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2015-04-14
Technical Paper
2015-01-1718
Jan Macek, Zdenek Zak, Oldrich Vitek
Aiming at high low-end ICE torque with turbocharged and massively downsized engines revitalized high pulsation exhaust manifolds, which improve exhaust gas energy transfer especially while engine runs at reduced speed. The lack of turbine maps if twin scroll or divided scroll is used for radial turbine stator entry is well-known. The remedy is not simple. The measurements of maps for twin-entry turbines are costly and time consuming. Any lookup-map based interpolation suffers from lack of physical fundamentals, since the mixing processes take place inside a turbine at governing pressure differences significantly different from turbine inlet pressures. The paper describes a way to a 1-D central streamline model of a radial turbine flow suitable for twin-scroll description based on approximation to real physics of flow mixing and energy transformation.
2015-04-14
Technical Paper
2015-01-1719
Daniel Pachner, Lukas Lansky, David Germann, Markus Eigenmann
Turbocharger maps measured on the gas stand are commonly used to represent turbine and compressor performance. The maps are useful source of information for mean value modeling, engine calibration optimization, virtual sensing and feedback control design. For some tasks, representing the maps by fitted functional forms can be more convenient than using the interpolation of the map data directly. The functional representation usually allows for wider extrapolation ranges and more reliable application of numerical optimization methods. Several functional forms have been proposed for compressor map modeling, often based on empirical polynomial models. However, most successful models are based rational polynomials of dimensionless head and flow parameters (Winkler, Jensen). The turbines are usually modeled as orifices, or orifices with variable cross-section in case of variable nozzle (VNT) turbines.
2015-04-14
Technical Paper
2015-01-1716
Oldrich Vitek, Jan Macek, Jiri Klima, Martin Vacek
The proposed paper deals with an optimization of a highly-turbocharged large-bore gas SI engine. Only steady state operation (constant engine speed and load) is considered. The results are obtained by means of simulation using complex 0-D/1-D engine model including the control algorithm. Different mixture composition concepts are considered to satisfy TA Luft norm (different levels of TA Luft NOx limit are evaluated) – fresh air and external cooled EGR is supposed to be the right way while optimal EGR level is to be found. Considering EGR circuit, 5 different layouts are tested to select the best desing. As the engine control is relatively complex (2-sage turbocharger group, external EGR, compressor blow-by, controlled air excess), 5 different control means of boost pressure were considered. Each variant (based on above mentioned possibilities) is optimized in terms of compressor/turbine size (swallowing capacity) to obtain the best possible BSFC.
2015-04-14
Technical Paper
2015-01-1717
Li-Chun Chien, Matthew Younkins, Mark Wilcutts
Dynamic skip fire is a control method for internal combustion engines in which engine cylinders are selectively fired or skipped to meet driver torque demand. Each cylinder is operated at or near its best thermal efficiency and flexible control of acoustic and vibrational excitations is achieved. In this type of engine operation, fueling, and possibly intake and exhaust valves of each cylinder are actuated on an individual firing opportunity basis. The implementation and benefits of this system have been described in several previous papers. This paper describes engine thermofluid modeling for this type of operation for purposes of air flow and torque prediction. Airflow dynamic and thermodynamic results for skip fire engine operation are presented and compared with experimental data under several different firing sequences. Unique impacts of dynamic skip fire on air estimation, and performance parameters are discussed.
2015-04-14
Technical Paper
2015-01-1636
Asuka Takasaki, Takashi Inoue, Kazumitsu Sugano, Koji Nagata
Recently, an important policy for automobile manufactures is to develop vehicles with high fuel efficiency and clean emissions to prevent global warming. Engine efficiency has the greatest potential for fuel economy improvement, and there are various methods for improving. One engine technology used to improve fuel efficiency is downsizing engine displacement and adding a turbocharger. Toyota Motor Corporation has developed a turbocharged engine for the Lexus NX200t. A turbocharger for downsized engines reduces engine displacement without changing a vehicles rank. To countermeasure the reduction of engine torque resulting from downsizing a gasoline engine, torque is recovered by use of a turbocharger. Although both improvement of fuel efficiency and power performance can be achieved by turbocharging, driveability might decrease seen as non-linear acceleration characterized as a lag followed by a sudden and large increase of engine output torque. 
2015-04-14
Technical Paper
2015-01-1632
Karim Bencherif, Dirk von Wissel, Lukas Lansky, Dejan Kihas
Over the past few years, innovative engine layouts have enabled significant fuel consumption and pollutant emissions reduction. An exponential growth in powertrain control strategies complexity has accompanied these achievements. As a result, controls and calibration development time and effort have become an important issue in powertrain design. One illustration of this complexity is the Diesel Diesel Particulate Filters; the main issue for these devices is the periodical regeneration necessary to eliminate the accumulated soot. The challenging enhancement of the regeneration event can be achieved with a better regeneration temperature control. In this paper, we describe the DPF regeneration process, the main constraints, identification tests and a simulation comparison of two control solutions based on model based approach to DPF thermal control during regeneration DPF.
2015-04-14
Technical Paper
2015-01-1640
Farraen Mohd Azmin, Richard Stobart
Design of Experiments (DOE) introduced a number of design types such as space filling design and optimal design. However, optimal design type is best for a system with high prior knowledge. Meanwhile, space filling design is good for unknown systems which is normal for engine calibration process. Space filling is a design type that randomly spread test points in an engine operating envelope. There are several types of space filling designs such as Latin Hypercube Sampling, Lattice and Stratified Latin Hypercube. However, these designs have a weakness for engine calibration applications. Engine testing for model based calibration can be demanding in terms of resources and time. Ideally, it would be better to have a design that can support constructive model building where a calibration engineer can spend most of the day running a block of engine test and later for the rest of the time modeling the engine.
2015-04-14
Technical Paper
2015-01-1641
Hardik N. Lakhlani
Now day’s technology is changing day by day and with that customer expectation is increasing day by day. Generally customers relate their reputation with their vehicle. Smoke coming out of vehicle affects badly on the reputation of the customer that’s why today’s customer wants smoke free vehicle during transient condition. Low Air Fuel Ratio leads to smoke due to rich combustion mixture. Smoke could be generated due to turbo leg, sudden acceleration, gear changing, cold condition, altitude etc. During sudden acceleration, turbo leg leads to rich mixture which is favorable condition for smoke generation. It’s difficult to reduce turbo leg in waste gate type turbocharger while maintaining EGR requirement in EGR based Engine. Smoke can be optimized by controlling fuelling in sudden acceleration or in transient condition. However it will adversely impact on vehicle pick up and can improve fuel economy.
2015-04-14
Technical Paper
2015-01-1618
Ke FANG, Zongyan Li, Andrew Shenton, David Fuente, Bo Gao
Black Box Dynamic Modelling of a Gasoline Engine for Constrained Model-Based Fuel Economy Optimization Ke Fang (a), Zongyan Li(b), Tom Shenton(c), David Fuente(a), Bo Gao(a) a. AVL Powertrain UK b. University of Loughborough c. University of Liverpool New environmental legislation on emission and fuel efficiency targets increasingly requires good transient engine performance and this in turn means that the previously acceptable static engine calibration and control methodologies based on steady-state testing must be re-placed by dynamical optimization using dynamical models. Although many advances have been made in predictive models for internal combustion engines, the phenomena involved are so many, complex and nonlinear that dynamical black-box models typically employing neural network structures must be determined from system identification through experimental testing.
2015-04-14
Technical Paper
2015-01-1628
Nilufar Damji, Daniel Dresser, Jerome Bellavoine, Mohan Swaminathan
Increasing powertrain complexity and the growing number of vehicle variants are putting a strain on current calibration development processes. This is particularly challenging for vehicle drivability calibration, which is traditionally completed late in the development cycle, only after mature vehicle hardware is available. Model-based calibration enables a shift in development tasks from the real world to the virtual world, allowing for increased system robustness while reducing development costs and time. A unique approach for drivability calibration was developed by incorporating drivability analysis software with online optimization software into a virtual engine test cell environment. Real-time, physics-based engine and vehicle simulation models were coupled with real engine controller hardware and software to execute automated drivability calibration within this environment.
2015-04-14
Technical Paper
2015-01-1622
Nicolo Cavina, Giorgio Mancini, Andrea Businaro, Matteo De Cesare, Federico Covassin
In the field of passenger car engines, recent research advances have proven the effectiveness of downsized, turbocharged and direct injection concepts, applied to gasoline combustion systems, to reduce the overall fuel consumption while respecting particularly stringent exhaust emissions limits. Knock and turbocharger control are two of the most critical factors that influence the achievement of maximum efficiency and satisfactory drivability, for this new generation of engines. The sound emitted from an engine encloses many information related to its operating condition. In particular, the turbocharger whistle and the knock clink are unmistakable sounds. This paper presents the development of real-time control functions, based on direct measurement of the engine acoustic emission, able to provide information about turbocharger speed and knock intensity.
2015-04-14
Technical Paper
2015-01-0694
Tadashi Naito, Yuta Urushiyama
Carbon Fiber Reinforced Plastic (CFRP) composite material is stronger, stiffer than steel. It reduces the weight of automobile structure. CFRP tends to show micro-fracture of resin inside the structure; oftentimes its strength is determined by its fracture mode. There are differences in strength between intra-ply fractures and inter-ply fractures, latter mode being critical in most cases. When applying CFRP to an automobile structure consisting of complex three-dimensional geometries, load input in out-of-plane direction is inevitable. The strength is determined by inter-ply fracture due to stress applied in combination of peel and shear direction between the plies. For the accurate prediction of structural strength by simulation, the model needs to reproduce this failure mode. There are several fracture models proposed for inter-laminar failure evaluation.
2015-04-14
Technical Paper
2015-01-0693
Tadashi Naito, Yuta Urushiyama, Michael Bruyneel
Carbon Fiber Reinforced Plastic (CFRP) composite material has more strength and stiffness than steel. FEM analysis of coupon test specimens were performed which are accompanied by intra-ply fracture, applying damage model. This model considers the damage evaluation for different fracture modes, stiffness degradation due to the damage, and coupling between different damage modes. The intra-ply damage is divided into three modes; fiber direction damage which represents fiber fracture, and damages in transverse and shear direction with respect to fiber, which arise from resin fractures. Each damage mode is represented by function of thermodynamic force which has the same dimension as strain energy. Damages in transverse and shear directions are coupled by coupling factor and thermodynamic forces. Permanent deformation of resin and non-linearity of the fiber modulus are also considered.
2015-04-14
Technical Paper
2015-01-0535
Neil Bishop, Paresh Murthy, Karl A. Sweitzer, Stuart C. Kerr
It has been recognised since the 1960’s that the frequency domain method for structural analysis offers superior qualitative information about structural response; But computational and technological issues have held back the implementation for fatigue calculation until now. Recent technological developments have now enabled the practical implementation of the frequency domain approach and this paper will demonstrate this, with particular reference to the technology limitations that have been overcome, the resultant performance advantages, and accuracy.
2015-04-14
Technical Paper
2015-01-0554
Rafaa Esmaael, Vernon fernandez
An accurate prediction of elasto-plastic cyclic deformation becomes extremely important in design optimization. Which lead to a more accurate fatigue life prediction and weight savings. In this project a two-step notch root prediction method based on interpolation between linear and Neuber’s notch strain amplitude solutions is proposed. The accuracy of this method is assessed by comparing the results with the results obtained from elasto-plastic finite element analysis. Different types of steels with different yield strengths were used in this study. Notch deformation behavior under cyclic loading conditions was monitored for a double notched flat plate and a circumference notched round bar to cover plain stress and plain strain conditions. Elastic as well as elasto-plastic finite element analyses are performed.
2015-04-14
Technical Paper
2015-01-1147
Dongxu Li
Driveline NVH characteristics is very important to vehicle drive quality and possible issues may be perceived by a customer through audible sound, drive torque and chassis etc. The strong need to further improve fuel efficiency demands powertrain systems of increased complexity that may result in new NVH issues. Many NVH phenomena are determined by driveline architecture (FWD, RWD, and AWD) as well powertrain subsystem architecture and components. In addition to transmission type (AT, DCT, CVT), architecture of a particular transmission and arrangement of components can affect driveline behavior to a large degree. As the driveline components are highly coupled, component identification and isolation for certain vibration phenomenon experienced from the driveline can be very challenging. In this context, development of a refined powertrain and driveline system with desired performance requires a deep understanding of such system is highly desired.
2015-04-14
Technical Paper
2015-01-1143
Ivan Rot, Daniel Fritz Plöger, Stephan Rinderknecht
A model based gearbox calibration process provides high potential for an efficient calibration of transmission control unit parameters of automatic transmissions in automotive powertrains. This process requires mathematical models which represent the dynamic behavior of the physical system. A black box model is an alternative to white or grey box models and offers a possibility to reproduce the transient system behavior. Beneficially it does not require detailed system knowledge. Hence a significant advantage of a black box model is a rapid adaption of the model to modifications of the system configuration. In an environment with frequently changing powertrain constellations a black box approach can lead to higher process efficiency. In this investigation two different nonlinear dynamic black box model approaches will be introduced. The objective of the models is to reproduce the transient gearshift process.
2015-04-14
Technical Paper
2015-01-1750
Stijn Broekaert, Thomas De Cuyper, Kam Chana, Michel De Paepe, Sebastian Verhelst
Homogeneous charge compression ignition (HCCI) engines are a promising alternative to traditional spark- and compression-ignition engines. The HCCI combustion principle makes it possible to achieve both a high thermal efficiency and near-zero emissions of NOx and soot. This is obtained by introducing a lean premixed fuel-air mixture into the combustion chamber and letting it auto-ignite due to the temperature rise during the compression stroke. The main drawbacks of HCCI combustion are the lack of direct control over the start of combustion and a limited operating range. Trying to overcome these drawbacks and further optimizing the engine, solely using an experimental approach is very time consuming. Therefore simulation tools are being developed. An important model required by these simulation tools, is a model that calculates the heat transfer from the bulk gas to the walls of the combustion chamber.
2015-04-14
Technical Paper
2015-01-1752
Alex Melin, David Kittelson, William Northrop
In recent years, there has been growing interest in using alternative cycles to the standard Otto cycle in an effort to improve efficiency and lower emissions of spark-ignition engines. One such proposed concept is the 5-stroke engine. The 5-stroke uses two types of cylinders, a combustion cylinder and expansion cylinder with a transfer port between them. Excess pressure in the combustion cylinder can be further expanded by using a second expansion cylinder to harness additional work; a practical implementation of the Atkinson Cycle. Since the expansion cylinder runs on a two-stroke cycle, an additional increase in efficiency can result by connecting two combustion cylinders to one expansion cylinder in a three cylinder configuration. Although previous work has investigated the performance of prototype 5-stroke engines compared to1-D modeling results, none have conducted a thorough study on the interactions of various design parameters.
2015-04-14
Technical Paper
2015-01-1753
Mario Vila Millan, Stephen Samuel
Nanofluids and thermal management strategy for Automotive Application Mario Vila Millan, Stephen Samuel Oxford Brookes University, United Kingdom Stringent emission norms introduced by the legislators over the decades have forced the automotive manufacturers to improve the fuel economy and emission levels of their engine continuously. This constant improvement leads to increased use of smart systems where components are controlled by the engine management systems to get a desired and optimized performance. Therefore, the emission levels of the modern engines are significantly lower than pre-1990 engines. However, the improvement in fuel economy is marginal when compared to that of the scale of improvement achieved for reducing emission levels. For example, approximately 30% of the total energy in the fuel is still being wasted through the cooling systems in the modern engines during normal operating conditions. This is even worse during the engine warm up.
2015-04-14
Technical Paper
2015-01-1749
Hung Nguyen Ba, Ocktaeck Lim, Norimasa Iida
In a linear engine, the piston motion is not restricted by a crankshaft mechanism, but it is determined by the interaction between the gas and load forces. Therefore, the compression ratio of the linear engine is variable and it allows the engine to operate with the HCCI combustion. However, it is difficult to obtain a high compression ratio as well as a HCCI combustion from motoring mode of the linear engine due to lack of a crankshaft. In this paper, an idea using SI-HCCI transition to achieve the HCCI combustion is proposed. The spark ignition (SI) mode is used first to increase compression ratio before the homogeneous charge compression ignition (HCCI) mode is activated by turning off spark plugs. The operation of the linear engine is modeled and simulated by dynamic and thermodynamic models.
2015-04-14
Technical Paper
2015-01-0343
Carlo N. Grimaldi, Claudio Poggiani, Alessandro Cimarello, Matteo De Cesare, Giovanni Osbat lng
The CO2 emission limits for vehicles are becoming more stringent with the aim of reducing greenhouse gas emissions and for improving fuel economy. The New European Driving Cycle (NEDC), adopted to measure all new internal combustion engine emissions in the European Union, is performed on cold vehicle, starting at a temperature of 22°C ± 2°C. So the cold-start efficiency of internal combustion engine is becoming of predominant interest. Since at the cold start the lubricant oil viscosity is higher than at target operating temperature, the consequently higher energy losses due to the friction losses can substantially affect the emission cycle result in terms of fuel consumption and CO2 emission. A suitable thermal management system, such as an exhaust-to-oil heat exchanger, could help to raise the oil temperature more quickly.
2015-04-14
Technical Paper
2015-01-0444
xueqian chen, Zhanpeng SHEN, Qinshu He
In some engineering problems, more than one model can be created to simulate the structural behavior. The model selection uncertainty is needed to be considered now. At the same time, the model form uncertainty can’t be ignored in order to obtain the reliable prediction results. In this research, different models’ degree of belief is computed by combining the Bayesian method with the test data. The adjustment factor approach is used to propagate the model selection uncertainty into prediction of a system response, and then the response confidence interval is obtained via the calculating results of the synthesis model. The last simulation results are gotten by combining the confidence interval of the model form uncertainty with the results of the synthesis model. The confidence interval at the prediction point is calculated by the interpolation method.
2015-04-14
Technical Paper
2015-01-0555
Zhigang Wei
Computer aided engineering (CAE) based virtual damage and life assessment tools are now commonly used in component-level, system-level and even vehicle-level product design and validation thanks to the rapid development in computer and computing technologies. CAE simulation covers a wide variety of engineering areas such strength, fatigue related durability, noise-vibration-harshness (NVH), crashworthiness, driving stability etc. Recently, several CAE based thermal-fatigue life assessment tools have been developed and some are commercially available. However, most of these tools are deterministic in nature, therefore, cannot reflect the observed data variation and uncertainty, which are caused by many factors including the complex underlying fatigue-creep-oxidation failure mechanisms. The major obstacle to realistic life assessment is essentially the lack of reliable methodologies and associated database support.
2015-04-14
Technical Paper
2015-01-1055
Apoorv Kalyankar, Achuth Munnannur, Z. Gerald Liu
Selective catalytic reduction (SCR) is a promising technology for meeting the stringent requirements pertaining to NOx emissions. One of the most important requirements to achieve high DeNOx performance is to have a high uniformity of ammonia to NOx ratio (ANR) at the SCR catalyst inlet. Steady state 3D computational fluid dynamics (CFD) models are frequently used for predicting ANR spatial distribution but are not feasible for running a transient cycle like Federal Test Procedure (FTP). On the other hand, 1D kinetic models run in real time and can predict transient SCR performance but do not typically capture the effect of non-axial non-uniformities. In this work, two 3D to 1D coupling methods have been developed to predict transient SCR system performance, taking the effect of ANR non-uniformity into account. First is a probability density function (PDF) based approach and the second is a geometrical sector based approach.
2015-04-14
Technical Paper
2015-01-1355
Adarsh Viji Elango, Apurva Gokhale, Sumeet Parashar
With the increase in computational capability, there is an increase in classes of engineering optimization problems that are considered solvable. Optimal solutions to such problems have already led to an increase in performance of engineering systems. Not all problems benefit from similar types of approaches when searching for an optimal solution. Some have objective functions that can be described as largely unimodal while others have complex behavior with local extrema. Further, there are problems that have behavior that are not clearly apparent due to the involvement of CAD/CAE tools and high number of inputs/factors. There has been a push to combine dissimilar optimization approaches in order to tackle such hard-to-solve problems for variety of reasons including: ease of selection for user, exploiting advantages of different categories of algorithms, and avoiding experimentation to pick an algorithm for different class of problems.
2015-04-14
Technical Paper
2015-01-1360
Sajjad Beigmoradi
Improvements of aerodynamics and wind noise are 2 important objects for automotive engineers. Improvement of aerodynamics behavior and the reduction of wind noises have been always greatly concerned by automotive engineers since they negatively affect passengers comfort, fuel consumption, car performance and stability. In this paper, optimum levels of four dominant rear shape parameters for a simplified car model are investigated considering drag coefficient and aerodynamics noise objects. C-Pillar angle, trunk angle, boat tail angle and rear box length are considered as variable parameters. Taguchi method is used for finding aerodynamic and acoustic optimum levels. Numerical simulation for base case is compared with experimental results in the literature. Numerical results show good agreement with experimental test. Afterwards, optimum levels for parameters regarding objects are performed. Optimization results have good agreement with simulation results.
2015-04-14
Technical Paper
2015-01-0446
Ronald Lannan
The Business Case for MBD Abstract : Use of MBD processes for embedded controls software development has been purported to result in cost, quality, and delivery improvements. Initially the business case for MBD was rather vague and qualitative, but more data is now becoming available to support the premise for this development methodology. Often, the implementation of MBD in an organization is bundled with other software process improvements, so trying to unbundle the contributions from MBD has been problematic. This paper addresses the dominant factors for MBD cost savings and the business benefits that have been realized by companies in various industries engaged in MBD development. It also summarizes some key management best practices and success factors that have helped organizations achieve success in MBD deployment. Note: This paper complements the other paper submitted: The Benefits of MBD
2015-04-14
Technical Paper
2015-01-1344
Shivayogi S Salutagi, Milind Kulkarni, Aniruddha Kulkarni
Efficiency, reliability, uptime and power density are important performance requirements for manufacturers and users of off-highway equipment. Hydraulics technology is most preferred for off-highway equipment due to its high power density. Hydraulics deliver precisely the power and control that helps operators tackle the task at hand as well as providing the power to move equipment within and around work sites. The pumps, motors, valves, cylinders and hoses constitute a typical hydraulic system that powers machinery. How the individual components are designed or integrated determines the efficiency, reliability and power density of the system and the equipment itself. To meet these requirements, understanding fluid flow behavior is a critical aspect in designing the hydraulic systems and components. Build-test-break knowledge and experience are not sufficient to design and develop optimized solutions. In some cases, physical testing of actual product is impossible.
2015-04-14
Technical Paper
2015-01-1696
Federico Perini, Kan Zha, Stephen Busch, Paul Miles, Rolf Reitz
In this work computational and experimental approaches are combined to characterize in-cylinder flow structures and local flow field properties during operation of the Sandia 1.9L light-duty optical diesel engine. A full computational model of the single-cylinder research engine was used that considers the complete intake and exhaust runners and plenums, as well as the adjustable throttling devices used in the experiments to obtain different intake swirl ratios. The in-cylinder flow predictions were validated against an extensive set of planar PIV measurements at different vertical locations in the combustion chamber for different swirl ratio configurations. Principal Component Analysis was used to characterize precession, tilting and eccentricity, and regional averages of the in-cylinder turbulence properties in the squish region and the piston bowl.
Viewing 1 to 30 of 29901