Abstract: Attapulgite, a unique clay mineral is a crystalloid hydrous magnesium-aluminium silicate, composed of silicon oxide, aluminium oxide, magnesium oxide, iron oxide etc. having formula Mg5Si8O20(HO)2(OH2)4•4H2O. Its structure is somewhat between laminated and chain structure having very high surface area and porosity. Its magnesium silicate structure resembles a brick wall with every second brick missing. This leaves elongated porous channels that are highly absorbent. Its fibers were proven to be excellent substitute for asbestos in brake-pads. Hardly anything in details is reported on its exact role in controlling tribo-properties of friction materials (FMs) especially Cu-free FMs. Hence, in this work a series of brake-pads with 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.
Graphite plays a crucial role in friction materials, since it has good thermal conductivity, lubricity and act as a friction modifier. The right type, amount, shape, and size of the particles control the performance of the brake-pads. The theme of the study was investigating the influence of size of graphite particles (having all other specifications identical) on performance properties of brake-pads containing graphite particles in the average size of 60 µm, 120 µm, 200 µm and 400 µm. Physical, mechanical and chemical characterization of the developed brake-pads was done. The tribological performance was studied using a full- scale inertia brake dynamometer following a Japanese automobile testing standard (JASO C406). Tribo-performance in terms of fade resistance, friction stability and wear resistance were observed best for smaller graphite particles. It was concluded that smaller size serves best for achieving best performance properties barring compressibility.
High temperature distribution in disc brake mounted within in-wheel motor driven vehicle has several negative effects on braking performance. This is mainly due to the enclosed nature of the braking system. This paper aims to determine the effect of contact geometry on temperature distribution and thermal buckling in such a brake. Numerical analysis is conducted to investigate the variation of temperature field on the brake disc at different cover angles of pads while maintaining the same moment of friction. The effect of different radial positions of the pads is a second consideration in the current work, using a transient modeling approach. To validate the simulation results, an approximate, analytical solution is derived according to energy conservation. The results show that, for the same work done by the pads, the maximum temperature on the disc increases with a decrease in the pad cover angle.
Last decade in mobility industry has seen tremendous amount of technology disruption and evolution that happened at a pace never seen before. Emission of Green House Gases and ever degrading air quality have been at the helm of this evolution. I.C Engine driven automobiles though being current state of art, have faced challenges and stiff competition from EVs. In this context, many technologies ranging from Friction reduction, Right-sizing, Light-weighting, use of advanced materials, Thermal Management Systems, Advanced Exhaust Gas After Treatment Systems etc. have evolved and successfully improved the performance and contention of IC Engines. However this is not enough. It is well established that a big portion of fuel energy goes wasted in the form of exhaust gases. Some part of this waste energy is recovered with the help of Turbochargers. However, even after the use of Turbocharger, there is enough energy which still can be harnessed into useful work.
Currently automotive design is facing multi facet challenges such as reduction in greenhouse gases, better thermal management, low cost solution to market, etc. Considering these challenges, effort has been taken to improve thermal management of engine while optimizing the cost of engine. Engine Lubrication system consist of Engine oil and oil cooler, which play vital role in thermal management as well as optimization of frictional losses by ensuring proper lubrication and cooling of engine components. For better thermal management of engine, a lubrication system is designed without Oil cooler, proto type made and tested. This paper deals with evaluation of various engine performance parameter and engine temperature with and without oil cooler for light duty Diesel engines on passenger car application. Further solution of Oil cooler removal and Engine cooling improvement with the help of oil change is validated at vehicle level to understand real world behavior of the system.
In automobiles, the most commonly used braking system is disk brake. The disk is the important component in either slowing or stopping the vehicle.When a brake is applied, there occurs a friction between the brake pad and the disk. Due to this action, a large amount of heat is generated. In order to reduce the generated heat, different sandwich structures were designed. The main objective is to analyze the thermal behaviour of the sandwich ventilated structures of different profiles and compare their results and suggest the suitable ventilation structure that highly influences the convective heat transfer of the brake disc under on-road rigorous braking conditions. The chosen brake disc material is titanium alloy. The profiles which are analyzed are X-core, Corrugated, Round O-core and Honeycomb. The heat transfer and the pressure drop characteristics of the sandwich structures were found with one face sheet heated by constant heat flux and cooled by forced air convection.
Recent years, researches are more focused on various enhancement methods for compact heat exchangers without altering the surface area of the heat exchangers. The advancements in the area of Nano fluids with better thermal properties have helped in development of light-weight, highly efficient automobile radiators. The main objective of this project is to increase the thermal performance of the radiator and thereby reducing the size of the radiator. In this project a numerical model with porous medium approach was developed and validated. Nano fluids (Aluminium oxide, Copper oxide, Graphite) of different volumes (ranging from 1%-13% in an interval of 2)are used along with water and it was observed that the heat transfer rate of the radiator is increased by 4.49% and the volume of the radiator is reduced by 5.4% for the addition of 5% of Aluminium oxide in water.
The ideology behind the project is to alter the helical angle of the baffles attached to the heat exchanger such that it increases the velocity of the flow of high viscous fluids. Investigations of thermo-hydraulic performance were conducted on five trisection helical baffle heat exchangers with different inclination angles, baffle shapes, or connection patterns, and one segmental baffle heat exchanger (SEG). A comparative analysis of three sector baffle schemes with inclination angles of 10° (10°S), 15° (15°S), and 20° (20°S); an ellipse baffle scheme with an inclination angle of 15° (15°E); and an axial overlap sector baffle scheme with an inclination angle of 20° (20°D) was performed. Local images were constructed to obtain pressure loss characteristics and flow field distributions. The flow field characteristics, such as the Dean vortex secondary flow and bypass leakage between adjacent baffles, are clearly shown and discussed.
Heat transfer analysis in the combustion chamber of internal combustion engine is crucial to design the combustion chamber. Manufactures will always look for the durability, better engine performance and also on the material cost for designing the combustion chamber. This will be achieved by designing the efficient combustion chamber effectively. The purpose of this paper is to determine the Adiabatic Flame Temperature using stoichiometric equations and find the gas temperatures at different points in the ideal diesel cycle. These values are used in the existed heat transfer coefficient equations and estimate the heat transfer to the coolant through the cylinder wall using one dimensional heat equation. This theoretical value of heat transfer rate is compared with the experimental heat transfer rate of the three cylinder engine. The average error percentage of the theoretical and experimental values is less than the 15 %.
During braking a large amount of kinetic energy being taken form into thermal energy thereby increasing the brake disc temperature around 200oC to 400oC in motorcycles and ATVs, which forces to improve the heat transfer in brake disc through grooves and holes thereby minimising the clamping force. In which the present study is mainly done to improve the clamping force on the brake disc through re-coined the shape of grooves with various disc materials by design and analysis route. The brake disc solid work model was developed with slanted rectangular grooves along the radial direction of Aluminium metal matrix composite (AA8081 reinforced with 15wt% of SiC and 3wt% of Gr), Stainless Steel (SUS 410), Gray Cast iron (Grade 250) materials data set. The couple field analysis attempts of both thermal and structural analysis was done to find the impact on the brake disc heat transfer rate, deformation, von mises stress and strength which were analysed by ANSYS workbench.
Piston is the most imperative part of an automotive engine in which it exchanges drive due to expanding gas in the cylinder to the crankshaft through the piston rod. During the combustion of fuel charge inside the ignition chamber, high pressure and temperature are developed and the piston is imperiled to high mechanical and thermal stresses. The main objective of the proposed work is to analyse the stress distributions and thermal behaviour of uncoated A356 - 5% SiC - 10% Fly ash HMMC piston crown and Plasma sprayed Yttrium Stabilized Zirconia(Y-PSZ) coated A356 - 5% SiC - 10% Fly ash HMMC piston crown. A356 - 5% SiC - 10% Fly ash HMMC were fabricated via squeeze casting to improve the performance of a petrol engine. A structural model of an HMMC piston crown was made using CREO software and structural and thermal analysis was done using ANSYS. Further coupled field analysis is done to find the stress and temperature distribution on the piston.
In this paper the heat transfer coefficient and the heat transfer rate of a heat exchanger is scrutinized by using nanofluids. The silicon carbide nanoparticles, milled and sonificated as nanofluidsof volume fractions 0.01499(%) and 0.01399(%).The heat transfer characteristics of SiC(P)/water, SiC(M)/water, SiC(P)/EG, SiC(M)/EG are measured in a concentric tube heat exchanger under laminar flow condition. The consequence of nanoparticle physiognomies, Reynolds number, on the heat transfer characteristic is scrutinized.It has been found that the addition of milled nanoparticlein the base fluids enhances the heat transfer characteristics rather than the normal nanoparticle. The experimental results shows that the heat transfer characteristicsof SiC(M) is higher than that of SiC(P) in both the case of water and EG. This is because of the structural changes of SiC-M by the deformation caused by the ball milling
Off highways vehicles especially tractors are prone to operate on fields where tractors are exposed to dry crops, chaffs (the husks of corn or other seed separated by winnowing or threshing) and particles which can catch fire easily when it is exposed to surface/skin temperature of more than 200 degree Celsius. It will be a basic projection that tractor will be having vertical exhaust tube at a height but there are certain tractors and applications where exhaust pipe must be below certain height, and which will be close to the ground. In these scenarios the skin temperature of exposed exhaust tail pipe part must be within a limit and that must be within the existing design. Break firing point of chaffs and husk also experimented at different moisture level. Several options are being verified on different heat flow and geometry changes, additional air entry jet nozzle with double pipe arrangement.
To tackle the problem arising due to emissions and to reduce them, complex after-treatment system is used. For efficient working of the after treatment system it must operate at sufficient high temperature even at low loads for better conversion efficiency. Also, there is different temperature requirements for different catalyst used in SCR (Selective catalyst reduction) system. For this, various on engine strategies are implemented on modern diesel engines such as multiple fuel injection, late fuel injection, high injection pressure and exhaust gas recirculation. Thermal management is an operating condition which must be triggered when there is need of elevated temperatures for efficient functioning of the after treatment system. Thermal management includes SCR thermal management and regeneration. The process of removing deposits from after treatment system is known as regeneration.
The implementation of increasingly stricter regulations on CO2 emissions by the European Community is pushing the automotive industry towards a radical change. In a rush to electrify their model ranges, global carmakers are investing heavily on developing new electrified powertrains. Within this context, this work focuses on the analysis of electric axles drives (eAxles) for a BEV (battery electric vehicle) sport car, with the aim to develop an analytical tool useful to perform predictive analysis in the concept design phase. Through a parametric definition of the procedure, the tool with its 2800 lines of code is able to “adapt” to any drivetrain layout analysed. The tool actually allows to enter more than 100 input values including lubrication conditions (oil viscosity and operating temperature), gears (number, macrogeometry, mesh), bearings (number, type, geometry, mounting layout, angle mesh), shafts, oil seals, external layout and external fluid conditions.
The electrochemical performance of a lithium-ion battery is strongly affected by the temperature. During charge and discharge cycles, batteries are subjected to an increment of temperature that can accelerate aging and loss of efficiency if critical values are reached. Knowing the thermal parameters that affect the heat exchange between the battery surface and the surrounding environment (air, cooling fins, plates, etc…) is fundamental to their thermal management. In this work, thermal imaging is applied to a laminated lithium-ion battery as a non-invasive temperature-indication method. Measurements are taken during the discharge phase and the following cooling down until the battery reaches the ambient temperature. The 2d images are used to analyze the homogeneity of the temperature distribution on the battery surface. Then, experimental results are coupled with mathematical correlations.
Mechanical friction and heat transfer in internal combustion engines are two highly researched topics, due to their importance on the mechanical and thermal efficiencies of the engine. Despite the research efforts that were done throughout the years on both these subjects, engine modeling is still somewhat limited by the use of models which do not fully represent the phenomena happening in the engine. Developing new models require experimental data which is accurate, repeatable and which covers wide range of operation. In 2018-01-0121, the conventional pressurised motored method was investigated, and compared with other friction determination methods. The pressurised motored method proved to offer a good intermediate between the motored tests, which offer good repeatability, and the fired tests which provide the real operating conditions, but lacks repeatability and accuracy.
The management of the self-generated heat of batteries is one of the main aspects to handle to preserve their performance over time. The present study investigates the thermal behavior of a laminated Li-ion battery during the discharge phase. The main focus is on the temperature variation over time and the local inhomogeneity. A thermal camera is used to detect the bi-dimensional temperature distribution on the battery surface. The measurements of temperature are used in a theoretical model of heat transfer to evaluate the power dissipated via thermal losses. Results reveal a gradient of temperature from the current connectors to the opposite edge of the battery. Moreover, the evolution of the absolute temperature and the range of variation are followed over time for different regions of interest identified on the battery surface. The dissipated thermal power is seen to increase over time because of the delta of temperature with the ambient.