M.Ing. / Vehicles used in military, agricultural, forestry, or construction applications often encounter different road surfaces during a single journey. In order to optimise the mobility of these vehicles, different tyre pressures are required for different types of terrain (sand, mud, cross country, tar road, etc.). An in-motion tyre pressure control system will enable the vehicle's operator to change the tyre pressures without leaving the vehicle. Such a system will not only allow optimum surface contact between the tyres and the terrain - thus improving vehicletraction, but it can also increase the lifespan of the tyres and reduce fuel consumption. The key design criteria for such a system are: quick reaction times, an effective operator interface, and reliability. In case of system failure, the operator must be able to override the control, and the tyres should be inflated to a pre-set default pressure. When the fault had been corrected, the system can be restarted from within the cabin, to inflate or deflate the tyres as required. The focus of this thesis is on the design criteria of a tyre pressure control system, receiving inputs from the driver and from onboard vehicle sensors; and then adjusting individual tyre pressures if necessary, while the vehicle is on the move. Based on the inputs to the control system, the optimum setting for the tyre pressure is determined from a look-up table stored in memory of an onboard computer. This table contains the pressure-speed and pressure-axle load relationship. A unique relation is programmed into the microprocessor for each different vehicle. To install a tyre pressure control system on a vehicle, a computer program is used to control the following hardware which are necessary to inflate or deflate tyres: An air compressor and storage tank. Pneumatic valve. Rotating seal. Pressure and speed sensing elements. Electronic control unit. An experimental set-up was built, from various components or sub-systems, which were integrated systematically until the system was working as a unit. The functionality of the system was tested, and although the results obtained do not yet justify the commercial manufacturing of such systems, it is trusted that this research has contributed towards the increased emphasis that is placed upon vehicle safety and comfort systems.

Note:

Pneumatic tire friction on ice is an under-researched area of tire mechanics. This study covers the design and analysis of a series of pneumatic tire tests on a flat-level ice road surface. The terramechanics rig of the Advanced Vehicle Dynamics Lab (AVDL) is a single-wheel test rig that allows for the experimental analysis of the forces and moments on a tire, providing directly the data for the drawbar pull of said tire, thus supporting the calculation of friction based on this data. This indoor testing apparatus allows for some degree of replication by helping to maintain test conditions and by imposing a desired tire slip; the normal load, camber angle, toe angle, and other testing configurations can also be pre-set, as required. Methods of and issues related to controlling the production of ice and maintaining the conditions of numerous factors for each trial run were also documented. The AVDL terramechanics rig allowed for the collection of data from tests that varied the tire tread, tire inflation pressure, normal load on the wheel, and the slip ratio of the moving tire. This empirical data was then analyzed through the statistical analysis program JMP 8 in order to determine which factors (or combination of factors) significantly influence pneumatic tire friction on ice. The analysis verified that the slip ratio had a significant effect on the observed coefficient of friction, which decreased as the slip ratio increased. The combinations of the slip ratio and inflation pressure and the slip ratio and tire setup also had a significant effect on the observed coefficient of friction. The tests appear to have validated the theory that the drawbar pull and the traction was higher for the tire with tread. / Master of Science

Thesis (M.S.)--West Virginia University, 1999. / Title from document title page. Document formatted into pages; contains ix, 129 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 114-120).

Extensive use of steel belted radial tires made it necessary to investigate the rubber-brass adhesion. Surface analysis techniques were used to give a better understanding of this bond, After about a decade of research, investigators have been successful in optimizing many of the parameters to obtain a bond of high strength. However there are still certain areas in which more work has to be done to make better quality tires. One such area is the effect of compound formulation on adhesion. Compound formulations still to a large extent are empirical. The purpose of this work is to give a scientific basis for formulating the rubber compound for best possible adhesion. / Master of Science

Abstract: The carbon black material used as reinforcing filler in tires was recovered by pyrolysis at a temperature of 490¢XC and at atmospheric pressure. The pyrolytic carbon black obtained (CBp) was contamined by various additives of the original tire. Contaminants were also produced by chemical reactions occurring in the pyrolysis reactor. The recovered carbon black was performed and a possible reduction of the ash content by hydrochloric acid treatment. After the demineralization treatment, the recovered pyrolytic carbon black (CBP) was heated in a post-pyrolysis process at temperatures ranging from 670 to 1170 ¢XC. The CBP were studied by low-pressure nitrogen adsorption and surface spectroscopic method ( SIMS), Raman spectroscopy, XRD, TPD, TEM. Furthermore, the CBP properties were correlated to their electrical conductivities.

Thesis (Ph. D.)--Columbia University, 1935. / "A study of the automobile tire manufacturing industry in the United States."--Introd. Includes bibliographical references (p. 217-228) and index.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 433-438). Also available in electronic version.

No description available.

Thesis (MBA)--Stellenbosch University, 2012. / Tyre waste from end-of-life tyres (ELTs), sometimes erroneously defined as a type of waste, in fact represents a renewable energy resource that is highly competitive as replacement fuel to coal in the form of tyre-derived fuel (TDF) or useable as rubber crumb in other products. In this research study, the main utilisation options considered were based on rubber crumbing through ambient and cryogenic processing. Pyrolysis, the so-called ‘holy grail’ of tyre technologies, rubberised asphalt products, TDF options and various other product options from tyre crumb as basis were considered. Although pyrolysis technology is highly commendable and environmentally friendly, it is still a process with too many variants and presents an unstable economic model that is not attractive to entrepreneurs. Rubberised asphalt depends on policy decisions from local and national authorities supporting initial higher spending and allowances on budgets to acquire future savings from the longevity in the product. The policy requirements and the instability that politically-inspired decisions carry with them are contributing to the unattractiveness of this solution to the entrepreneurial fraternity. Through government requiring a certain percentage of asphalt pavements to contain rubber (like in the United States of America (USA)), rubberised asphalt could be a very useful and viable option to produce. In the USA, the Environmental Protection Agency (EPA) recently avoided the return to coal in industrial kilns currently using TDF based on its beneficial carbon dioxide (CO2) emission and cost structures by defining TDF as Reasonably Available Control Technology (RACT) to existing coal-burning industrial kilns. In South Africa, the usage of TDF should be of interest to Eskom and the cement industry. TDF (produced from end-of-life tyres), defined as a renewable energy resource due to its proven biomass component and with its high calorific value, presents higher energy output values in comparison to coal and furthermore presents the industry with lower input costs per ton and reduces the CO2 emission factor. Entrepreneurial intervention involving Eskom and/or the cement industry in South Africa with the utilisation of end-of-life tyres as renewable energy resource is an overdue business opportunity. With more than ten million tyres per year available in South Africa and a stockpile of more than fifty million waste tyres, sustainability of TDF supplies is a reality. TDF is much cheaper per ton than coal and emits approximately 20 percent less CO2 and/or CO2e than low-grade coal to produce the same electricity output. From all the information gathered, it is clear that in countries where coal energy is extensively used, TDF utilisation not only reduces the tyre waste issues, but it also serves as an environmentally-friendly renewable energy resource in electricity production and cement kilns; the industry with some of the highest CO2 emission risks. The final chapter of this report presents a schedule representing the choice of tyre processing and disposal methods ranked by environmental preference and defining the priorities linked to process and product choice.