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Viewing 151 to 180 of 9802
Technical Paper
2014-04-01
Felix Regin A, Abhinav Agarwal, Niraj Kumar Mishra
Abstract Increased engine thermal load, front end styling and compact vehicle requirements have led to significant challenges for vehicle front end designer to provide innovative thermal management solutions. The front end cooling module design which consists of condenser, radiator, fan and intercooler is an important part of design as it ensures adequate heat removal capacity of radiator over a wide range of operating conditions to prevent overheating of engine. The present study describes the optimization of cooling air flow opening in the front end using CFD methodology of a typical passenger car. The predicted vehicle system resistance curve and coolant inlet temperature to the radiator are used for the selection of cooling modules and to further optimize the front end cooling opening area. This leds to the successful optimization of the front end, selection of cooling modules with significant cost savings by reducing prototype testing and design cycle time.
Technical Paper
2014-04-01
Mickael Cormerais, Thierry Marimbordes, Stephane Warnery, David Chalet, Haitham Mezher, Laurent Roussel
Abstract The future environmental constraints [e.g. WLTC +RDE, CAFE, Euro 6.2, 7] for the pollutant emissions lead to new challenges for the internal combustion engine. One of the solutions to decrease the fuel consumption, the CO2 and pollutant emissions whilst keeping the same driving and thermal comforts is the engine's thermal management, in particular during the warm-up phase. Furthermore, the traditional cooling system is not designed to work at the new engine transient thermal conditions at a non-optimal temperature in terms of fuel economy and exhaust emission. This paper describes a new technology for engine cooling systems that is able to control the coolant flow and temperature in relation to the engine conditions such as load and rotational speed. With a no flow in crankcase cooling strategy and a high engine temperature regulation, the Active Cooling Thermomanagement Valve succeeds in decreasing the fuel consumption without deteriorating engine's performance. To validate this concept, endurance tests were performed to verify the wear and durability.
Technical Paper
2014-04-01
Carrie Kowsky, Edward Wolfe, Sourav Chowdhury, Debashis Ghosh, Mingyu Wang
Abstract With more vehicles adopting fuel-saving engine start-stop routines and with the number of hybrid and electric vehicles on the rise, automotive A/C (air conditioning) systems are facing a challenge to maintain passenger comfort during the time when the compressor is inactive due to engine shut down. Using PCM (Phase Change Material) in the evaporator enables it to store cold when the compressor is active and release it to the cooling air stream when the compressor is not running. A unique feature of Delphi's design is that a refrigerant thermosiphon mechanism inside the evaporator drives the energy transport between the PCM and air stream. Delphi's PCM evaporator extends comfort for short duration idle stops, reduces emissions, and increases fuel economy and electric drive range. In this paper, the design aspects of a thermosiphon based PCM cold storage evaporator are described and the performance and operation of the PCM evaporator in a MAC (Mobile Air Conditioning) system discussed.
Technical Paper
2014-04-01
Kristian Haehndel, Angus Pere, Torsten Frank, Frieder Christel, Sylvester Abanteriba
Abstract As computational methodologies become more integrated into industrial vehicle pre-development processes the potential for high transient vehicle thermal simulations is evident. This can also been seen in conjunction with the strong rise in computing power, which ultimately has supported many automotive manufactures in attempting non-steady simulation conditions. The following investigation aims at exploring an efficient means of utilizing the new rise in computing resources by resolving high time-dependent boundary conditions through a series of averaging methodologies. Through understanding the sensitivities associated with dynamic component temperature changes, optimised boundary conditions can be implemented to dampen irrelevant input frequencies whilst maintaining thermally critical velocity gradients. A sub-module derived from real vehicle geometry was utilised to evaluate a series of alternative averaging schemes (consisting of steady-state CFD points) in comparison to full CFD transient conditions.
Technical Paper
2014-04-01
Gianluca Montenegro, Augusto Della Torre, Angelo Onorati, Dalia Broggi, Gerd Schlager, Christian Benatzky
Abstract This work proposes a focus on the simulation of a rotative volumetric expander via a CFD code. A customized application of OpenFOAM® has been developed to handle the particular motion of the calculation grid. The model uses a mesh to mesh interpolation technique, switching from a calculation grid to the new one on the basis of mesh quality considerations performed on the fly. This particular approach allows to account for the presence of leakages occurring between the stator and blade tips and also occurring at the top and bottom of the vanes. The fluid considered is the refrigerant R245fa, whose particular properties have been determined resorting to the NIST database. Experimental data, measured at different conditions of mass flow and fluid temperature, are compared to calculation results. Moreover, the CFD analysis has allowed the estimation of the influence of the leakage mass flow occurring at the tip of the vanes on the overall machine performances.
Technical Paper
2014-04-01
Jiazhen Ling, Magnus Eisele, Hongtao Qiao, Vikrant Aute, Yunho Hwang, Reinhard Radermacher
Abstract As a potential replacement to traditional automotive R134a direct expansion (DX) systems, a secondary-loop system allows for the usage of flammable but low-GWP refrigerants such as propane (R290). However, as the secondary-loop system has an additional layer of thermal resistance, the cycle's transient behavior and cabin thermal comfort during pull-down and various driving cycles may be different from traditional DX systems. This paper presents a Modelica-based model to simulate both steady-state and transient operation of automotive secondary-loop systems. The model includes a lumped cabin component and a secondary-loop automotive air-conditioning system component. The air-conditioning system component consists of a condenser, a compressor, an expansion device, a coolant plate type heat exchanger, a coolant to air heat exchanger and a coolant pump. The developed model was validated against both steady-state and transient experimental data for an R290 secondary-loop system. The steady-state comparison demonstrates a 7.5% deviation of air-side COP compared to the experimental data.
Technical Paper
2014-04-01
Kristian Haehndel, Anthony Jefferies, Markus Schlipf, Torsten Frank, Frieder Christel, Sylvester Abanteriba
Abstract At the rear of the vehicle an end acoustic silencer is attached to the exhaust system. This is primarily to reduce noise emissions for the benefit of passengers and bystanders. Due to the location of the end acoustic silencer conventional thermal protection methods (heat shields) through experimental means can not only be difficult to incorporate but also can be an inefficient and costly experience. Hence simulation methods may improve the development process by introducing methods of optimization in early phase vehicle design. A previous publication (Part 1) described a methodology of improving the surface temperatures prediction of general exhaust configurations. It was found in this initial study that simulation results for silencer configurations exhibited significant discrepancies in comparison to experimental data. This was mainly due to the inability to represent complex fluid flows through the components of the silencer, which was greatly simplified in the simulation models and software utilised.
Technical Paper
2014-04-01
Shi-Ing Chang, Iman Goldasteh, Salamah Maaita, Gursaran Mathur
Abstract The performance of an automobile engine depends on the adequate heat rejection through the radiator assembly. Despite of the existence of well-known theoretical models for various heat transfer applications, design of heat exchanger devices demands tremendous experimental work and effort. This study concerns the use of computational fluid dynamics (CFD) to analyze the heat transfer and fluid flow in finned tube heat exchangers which are widely used in automotive industries. Here, two different types of the finned tube heat exchangers were studied using the Star-CCM+ commercial CFD package. Because of the symmetric nature of the geometry, only a single fin was considered in simulations. Two different designs of finned tube heat exchanger were considered in the analysis and major attention was given to the fin configurations, louvers number and louvers angle. Although the contact surface of the fin to the coolant tube is different, the thermal performance was not affected under present steady state analysis.
Technical Paper
2014-04-01
Hai Wu, Wen Chen, Meng-Feng Li, Xinlei Wang
Abstract A hot and cold water mixing process with a steam condenser and a chilled water heat exchanger is set up for an engine EGR fouling test. The test rig has water recycled in the loop of a pump, heat exchangers, a three-way mixing valve, and a test EGR unit. The target unit temperature is controlled by a heating, cooling and mixing process with individual valves regulating the flow-rate of saturated steam, chilled water and mixing ratio. The challenges in control design are the dead-time, interaction, nonlinearity and multivariable characteristics of heat exchangers, plus the flow recycle in the system. A systems method is applied to extract a simple linear model for control design. The method avoids the nonlinearity and interaction among different temperatures at inlet, outlet and flow-rate. The test data proves the effectiveness of systems analysis and modeling methodology. As a result, the first-order linear model facilitates the controller design. The simulation studies with internal recycle processes produced promising results.
Technical Paper
2014-04-01
Zun Wang, Jaehoon Han, Devadatta Mukutmoni
Abstract At the onset of soak, air and surface temperatures in an engine bay enclosure are elevated since temperature of heat sources are high while convective cooling is sharply reduced as a result of airflow being shut off from the inlet grilles of the vehicle leading to temperature spikes. Accurate simulation of this important thermal and flow regime that is natural convection driven, highly transient and complex is therefore very important. In this investigation, we simulate flow in the engine bay at the onset of soak with fixed thermal boundary conditions where the geometries representing the engine bay and components are simplified. Good agreement was observed with detailed experimental data available in references for both velocities and temperatures.
Technical Paper
2014-04-01
Alaa El-Sharkawy
Abstract Computational tools have been extensively applied to predict component temperatures before an actual vehicle is built for testing [1, 2, 3, 4, and 5]. This approach provides an estimate of component temperatures during a specific driving condition. The predicted component temperature is compared against acceptable temperature limits. If violations of the temperature limits are predicted, corrective actions will be applied. These corrective actions may include adding heat shields to the heat source or to the receiving components. Therefore, design changes are implemented based on the simulation results. Sensitivity analysis is the formal technique of determining most influential parameters in a system that affects its performance. Uncertainty analysis is the process of evaluating the deviation of the design from its intended design target. In the case of thermal protection, uncertainty analysis is applied in order to determine the variation of the calculated component temperature around its nominal value.
Technical Paper
2014-04-01
Akihito Hosoi, Atsushi Morita, Naoto Suzuki
At the engine restart, when the temperature of the catalytic converter is low, additional fuel consumption would be required to warm up the catalyst for controlling exhaust emission.The aim of this study is to find a thermally optimal way to reduce fuel consumption for the catalyst warm up at the engine restart, by improving the thermal retention of the catalytic converter in the cool down process after the previous trip. To make analysis of the thermal flow around the catalytic converter, a 2-D thermal flow model was constructed using the thermal network method. This model simulates the following processes: 1) heat conduction between the substrate and the stainless steel case, 2) heat convection between the stainless steel case and the ambient air, 3) heat convection between the substrate and the gas inside the substrate, 4) heat generation due to chemical reactions. The points to be especially noted are: a) in the cool down process, free convection of the gas inside the substrate was based on Darcy's law, b) in the engine operating condition, chemical phenomena and species mass balance in gas phase and catalyst surface was considered.
Technical Paper
2014-04-01
Vinod Kumar Srinivasa, Renjith S, Biswadip Shome
Abstract Increasing demands on engine power to meet increased load carrying capacity and adherence to emission norms have necessitated the need to improve thermal management system of the vehicle. The efficiency of the vehicle cooling system strongly depends on the fan and fan-shroud design and, designing an optimum fan and fan-shroud has been a challenge for the designer. Computational Fluid Dynamics (CFD) techniques are being increasingly used to perform virtual tests to predict and optimize the performance of fan and fan-shroud assembly. However, these CFD based optimization are mostly based on a single performance parameter. In addition, the sequential choice of input parameters in such optimization exercise leads to a large number of CFD simulations that are required to optimize the performance over the complete range of design and operating envelope. As a result, the optimization is carried out over a limited range of design and operating envelope only. In this paper, a Design of Experiments (DoE) based CFD approach has been used to optimize the fan and fan-shroud design of a cooling pack system.
Technical Paper
2014-04-01
Fabien Rabeau, Sebastien Magand
Abstract Thermal management is a key issue to minimize fuel consumption while dealing with pollutant emissions. It paves the way for developing new methods and tools in order to assess the effects of warm up phase with different drivetrains architectures and to define the most suitable solution to manage oil and coolant temperatures. DEVICE (Downsized hybrid Diesel Engine for Very low fuel ConsumptIon and CO2 Emissions) project consists in designing hybrid powertrain to cut off significantly CO2 emissions. It combines a 2-cylinder engine with an electric motor and a 7-gear dual clutch transmission. Hybridization and downsizing offer a great improvement of fuel economy and it is valuable to study their effects on thermal management. Hence, a dedicated AMESim platform is developed to model the fluids temperatures as well as the energy balance changes due to the powertrain architecture. After using a 4-cylinder reference engine to validate the model, the warm up phase (comparing hot and cold start NEDC) leads to a 12% fuel consumption penalty with DEVICE powertrain.
Technical Paper
2014-04-01
Ram Iyer, Jin Zhou, Li Lu, Jeffrey Webb, Qaiser Khan
Abstract A CAE simulation methodology was developed to predict the warpage and shape deviation from nominal in finished plastic sub-assemblies that are joined using Infra-Red (IR), hot-plate or vibration welding processes. An automotive glove box bin and door sub-assembly was used to develop the methodology. It was seen that part warpage from injection molding and welding causes warpage in final assembled product which results in gaps and the consequent loss in quality of appearance. The CAE simulation methodology included prediction of the part warpage with residual stress from the injection molding process, use the post-molded shape as an initial part condition for the welding process, and simulation of the welding process itself. The welding process simulation included fixturing of the parts in the welding process, localized heating in the case of an IR welding process, fusion of the parts at the weld locations and thermal creep resulting in long term stress and shape relaxation of the part.
Technical Paper
2014-04-01
Seishiro Murata, Hiroyuki Ito, Steven Sopher
Flexible polyurethane (PU) foam has been widely used for seat cushions in automotive passenger vehicles due to the excellent cushioning performance and the ability to shape mold. Originally introduced in the late 1950's, it has been used for more than 50 years. However, there is a limitation using polyurethane foam with efforts to reduce the weight and address ever increasing risks to environment. This paper provides information about a new automotive seat concept which does not use polyurethane foam at all. Expanded polyolefin foam is used for this application to replace polyurethane foam and achieve comparable cushioning performance. Other features of the material include 100% recyclability, and no VOC's. By replacing polyurethane foam with expanded thermoplastic foam, hazardous outgassing is eliminated during the seat cushion production, thus improving workplace environmental health and safety.
Technical Paper
2014-04-01
Mohammed K Billal, Vinothkumar Subramani, Mohan Rao, Tim Potok
Abstract An automotive cockpit module is a complex assembly, which consists of components and sub-systems. The critical systems in the cockpit module are the instrument panel (IP), the floor console, and door trim assemblies, which consist of many plastic trims. Stiffness is one of the most important parameters for the plastic trims' design, and it should be optimum to meet all the three functional requirements of safety, vibration and durability. This paper presents how the CAE application and various other techniques are used efficiently to predict the stiffness, and the strength of automotive cockpit systems, which will reduce the product development cycle time and cost. The implicit solver is used for the most of the stiffness analysis, and the explicit techniques are used in highly non-linear situations. This paper also shows the correlations of the CAE results and the physical test results, which will give more confidence in product design and reduce the cost of prototype testing.
Technical Paper
2014-04-01
Ayse Ademuwagun, Joel Myers
Abstract Coconut shell and torrefied wood are bio-sourced and renewable materials that can be used as fillers in various polymer matrices. Torrefied wood material can be produced from numerous cellulose based materials, such as wood, sunflower hulls, flax shive, hemp and oat hulls. These bio-fillers would replace talc and glass bubbles which are not a renewable resource. Additionally, the implementation of torrefied wood and coconut would reduce the carbon footprint and improve sustainability of Hyundai and Kia vehicles, improving customer perception of our product line. In this study, coconut and torrefied wood filled polypropylene properties are tested for a HVAC Case application.
Technical Paper
2014-04-01
Venkat Pisipati, Srikanth Krishnaraj, Edgar Quinto Campos
Abstract Motor vehicle safety standards are getting to be more demanding with time. For automotive interiors, instrument panel (IP) head impact protection is a key requirement of the Federal Motor Vehicle Safety Standard (FMVSS) 201. To ensure compliance of this requirement, head impact tests are conducted at 12 and 15 mph for performance verification. Computer simulation has become more prevalent as the primary development tool due to the significant reduction in time and cost that it offers. LS-DYNA is one of the most commonly used non-linear solvers in the automotive industry, particularly for safety related simulations such as the head impact of automotive interiors. LS-DYNA offers a wide variety of material models, and material type 024 (MAT 024, piecewise linear plasticity) is one of the most popular ones [1]. Although it was initially developed for metals, it is commonly used for polymers as well. LS-DYNA also offers several other material models specifically developed to simulate polymers, such as material types 019, 089, 123, to name a few.
Technical Paper
2014-04-01
Michael Kolich, Daniel Dooge, Mark Doroudian, Efim Litovsky, Richard Ng, Jacob Kleiman
Thermophysical properties of materials used in the design of automotive interiors are needed for computer simulation of climate conditions inside the vehicle. These properties are required for assessment of the vehicle occupants' thermal sensation as they come in contact with the vehicle interior components, such as steering wheels, arm rests, instruments panel and seats. This paper presents the results of an investigation into the thermophysical properties of materials which are required for solving the non-linear Fourier equations with any boundary conditions and taking into account materials' specific heat, volume density, thermal conductivity, and thermal optical properties (spectral and total emissivity and absorptivity). The model and results of the computer simulation will be published in a separate paper. The tested materials included foam, leather/foam laminated materials, and a few plastic laminated materials, which were used in the construction of various automotive interior parts.
Technical Paper
2014-04-01
Dinesh Pahuja, Arpit Kapila, Sanjay Haldar, Sandeep Raina
Interiors of past vehicles were created to satisfy specific functions with appearance being a secondary consideration, but in the present & future market with ever increasing vehicle luxury, decoration of vehicle has become a prime focus in automobile industry along with the safety & economy. Automotive interiors have evolved over the years from a collection of trims covering bare sheet metal panels to add quality & richness of interior cabin, ultimately delivering greater value to customers. One such area in interiors is Side door trims serving the dual purpose of functionality and creating a pleasing environment too. The aesthetic appeal to the Side door trim is added usually through a Door trim insert having a decorative skin pasted on to the plastic base. And the selection of pasting technique for pasting decorative film on to the plastic base insert is a challenge for an automotive interior designer. The objective of this paper will be to review technologies available for manufacturing Door trim inserts with decorative skins, and discuss a direction toward selecting an appropriate pasting technique with cost effectiveness.
Technical Paper
2014-04-01
Ashok Mache, Anindya Deb, G.S. Venkatesh
Abstract Natural fiber-based composites such as jute-polyester composites have the potential to be more cost-effective and environment-friendly substitutes for glass fiber-reinforced composites which are commonly found in many applications. In an earlier study (Mache and Deb [1]), jute-polyester composite tubes of circular and square cross-sections were shown to perform competitively under axial impact loading conditions when compared to similar components made of bidirectional E-glass fiber mats and thermo-setting polyester resin. For jute-reinforced plastic panels to be feasible solutions for automotive interior trim panels, laminates made of such materials should have adequate perforation resistance. In the current study, a systematic characterization of jute-polyester and glass-polyester composite laminates made by compression molding is at first carried out under quasi-static tensile, compressive and flexural loading conditions. Low velocity impact perforation tests at speeds of around 4 m/s are then performed in an instrumented drop-weight testing device on square plates extracted from the same laminates.
Technical Paper
2014-04-01
Egon Moos
Abstract In today's vehicles underbody parts are absolutely necessary to reach a certain performance level regarding fuel saving, corrosion protection, driving performance and exterior as well as interior noise. With the constant demand for additional parts, which means additional weight on the car, lightweight materials have come more and more into the focus of development work. LWRT (low weight reinforced thermoplastic) is the acronym for this material group. The ongoing success of such materials in underbody applications that compared to compact materials such as GMT (glass mat reinforced thermoplastic) is the weight saving of up to 50 %, or in other words, with LWRT you can cover twice as much surface then with GMT. The production process is compression molding, but with low pressure because LWRT-material needs only partial compact areas, most regions of these parts can have a density even below 0.5 g/cm3. Another advantage coming with the process is the possibility to use multi-cavity tools, so a high volume production becomes very economical.
Technical Paper
2014-04-01
Ankang Jin, Weiguo Zhang, Shihu Wang, Yu Yang, Yunqing Zhang
The suspension system of a heavy truck's driver seat plays an important role to reduce the vibrations transmitted to the seat occupant from the cab floor. Air-spring is widely used in the seat suspension system, for the reason that its spring rate is variable and it can make the seat suspension system keep constant ‘tuned’ frequency compared to the conventional coil spring. In this paper, vibration differential equation of air-spring system with auxiliary volume is derived, according to the theory of thermodynamic, hydrodynamics. The deformation-load static characteristic curves of air-spring is obtained, by using a numerical solution method. Then, the ADAMS model of the heavy truck's driver seat suspension system is built up, based on the structure of the seat and parameters of the air-spring and the shock-absorber. At last, the model is validated by comparing the simulation results and the test results, considering the seat acceleration PSD and RMS value.
Technical Paper
2014-04-01
Zheng Zhong Wang, Youzhong Xu, Kuaichu Fan, Binglin Da
The series of work introduced in this paper is originated from a structural failure of the vehicle A/C (Air-Conditioner) pipe, and when many possible factors having been excluded, the main investigating endeavor is focused on RLD acquisition and analysis, which eventually leads to the successful design improvement. During this process, many important signal collectives, such as micro-strains, accelerations, and engine speed are provided by RLD acquisition in some predefined conditions. Subsequently, these signals are analyzed both in time and frequency domain. Furthermore, order analysis by correlation of acceleration and engine speed is also performed to find a definite reason. As a conclusion, the root cause to the crack is not excitation from the road, but mainly from the engine. Based on this conclusion, structure design is improved and is theoretically proved to be effective by the RLD comparison analysis. And the quantified validation to this work is given by the real road test finally.
Technical Paper
2014-04-01
Tau Tyan, Jeff Vinton, Eric Beckhold, Xiangtong Zhang, Jeffrey Rupp, Nand Kochhar, Saeed Barbat
The objective of this paper focused on the modeling of an adaptive energy absorbing steering column which is the first phase of a study to develop a modeling methodology for an advanced steering wheel and column assembly. Early steering column designs often consisted of a simple long steel rod connecting the steering wheel to the steering gear box. In frontal collisions, a single-piece design steering column would often be displaced toward the driver as a result of front-end crush. Over time, engineers recognized the need to reduce the chance that a steering column would be displaced toward the driver in a frontal crash. As a result, collapsible, detachable, and other energy absorbing steering columns emerged as safer steering column designs. The safety-enhanced construction of the steering columns, whether collapsible, detachable, or other types, absorb rather than transfer frontal impact energy. Recently, more advanced steering column designs with adaptive features, mechanically or pyrotechnically activated, have been introduced for different crash conditions, including different crash severity, occupant mass/size, seat position and seatbelt usage.
Technical Paper
2014-04-01
Mitsuru Enomoto, Michiko Kakinuma, Nobuhito Kato, Haruo Ishikawa, Yuichiro Hirose
Abstract Design work for truck suspension systems requires multi-objective optimization using a large number of parameters that cannot be solved in a simple way. This paper proposes a process-based systematization concept for ride comfort design using a set-based design method. A truck was modeled with a minimum of 13 degrees of freedom, and suspension performance under various vehicle speeds, road surface conditions, and load amounts was calculated. The range of design parameters for the suspension, the range of performance requirements, and the optimal values within these ranges were defined based on the knowledge and know-how of experienced design engineers. The final design of the suspension was installed in a prototype truck and evaluated. The performance of the truck satisfied all the objectives and the effectiveness of the set-based design approach was confirmed.
Technical Paper
2014-04-01
Shuming Chen, Dengzhi Peng, Dengfeng Wang
Abstract Automobile cabin acoustical comfort is one of the main features that may attract customers to purchase a new car. The acoustic cavity mode of the car has an effect on the acoustical comfort. To identify the factors affecting computing accuracy of the acoustic mode, three different element type and six different element size acoustic finite element models of an automobile passenger compartment are developed and experimentally assessed. The three different element type models are meshed in three different ways, tetrahedral elements, hexahedral elements and node coupling tetrahedral and hexahedral elements (tetra-hexahedral elements). The six different element size models are meshed with hexahedral element varies from 50mm to 75mm. Modal analysis test of the passenger car is conducted using loudspeaker excitation to identify the compartment cavity modes. All the acoustic cavity models are coupled with the structure model respectively, the cavity modes are calculated with structural-acoustic coupling model.
Technical Paper
2014-04-01
Prasad Kumbhar, Ning Li, Peijun Xu, James Yang
In vehicle driving environment, the driver is subjected to the vibrations in horizontal, vertical, and fore-aft directions. The human body is very much sensitive to whole body vibration and this vibration transmission to the body depends upon various factors including road irregularities, vehicle suspension, vehicle dynamics, tires, seat design and the human body's properties. The seat design plays a vital role in the vibration isolation as it is directly in contact with human body. Vibration isolation properties of a seat depend upon its dynamic parameters which include spring stiffness and damping of seat suspension and cushion. In this paper, an optimization-based method is used to determine the optimal seat dynamic parameters for seat suspension, and cushion based on minimizing occupant's body fatigue (occupant body absorbed power). A 14-degree of freedom (DOF) multibody biodynamic human model in 2D is selected from literature to assess three types of seat arrangements. The human model has total mass of 71.32 kg with 5 body segments.
Technical Paper
2014-04-01
Akira Kikusato, Katsuya Terahata, Kusaka Jin, Yasuhiro Daisho
Abstract The objective of this work is to develop a numerical simulation model of spark ignited (SI) engine combustion and thereby to investigate the possibility of reducing heat losses and improving thermal efficiency by applying a low thermal conductivity and specific heat material, so-called heat insulation coating, to the combustion chamber wall surface. A reduction in heat loss is very important for improving SI engine thermal efficiency. However, reducing heat losses tends to increase combustion chamber wall temperatures, resulting in the onset of knock in SI engines. Thus, the numerical model made it possible to investigate the interaction of the heat losses and knock occurrence and to optimize spark ignition timing to achieve higher efficiency. Part 2 of this work deals with the investigations on the effects of heat insulation coatings applied to the combustion chamber wall surfaces on heat losses, knock occurrence and thermal efficiency. To reduce engine heat losses and improve the thermal efficiency, the heat insulation coating was applied to the combustion chamber wall surfaces.
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