When passenger vehicle drivers hit the brakes of their cars, the friction releases airborne wear particles from the contact between rotor and brake pad onto the road which are eventually washed down storm drains and into rivers. The wear particles includes copper, which functions as solid lubricant for increasing thermal heat fade as well as increasing friction coefficient for the brake pad. Nevertheless, copper not only endangers aquatic life, but it also directly affects the economy by lowering the supply of salmon. Copper is toxic to most aquatic life and is especially harmful to the sensory systems of salmon. Copper impairs salmon's sense of smell, thus reducing their ability to escape from predators. Up to half of the copper found in waterways from urban areas are from copper brake pads and is a key factor in the reduction of salmon population. In 2010, Washington and California each passed laws to ban production of brake pads containing more than 0.5% copper which will be effective in 2025. Since then, several other states including New York, Rhode Island, and Oregon have all introduced similar bills to ban copper brake pads. The raw materials that were added to the newly developed copper free sample brake pads are geopolymers; they are synthetic mineral products that combine properties of polymers, ceramics and cements. Geopolymers have the characteristic of behaving as adhesive rubber in order to replace phenolic resin matrix in the brake materials also it can be harden at room temperature which can increase friction coefficient of the brake pad. Sample brake pads manufactured on site with known constituents were tested with friction assessment and screening test machine, which measured and recorded the friction coefficient and wear of the brake pad. According to the experience in the past, the sample brake pads will be analyzed with density test and Shore Durometer test. The results presented in this report shows that geopolymers brake pad shows promising results for copper replacement for low-metallic friction material. Developed copper free friction sample shows promising result of coefficient of friction of 0.44 with thickness loss of 0.62 mm from friction assessment and screening test machine compare to commercial brake pad.

Due to new environmental regulations, the demand for brake systems producing low polluting emissions and keeping high performance, is increasing. Therefore, a reduction in the toxic substances contained in brake friction materials is required that still meets all applicable safety standards and retaining properties such as low wear, high temperatures resistance, friction coefficient stability and consistency. Among the various ingredients used in formulations, copper has recently become the subject of different regulations on brake pad materials and will be reduced, or even prohibited, in the coming years. Recent studies have found that brake pads are major contributors to the deposit of copper in rivers and lakes, and this has a toxic impact on the environment. This metal is currently added in brake material formulations because of its good physical properties and its contribution to the formation of a uniform and stable friction layer. Its characteristics make it a constituent that is not easy to replace and an adequate substitute covering all the roles of copper has not been found as yet. The present research aims at developing, producing and testing new formulations for brake pads without copper. A relatively wide range of friction materials was investigated, in order to understand the role that selected constituents have in friction and wear behaviour. In the first place, an investigation on the role of copper in friction materials was performed. The study was followed by the selection of a suitable replacement for this constituent in the formulation. To do so, different friction components were studied. Additionally, other aspects relating to friction materials, such as the deterioration of the binder, were subject of investigation. The novel formulations, produced starting from commercially available compositions, were ranked in terms of wear and friction behaviour by means of a pin-on-disc tribometer. Cylindrical specimens were produced directly from powders, so that constituents could be easily modified based on the test outcome. This is a very effective method to study the role of individual constituents in the mixture, considering the relatively small amount of each specific composition to be prepared and the ease of processing it. In order to identify the principal wear mechanisms and their dependence on material properties and test conditions, the worn materials were analysed via scanning electron microscopy (SEM) techniques and Energy Dispersive X-Ray Spectroscopy (EDXS). Part of the acquired knowledge from the first part of the work was used in the initial stages of the ECOPADS project (the project started during the doctoral period) to develop and manufacture real brake pads that were tested on brake dynamometers and evaluated in terms of both performance and emissions.

Braking is mainly controlled by the engine. Friction between a pair of pads and a rotating disc converts the kinetic energy of the vehicle into heat. High temperatures can be reached in the system which can be detrimental for both, components and passenger safety. Numerical techniques help simulate load cases and compute the temperatures field in brake disc and brake pads. The present work implements a Finite Element (FE) toolbox in Matlab/Simulink able to simulate different braking manoeuvres used for brake dimensioning mainly in the early phase of car development process. The brake pad/disc geometry is considered as an axisymmetric body assuming negligible temperature gradient along the circumference of the disc. Calibration using three control factors namely: heat coefficient during braking , acceleration  and emissivity  for the implemented thermal model is performed using experimental investigation at Volvo Car Corporation (VCC) for three specific severe load cases. The thermal model is extended to measure brake fluid temperatures to ensure no vaporisation occurs. Simulation results of the brake disc and brake pad show good correlation with the experimental tests. A sensitivity analysis with the control factors showed convective coefficient during acceleration  the most sensitive, with temperature change of around 16%.

Friction brakes represent the most important safety feature literally in all vehicles and their rigorous “friction testing” is usually performed on several platforms/scales and completed with field tests. Since friction and wear are system properties, it is not trivial to design “small scale” tests and to correlate data generated at different levels of testing complexity. Nevertheless, the economy of the brake materials development process could be improved, when interpretation of friction and wear test data is based on a deeper/proper understanding of physics and chemistry of ongoing friction phenomena. This contribution follows the two series previously presented at SAE Brake Colloquia and compares the data generated in the full-scale brake dynamometer SAE J 2522 performance test (Link Engineering 2800M dynamometer) with data generated in bench-top (small scale) friction tester (Bruker UMT) equipped with environmental chamber controlling temperature. Scaling laws of physics were adopted for design of the small-scale testing procedure, however, a different scaling philosophy as well as different friction materials were used when compared to the previously reported findings. Identical commercial OEM brake pad samples containing biodegradable environmentally friendly fibers and commercial OEM cast iron rotors were used in both dynamometer and scaled-down bench-top friction tests. Friction and wear surfaces/mechanisms were studied by using scanning electron microscopy (Quanta FEG 450 by FEI) equipped with the energy dispersive X-ray microanalysis (Inca System), and 3D optical microscope (NPFLEX by Bruker). Major conclusions proposed for this study can be summarized as follows: 1) Proper scaling by using physics principles allows for reasonable correlation of dynamometer and bench-top test data, although the results differentiate, particularly during fade and high temperature tests. These findings further support the previously published data and indicate that differences in scaling philosophy neither the types of tested materials have considerable impact on the generated data. 2) It is very important to properly select representative pad samples, as their size is considerably smaller compared to full pads. When the identical rotor materials are used, the repeatability of data is excellent and the sensitivity to typical differences of the bulk microstructure of cast iron is minimal. 3) When the testing results generated on dynamometer and bench tester matched well. the friction surfaces of full pads tested in dynamometer and the friction surfaces of small pad samples exhibited identical topography and chemistry.

This thesis draws up a basic overview of the current groups pedal cars. It focuses on creating a computer model of the pedal group with the help of the mathematical model and simulation stress of individual components and proposed relief.

This diploma thesis is focused on conversion of Skoda Octavia RS mark I brake system. This vehicle will be used for race use. The aim of the thesis is to design adequate components of the brake system to achieve good brake deceleration and so that the design will be correspond to hard conditions on the race track. Thesis contains complete design of hydraulic system including control and brake forces, pressures, options of brake forces management and evaluate of brake stability. Followed by the design of brake caliper adapters and the static structural analysis by FEM. The thesis contains picture and assembly drawing attachment too.

In the railway industry, and premium luxury and super sports sectors of the automotive industry, traditional cast iron brake discs are gradually being replaced with advanced composites such as carbon fibre reinforced carbon silicon carbide (Cf/C-SiC). These materials offer the ability to operate at higher temperatures, whilst displaying improved friction performance, and vastly reduced wear rates. Their primary benefit comes from being approximately one third of the density of the incumbent material used in the industry, grey cast iron (GCI), a cast iron with a high proportion of graphite flakes formed during solidification. This reduced density means that brake discs manufactured from Cf/C-SiC materials are a highly suitable proposition for a future automotive market, where weight saving in an attempt to meet ever restrictive CO2 emissions is a must. The understanding surrounding the friction mechanisms involved with these new materials has been lacking, until recently, with the majority of the international research focused on the manufacturing methods. Research has shown that friction performance, particularly bedding friction, is highly dependent on the successful formation of a friction transfer film (FTF) at the surface of any disc, comprised from wear debris from both the disc and pad. Prior research carried out at Loughborough University has identified that Cf/C-SiC materials do not readily form such a layer, as might be seen on a GCI equivalent, due to the intrinsically heterogeneous nature of the composite material.

<p>Applications relying on a high static friction include various types of fixtures, couplings, bolted joints, torsion joints, etc. The common characteristic of these applications is that they rely on the friction force to maintain the relative position of two mating surfaces. Also applications relying on high dynamic friction are common, the main example being brakes, where a low friction could be devastating.</p><p>The plateau model for the friction of brakes has been refined. By using advanced electron microscopy, it has been shown that during braking a partly amorphous friction film, comprising nanosized iron oxide agglomerates, dissipates the friction energy. The film is only about 100 nm thick. It is separated from the underlying less mobile material by a thin boundary. The actual braking power is thus localised to this very thin film, leading to remarkably high power densities. In a typical case it was estimated to 40 GW/dm3.</p><p>Squeal and vibrations are critical problems for brakes. The present work has shown that a textured disc pattern may counteract squeal efficiently. The most successful pattern has spiral shaped arms in which wear resistant ceramic particles are embedded. The different wear characteristics of treated and untreated disc surface lead to an elevation of the patterned area above the rest of the disc. In a related experiment, laser technique was used to inject the particles deeper into the disc surface, and thus prolonging the time of silence. </p><p>Textured diamond surfaces have been used to study the influence of load, repeated scratching and surface roughness on the static coefficient of friction. It was shown that these surfaces were remarkably stable at high friction levels. A maximum load limit was found above which the coefficient of friction falls. This and a number of other factors were found important for the successful design of high-friction joints.</p>

Generators are widely used across the world as portable power units in case of power outages, used for emergency services and are also used in rural areas without access to electricity. The majority of commercially available generators use internal combustion engines designed as automobile engines with little or no optimization for use in generators. With operating conditions vastly different than that of automobile engines, they can be re-designed to operate much more efficiently as generator engines. The development objective here was to design a low cost, 1.6L, lean burn, internal combustion engine which minimizes heat losses, time losses and frictional losses to improve thermal efficiency. Various high swirl, high squish, easily CNC’d combustion chambers were created in the re-design process. A computer model was used to provide insight into the trade-off between time losses and heat losses. A maximum brake thermal efficiency of 37.2% was achieved.

The air brake system is one of the critical components in ensuring the safe operation of any commercial vehicle. This work is directed towards the development of a fault-free model of the pneumatic subsystem of the air brake system. This model can be used in brake control and diagnostic applications. Current enforcement inspections are done manually and hence are time consuming and subjective. The long-term objective is to develop a model-based, performance-based diagnostic system that will automate enforcement inspections and help in monitoring the condition of the air brake system. Such a diagnostic system can update the driver on the performance of the brake system during travel and with recent advancements in communication technology, this information can be remotely transferred to the brake inspection teams. Since this system is performance-based, it will eliminate the subjective nature of visual inspections. The first step in the development of such a diagnostic system is to obtain a fault-free model of the air brake system. The model of the pneumatic subsystem correlates the pressure transients in the brake chamber with the brake pedal actuation force and the brake valve plunger displacement. An experimental test bench was set up at Texas A&M University and the experimental data is used to corroborate the results obtained from the model.