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Development and Industrialization of a Laser-Based Hard Material Coating System for Brake Discs

2020-11-09
Fine dust emissions caused by road transportation are being investigated and discussed in detail by governments and vehicle manufacturers. Brake abrasion contributes to a significant extent to this ambient air pollution. There are different approaches to minimize this brake disc abrasion, one of the most promising is the coating of the friction surface with wear resistant layers, i.e. with metal matrix composite (MMC). One coating technology, the extreme high-speed laser material deposition, has proven to be extremely effective, especially in combination with appropriately adapted brake pads. In detailed investigations with various brake disc manufacturers, HPL Technologies in Aachen, Germany, examined influences on the quality such as reliable corrosion and wear resistance.
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Impact of Phenolic Resin Type on the Performance of Newly Developed Friction Materials for Vehicles with Regenerative Braking

2020-11-09
Automotive industry is undergoing a paradigm shift towards vehicles with alternative power. The sales of electric vehicles have increased by over 165% over the past 2 years in the United States [1]. With government incentives coupled with the decrease in battery cost, the trend seems to continue. As the friction brake accounts for about 5 to 30% of total braking in electric/hybrid vehicles, this also warrants for more research into the development of new lightweight, wear resistant, and sustainable friction materials also for reviewing the existing testing procedures. Phenolic resin is typically used as binding material in majority of the current brake friction materials. Numerous authors demonstrated that the type of phenolic resin has effect on properties of brake pads [2].
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Enclosure-in-Chamber Setup to Achieve Near-Zero Background Concentrations for Brake Emissions Testing (SAE Paper 2020-01-1634)

2020-11-09
Measuring brake emission continues to be a challenging non-standardized task. Extensive research is ongoing and as seen in the work in progress presented at SAE Brake Colloquium and PMP meetings. However, open items include how to achieve lower background concentration and how to design the brake enclosure. A low background concentration is essential as brake events are short and some emissions are in the range of reported background levels. Hence these emissions are difficult to distinguish from the background level. Even more critical, a high background concentration can result in a wrong particle number emissions value, either overestimated, background counted as emissions, or underestimated, background level subtracted, and low emission events no longer detected and counted. Reducing the background level to less than 100 #/cm3 appeared to be quite challenging.
Video

Experimental and Numerical Investigation of the Multiphase Flow and Heat Transfer in an Oil Jet Cooled Engine Piston

2020-11-04
The piston temperature has to be carefully controlled to achieve effective and efficient thermal management in the internal combustion engines. One of the common methods to cool piston is by injecting oil from the crankcase underside to the piston under-crown area. In the present study, a novel 3-D multiphase thermal-fluid coupled model was developed using the commercial CFD software SimericsMP+ to study the piston cooling using the oil jet. In this model, an algorithm was proposed to couple the fluid and solid computation domain to account for the different timescale of heat transfer in the fluid and solid due to the high thermal inertia of the solid piston. The heat transfer coefficient (HTC) and reference temperature were mapped to the piston top surface and the liner temperature distribution was also used as the boundary condition. The temperature-dependent material properties, piston motion, and thermal contact resistance between the ring and piston were also accounted for.
Video

Wheel Bearing Warranty Analysis Trends and Countermeasures

2020-11-04
Wheel bearing warranty in the market has gained an increased amount of attention over the last decade by most vehicle OEMs. In addition, the needs of electric and autonomous vehicles put new life and robustness requirements on wheel bearing assemblies. Detailed warranty analysis of failure modes is required to determine root causes of field failures in order to recommend potential countermeasures. In the field there exist failure modes such as sealing failures, impact damage, fretting, material fatigue failures and perceived "no Trouble Found" parts. This oral presentation will explore and describe the mechanism of some of these field failure modes as well as detailing some of the potential countermeasures that can be applied. The warranty analysis procedure of creating investigative documents and failure distributions will be reviewed as well as predictive analysis of implemented countermeasures to determine the countermeasures effectiveness in the field.
Video

Analysis of Heat Pipe Impact on PCM Based Battery Thermal Management

2020-11-04
We have performed a numerical and experimental study on the impact of adding heat pipes to a PCM based battery thermal management system. Phase change materials (PCMs) are used as a battery thermal management system to absorb heat by melting in a specific temperature range, leading to a temporary constant and uniform temperature around battery cells. They also can be used as mechanical support for battery cells and safety measure to prevent fire propagation in case of thermal runaway. The main drawback of these materials is their low thermal conductivities. Our proposed approach is the integration of heat pipes with PCM as a hybrid system to take advantage of both technologies including the temperature peak absorption and structural support of PCM along with very high effective thermal conductivity, temperature uniformity and passive operation of heat pipes. Flat heat pipes integrated with PCM are tested with 18650 cells under various C-rates and ambient temperatures.
Video

Influence of Increasing Amount of Attapulgite on the Performance Properties of Cu-Free Brake-Pads (SAE Paper 2020-01-1601)

2020-11-04
Copper is almost inevitable functional filler in the brake-material and efforts to replace it are continuing since it is now known as a hazard to the aquatic life. It is always desirable to search for ingredients for Cu-free brake-pads, which will be beneficial for friction-related properties and especially fade resistance. Attapulgite, is a mineral which was proven to be an excellent substitute for asbestos in brake-pads long back. However, hardly anything in details is reported on its exact role in controlling tribo-properties of friction materials (FMs). It was of interest, if it can be helpful in enhancing the performance of Cu-free FMs.Hence, in this work a series of brake-pads (five types) was formulated and developed with increasing amount of attapulgite (0, 5, 10 and 15 wt. %) by compensating with inert barite particles in Cu-free FMs. The parent composition was fixed and instead of Cu powder, 10 wt.% stainless steel powder was used.
Video

Anodization: Recent Advancements on Corrosion Protection of Brake Calipers (SAE Paper 2020-01-1626)

2020-11-03
Brake calipers for high-end cars are typically realized using Aluminum alloys, with Silicon as the most common alloying element. Despite the excellent castability and machinability of Aluminum-Silicon alloys (AlSix), anodization is often required in order to increase its corrosion resistance. This is particularly true in Chlorides-rich environments where Aluminum can easily corrode. Even if anodization process is known for almost 100 years, anodization of AlSix -based materials is particularly challenging due to the presence of eutectic Silicon precipitates. These show a poor electric conductivity and a slow oxidation kinetics, leading to inhomogeneous anodic layers. Continuous research and process optimization are required in order to develop anodic layers with enhanced morphological and electrochemical properties, targeting a prolonged resistance of brake calipers under endurance corrosive tests (e.g. >1000 hours Neutral Salt Spray (NSS) tests).
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Eco-Friendly Brake-Pads using Ferritic Stainless-Steel Particles of Varying Sizes: Influence on Performance Properties

2020-11-03
Metallic particles in brake-friction materials (FMs) play a vital role in improving mainly strength, friction level, thermal conductivity and hence resistance to fade and during braking operations. Although Copper was the most efficient and popular metallic ingredient in FMs, it is being phased out because of its proven threat to the aquatic life in the form of wear debris. Hardly any successful efforts are reported in open literature barring few on initial exploration of stainless steel swarf (SSS) and particles of stainless steel (SSP) in the authors? laboratory. It is a well known fact that the size and shape of particles affect the performance of FMs apart from their type, concentration etc. In this research, Ferritic stainless steel (SS 434) particles were selected as a theme ingredient in two forms, first particulate (SSP) with two sizes, large (30-45 micron) and small (10-20 micron) and also in the form of swarf.
Video

Evaluation of a Low-Metals, Non-Petrochemical Coke for Use in Automotive Friction Materials (SAE Paper 2020-01-1603)

2020-11-03
A study was performed to compare the performance of small and large automotive, semi-metallic, friction pads, each manufactured with one of two different calcined coke fillers. Coke #1 is a conventional calcined petroleum coke, and Coke #2 a proprietary, calcined coke manufactured from a non-petrochemical feedstock and sold by Asbury Carbons under the trade name "EcoGreen". The subject coke materials were fully characterized, physically and chemically. Chemical characterization included a modified TCLP leaching study performed on each coke. Both coke materials are similar in their respective physical properties, including morphology, hardness, and crush strength. However, there is a significant difference in the trace metal content of the two materials, with Coke #1 containing a higher content of sulfur, calcium, iron, nickel, and vanadium than Coke #2. Nickel, vanadium, and sulfur are considered potential environmentally hazardous substances.
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Experimental Investigation of Corrosion of Cast Iron Rotors in the Automotive industry

2020-11-03
Electric and hybrid vehicles use regenerative braking, where application of the brake triggers the electric motor to drive as a generator to produce electricity, which in turn charges the battery. Although allowing use of up to ~60% of the kinetic energy of a vehicle, this ?electric braking? action is usually combined with the use of a friction brake, often called foundation brake, in the ?blended regime.? This not only saves energy, but results in much less frequent use of the friction brake and correspondingly reduces brake wear/pollution. The less frequent friction engagements, however, lead to changes of the corrosion and wear behavior, also changes in the performance of the friction brake [can you add a reference here?, if not just ignore, also further requests].
Video

Effective Grease Academy Training for Optimized Wheel Bearing Lubrication

2020-11-03
Grease is a three component matrix consisting of a thickener, base oil and additives. It is really critical to understand grease know how and technology for providing optimized lubrication solutions for many applications. This is no exception especially when the auto industry and the OEMs are striving towards development and making of energy efficient workable components such as wheel bearings and associated units. This academy will address key notes worthy of review and consideration in terms of grease terminology and associated parameters as a source of knowledge that can be used with engineers for a holistic and sustained solution for wheel bearing lubrication.
Video

Changing Properties of Brake Pads and Discs during Brake Testing (SAE Paper 2020-01-1628)

2020-11-03
Earlier publications show that brake pad physical properties such as hardness, modulus and natural frequencies continue to increase at room temperature over a period of 12 months and that the changes are faster during the first 3 - 6 months. The current investigation was undertaken to see how the properties might change during testing for the pads as well as for the discs. Low-copper and copper-free formulations were tested on pickup truck and passenger car brakes. In all cases, the dynamic modulus and natural frequencies are found to decrease (not increase) after the SAE J2522 performance testing, indicating that the stiffness of the pad and that of the disc decrease faster than the mass loss due to wear. Also, the inboard pad and the outboard pad change at two different rates.
Video

Wear Performances of Gray Cast Iron Brake Rotor with Plasma Electrolytic Aluminating Coating against Different Pads (SAE Paper 2020-01-1623)

2020-11-03
Gray cast iron brake rotor experiences substantial wear during braking and contributes largely to the wear debris emissions. Surface coating on the gray cast iron rotor represents a trending approach dealing with the problems. In this research, a new plasma electrolytic aluminating (PEA) process was used for preparing an alumina-based ceramic coating with metallurgical bonding to the gray cast iron. Three different types of brake pads (ceramic, semi-metallic and non asbestos organic (NAO)) were used for tribotests. Performances of PEA coatings vs. different brake pad materials were comparatively investigated with respect to their coefficients of friction (COFs) and wear. The PEA-coated brake rotor has a dimple-like surface which promotes the formation of a thin transferred film to protect the rotor from wear. The transferred film materials come from the wear debris of the pads. The secondary plateaus are regenerated on the brake pads through compacting wear debris of the pads.
Video

Chassis Committee Panel: Durability Discussion for Commercial and Military Vehicles

2020-11-03
Moderator - Xiaobo Yang, Oshkosh Corporation Panelists - Mehdi Ahmadian, Virginia Tech. Neil Bishop, CAEfatigue, Ltd. Ram Iyer, ArcelorMittal This technical panel focuses on innovative and improved durability development, analysis methodologies, and problem-solving techniques in the commercial and military vehicle industry. The subjects of interest include: studies and discussion on (1) duty cycle development and customer usage correlation; (2) fatigue of metallic and non-metallic materials (3) environmental effects on fatigue performance (4) effect of manufacturing processes and operating condition uncertainties on durability performance, and (5) durability performance validation and testing methodologies.
Video

Deposit Formation in SCR-Systems - Optical Investigations

2020-11-03
The permanently tightening emission regulations for nitrogen oxides (NOx) pollutants force further development of mobile exhaust aftertreatment systems with selective catalytic reduction (SCR). Of particular interest is the long-term reliability of SCR-systems with regard to unfavorable operating conditions, such as high injection rates of urea water solution (UWS) or low exhaust gas temperatures. Both may lead to the formation of solid deposits which decrease system efficiency by increasing backpressure and impairing ammonia formation. In order to study the most relevant processes of deposit formation, an optical box with heat resistant glass was designed. Three UWS injectors with different spray characteristics were used to study their influence on the deposit formation under a wide range of stationary and transient operating conditions. Infrared thermography was applied to observe spray-induced wall cooling, both below and above the Leidenfrost point.
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A Comparative Study On-Dynamometer Performance Evaluation of Fly Ash Containing Non Ferrous Organic and Low-Metallic Disc Brake Pads for Passenger Vehicles and Thereby Promoting a Very Cheap Inorganic Filler Available in Abundance (SAE Paper 2020-01-1613)

2020-11-03
A number of functional and non- functional fillers are invariably used for friction material composites. In recent years disposal of fly ash has been a big challenge due to low availability of damping sites. Current work investigates the characterization of Low -metallic and Organic composites made with fly ash with variable concentrations and evaluated for braking performance (SAE J2522) & wear (SAE J2707) on a brake inertia dynamometer. Composites have been characterized for their physical, thermal, mechanical and tribological performance. Low-metal based composites (LMBC) have shown better thermal resistance than non-ferrous organic formulation based composites (NFOC). Mechanical properties such as hardness, shear strength and compressibility have been found to be similar for both the composites. NFOC composites have shown better wear resistance while acquiring slightly lower coefficient of friction values.
Video

Quality Assurance Strategy in Light of Continuously Changing Properties of Disc Pads and Discs Panel Discussion

2020-11-03
Panelists - Joe Betoski, Business Development, Woodworth Inc. Pietro Durando, North America Friction R&D Manager, ITT Friction Technologies Charles (Chip) Evans, Specialist, Ford Motor Company Peter Kula, Application Integ Engineering, ZF Meechai Sriwiboon, R&D Director, Compact International (1994) Co., Ltd. Brake discs and brake pads tend to change their physical properties over time, either during storage or during brake testing. These changes are caused by internal residual stress relief in the case of discs, and by internal residual stress relief/cross linking of the resin in the case of pads, in addition to dimensional changes. This causes needs for revised quality assurance strategies. Panel participants will present their suggestions and discussed future directions for your consideration.
Video

Increasing the Efficiency of High-Pressure Systems in Aerospace Through 3D Metal Printing

2020-11-02
Heat exchangers are a prolific application found in all things that concern fluid and power; they are mission-critical applications that affect overall performance in aircraft of all sizes. Yet, for years, heat exchangers have been constrained, by traditional manufacturing, in terms of limited geometric freedom and lengthy lead times. Consider the following � Heat exchangers are commonly fabricated with stainless steel and then gold brazed, which can be extremely costly � Each weld joint costs $100; in traditionally manufactured fuel and high-pressure systems, there could be hundreds of welds � There can be a lack of integration with other systems like electrical motors or conformal cooling with batteries. Assembly integration, testing, and validation are lengthy and difficult. Additive manufacturing (aka 3D printing) has opened new possibilities for thermal conductivity and heat-exchanger design that enable end users to push the limits of what is possible.
Video

Performance Evaluation of Geometric Tolerance for Automotive Wheel Bearing Seals

2020-11-02
Automotive wheel bearings play an important role through transmitting power and carrying vehicle weight and automotive wheel bearing seals are to prevent lubrication from escaping and foreign material from entering. Bearings with low friction rotation are in great demand in the automotive market as a direct result of enforced vehicle fuel economy and reduced CO2 emissions regulations. Therefore, bearings with good sealing function and low friction rotation are required. In this study, the torque performance was evaluated considering the geometric tolerance of automotive wheel bearing seals. The deformation of the seals was analyzed using numerical analysis based on the finite element method. Three types of experiments for material properties of rubber were conducted to improve the reliability of deformation analysis for the rubber seals. To consider the geometric tolerance of the seals, Monte Carlo simulation was performed considering variations in dimension.
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