for the most of the problems found in automotive engineering regarding commercial vehicles. Screw processes were made during the last 150 years. Nowadays current frame modifications on aftermarket are made with arc weld process that affects directly the material properties and the process needs to be performed by critical personal with training and capacity. In addition cost and timing does not fit for the best equation on how to proceed with the modifications. The solution proposed brings more flexibility on frame assemblies that can be extended to other products.
Technical Paper

Experiments in Active Diesel Particulate Filter Regeneration

2003-11-10
2003-01-3360
Diesel particulate filters (DPFs) are a technology likely to be deployed to meet future stringent emission levels for heavy and light duty diesel powertrains in North America and Europe. This paper discusses experimental results in the active regeneration of DPFs. Attention is given to the system components, the information based on which regeneration is triggered, and the means to achieve a regeneration. The paper will report on successful regenerations under several extreme conditions.
Journal Article

Effect of Biodiesel (B20) on Vehicle-Aged Engine Oil Properties

2010-10-25
2010-01-2103
High concentrations of diesel fuel can accumulate in the engine oil, especially in vehicles equipped with diesel particle filters. Fuel dilution can decrease the viscosity of engine oil, reducing its film thickness. Higher concentrations of fuel are believed to accumulate in oil with biodiesel than with diesel fuel because biodiesel has a higher boiling temperature range, allowing it to persist in the sump. Numerous countries are taking actions to promote the use of biodiesel. The growing interest for biodiesel has been driven by a desire for energy independence (domestically produced), the increasing cost of petroleum-derived fuels, and an interest in reducing greenhouse gas emissions. Biodiesel can affect engine lubrication (through fuel dilution), as its physical and chemical properties are significantly different from those of petrodiesel. Many risks associated with excessive biodiesel dilution have been identified, yet its actual impact has not been well quantified.
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

Computational Aeroacoustics of Mufflers for Exhaust Air Rush Prediction and Experimental Validation

2017-03-28
2017-01-1311
Air rush noise is exhaust gas driven flow-induced noise in the frequency range of 500-6500 Hz. It is essential to understand the flow physics of exhaust gases within the mufflers in order to identify any counter measures that can attenuate this error state. This study is aimed at predicting the flow physics and air rush noise of exhaust mufflers in the aforementioned frequency range at a typical exhaust flow rate and temperature. The study is performed on two different muffler designs which show a significant air rush noise level difference when tested on the vehicle. The transient computational study was performed using DES with 2nd order spatial discretization and 2nd order implicit scheme for temporal discretization in StarCCM+. To compare with test data, a special flow test stand is designed so that all high and low frequency contents emanating from the engine are attenuated before the flow enters the test part.
Technical Paper

Co-fueling of Urea for Diesel Cars and Trucks

2002-03-04
2002-01-0290
Urea SCR is an established method to reduce NOx in dilute exhaust gas. The method is being used currently with stationary powerplants, and successful trials on motor vehicles have been conducted. The reason most often cited for rejecting urea SCR is lack of urea supply infrastructure, yet urea and other high nitrogen products are traded as commodities on the world market as a fertilizer grade, and an industrial grade is emerging. For a subset of commercial vehicles, urea can be provided by service personnel at designated terminals. But this approach does not support long distance carriers and personal use vehicles. The preferred delivery method is to add urea during vehicle refueling through a common fuel nozzle and fill pipe interface: urea / diesel co-fueling. Aqueous urea is well suited to delivery in this fashion.
Technical Paper

CAE Approach for Light Truck Frame Durability Evaluation Due to Payload Increase

2004-11-16
2004-01-3411
The growing competition of the automotive market makes more and more necessary the reduction of development time and consequently, the increase of the capacity to quickly respond to the launching of the competitors. One of the most costly phases on the vehicle development process is the field durability test, both in function of the number of prototypes employed and the time needed to its execution. More and more diffused, the fatigue life prediction methods have played an important part in the durability analysis via CAE. Nevertheless, in order they can be reliable and really being able to reduce the development time and cost, they need to be provided with load cases that can accurately represent the field durability tests. This work presents a CAE approach used for light trucks in order to get a reasonable understanding of component durability behavior due to payload increase. In general, road load data is not available for a new payload condition.
Technical Paper

Application of LIN Network Interface for Ford South America Vehicles

2003-11-18
2003-01-3692
Some communication buses are too powerful and expensive for simple digital on/off operations such as activating lights, wipers, windows, etc. For these applications the LIN bus is currently the most promising communication protocol across the world's automotive industry. This paper addresses a study using LIN (Local Interconnect Network) for Ford South America vehicles. This will propose a new electrical architecture designed with LIN network, which will be replacing the conventional rear and front lights cables in Trucks, where other higher protocols, such as CAN, are not cost effective. LIN is a new low cost serial communication system intended to be used for distributed electronic system that will allow gaining further quality enhancement and cost reduction on cables, connectors and switches.
Technical Paper

A Systems Engineering Approach to Engine Cooling Design

1999-11-15
1999-01-3780
This paper is divided into two parts: Part 1 - Systems engineering fundamentals Part 2 - Engine cooling design from a systems engineering perspective In Part 1, we explain how the task of designing a complex system can be made easier by the application of Systems Engineering principles. (This part is self contained and may be of general interest to those who have no special interest in engine cooling). Systems Engineering provides three key benefits: It facilitates communication: Requirements define the problem, they allow team members to see their own work in context Key information is standardized and made easier to visualize and verify. An “audit trail” is maintained ensuring that important information is documented, and human memory is no longer relied on for important decisions. Translates requirements into design.
Technical Paper

A Finite Element and Experimental Analysis of a Light Truck Leaf Spring System Subjected to Pre-Tension and Twist Loads

2005-11-01
2005-01-3568
In this study the finite element method is used to simulate a light truck multi-leaf spring system and its interaction with a driven axle, u-bolts, and interface brackets. In the first part of the study, a detailed 3-D FE model is statically loaded by fastener pre-tension to determine stress, strain, and contact pressure. The FE results are then compared and correlated to both strain gage and interface pressure measurements from vehicle hardware test. Irregular contact conditions between the axle seat and leaf spring are investigated using a design of experiments (DOE) approach for both convex and discrete step geometries. In the second part of the study, the system FE model is loaded by both fastener pre-tension and external wheel end loads in order to obtain the twist motion response. Torsional deflection, slip onset, and subsequent slip motion at the critical contact plane are calculated as a function of external load over a range of Coulomb friction coefficients.
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