Increasing pollution all over the world has led to stringent emission norms and development of more environment friendly technologies. In near future, rapid transition towards greener and cleaner technologies is anticipated by automotive organisations. In India, FAME (Faster Adoption and Manufacturing of Electric Vehicles) scheme by NITI Aayog has made the intent about the usage of Hybrid & Electric vehicles (EV) clearer. As range is a major concern in EVs, the component that has become the subject of major interest is Battery due to its energy storage ability. Choosing batteries depends on energy density, weight and cost, which makes Li-ion battery technology leading option among others due to its better Power density v/s Energy density relations. For optimum performance and safety, one of the major concerns in the development of lithium-ion (Li-ion) battery packs for EVs is thermal management.
Brake system design is intended to reduce vehicle speed in a very short time by ensuring vehicle safety. In the event of successive braking, brake system absorbs most of vehicles kinetic energy in the form of heat energy at the same time it dissipates heat energy to the surrounding. In this period temperatures on the brake disc shoots to higher side and during successive braking rotor may attain peak temperatures (above allowable limits). High temperatures on rotor disc affects durability & thermal reliability of the brake rotor. Excessive temperature on brake rotors can induce brake fade, disc coning which results in reduced braking efficiency. To address the complex heat transfer and highly transient phenomenon while successive braking, numerical simulations can help to analyse complex 3D flow physics and heat dissipation from rotors in the vicinity of brake system.
This paper describes steady state, computationally rigorous, three-dimensional conjugate heat transfer 3D CFD analysis of an engine mounted oil cooler. Thermal performance of an oil cooler is very significant from engine oil consumption, bearings performance etc. In an engine water jacket, coolant flows around and through the oil cooler making the flow three dimensional. Therefore, demanding the need of a 3D CFD analysis for capturing all the flow and heat transfer aspects and thereby accurate prediction of thermal performance. An oil cooler contains intricate turbulators in flow paths and have dimensions varying from as small as 0.25 mm to as large as 300 mm, therefore making the meshing and solution a formidable task. In current work an oil cooler with all the intricate details is modelled in a commercial CFD code. Objective is to develop a solution approach which can predict thermal performance of an oil cooler in an accurate way.
Valve seat inserts (VSI) are installed in cylinder heads to provide a seating surface for poppet valves. Insert material is more heat and wear resistant than the base cylinder head material and hence it makes them better suited for valve seating and improved engine durability. Also using inserts permits easier repair or rebuild of cylinder heads as only the wear surfaces need to be replaced. Desirable performance characteristics are appropriate sealing, heat-transfer and minimizing valve to VSI wear and undesired outputs include valve seat dropping and cracking. With downsizing trend of diesel engines, it leads to increasing power density and therefore higher cylinder pressure and temperatures. Hence the engine components are getting exposed to more severe loadings and hence to failure modes, which were not heretofore experienced based on the warranty data.
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.
The shift over of the automobile sector from the ICE to the electric drives is imminent due to arising global issues of pollution and ever rising pressure on the demand of the natural resources due to lower efficiency of the ICE drives. This has led to uprising of the Lithium-ion batteries, with addition of the burden of living to expectation of clean energy and higher efficiencies. Alongside, with limitation in the availability of the lithium-ion batteries they carry a hefty price tag with them, hence causing huddles in the research. Lack of research leads to failure of batteries and may cause life threatening situations when operating in the vehicle. In order to insight the working of the cylindrical lithium-ion batteries under different driving and environmental conditions a methodology is developed for the coupled electro-chemical and thermal phenomenon. This allows anticipating the behaviour of the battery under different conditions that influence its performance.
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.
The Common Rail Fuel Injection System (CRS) has completely changed the whole diesel engine combustion cloud dynamics and enhanced the applicability of diesel engines further with a motto of providing a more cleaner sky and greener earth. The most cutting-edge technological developments made in CRS and EGT system enables OEMs to achieve further more stringent emission norms and adopt the environmental protection compliances. Today’s CRS systems are the most advanced generation fuel injection systems providing further high injection pressures, wide multiple injections capability with shorter dwell periods enabling real smoother Digital Rate Shaping (DRS) benefits and Smart thermal management of exhaust systems while meeting stringent emission compliances and achieving future CO2 reductions goal. Initial DRS I system developments were tried with a dwell period up to 500us-800us due to injector durability life limitations.
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.
Cast Iron is being used in various Industries like Automotive, Agriculture, Construction etc., for many decades. Metal casting processes have its unique advantages like ease of heavy weight castings, intricate shapes, higher productivity. Commercially viable (low cost) etc., using wide range of materials like Gray cast iron, Spheroidal cast iron, Malleable cast iron ,cast steel etc., Cast iron have an excellent properties like high dampening capacity, higher thermal conductivity, wear resistance required by many critical applications. These unique combinations will be chosen to serve the purposes both functionally and commercially. However, in last one-decade automotive and agriculture industries are facing issue of fuel economy which directly influenced by the weight of the vehicle. For off-road vehicle like tractors, One of the major contributor in vehicle weight is cast iron.
During the cold start conditions engine must overcome higher friction loss, at the cost of fuel penalty till the optimum temperatures are reached in coolant and lubrication circuits. The lower thermal capacity of the lubrication oil (with respect to the coolant) inverses the relation of viscosity with temperature, improves engine thermal efficiency benefit. Engine oil takes full NEDC test cycle duration to reach 90°C. This leads to higher friction loss throughout the test cycle, contributing a significant increase in fuel consumption. Increasing oil temperature reduces viscosity, thereby reducing the engine friction. This helps to identify the focus for thermal management in the direction of speeding up the temperature rise during a cold engine starting. This work aims at the study and experiment of an exhaust recovery mechanism to improve the NEDC fuel economy.
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.
The present work deals with the 3-D, transient, system level CFD simulation of automotive coolant system, which includes actual CAD of radiator, cooling jacket, coolant pump, bypass valve and thermostat valve, using a 3D CFD solver Simerics MP+®. This work is in continuation of the work done by Srinivasan et al. (2017) where wax melting, conjugate heat transfer, Fluid Structure Interaction of the valve had been solved. Thermostat valve was controlled by wax phase change model which incorporates the hysteresis effect of wax melting and solidification. The current model will also include rigorous treatment of cavitation to account for the presence of dissolved gases and vaporization of the liquid coolant. The previous work dealt with simulation of opening and closing cycle of the thermostat/by-pass valve system. A methodology has been developed and implemented where the run-time of such a system has been made considerably faster enabling us to simulate complete drive cycle tests.
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.
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.
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.
The present work represents the continuation of the introductory study presented in part I  where the experimental plan, the measurement system and the tools developed for the testing of a modern Wankel engine were illustrated. In this paper the motored data coming from the subsequent stage of the testing are presented. The AIE 225CS Wankel rotary engine produced by Advanced Innovative Engineering UK, installed in the test cell of the University of Bath and equipped with pressure transducers selected for the particular application, has been preliminarily tested under motored conditions in order to validate the data acquisition software on the real application and the correct determination of the Top Dead Centre (TDC) location which is of foremost importance in the computation of parameters such as the indicated work and the combustion heat release when the engine is tested later under fired conditions.
Semiconductor power modules is one of the main hardware components of a traction inverter. Its function is motor speed and torque driving, managing the energy exchange between battery and motor. The demanding request for electric and hybrid vehicle is pushing the development of innovative high performance power modules based on wide band gap compound. Silicon Carbide (SiC) power MOSFET modules are one of the most promising solution thanks to SiC excellent electrical properties in terms of on-state resistance, stray inductance and performance at high commutation frequency. These advantages shall be supported by innovative packaging solution, such as direct cooling system and novel insulator materials with high thermal conductivity (e.g., active metal brazed substrates) that improve the power module thermal and reliability performances.