The need to develop genuine ceramic composites for PV applications arose to overcome the challenges associated with traditional semi-metallic pads. The main focus is to achieve better performance, low noise, better pad and rotor wear, and low dust compared 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 the 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 rotor and pad wear and low dust compared to semi-metallic pads. The traditional steel has been replaced by Aramid, engineered ceramic fibre, potassium titanate (TISMO D), lapinus fibre (RB 250) to impart similar/better performance. The current work investigates the characterisation of genuine ceramic and semi-metallic composites.
The work investigates the use of cathodic protection -based strategies (e.g. sacrificial anodes) with the aim of extending the corrosion resistance of Aluminum components to be used in disc brake systems. Lab-scale electrochemical measurements, including voltammetry and zero resistance ammetry (ZRA), are used to: a) define the requirements of a cathodic protection system for a 42200 Aluminum alloy; b) evaluate the protection capability of a Zn-based sacrificial anode; and c) demonstrate an extended corrosion resistance of the protected part even in the presence of a galvanic coupling, with respect to the unprotected condition.
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 Finite Element Code. 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 and elastic moduli in the longitudinal direction can stabilize the system.
Friction materials containing metal ingredients used in the automotive industry can cause unfavorable environmental impacts. Existing laws and regulations require heavy metals in brake pads to be phased out of production. Substitutions for metals in friction materials, however, may introduce operational safety issue and other unforeseen problems. 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. Simulations which incorporate interfacial contact between surface asperities were performed to predict the elastic modulus, thermal conductivity, wear rate, and coefficient of friction. The resulting predicted properties may help enhance the performance of engineered metal-free friction materials against thermal-mechanical failures.
This Aerospace Recommended Practice (ARP) clarifies terms used in Aerospace materials and process specifications. The terms clarified in this ARP are not intended to supersede those terms for which clarification is already provided in existing specifications.
This SAE Aerospace Recommended Practice (ARP) identifies and defines a method of measuring those factors affecting installed power available for helicopter powerplants. These factors are installation losses, accessory power extraction, and operational effects. Accurate determination of these factors is vital in the calculation of helicopter performance as described in the RFM. It is intended that the methods presented herein prescribe and define each factor as well as an approach to measuring said factor. Only basic installations of turboshaft engines in helicopters are considered. Although the methods described may apply in principle to other configurations that lead to more complex installation losses, such as an inlet particle separator, inlet barrier filter (with or without a bypass system), or infrared suppressor, specialized or individual techniques may be required in these cases for the determination and definition of engine installation losses.
Water and ethylene glycol are considered as conventional coolants from years in automotive industry for engine cooling. With the advancements in nanotechnology, Nano fluids have become prominent in increasing the rate of heat transfer compared to that of conventional fluids. Present study enlightens the CFD simulation of Nano-fluids in a radiator with base fluid as Ethylene glycol- water and Al2O3 as nanoparticles at different volume concentrations. The Nano fluid rheology is simulated in Ansys-Fluent CFD tool using standard k-ε two equation turbulence model with enhanced wall treatment and a standard y plus values. Various available fluent single phase and multiphase models are evaluated and compared with the experimental results in a simple circular pipe to setup the standard simulation methodology for radiator analysis. The effective temperature dependent thermos-physical properties of Nano fluids were estimated from the literatures.
This paper discusses design and optimization process for the integration 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 for this engine. 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.
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, DMF’s 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, by capturing the Real-World Usage Profile (RWUP) conditions, a new methodology is developed to evaluate the robustness of a DMF fitted in a Sports utility vehicle (SUV). Ventilation holes are provided on clutch housing to improve convective heat transfer. Improvement in convective heat transfer will increase the life and will reduce clutch burning concerns. Cities like Mumbai, Chennai, Bangalore, roads will have clogged waters during rainy season. When the vehicle was driven in such roads, water enters inside the clutch housing through ventilation holes.
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.
Disc brake is the customarily used braking system in automobiles. In the disc brake assembly, rotor is subjected to rotation and the brake pads are operated by the driver through mechanical action. So, the disc plays a decisive role in dropping the speed 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 their characteristics and recommend a fitting material that highly replaces the conventional material and has better performance at on-road braking conditions.