Cementitious-Based Brake Pads Technology: Performance, Low Energy Consumption, Emission Drop

<div class="section abstract"><div class="htmlview paragraph">This work pioneers the development of eco-friendly brake pads using coconut fiber and sawdust as reinforcement materials, combined with abrasives and friction modifiers. The innovation lies in the utilization of these natural fibers, which are not only cost-effective and abundantly available but also contribute to the sustainability of brake pad manufacturing. The study aims to explore the feasibility and performance of these organic fibers in brake pad applications. Coconut fiber and sawdust were chosen for their unique properties, such as high strength-to-weight ratio and thermal stability, making them ideal candidates for enhancing brake pad performance. The inclusion of abrasives and friction modifiers further optimizes the braking efficiency and durability of the pads. Comprehensive testing was conducted, including hardness, compression, wear (using a pin-on-disc apparatus), and thermogravimetric analysis (TGA), to thoroughly evaluate the mechanical properties and thermal stability of the fabricated brake pads. The results demonstrated that the brake pads possess satisfactory hardness, compression strength, and wear resistance, aligning with industry standards for organic brake pads. Notably, the TGA indicated excellent thermal stability, even under elevated temperatures, underscoring the material’s robustness. This project underscores the potential of using coconut fiber and sawdust in the formulation of organic brake pads, offering a sustainable and high-performance alternative to conventional materials. The novelty of this work lies in the strategic selection and combination of natural fibers with advanced testing to validate their application in automotive braking systems. Future research will focus on optimizing the composition and refining the manufacturing processes to further enhance performance and environmental benefits, paving the way for more sustainable practices in the automotive industry.</div></div>

<div class="section abstract"><div class="htmlview paragraph">The Los Angeles City Traffic (LACT) brake test is well known acclaimed procedure used by many vehicle manufacturers to assess the brake pad wear behavior and to investigate the Noise, Vibration and Harness (NVH) performance of the brake system. The LACT driving route consists of a set of real-world driving conditions, which has been considered representative of the US passenger vehicle market.</div><div class="htmlview paragraph">The scope of this study is to mimic the LACT test using finite element analysis (FEA) to calculate the wear displacement based on Rhee’s theory. The Leading-edge and trailing edge of the brake pad’s wear tendency is also predicted from the simulation. The finite element model for wear simulation consists of brake system viz., Rotor, Knuckle, Pads, Anchor bracket, Piston, and Caliper. Various braking scenarios consist of different driving characteristics (Number of brake applications, vehicle speed, brake pressure, rotor temperature, and brake rotor interface friction variation) based on LACT Route traffics are replicated in FEA.</div><div class="htmlview paragraph">The wear displacement results from the finite element analysis are in good agreement with physical test results. Further, based on the wear displacement values, the brake pad’s life span is calculated and correlated well with the test measurements.</div></div>

<div class="section abstract"><div class="htmlview paragraph">The effects of particle size and composition of platelet titanates, including potassium titanate and potassium-magnesium titanate, were investigated to determine their friction stability, wear resistance, and transfer film formation. The composition and properties of titanates were characterized using X-ray diffraction (XRD), X-ray fluorescence (XRF), and particle size analysis. Tribological properties were evaluated using a tribometer (MFT-5000), while the worn surfaces were analyzed with scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS).</div><div class="htmlview paragraph">Results indicate that the transfer film characteristics are significantly influenced by the particle size and composition of platelet titanates. Brake pads containing potassium-magnesium titanates formed a more uniform transfer film, leading to improved friction stability and reduced wear rates. In contrast, potassium titanates increased friction levels but also resulted in higher wear on the brake friction materials.</div><div class="htmlview paragraph">These findings demonstrate the importance of carefully controlling titanate composition and particle size to enhance brake pad performance. This research provides valuable insights for designing more durable and stable brake materials.</div></div>

<div class="section abstract"><div class="htmlview paragraph">To date, no generally valid statements can be made about the service life of brake pads, which may be due to factors such as driving style, the friction material used or the varying vehicle weight. While dynamic friction models including friction history are already established [<span class="xref">1</span>], the investigation of wear and wear dust behavior is currently in the focus of many research projects. One example is the investigation of calculation models for brake pad wear while neglecting the temperature development in the brake [<span class="xref">2</span>].</div><div class="htmlview paragraph">In cars, temperatures of up to 800°C occur in the brake under high loads, which leads to a significant increase in wear. Accordingly, the question arises how an estimation of brake pad wear can be applied to highly dynamic load cases. To do this, however, the processes taking place in the boundary layer between pad and disc must first be comprehensively understood and described. For this purpose, high-precision measurement technology is necessary, which was developed and optimized over several years at the Institute of Dynamics and Vibrations (IDS) in the form of the Automated Universal Tribotester (AUT).</div><div class="htmlview paragraph">In cooperation with Volkswagen AG, several test procedures have therefore been developed for the AUT, which provide information about the factors influencing the wear of brake pads under non-stationary conditions. For example, a previously developed stationary test procedure is carried out with four different temperature levels, which demonstrates a different temperature sensitivity depending on the pad material. In addition, decreasing velocity profiles with equivalent idle work to the stationary test procedure have been investigated in order to be able to analyze the influence of the dynamics of braking on wear more precisely. Depending on the friction pairing used, both the tendency and the absolute generated wear show differences with respect to the stationary reference measurement. The obtained results therefore represent a starting point for the better understanding of the influencing factors on brake pad wear.</div></div>

<div class="htmlview paragraph">The paper offers an investigation of whether the knowledge of the laws materials will follow and of the parameters for the materials can be obtained from integral testing, i.e. the testing of complete brake pads. Dynamic tests were designed for the purpose, with attention to both the axial and the radial / tangential directions of stress as mechanical properties of brake pads. The tests were run and evaluated on brake pads with a variety of patterns and constructions. The term used throughout this paper to describe these features is the matrix. It was shown that brake pads clearly demonstrate visco-elastic behaviour which is most definitely non-linear, and whose characteristic values for stiffness, damping and internal friction will alter in ratio to the load.</div>

<div class="section abstract"><div class="htmlview paragraph">The moisture adsorption kinetics of copper-free brake pads was studied to confirm an earlier finding that the adsorption weight gain follows a logarithmic relationship with respect to the square root of humidity exposure time and the relationship is linear in the beginning. When the pad cure temperature was raised from 120 to 180 and 240 °C, the adsorption rate increased. The 180 °C cure produced the highest pad modulus. With increasing moisture adsorption, the pad compression modulus increased just like the pad dynamic modulus, meaning decreasing compression/compressibility while the ISO ‘compressibility’ determined after 3 compressions under 160 bars increased in contradiction. It is concluded that the ISO ‘compressibility’ is a destructive hardness measurement like the Gogan or Rockwell hardness: the key difference is the indenter covers the entire surface of the pad. The true compressibility must be determined as an inverse function of bulk modulus. It is recommended that the pad compression modulus should be measured under low pressures like 10 bars for the purpose of determining the initial quality of virgin pads if the current ‘compressibility’ machines are to be used. Compression tangent modulus and dynamic modulus measurements produce the same results, meaning that one could replace the other. Pad cure temperature affects friction coefficient and moisture adsorption influences friction coefficient in opposite direction for moderate-speed snubs of 80 km/h vs. low-speed stops of 5 km/h.</div></div>

<div class="htmlview paragraph">The analysis reported on in this paper examines environmental, energy and economic benefits for specific, though different, proposed state wide high speed rail (HSR) systems combined with a regional maglev proposal under review in Florida. One of the HSR proposals and the maglev system are projected to be fully permitted within the next eighteen months and operational by the 1994-96 period.</div> <div class="htmlview paragraph">The specifics of each applicants proposals are integrated into a complex computer model which reflect different; 1) technologies and speeds, 2) energy demands and other resource needs, 3) system service level characteristics, 4) ridership levels, 5) modal splits combined with 6) other system differences.</div> <div class="htmlview paragraph">This computer model then integrates the unique a) fuel consumption and b) emission levels of the actual electrical generation grid supplying the HSR and maglev systems in central and south Florida.</div> <div class="htmlview paragraph">Finally, the model quantitatively combines this data with equivalent emissions, energy and other system information on auto and airplane transportation modes. This data and pertinent user characteristics enable the model to estimate precise environmental, energy and economic benefits (expressed in 1990 dollars) for each unique HSR and maglev transportation system for the year 1999 alone.</div> <div class="htmlview paragraph">The results of this Florida specific analysis conclude that implementation of a HSR proposal and the maglev system will annually result in:</div> <section id="s_1" class="section"> <h2 class="title">Economic and Energy Benefits</h2> <div class="htmlview paragraph">- Time savings valued to $85 million.</div> <div class="htmlview paragraph">Automobile wear and maintenance savings valued to $37.4 million.</div> <div class="htmlview paragraph">Property and injury loss savings valued to $8 million.</div> <div class="htmlview paragraph">Reduction in annual transportation energy consumption of between 1.13 to 1.69 trillion Btus.</div> <div class="htmlview paragraph">Reduced dependence of $28.4 million on fossil fuel to power our transportation systems.</div> <div class="htmlview paragraph">Reduction of $23.5 million in imported oil thereby strengthening this nation's domestic economy by A) reducing negative balance of payments, B) increasing reliance on domestic sources of energy, and C) increasing domestic security.</div> <div class="htmlview paragraph">Reduce the annual economic damages (externalities) from transportation air pollution emissions.</div> <div class="htmlview paragraph">Additionally HSR/maglev systems will result in</div> <div class="htmlview paragraph"> <ul class="list disc"> <li class="list-item"> <div class="htmlview paragraph">Savings in new highway construction costs exceeding $1 billion.</div> </li> <li class="list-item"> <div class="htmlview paragraph">Up to 217,979 man year direct and indirect construction employment.</div> <div class="htmlview paragraph">Up to $20 billion in indirect construction income.</div> </li> <li class="list-item"> <div class="htmlview paragraph">As much as 9,908 annual permanent operations jobs created both direct and indirect.</div> <div class="htmlview paragraph">Over $300 million annually in direct and indirect operation employment income.</div> </li> <li class="list-item"> <div class="htmlview paragraph">- Enhanced transportation productivity by a factor of three over current modes.</div> </li> </ul> </div> </section> <section id="s_2" class="section"> <h2 class="title">Environmental Emissions Benefits and Costs</h2> <div class="htmlview paragraph">- Annual reductions of between 555 to 633 tons/year of Volatile Organic Carbons (VOC) emissions.</div> <div class="htmlview paragraph">Annual reductions of between 3,035 to 4,746 tons (2753 to 4305 mtons) year of Carbon Monoxide (CO).</div> <div class="htmlview paragraph">Annual reductions of between 53,890 to 54,467 tons (48878 to 49402 mtons) year of Carbon Dioxide (CO<sub>2</sub>).</div> <div class="htmlview paragraph">Annual reductions of between 877 to 1,184 tons (795 to 1074 mtons) year of Nitrogen Oxides (NOx).</div> <div class="htmlview paragraph">Annual reductions of between 57 to 84 tons (52 to 76 mtons) year of Total Suspended Particulate (TSP) matter.</div> <div class="htmlview paragraph">Annual reductions of between 49 to 78 tons (44 to 71 mtons) year of tire wear particulate matter.</div> <div class="htmlview paragraph">Annual increases of between 132 to 173 tons (120 to 157 mtons) year of Sulfur Oxides (SOx).</div> <div class="htmlview paragraph">Total non-CO<sub>2</sub> auto and airplane emissions exceed HSR and maglev emissions by a factor of 14.</div> <div class="htmlview paragraph">Total automobile and airplane emissions (including CO<sub>2</sub>) exceed HSR and maglev emissions by 200%.</div> <div class="htmlview paragraph">With proper mitigation measures, environmentally related noise impacts can be resolved.</div> </section> <section id="s_3" class="section"> <h2 class="title">Growth in all Benefits/Costs</h2> <div class="htmlview paragraph">All of these HSR/maglev social benefits will rise by a factor of 1.75 of any percentage improvements in trip times while ridership revenues to system owners could rise by a factor of 2.7.</div> </section>

<div class="htmlview paragraph">The method of fatigue life evaluation and validation testing under operational conditions is a prerequisite to achieve optimal designs with respect to weight and long-term durability of the structure considered.</div> <div class="htmlview paragraph">Criteria like driving behavior and braking performance, influenced by global stiffness as well as fatigue life evaluation were taken into account when optimizing a forged 6.5 front axle beam of a heavy truck. The procedure for weight optimization includes the following steps: <ul class="list disc"> <li class="list-item"><div class="htmlview paragraph">Stress analysis e.g. using strain gage techniques and/or Finite Element Method,</div></li> <li class="list-item"><div class="htmlview paragraph">Road load data acquisition and derivation of design spectrum describing customer usage,</div></li> <li class="list-item"><div class="htmlview paragraph">Fatigue testing under constant amplitude and/or variable amplitude loading to establish component related SN-curves and/or fatigue life curves,</div></li> <li class="list-item"><div class="htmlview paragraph">Fatigue life evaluation using damage accumulation hypothesis (Miner's Rule),</div></li> <li class="list-item"><div class="htmlview paragraph">Optimization and weight reduction (in this case 14% weight savings were achieved) based on fatigue life evaluation.</div></li> <li class="list-item"><div class="htmlview paragraph">Validation testing using multi-axial computer controlled, servohydraulic test rigs.</div></li> </ul></div> <div class="htmlview paragraph">Since vehicle manufacturers tend to leave more of the development responsibility to the component manufacturer, the methodology described is directed to the component manufacturer and is condensed, introducing the “service strength evaluation diagram” used for design optimization. Using this technique a designer can get a good feel for the relative impact of design changes with respect to durability life under service conditions.</div>

<div class="section abstract"><div class="htmlview paragraph">Sports Utility Vehicles (SUVs) Braking performance is a critical parameter, and it is described by the measure of stopping distance & stability of the vehicle at a specified speed. When it comes to electric vehicles, balancing tyre performance parameters like RRc, traction, wear, ride and handling, weight and NVH is challenging due to higher axle weights, higher moment of inertia and high instant torque delivery. This study presents the braking performances of EV-intended tyres at various contact surfaces in both dry & wet conditions. Impact of tyre design attributes like tyre tread pattern, contact patch, tread compound, tyre carcass construction & characteristics studied on 3 different tyres including ultra-high-performance tyres on braking performances. This paper contains the study & analysis of 1) Footprint analysis concerning the shape of the contact patch, pressure distribution, land-sea ratio, and contact area 2)Tyre tread design such as NSD, grooves, ribs & sipes design and pitch length 3) Compound property studies like hardness, modulus, tensile strength, tear strength & elongation at break 4)Materials like polymer blend, filler ratio & new-gen materials 5)Tyre performance characteristics which are contributing to vehicle stability like lateral stiffness, longitudinal stiffness, dynamic stiffness & mu slip curves and 6) Longitudinal & lateral forces at various speed conditions with CAE Simulations.</div><div class="htmlview paragraph">BEV requires low rolling resistance for improving vehicle range and which calls for reducing the hysteresis of tyre tread compound which affect vehicle barking performance at wet surface and it should be compensated by adjusting other design parameters.</div><div class="htmlview paragraph">Mu slip curve very important characteristics for designing brakes system to get peak mu and programming software for ABS system.</div></div>

<div class="htmlview paragraph">Aluminum cylinder heads have been widely used on automobiles during the past fifteen years to increase the efficiency of engine operation. The great majority have given satisfactory service during many years of use and high mileages. In 1938 their use was greatly curtailed because of competitive costs. The competitive situation now prevailing favors the re-adoption of aluminum cylinder heads. Because of this, it is fortunate that the two problems formerly associated with the use of aluminum cylinder heads have been solved. One was difficult removal resulting from corrosion at the stud clearances. Tests have shown that this can be prevented easily by the use of cap screws, larger stud clearances, or stud coating compounds.</div> <div class="htmlview paragraph">The other problem was corrosion at the coolant inlet ports. The causes and means of prevention of this difficulty have been determined recently by means of road tests of seventeen automobiles, and cyclic tests of V-8 engines with divided radiators. It was learned that the corrosion can be prevented by simple methods which can be applied by the engine manufacturer at little or no added cost. The corrosion was found to result primarily from the galvanic couple formed with the iron cylinder block. Corrosion did not occur in road tests of engines having aluminum blocks as well as aluminum cylinder heads.</div> <div class="htmlview paragraph">One of the major factors affecting the rate of galvanic attack is the electrode potential of the cylinder head alloy. To achieve the low potential desired, the alloy should contain an adequate concentration of copper, and no more than a few tenths of a percent of zinc. Also, the alloy should be in the as-cast or solution heat-treated condition to retain sufficient copper in solid solution.</div> <div class="htmlview paragraph">Another effective means of reducing port corrosion was found to be the use of a protective design of cylinder head gasket which covered the port shoulders of the cylinder head and preferably extended into the ports. Such gaskets protect the shoulders against erosion and lengthen the paths of the galvanic currents.</div> <div class="htmlview paragraph">Proprietary alcohol and ethylene glycol antifreezes, and inhibitors used to prevent rusting of the iron cylinder block, were found to be important accelerators of port corrosion, particularly when mixed with water containing several hundred parts per million of chloride. These conclusions are contrary to those previously drawn from continuous engine tests before the development of cyclic testing. In the recent cyclic and road tests, the high chloride water when tested alone caused practically no corrosion. Also another municipal water high in chloride, sulphate, alkalinity, and copper, caused no appreciable corrosion. Straight ethylene glycol and methanol were less corrosive than the proprietary products, which contain inhibitors of iron corrosion. The amount of dilution of alcohol and glycol antifreezes with water proved to be an important factor, 70 to 80% of water causing maximum corrosion. The preferred non-freezing coolant of these types is water containing at least fifty percent by colume of any proprietary ethylene glycol antifreeze. These vary somewhat in corrosiveness depending on the inhibitors of iron corrosion employed. Sodium benzoate and certain oils were the most satisfactory inhibitors from the standpoint of aluminum cylinder heads. Kerosene showed promise as a non-corrosive, non-freezing coolant under special conditions.</div> <div class="htmlview paragraph">Inhibitors are sometimes used in tap water coolants to prevent rusting of the block and consequent clogging of the radiator. They cause corrosion of aluminum heads, even in the absence of antifreezes. Of the inhibitors tested in high chloride water, soluble oil was the least harmful to aluminum heads, and is therefore recommended where an inhibitor of iron corrosion must be used. Sodium benzoate has not yet been tested by the authors for such use but appears promising in view of the results reported by Vernon.<sup>(<span class="xref">1</span>)</sup> Chromates caused severe corrosion and their use with engines having aluminum cylinder heads and iron blocks cannot be too strongly condemned.</div> <div class="htmlview paragraph">If the engine manufacturer uses aluminum cylinder heads of the recommended alloy composition and condition, and a protective design of gasket, harmful corrosion will be avoided with only moderate attention to the recommendations concerning antifreezes and inhibitors.</div>

<div class="htmlview paragraph">Hino Motors has developed the new K13C, a 12.9 liter six cylinder in-line, heavy duty diesel engine that provides superior fuel consumption, extra low noise and excellent driveability together with a lower exhaust emissions. The initial K13C engine, whose production began in 1986 and about 30,000 units have been produced, is recognized all over the world for its good reliability and fuel economy. The new K13C is using the basic design and manufacturing/assembly processes of the previous one but includes a common-rail type fuel injection system with enhanced electronic controls to meet future regulation and customer requirements. Major design changes consist of a new cylinder head, a new front gear train, a new air intake system, a new turbocharger, a new compression brake system and electronic control module.</div> <div class="htmlview paragraph">The optimization of the intake system includes a new intake port and an electronically controlled inertia charging system. The highly effective turbocharger in conjunction with the electronically controlled common-rail system leads to better fuel consumption and lower exhaust emissions.</div> <div class="htmlview paragraph">In order to reduce engine noise, the following measures were taken: reduction of the mechanical noise by a newly designed gear train, reduction of air-bone noise from the cylinder head cover and intake system by using isolating rubber, and the reduction of combustion noise especially at engine idle speed by means of pilot injection.</div> <div class="htmlview paragraph">For safer driving and better driveability on both expressways and normal roads, braking performance and starting ability have been improved. The braking performance has been increased by adopting a new compression brake system with an electronically controlled waste gate valve in addition to an existent exhaust brake. The starting ability at clutch engagement is also improved by the increased injection pressure obtained by the common-rail fuel system. Moreover, the new starting assist system was developed. The vehicle equipped with the new K13C has almost the same starting ability as a 20 liter naturally aspirated engine which is the most popular for dump trucks in Japan.</div>

<div class="htmlview paragraph">Ten sets of tires with nine different off-road tread patterns were tested on a paved surface using a towed, instrumented trailer to measure their cornering characteristics (wet and dry) and their braking performance (wet, full skid).</div> <div class="htmlview paragraph">The data obtained and a method for rank ordering are presented.</div>

<div class="htmlview paragraph">During Extravehicular Activities (EVA) an astronaut has to be protected against various external factors ranging from mechanical hazards to solar radiation and micrometeoroids.</div> <div class="htmlview paragraph">An important element in this external protection is the outermost fabric layer. It has to ensure the mechanical protection of the pressure retention bladder and at the same time - by its thermooptical properties - plays an important role in the thermal control of the space suit.</div> <div class="htmlview paragraph">New weaving and knitting technologies enable the fabrication of so-called 3-D fabrics with interconnected layers and local variation of properties in one manufacturing step. By this a tailored design of protection properties is possible.</div> <div class="htmlview paragraph">A study has been performed to define concepts adapted for use on a European Space Suit. Different fabric samples were manufactured and tested, amongst others, for strength, flexibility, puncture and wear resistance, UV stability, flammability, out/offgassing and micrometeoroid protection effctiveness.</div> <div class="htmlview paragraph">The present paper will describe the different fabric concepts and their corresponding property profiles, including coating systems for the fabric surfaces.</div> <div class="htmlview paragraph">Test results will be presented.</div>

<div class="section abstract"><div class="htmlview paragraph">Driven by consumer demand and environmental regulations, market share for plug-in hybrid electric vehicles (PHEVs) continues to increase. An opportunity remains to develop PHEVs that also meet consumer demand for performance. As a participant in the EcoCAR 3 competition, Colorado State University’s Vehicle Innovation Team (CSU VIT) has converted a 2016 Chevy Camaro to a PHEV architecture with the aim of improving efficiency and emissions while maintaining drivability and performance. To verify the vehicle and its capabilities, the CSU Camaro is rigorously tested by means of repeatable circumstances of physical operation while Controller Area Network (CAN) loggers record various measurements from several sensors. This data is analyzed to determine consistent output and coordination between components of the electrical charge and discharge system, as well as the traditional powertrain. The aim is to improve drivability and efficiency as measured by vehicle technical specifications (VTS) including acceleration, energy consumption, and emissions. In this interest, the team focused on the areas of mass reduction, efficient powertrain operation as well as optimal engine and motor use. While there is incomplete evidence showing that targets have been met in these areas, this study definitively shows improvement from year to year of the competition and specifically during Year 4 when the vehicle was tested extensively. Mass reduction resulted in more acceleration. Efficient powertrain operation resulted in better energy consumption and emissions. Optimal engine and motor use increased our EV range and further improved fuel economy and emissions. Our study reveals that our efforts have made drivability smoother and more responsive, lowered energy consumption while elongating range, and decreased emissions over previous iterations of our vehicle.</div></div>

<div class="section abstract"><div class="htmlview paragraph">Prevailing cut-throat competition in Indian Two wheeler market requires design engineers to enhance performance of traditional braking systems with reduction in cost and weight. The increasing need of road safety however requires the braking system to minimize stopping distance and increasing Mean Fully Developed Deceleration (MFDD). The purpose of this study is to augment the braking performance of two wheeler by comparing various combinations of twin leading drum brake layouts by method of Virtual Simulation.</div><div class="htmlview paragraph">The conventional drum brake system utilizes one cam, one pivot, one leading shoe member and one trailing shoe member. In the event of braking, leading shoe causes the generation of drag force. The other shoe is “trailing”, moving against the direction of rotation, is thrown away from the friction surface of the drum and is far less effective. The present study highlights the incorporation and enhancement of braking characteristics of bigger brake drum system into smaller brake drum system through the adoption of double leading shoe concept with the added advantage of reduction in cost. The study necessitates the designing of a multi body dynamic model so as to extract the best braking performance with respect to typical braking system against different double leading shoe geometry and actuation mechanisms.</div></div>