Decoding Genuine Ceramic Pad Formulations - materials and processing Bharat S. Tomar, Dr. Sharafat Ali, Dr. Keith Ellis, Yogesh Chaudhary Allied Nippon Private Limited, Sahibabad, Ghaziabad 201010, UP, India --------------------------------------------------------------------------------------------------------------- ABSTRACT The need for development of genuine ceramic composite for PV application arose to overcome the challenges associated with traditional semi-metallic pads. The main focus is to achieve better performance, pad and disc wear along with low dust in comparison to semi-metallic pads. In general, brake pads convert kinetic energy to thermal energy through friction and operating temperature in semi-metallic brake pads is higher due to presence of steel having high thermal conductivity. Over the last decade, the customer preference has moved over to ceramic pads due to light coloured pad surface, low disc and pad wear and low dust in comparison to semi-metallic pads.
Friction materials containing metal ingredients used in automotive industry can cause unfavorable environmental impacts. Existing laws and regulations require phase out of heavy metals in brake pads. Substitutions for metals in friction materials, however, may introduce operational safety issues. In the current study, a molecular dynamics model based on LAMMPS has been developed to study the effect of material composition, density and geometric configurations on the tribological, mechanical and thermal properties of silicon carbide under various contact conditions at the atomic level. Successful simulations are performed to predict the elastic modulus, thermal conductivity, wear rate and coefficient of friction, with the incorporation of interfacial contact between surface asperities. The predicted properties can help enhance the performance of engineered metal free friction materials against thermal-mechanical failures.
The invention of metal-free friction materials is gaining popularity in the manufacturing of brake pads and clutch friction discs because of the negative factors associated with metals such as copper. To gain more insight into the failure mechanism of the recent invention during brake or clutch applications, a nonlinear transient thermomechanical model is established using ABAQUS. The model is based on a two-dimensional configuration for an investigation on the onset of TMI (Thermo-Mechanical Instability) during sliding contact in such material. The model is validated by comparing the transient simulation results for a full-contact regime to the result from the existing eigenvalue method. A parametric study is carried out to examine how the thermal conductivities and the elastic moduli influence TMI. The simulation results show that the thermal conductivities in the transverse direction can stabilize the system.
This paper discusses design aspects of an integrated design of exhaust manifold with turbocharger for a 3 cylinder diesel engine, simulation activities (CAE and CFD), and validation of manifold while upgrading to meet current BS6 emissions. Exhaust after-treatment system needs to be upgraded from a simple DOC (Diesel Oxidation Catalyst) to a complex DOC+sDPF (Selective catalytic reduction coated on Diesel Particulate Filter) to meet the BS6 emission norms. To avoid thermal losses and achieve a faster light-off temperature in the catalyst, the exhaust after-treatment (EATS) system needs to be placed close to the engine – exactly at the outlet of the turbocharger. This has given to challenges in packaging the EATS. The turbocharger in case of BS4 is placed near the 2nd cylinder of the engine, but this position will not allow placing the BS6 EATS.
The performance of lithium-ion batteries and its service life depends on its operating temperature. Operating the battery above 45 °C degrades the performance of the battery and reduces its service life. The high-temperature operation also leads to thermal runaway. So there is a need to monitor the operating temperature and voltage output of the battery using a battery thermal management system to ensure its safety. Battery Thermal Management System (BTMS) is a part of the battery management system. The effectiveness of the battery thermal management system depends on the battery pack design, battery chemistry, vehicle operating characteristics and ambient conditions. In this work, a refrigerant-based BTMS is modeled using MATLAB Simulink. Refrigerant R134a used in the air conditioning system of an Electric Vehicle is used as an evaporative cooling medium to cool the batteries.
Experimental research on the Vapor Compression Refrigeration System (VCRS) used in automobiles and other air conditioning systems is abundant in literature but it comes with inherent problems like the cost of the setup, time consumption, and tediousness of the process. Therefore, the objective of this study is to develop the fully-fledged transient or dynamic model of R134a based VCRS and further utilize it to virtually determine the optimal refrigerant charge quantity. The Simulink model developed in this work is an integration of physics-based mathematical models for each component (compressor, heat exchangers, and expansion valve), working together in a cycle where the compressor dictates the transient process. A sample simulation has been performed by taking 5 bar as the initial pressure of suction and discharge tanks and the steady state results (Discharge pressure, suction pressure, refrigerant mass flow rate, superheat and subcool temperatures) obtained.
Dual mass flywheel (DMF) is an excellent solution to improve the noise, vibration and harshness (NVH) characteristic of any vehicle by isolating the driveline from the engine torsional vibrations. For the same reason, DMFs are widely used in high power-density diesel and gasoline engines. However, the real-world usage conditions pose a lot of challenges to the robustness of the DMF. In the present work, a new methodology is developed to evaluate the robustness of a DMF capturing the RWUP conditions fitted in a Sports utility vehicle (SUV) with front-wheel drive architecture. During engagement of clutch system, enormous amount of energy is dissipated. To sustain the operating temperature of the clutch system, generated energy is dissipated through conduction & convection. If the temperature of the clutch friction material is not retained, clutch burning & burst failures happens. Ventilation holes are provided on clutch housing to improve convective heat transfer.
In order to investigate the possible use of normal capital, we have tried by hand to manufacture sisal fibre polymer composites. Natural fibre composites are reusable, low-cost and biodegradable. Simple source, lesser compactness, superior basic property, lower quality, acceptable physical and mechanical properties, non acidic in environment, make them a good-looking biological substitute for glass, carbon or other artificial fibres. The outcome of SiC on the physical and mechanical properties of organic sisal composite materials is studied in this work. The composite was manufactured with and without SiC, mixing natural sisal fibre with polyester as a reinforcement medium. The investigational results showed that the tensile force of the mixture with 12 % SiC was 2.52 times better than that of the composite devoid of SiC. The collision strength of the 12% SiC merged is 1.72 times higher than that of the SiC pure polyester composite.
Thermal Barrier Coatings (TBCs) are one of the most promising technologies for reducing heat dissipation through the combustion chamber in internal combustion engines. In this paper, Gadolinium Zirconate (GZ) was chosen as coating material and prepared using a solid-state synthesis process. Cast iron (GJL 300) was selected as substrate, which is predominantly used as the cylinder head material, and GZ was deposited using Electron Beam Physical Vapor Deposition Technique (EB-PVD). The mechanical, thermal, and tribological properties were evaluated as per the ASTM standards. Improved hardness and wear resistance is noted on coated substrates. The thermal conductivity and Coefficient of Thermal Expansion (CTE) of the coated substrates were decreased by 2.43% and 6.15% respectively when compared to uncoated substrates. Hence, it is confirmed that thin-film TBCs will also be helpful in retaining some heat inside the combustion chamber of IC engines.
In automobiles, the most commonly used braking system is disc brake. In the brake disc, rotor is the rotating part of a wheel's disc brake assembly, against which the brake pads are applied by the driver through mechanical action. So, the disk is the important component in either slowing down or stopping the vehicle. These discs were commonly made of cast iron conventionally. But the limitations with respect to cast iron are that they have less corrosion resistance and heavy in weight. In order to overcome the above-said complications, alternate materials for disc have to be found. The main objective of this paper is to analyze the characteristics of three different materials and compare their results and suggest a suitable material that highly influences the conventional material and has better performance under on-road rigorous braking conditions.
The automobile sector is moving towards electrification as a replacement for the conventional IC Engine as the power source of vehicles. In electric vehicles, Li-ion battery is the widely used energy source for traction and is a major differentiator among various sub components that affect vehicle performance, safety and efficiency. The life of the battery pack is affected by different stress factors like SoC (state of charge), DoD (depth of discharge), C-rates (charge and discharge currents) and battery temperature. Out of the mentioned stress factors, the life of batteries is most influenced by the temperature excursion seen by the li-ion cells in the battery pack. There are various thermal management strategies available to keep the temperature under control like air cooling , chilled liquid cooling and hybrid cooling systems.
Technology improving on a daily base, the innovating structures and development of LED’S has led to dramatic improvements of the performance in LED technology. Replacing incandescent lights and CFLs clearly concludes the character of the LED. Producing high lumen output and efficiency has been the greatest advantage. Every industry including automobile is slowly shifting from halogen lamps to LED lamps. LED producing localized heat and maintaining the junction temperature for maximum lumen output range causing failure of LED has been the greatest hurdle for the engineers. Researches carried out in order to minimize the disadvantages are the main focus in lighting industry. In traditional methods, Thermal management of LED’s are done by passive cooling of LED using heat sinks and fluids such as coolant based heat sink model.
Clutch is a very important component of any vehicle equipped with the manual transmission (MT), automated manual transmission (AMT) or dual-clutch transmission (DCT). During launch of a vehicle(moving from “0” speed), clutch is being slowly engaged by the Driver or TCU(for AMT vehicle) for smooth torque transfer between engine and transmission. The clutch is design to transfer max engine torque with min heat generation. During the clutch engagement, the difference in the input (engine flywheel) and output shaft (clutch disc) speed of clutch called the clutch slipping phase which then leads to a huge amount of energy being dissipated in terms heat due to friction. As a result, clutch surface temperature increase consistently, when the surface temperature cross the threshold limit, the clutch wear out quickly or burns spontaneously. Hence it is crucial to predict the energy dissipation and temperature variation in various components of clutch assembly through virtual simulation.
In previous work, AC Compressor Cycling (ACC) was modeled by incorporating evaporator thermal inertia in Mobile Air Conditioning (MAC) performance simulation. Prediction accuracy of >95% in average cabin air temperature has been achieved at moderate ambient condition, however the number of ACC events in 1D CAE simulation were higher as compared to physical test . This paper documents the systematic approach followed to address the challenges in simulation model in order to bridge the gap between physical and digital. In physical phenomenon, during cabin cooldown, after meeting the set/ target cooling of a cabin, the ACC takes place. During ACC, gradual heat transfer takes place between cold evaporator surface and air flowing over it because of evaporator thermal inertia.
The current paper focuses on the compact HVAC component development for electric passenger vehicles running in tropical countries where the external ambient conditions are harsh. Various previous studies have shown that the power required for HVAC system alone is about 12-15 percent of the overall vehicle energy demands. Due to very high thermal loads, the Electric Vehicles operating in tropical countries will obviously fall under the higher HVAC energy consumption band. In addition to the power demand, the cooling requirements like shorter pull-down time adds further challenges to the HVAC design. Another major challenge being faced by the EV manufacturers is the concerns due to range which has resulted in compact vehicles having less space for HVAC and other subsystem components. The current paper proposes an approach for replacing the conventional air-cooled condenser by water cooled condenser. A water-cooled condenser will be much more compact than a conventional condenser.
Condensation is a phenomenon that occurs inner surface of the headlamp lens, when the headlamp is submitted to very harsh and moist environments. Since the headlamp is not concealed, it will absorb the conditions of the environment as well as those from the engine compartment. This phenomenon leads to fogging of the headlamps inner side of outer lens. Headlamp designs have to meet very stringent condensation related internal test standard performance requirements defined by the automotive OEMs. The component development approach is mostly through physical validations which is costly and time-consuming approach. With the recent advances in CFD simulation techniques, headlamp condensation performance can be predicted in a virtual environment, enabling designers to make the necessary design changes and improvements on the headlamp early in the design process thereby lowering the product development cost and time.
With the rising emission level in Indian cities, the focus on pure battery electric vehicle is increasing also in India. The Government of India his also focusing on preparing right policies like FAME-2 to promote the acceptability of EV's by providing subsidies as well as creating the required infrastructure. The environmental conditions in India is much different than other developed countries of Euro, China etc. The max. temperatures in India can go up to 55℃ in the hottest summer time, while during winters temperature can go up to <-25℃ in the northern Himalia region. In these conditions the cooling system of the electric-powertrain components like E-Machine Battery pack etc have to be protected for worst case scenarios specific to Indian conditions. Major cost driver of EV's lie in the HV battery packs and it is very important for acceptability of EV's that the Battery is maximized.
To study the functioning of a fuel cell and optimize its operating parameters to achieve the best efficiency in operation it is important to have a robust fuel cell model that can simulate the behavior of the fuel cell stack under various operating conditions. The operating voltage of the fuel cell at different current densities depends upon thermodynamic parameters like temperature and pressure of the reactants as well factors like the state of humidification of the electrolyte membrane. A 1D model is developed to capture the variation in voltage at different current densities due to internal losses and changes to operating conditions like temperature and pressure. Additionally since the stack temperature and moisture content within the stack influence the stack operation directly models for the thermal management of the stack and humidification of the membrane are also developed.
Till recently supercharging was the most accepted technique for boost solution in gasoline engines. Recent advents in turbochargers introduced turbocharging technology into gasoline engines. Turbocharging of gasoline engines has helped in powertrains with higher power density and less overall weight. Along with the advantages in performance, new challenges arise, both in terms of thermal management as well as overall acoustic performance of powertrains. The study focuses mainly on NVH aspects of turbocharging of gasoline engines. Compressor surge is a common phenomenon in turbochargers. As the operating point on the compressor map moves closer to the surge line, the compressor starts to generate noise. The amplitude and frequency of the noise depends on the proximity of the operating point to the surge line. The severity of noise can be reduced by selecting a turbocharger with enough compressor surge margin.