Abstract Compact, high efficiency and high reliability are required for an xEV motor generator. IPM rotors with neodymium magnets are widely applied for xEV motors to achieve these requirements. However, neodymium magnet material has a big impact on motor cost and there is supply chain risk due to increased usage of these rare earth materials for future automotive xEV’s. On the other hand, a wound-field rotor does not need magnets and can achieve equivalent performance to an IPM rotor. However, brushes are required in order to supply current to the winding coil of the rotor. This may cause insulation issues on xEV motors which utilize high voltage and high currents. Therefore, it is suggested to develop a system which supplies electric energy to the rotor field winding coil from the stator without brushes by applying a transformer between stator coil and rotor field winding. Specifically, add auxiliary magnetic poles between each field winding pole and wind sub-coils to these poles.
Thermo-Swing Wall Insulation Technology; - A Novel Heat Loss Reduction Approach on Engine Combustion Chamber -
Abstract To improve fuel efficiency of engines, cooling heat loss is one of the most dominant losses among the various engine losses to reduce. The present work proposes a new heat insulation concept in combustion chamber, "TSWIN (Thermo-Swing Wall Insulation Technology)" that can reduce heat loss to the coolant without any sacrifice in other engine performances. Surface temperature of insulation coat on combustion chamber wall changes rapidly, according with the fluctuating temperature of in-cylinder gas. Reduced temperature differences between them lead to lower heat transfer. During the intake stroke, surface temperature of the insulation coat goes down rapidly, and prevents intake air heating. To realize the scheme mentioned above, a new insulation material with both low thermal conductivity and low volumetric heat capacity, "SiRPA (Silica Reinforced Porous Anodized Aluminum)" was developed and applied on the top surface of the piston.
Abstract The noise treatments weight reduction strategy, which consists in combining broadband absorption and insulation acoustic properties in order to reduce the weight of barriers, depends strongly on surface to volume ratio of the absorbing layers in the reception cavity. Indeed, lightweight technologies like the now classical Absorber /Barrier /Absorber layup are extremely efficient behind the Instrument Panel of a vehicle, but most of the time disappointing when applied as floor insulator behind the carpet. This work aims at showing that a minimum of 20 mm equivalent “shoddy” standard cotton felt absorption is requested for a floor carpet insulator, in order to be able to reduce the weight of barriers. This means that a pure absorbing system that would destroy completely the insulation properties and slopes can only work, if the noise sources are extremely low in this specific area, which is seldom the case even at the rear footwells location.
In passenger aircraft the most important noise control treatment is the primary insulation attached to the fuselage. Next to its acoustic properties the primary insulation main purpose is the thermal insulation and the minimization of condensed water. In general it consists of fibrous materials like glass wool wrapped in a thin foil. Due to stringent flame, smoke and toxicity requirements the amount of available materials is limited. Furthermore the amount of material installed in aircraft per year is much smaller compared to needs in the automotive industry. Therefore the best lay-up of the available materials is needed in terms of acoustics. This paper presents a tool for numerical optimization of the sound insulation package. To find an improved insulation the simulation tool is used in interaction with a measurement database. The databank is constructed from aircraft grade materials such as fibrous materials, foams, resistive screens and impervious heavy layers.
Abstract Intake noise has become one the main concerns in the design of highly-supercharged downsized engines, which are expected to play a significant role in the upcoming years. Apart from the low frequencies associated with engine breathing, in these engines other frequency bands are also relevant which are related to the turbocharger operation, and which may radiate from the high-pressure side from the compressor outlet to the charge air cooler. Medium frequencies may be controlled with the use of different typologies of resonators, but these are not so effective for relatively high frequencies. In this paper, the potential of the use of multi-layer porous materials to control those high frequencies is explored. The material sheets are located in the side chamber of an otherwise conventional resonator, thus providing a compact, lightweight and convenient arrangement.
Analysis of Heat Transfer Phenomena on High Response Heat Insulation Coatings by Instantaneous Heat Flux Measurement and Boundary Layer Visualization
Coating the heat insulation materials on the combustion chamber walls is one of the solutions to reduce the cooling loss of internal combustion engines. In order to examine the coatings, the evaluation of the heat transfer coefficient and the analysis of the heat transfer phenomena on the heat insulated walls are important. Firstly, the highly-responsive wall temperature sensor is developed, and the instantaneous wall heat flux is measured to evaluate the heat transfer coefficient on the heat insulated walls. The results show that the Nusselt number on the heat insulated walls is less influenced by the Reynolds number variation than that on the metal walls. Secondly, the high speed µ-PIV is employed to analyze the various turbulent flow characteristics. The results show that the turbulent dissipation on the heat insulated walls is smaller than that on the metal walls.
A Lightweight Dash Insulator Development and Engineering Application for the Vehicle NVH Improvement
Abstract A lightweight design method of vehicle dash insulators is proposed and investigated in this paper. The lightweight dash insulator, which is composed of double layers of cotton felt with different density and a layer of polyethylene (PE) film and has 55% decrease in weight, is developed and applied in a passenger car, instead of the traditional “heavy layer-soft layer” dash insulator. To evaluate the NVH performance of the lightweight dash insulator, the noise reduction (NR) level index is calculated by using SEA simulation and the sound pressure level and sound qualities in the vehicle are tested under the driving conditions for wide open throttle acceleration in third gear and 60km/h cruising in fourth gear. The simulation and test results show that the vehicle with the lightweight dash insulator has better NVH performance.
Thermal Effectiveness of Multilayer Heat Shielding Automotive Components - Influences of Different Layers on Heat Radiant and Convection Heat Measurements
Abstract Different heat shielding unilayer materials already in practical use and multilayer materials, consisting of a compound of E-glass fabric laminated with aluminum foil and different high temperature felts, are compared with regards to the difference between the external and internal surface temperature ΔT as a function of the external surface temperature. Beside that the general difference between the two standard methods convection heat measurement and radiant heat measurement is shown. Especially it is evaluated whether the radiant heat measurement method is suitable to make a general statement for classification of heat shielding materials.
Abstract This paper presents an experimental analysis on the effect of thermal insulation of engine internal walls on the performance and emissions of a heavy-duty diesel engine. Some parts of the engine, like pistons, cylinder head and exhaust manifold were thermally insulated from gas contact side in order to reduce heat losses through the walls. Each component has been analyzed, independently, and in combination with others. The results have been compared with that of the original engine configuration. The analysis focuses on NOx and, smoke emissions along with brake specific fuel consumption. In order to take advantage of the engine insulation, an optimization of the air management and injection settings was finally performed, which provided the best combination for each engine configuration.
Abstract Recent developments in diesel engines lead to increased fuel efficiency and reduced exhaust gas temperature. Therefore more energy efficient aftertreatment systems are required to comply with tight emission regulations. In this study, a computational fluid dynamics package was used to investigate the thermal behaviour of a diesel aftertreatment system. A parametric study was carried out to identify the most influential pipework material and insulation characteristics in terms of thermal performance. In the case of the aftertreatment pipework and canning material effect, an array of different potential materials was selected and their effects on the emission conversion efficiency of a Diesel Oxidation Catalyst (DOC) were numerically investigated over a driving cycle. Results indicate that although the pipework material's volumetric heat capacity was decreased by a factor of four, the total emission reduction was only considerable during the cold start.
Abstract Strategies for weight reduction have driven the noise treatment advanced developments with a great success considering the already mastered weight decreases observed in the last years in the automotive industry. This is typically the case for all soft trims parts. In the early 2010's a typical european B-segment car soft trims weights indeed 30 to 40% less than in the early 2000's years. The main driver behind such a gap has been to combine insulation and absorption properties on a single part while increasing the number of layers. This product-process evolution was conducted using a significant improvement in the simulation capacities. In that sense, several studies presenting very good correlation results between Transmission Loss measurements and finite elements simulations on dashboard or floor insulators were presented. One may consider that those kinds of parts have already achieved a considerable improvement in performance.
Abstract To satisfy the increased expectations of customers, engineers are challenged to increase fuel economy while also improving noise, vibration, and harshness (NVH) performance. In order to improve fuel economy, engine compartment designs have become more compact with reduced air flow. Elevated temperatures caused by these designs can degrade the durability and acoustic performance of the fibrous acoustic insulator material. A typical method for protecting insulators from elevated temperatures is to apply an aluminum foil patch to the surface. However, foil patches can restrict the insulator's ability to absorb sound and can be difficult to apply to complex part shapes. Foil patches can be perforated to allow the insulator to absorb sound, but there is a cost penalty as well as potential for long term performance degradation due to blocked perforations. Since NVH targets are also increasing, it's important to maximize the benefit of each part.
Abstract Due to continuous demands from OEM's to reduce weight and make more compact vehicles, high heat generation from vehicle has become common phenomenon. Thermal insulation is a need of the hour to cater to such demands. The temperature rise is more critical around engine areas. OEM's use many design solutions to cater to such heat build up's. One of the design solutions includes use of thermally insulating materials e.g. Foams, insulating fabrics etc… First section of this paper deals with comparative study of polyurethane (PU) soft foam and rigid skin polyurethane foam. To define the base line, the samples were subjected to various tests to determine physical, thermal and chemical properties. Also both the types of foams were subjected to high temperature and low temperature heat ageing. From the experiments, it was observed that soft PU foam provides better re-bounce property than rigid skin PU foam.
Multi-Layer Insulation (MLI) is the thermal insulation typically used in spacecraft or any other devices that are exposed to both extreme heat and cold. MLI blankets work to protect delicate internal and external applications from UV radiation, atomic oxygen, and mechanical stresses by using Teflon coated fiberglass cloth. The layers are usually made of a film made out of polyester or polyimide with vapor deposited layers of aluminum on one or both sides of the film to form reflector layers. These reflectors are separated by materials with low thermal conductivity. All the layers simply protect the system by preventing excessive heat loss from inner components and excessive heating from outer sources. Typically, MLI blankets are divided into a cover or outer layer, a reflector, a separator layer, an inner layer, and it has hardware installed to pass electrical charge from the surface of the blanket.
Vehicle sound insulation systems, such as front of dash mats or carpet assemblies, etc. play a key role in controlling vehicle interior noise. However, dash and carpet insulators are often designed to have varied thickness in compliance with packaging constraints or to fulfill manufacturing clearance requirements. While it is obvious to NVH engineers that thinned-down areas would significantly affect the insulation performance, design engineers would benefit from a quick tool to flag any design details that may negatively impact the performance. This paper therefore proposes a concept called the performance equivalent thickness for the sound insulation system. The aim is to link acoustic performance of an insulator layer to a geometric measure so that the component performance can be easily monitored and preserved at the design stage.
Insulation coordination requirements for electrical equipment applications are defined in various standards. The standards are defined for application to stationary mains connected equipment, like IT, power supply or industrial equipment. Protection from an electric shock is considered the primary hazard in these standards. These standards have also been used in the design of various automotive components. IEC 60664-1 is an example of the standard. Automobiles are used across the world, in various environments and in varied usage by the customers. Automobiles need to consider possible additional hazards including electric shock. This paper will provide an overview of how to adapt these standards for automotive application in the design of High Voltage (HV) automotive components, including High Voltage batteries and other HV components connected to the battery. The basic definitions from the standards and the principles are applied for usage in automotive applications.
Concept of “Temperature Swing Heat Insulation” in Combustion Chamber Walls, and Appropriate Thermo-Physical Properties for Heat Insulation Coat
The aim of this work is to investigate the possibility of heat insulation by “Temperature Swing”, that is temperature fluctuation, on combustion chamber walls coated with low-heat-conductivity and low-heat-capacity materials. Adiabatic engines studied in the 1980s, such as ceramic coated engines, caused constantly high temperature on combustion wall surface during the whole cycle including the intake stroke, even if it employed ceramic thermal barrier coating methods. This resulted in increase in NOx and Soot, decrease in volumetric efficiency and combustion efficiency, and facilitated the occurrence of engine knock. On the other hand, “Temperature Swing” coat on the combustion chamber walls leads to a large change in surface temperature. In this case, the surface temperature with this insulation coat follows the transient gas temperature, which decreases heat loss with the prevention of intake air heating, and also which is expected to prevent NOx and Soot from increasing.
Sound Package Evaluation of Dash Panel Focusing on Weight Reduction using Particle Velocity Measurements
The quest for weight and cost reduction of automotive components without changing their quality and performance is a constant concern of suppliers and automakers around the world. When dealing with products related to the internal insulation of the vehicle this concern is even greater since the evaluation of acoustic comfort is a factor of growing importance for the acceptance of the automobile by the final consumer. Based on it this paper aims to evaluate the acoustic insulation of the dash panel of a passenger vehicle and propose an alternative approach to mass reduction of this component by applying layers of sound absorption material inside the instrument panel. Using analysis of particle velocity and sound pressure level inside the vehicle, a comparative test was performed.
The control of noise and vibrations using conventional damping materials is typically associated to mass penalties in a vehicle. A lightweight alternative employs piezoceramic materials connected in series to a resistor and an inductor (R-L circuit) to perform as mechanical vibration absorber, called piezoelectric resonator. In this paper, piezoelectric resonators are designed to attenuate vibration in a vehicle panel. The choice of design parameters, such as correct placement for the piezoelectric patches and the optimal electrical circuit values, is assisted by Finite Element simulation (FE) and theoretical analysis. Measurements of Sound Transmission Loss (STL) and modal analyses are conducted to demonstrate the efficiency of the proposed technique when compared to a conventional damping material.
Currently, acoustic holography and beamforming are consolidated Noise Source Identification (NSI) techniques with expanding applications. These two microphone array based techniques can provide detailed sound field visualization. Even in enclosed space, such as a vehicle cabin, the sound field can be visualized using Spherical Harmonics Beamforming (SHB). Also, sound radiation from geometrically complex surfaces can be captured with conformal mapping using Statistically Optimized Near-field Acoustic Holography (SONAH). In this paper, an integrated approach using both techniques is presented as a manner to improve sound insulation during a vehicle development. Both vehicle and component level measurements are employed in order to identify the dominant sound transmission paths and add the appropriate acoustic treatments. It is shown that spherical beamforming and conformal mapping are powerful tools which expedite troubleshooting and allow vehicle acoustic content optimization.
Typically, in the automotive industry, the design of the body damping treatment package with respect to NVH targets is carried out in such a way to achieve panel mobility targets, within given weight and cost constraints. Vibration mobility reduction can be efficiently achieved thanks to dedicated CAE FE tools, which can take into account the properties of damping composites, and also, which can provide their optimal location on the body structure, for a minimal added mass and a maximized efficiency. This need has led to the development of different numerical design and optimization strategies, all based on the modeling of the damping composites by mean of equivalent shell representations, which is a versatile solution for the full vehicle simulation with various damping layouts.
Surface temperature and heat flux were measured in a single cylinder SI engine piston when uncoated and with two different surface coatings: a metal TBC and YSZ. Average heat flux into the piston substrate was 33 % higher with the metal TBC and unchanged with the YSZ relative to the uncoated surface. The increase with the metal TBC was attributed to its surface roughness. However, the metal TBC and YSZ reduced peak heat flux into the substrate surface by 69 % and 77 %, respectively.
The paper presents a numerical activity directed at the analysis and optimization of internal combustion engine water cooling jackets, with particular emphasis on the fatigue-strength assessment and improvement. In the paper, full 3D-CFD and FEM analyses of conjugate heat transfer and load cycle under actual engine operation of a single bank of a current production V6 turbocharged diesel engine are reported. A highly detailed model of the engine, made up of both the coolant galleries and the surrounding metal components, i.e., the engine head, the engine block, the gasket, the valve guides and valve seats, is used on both sides of the simulation process to accurately capture the influence of the cooling system layout under thermal and load conditions as close as possible to actual engine operations.
Exhaust gas recirculation (EGR) cooler fouling has become a significant issue for compliance with nitrogen oxides (NOx) emissions standards. In order to better understand fouling mechanisms, eleven field-aged EGR coolers provided by seven different engine manufacturers were characterized using a suite of techniques. Microstructures were characterized using scanning electron microscopy (SEM) and optical microscopy following mounting the samples in epoxy and polishing. Optical microscopy was able to discern the location of hydrocarbons in the polished cross-sections. Chemical compositions were measured using thermal gravimetric analysis (TGA), differential thermal analysis (DTA), gas chromatography-mass spectrometry (GC-MS), x-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD). Mass per unit area along the length of the coolers was also measured.
An Iterative Approach Based on Prony's Method to Calculate the Surface Impedance of Acoustic Materials Measured in situ
In many cases the in situ measurement of the absorption coefficient requires an iterative method for the correct calculation of the surface impedance of a sample. This happens because when spherical waves reflect on a sample's surface the pressure field above it is a function of the sample's surface impedance. As the pressure field involves an integral term, numerical integration is required in the iterative algorithm, which can be time consuming. The aim of this paper is to present an iterative approach based on Pony's method, which instead of numerical integration uses a series expansion with a few terms. Therefore the time of processing is decreased. Besides the description of the method, simulations and measurements (with a p-u probe inside an office room and a car) are presented. A comparison, with numerical integration, regarding the accuracy and the time of processing of Pony's method is also discussed.
Development of Composite Material the Base of Scrapes of Tires and Latex for Thermal Isolation in Vehicles
Now the great majority of the applications of thermal isolation in the strip of drops and averages temperatures (up to 180°C), it is made being used from aggressive materials to the nature such an as: glass wool, rock wool, polystyrene, EPS among others. Such materials, in spite of the effectiveness in the retention of the flow of heat, possess considerable cost and when discarded they are long years to be to decompose. In that context, trying to adapt the world politics the about of the preservation of the environment, a study began with intention of developing a material composite, with properties of thermal, originating from insulating industrial residues. For that, composite the base of it scrapes of tire and latex seeking to be applied for thermal isolation in "hot" systems (up to 180°C).
In South America and other emerging markets sound package development is limited by the cost and weight of its components. Reaching the right balance between cost and a good NVH performance provides an important competitive advantage, therefore any achieved design opportunities can be replicated to other vehicle lines and markets. In this work the main noise transmission paths are verified by evaluating the contribution of sound package components to noise attenuation in two cases, initially from the tire contact patch through vehicle body to a number of positions within the vehicle interior and, next, from the engine compartment, by placing a High Frequency Sound Source (HFSS) at engine faces to the same vehicle interior positions. The main objective is to optimize sound package distribution and to prioritize which areas should have the sound package reinforced in order to improve Tire and Engine noise reduction.
A balanced approach for wind noise control is presented in this paper. This approach is focused on improved sound insulation and low mass. Initially, the Sound Transmission Loss (STL) of tempered, standard laminated and acoustic laminated glasses for different thicknesses was measured in a STL suite. The critical frequency range was identified from in-vehicle noise measurements. These STL data and in-vehicle results provided the relevant information for a proposal with better acoustic performance and lower mass. The efficiency of this proposal was confirmed with new in-vehicle measurements.
Improved Distribution of Temperature inside Semitransparent Heat-Insulating Coatings of Combustion Chamber
The paper considers the radiative heat exchange under intensive short (radiant flux of red-hot soot particles) and long (radiation of“hot" hydrocarbonic atmosphere) IR components of total thermal flux in the combustion chamber (CC) of high-speed diesel engines. The analysis is conducted for only one spectral band in the ceramic coating and is assumed to be without any soot layer on it for this preliminary investigation. Temperature distributions are calculated for two layer coating. It consists of a top layer based on the semitransparent heat-insulating coating (SHIC) with varios thickness and a bottom one (semitransparent or opaque which could be metal substrate) with variation of reflection for transient (one complete cycle of piston movement) and steady state (cyclic heating). The improved distributions of temperature due to volumetric radiant heat losses inside semitransparent and opaque heat-insulating coatings are discussed.
Heat-insulating coatings (HIC) being used in automotive industry for thermal insulation of thermally highly loaded components of combustion chamber (CC) are usually semitransparent (SHIC) for radiation of red-hot soot particles. The paper presents physical and mathematical models of radiation and conductive heat transfer and solution methods for multilayered scattering and absorbing coating. Calculations of radiation field are carried out by means of the method of moments and defined by the solution of differential equation system for moments of radiant intensity. The analysis is assumed to be without any soot layer on semitransparent one for this preliminary investigation. It allows to simulate temperature distributions for SHIC with internal radiant source above substrate with different reflection for operating conditions in CC of high-speed diesel engines (cyclic heating).