Criteria

Display:

Results

Viewing 1 to 30 of 2142
2016-11-08
Technical Paper
2016-32-0077
Roland Baar, Valerius Boxberger, Maike Sophie Gern
On a worldwide scale, turbocharged four-cylinder engines are the most used ones in automotive industries. Three-cylinder engine is a technical alternative because of its higher thermodynamic potential that is due to higher cylinder displacement. Following this trend, the interest in two-cylinder engines is growing. These do have special demands concerning uniformity and dynamics of oscillating masses and firing order, but also very different conditions for the turbocharger. With two-cylinder engines, the pulsating influence grows and changes the operation of the turbine. In this paper different boosting technologies are compared in small engine applications. Besides of turbochargers the potentials and limits of superchargers and electric chargers as well as their combinations are compared. These technologies show dissimilarities concerning power supply, operation range and efficiency, and these effects have different meaning in small engines.
2016-11-08
Technical Paper
2016-32-0046
Stephan Schneider, Marco Chiodi, Horst Friedrich, Michael Bargende
The proposed paper deals with the development process and initial measurement results of an opposed piston engine for the use in a Free Piston Linear Generator (FPLG). The FPLG, which is being developed at the German Aerospace Center (DLR), is an innovative internal combustion engine for the generation of electrical power. With its arrangement, the piston freely oscillates between the compression chamber of the combustion unit and a gas spring with no mechanical coupling like a crank shaft. A linear alternator converts the kinetic energy of the moving piston into electric energy. The virtual development of the novel combustion system is divided into two stages: One the one hand, the combustion system including e.g. a cylinder liner, pistons, cooling and lubrication concepts has to be developed.
2016-11-08
Technical Paper
2016-32-0037
Christian Zinner, Stephan Jandl, Stephan Schmidt
The internal combustion engine is still the most important propulsion system for the individual mobility. Especially for the application of motorcycles and recreational vehicles is the extra ordinary high power density crucial. Today, these engines are mainly 4-stroke natural aspirated MPFI engines. The main difference to the automotive sector is the abandonment of all cost intensive technologies, like variable valve timing, intake air charging or gasoline direct injection. The need for further investigations and implementation of new technologies is given due to the very high share of total road transport emissions of motorcycles and the introduction of the emission limits of EURO5 in 2020. One possibility to reach the future emission limits is the downsizing strategy. For this the potential for emission and fuel consumption reduction is well known.
2016-11-08
Journal Article
2016-32-0010
Kei Yoshimura, Shunichi Mori, Kenjiro Nakama, Jin Kusaka
This paper presents the effect of in-cylinder charge stratification on high load homogeneous charge compression ignition (HCCI) combustion by 3 dimensional CFD coupled with a chemical reaction calculation. The first study with a simple engine model which has no gas exchange cycle reveals that thermal stratification is more effective to prolong combustion duration, which is a key factor for a high load limit of HCCI combustion, than equivalent ratio stratification. And, thermal stratification enables to maintain combustion efficiency, which would be a difficulty to relief HCCI combustion by in-cylinder charge stratification, compared to equivalent ratio stratification. In addition, the first study also reveals the effect of the direction of stratification in the cylinder.
2016-11-08
Journal Article
2016-32-0050
Francesco Testa, Vincenzo Gagliardi, Marco Ferrari, Stefano Fontanesi, Andrea Bertani
It is well known that 3D CFD simulation can give detailed information about fluid and flow properties in complex 3D domains and that1D CFD simulation can give important information at a system level, i.e. about the performance of the entire engine. The drawbacks of the two simulation methods are that the former requires high computational cost while the latter is not able to capture complex local 3D features of the flow. Therefore, the two simulation methods are to be seen as complementary, indeed a coupling of the two approaches can benefit from the pros of the two methods while minimizing the cons. In particular, with a multi-scale modeling approach (1D-3D) it is possible to simulate large and complex domains by modeling the complex part with a 3D approach and the rest of the domain with 1D approach.
2016-10-17
Technical Paper
2016-01-2229
Alessio Dulbecco, Stephane Richard, Olivier Laget, Philippe Aubret
Turbulence is a crucial topic to account for when dealing with Spark Ignition (SI) engines. In fact, it is well known that combustion in SI engines strongly depends on in-cylinder turbulence characteristics. By definition turbulence presents three-dimensional features; accordingly, three dimensional approaches are mainly used to investigate the in-cylinder flow and assist the engine design process over a large range of operating conditions. However, SI engine architectures are becoming more and more complex and the generalization of technologies such as Variable Valve Timing (VVT) and Direct Injection (DI) considerably increase the number of degrees of freedom to account for. In this context, the resources demanded by 3D CFD codes hugely increase and car manufacturers privilege system simulation approaches, commonly based on models adopting 0D / 1D formalisms.
2016-10-17
Technical Paper
2016-01-2235
Prithwish Kundu, Riccardo Scarcelli, Sibendu Som, Andrew Ickes, Yan Wang, John Kiedaisch, M Rajkumar
Heat loss through wall boundaries play a dominant role in the overall performance and efficiency of internal combustion engines. Typical engine simulations use constant temperature wall boundary conditions. These boundary conditions cannot be estimated accurately from experiments due to the complexities involved with engine combustion. As a result they introduce a large uncertainty in engine simulations and serve as a tuning parameter. Modeling the process of heat transfer through the solid walls in an unsteady engine CFD simulation can lead to the development of higher fidelity engine simulation models. These models can be used to study the impact of heat loss on engine efficiency and explore new design methodologies that can reduce heat losses. In this work a single cylinder diesel engine is modeled along with the solid piston coupled to the fluid domain.
2016-10-17
Technical Paper
2016-01-2313
Jianjun Zheng, Zhangsong Zhan, Huixian Shen, Xiaoyong Li, Zhiqin Xu, Yuhang Tang, Xiaodong Chen, Qingqiang Zeng, Huibin Qing, Tiegang Hu
This paper describes a simulation guided design methodology for developing direct injection combustion systems of gasoline engines. The first step is the optimization of engine gas flow. The intake port and runner geometry is optimized by CFD simulations to compromise the engine breath capacity and its tumble flow. Secondly, the piston crown shapes and the injection system designs (injection pressure, hole number, hole size and orientations) are optimized based on dedicated CFD simulation results. Thirdly, different injection strategies are used at different engine operating conditions to achieve best engine performance, split injections being used at cold starting and catalyst heating period to realize stratified charge combustion and fast catalyst light-off, and a single injection being used to achieve homogeneous mixture combustion for almost all other operating conditions.
2016-10-17
Technical Paper
2016-01-2278
Ashutosh Gupta, Huifang Shao, Joseph Remias, Joseph Roos, Yinhui Wang, Yan Long, Zhi Wang, Shi-Jin Shuai
Superknock is an undesirable combustion phenomenon that limits the fuel economy, drivability, emissions and durability performance of modern turbocharged engines. Numerous researchers have previously reported that the frequency of super knock is sensitive to engine oil and fuel composition in controlled laboratory and engine-based studies. Several studies indicate that droplets of oil and residual fuel ejected from the piston crevice could play a role. Recent studies by Tsinghua University and Afton Chemical Corporation have demonstrated that controlled injection of oil-fuel droplets into the combustion chamber can induce pre-ignition and superknock. Afton and Tsinghua recently developed a 3D CFD engine simulation which was able to realistically model all of the elementary processes involved in droplet induced pre-ignition. The model was able to successfully simulate droplet induced pre-ignition at conditions where the phenomenon has been experimentally observed.
2016-10-17
Journal Article
2016-01-2236
Jann Koch, Guoqing Xu, Yuri M. Wright, Konstantinos Boulouchos, Michele Schiliro
Three-dimensional reactive computational fluid dynamics (CFD) plays a crucial role in IC engine development tasks complementing experimental efforts by providing improved understanding of the combustion process. A widely adopted combustion model in the engine community for (partially) premixed combustion is the G-Equation where the flame front is represented by an iso-level of an arbitrary scalar G. A convective-reactive equation for this iso-surface is solved, for which the turbulent flame speed ST must be provided. In this study, the commonly used and well-established Damköhler approach is compared to a novel correlation, derived from an algebraic closure for the scalar dissipation of reaction progress as proposed by Kolla et al. [1].
2016-10-17
Technical Paper
2016-01-2158
Jian Gao, Giacomo Cuneo
In small and compact class vehicles equipped with diesel engines, the 2-valve-per-cylinder design still holds a significant share of the market, notably for European traditional diesel-oriented OEMs. Such engines are very efficient and reasonably fun-to-drive, while being complaint to the increasingly stringent emission regulations, showing the technical and commercial potential of 2-valve engine is far from exhausted. The current work describes the numerical simulation of port-valve-cylinder flow in a 1.2L 2-valve-per-cylinder diesel engine to characterize the performance of its manifold and intake ports at rated power conditions as part of the development activities for this new diesel engine architecture. First, evaluation metrics were defined and analysis procedure was established for CFD assessment of intake manifold performance in multi-cylinder engines.
2016-10-17
Technical Paper
2016-01-2196
Stefan Stojanovic, Andrew Tebbs, Stephen Samuel, John Durodola
With a push to continuously develop traditional engine technology efficiencies and meet stringent emissions requirements, there is a need to improve the precision of injection rate measurement used to characterise the performance of the fuel injectors. New challenges in precisely characterising injection rate present themselves to the Original Equipment Manufacturers (OEMs), with the additional requirements to measure multiple injection strategies, increased injection pressure and rate features. One commonly used method of measurement is the rate tube injection analyser; it measures the pressure wave caused by the injection within a column of stationary fluid. In a rate tube, one of the significant sources of signal distortion is a result of the injected fluid pressure waves reflected back from the tube termination.
2016-10-17
Journal Article
2016-01-2194
Muhsin M. Ameen, Prithwish Kundu, Sibendu Som
In this work, a turbulent combustion model is developed for large eddy simulation (LES) using a novel flamelet tabulation technique based on the framework of the multi-flamelet representative interactive flamelet (RIF) model. The overall aim is to develop a detailed model with elaborate chemistry mechanisms, LES turbulence models and highly resolved grids leveraging the computational cost advantage of a tabulated model. A novel technique of implementing unsteady flamelet libraries without the use of progress variables is proposed. These flamelet libraries use the residence time as one of the independent variables instead of using the traditional progress variable approach. In this study, LES of n-dodecane spray flame is performed using the tabulated turbulent combustion model along with a dynamic structure subgrid model. A high-resolution mesh is employed with a cell size of 62.5 microns in the entire spray and combustion regions.
2016-10-17
Technical Paper
2016-01-2198
Chikara Dodate, Sachio Mori, Masato Kawauchi, Rio Shimizu
In recent years, a lot of direct-injection gasoline engines are developed due to the high rated power, low end torque and fuel efficiency because of increased volumetric efficiency and reduced knocking. On the other hand, the measure for particular matters (PM) and the oil dilution become important. Therefore it is necessary to identify a spray behavior in cylinder with the combination of flow to design a direct injector. To identify the spray behavior, a CFD analysis has been utilized. However, before it was necessary to fit spray model constants and parameters based on measurement results including a penetration and SMD. Especially, in the case of the nozzle whose sectional area of exit is larger than that of inlet like a fan-shape spray nozzle, the fitting process is complicated, because of an inhomogeneity internal flow. In this study, new simulation method of spray is developed.
2016-10-17
Journal Article
2016-01-2197
Chengjun Du, Mats Andersson, Sven Andersson
Effects of nozzle geometry on diesel spray characteristics were studied in a spray chamber using three single-hole nozzles, one cylindrical and two conical, designated N1 (outlet diameter 140 µm, k-factor 0), N2 (outlet diameter 140 µm, k-factor 2) and N3 (outlet diameter 136 µm, k-factor 2). To characterize the hydraulic properties of the nozzles, impingement measurements were carried out under ambient conditions and injection pressures ranging from 800 to 1600 bar. Spray experiments were performed with each of these nozzles at two constant gas densities (15 and 30 kg/m3), one temperature 673 K, at which evaporation occurs. A light absorption scattering technique using visible and UV light was implemented, and the liquid and vapor phase distributions were imaged. The data show that effects of nozzle geometry on the vapor phase penetration and local spray cone angle differ with gas density and injection pressure.
2016-10-17
Technical Paper
2016-01-2201
Meng Tang, Le Zhao, Seong-Young Lee, Jeffrey Naber
Extensive studies have addressed diesel sprays under vaporizing and combusting conditions respectively, but further insights into the mechanism by which combustion alters the global spray penetration and shape of the spray under diesel engine conditions are needed. Contradictory observations are reported in the literature regarding the combusting diesel spray penetration compared to inert conditions, and it is the objective of this study to provide further insight and analysis on the combusting spray characteristics by expanding the range of operating parameters. Parameters varied in the studies are charge gas conditions including oxygen level (0 %, 15%, 19%), charge density (22.8 & 34.8kg/m3), and charge temperature (800K, 900K & 1050K) for injection pressures of 1200, 1500, and 1800 bar with a single hole injector with a nozzle diameter of 100 μm. These represent conditions for operation of a modern fuel injection system diesel engine at high load with EGR.
2016-10-17
Technical Paper
2016-01-2350
Zhien Liu, Jiangmi Chen, Sheng-hao Xiao
This paper combines fluid software STAR-CCM+ and finite element software ABAQUS to stimulate the internal field of this Gasoline engine exhaust manifold based on the theory of loose coupling. Through the simulation of car parking cooling - full load condition at full speed, we estimate thermal fatigue life of the exhaust manifold with the plastic strain increment as the evaluation parameters. Results shows that the manifold satisfies the target life performance. Here we also made a consideration about the how the bolt force affects the manifold elastic and plastic material behavior.
2016-10-17
Journal Article
2016-01-2160
Alexander Bech, Paul J. Shayler, Michael McGhee
A physics based, lumped thermal capacity model of a 1litre, 3 cylinder, turbocharged, directly injected spark ignition engine has been developed to investigate the effects of cylinder deactivation on the thermal behaviour and fuel economy of small capacity, 3 cylinder engines. When one is deactivated, the output of the two firing cylinders is increased by 50%. The largest temperature differences resulting from this are between exhaust ports and between the upper parts of liners of the deactivated cylinder and the adjacent firing cylinder. These differences increase with load. The deactivated cylinder liner cools to near-coolant temperature. Temperatures in the lower engine structure show little response to deactivation. Temperature response times following deactivation or reactivation events are similar. Motoring work for the deactivated cylinder is a minor loss; the net benefit of deactivation diminishes with increasing load.
2016-10-17
Technical Paper
2016-01-2191
Peter Deckelmann, Tina Dietrich
Abstract This paper will focus on a powertrain injector application solution for R&D and production. PIA is a product for triggering and analyzing current and newly developed injection valves (both solenoid and piezoelectric). The article examines an important obstacle of injection testing, which is creating realistic environmental conditions for injectors. It shows how PIA realizes this through high-end ECU simulation for current and new generations, creating different operating conditions. Berghof Testing combined control, performance and measuring technology into PIA. The compact, intelligent and economical device can be integrated into all existing injector test systems. In addition to the standard version the application offers enhancements such as intelligent injections, injector calibration, polarity detection and image processing for spray analyses.
2016-10-17
Technical Paper
2016-01-2193
Gen Shibata, Hideyuki Ogawa, Fukei Sha, Kota Tashiro
Abstract Diesel particulate filters (DPF) are widely used in diesel engines, and forced regeneration is necessary to remove particulate matter (PM) accumulating on the DPF. This may be achieved with fuel injected after the main combustion is complete, the socalled “post fuel injection”, and supplied to the diesel oxidation catalyst (DOC) upstream of the DPF. This increases the exhaust gas temperature in the DOC and the DPF is regenerated with the high temperature gas flow. In most cases, the post fuel injection takes place at 30-90CA ATDC, and fuel may impinge on and adhere to the cylinder liner wall in some cases. Buddie and Pischinger [1] have reported a lubricant oil dilution with the post fuel injection by engine tests and simulations, and adhering fuel is a cause of worsening fuel consumption.
2016-10-17
Technical Paper
2016-01-2200
Tobias Knorsch, Philipp Rogler, Maximilian Miller, Wolfram Wiese
Abstract To satisfy future emission classes, e.g. EU6c, the particulate number (PN) of Direct-Injection Spark-Ignition (DISI) engines must be reduced. For these engines, different components influence the combustion process and thus also the formation of soot particles and deposits. Along with other engine components, the injector nozzle influences the particulate number and deposits in both fuel spray behavior and nozzle “tip wetting”. In case of non-optimized nozzle layouts, fuel may impinge on the piston and the liner in an unfavorable way, which implies low-oxygen diffusive combustion by retarded vaporizing wall films. For the tip wetting, wall films are present on the actual surface of the nozzle tip, which is also caused by unadapted nozzles. For non-optimized nozzles, the latter effect can become quite dominant. This paper deals with systematic nozzle development activities towards low-deposit nozzle tips and thus decreasing PN values.
2016-09-27
Technical Paper
2016-01-8077
Guanyu Zheng
Selective Catalytic Reduction (SCR) has become a mainstream approach to reduce diesel engine NOx emissions. Urea Water Solution (UWS) injection and interactions with mixers and exhaust gases affect the homogeneity of ammonia distribution at catalyst inlet and solid deposits formation on walls / mixer surfaces, therefore influencing SCR performance and durability. Computational Fluid Dynamics (CFD) is used to simulate an EU V compliant SCR system with a dual baffle mixer for heavy duty diesel engines. The modeling procedure is carried out by a multi-dimensional CFD code CONVERGE that includes transient urea transport processes in an exhaust flow configuration, detailed spray break-up, evaporation, wall-film, turbulence, and Conjugate Heat Transfer (CHT) models as well as an automated mesh generation approach. Locations of urea deposits and system pressure drop are predicted and validated against measurements, providing uniformity index (UI) predictions at the catalyst inlet.
2016-09-27
Technical Paper
2016-01-8073
Rohit Saha, Mahesh Madurai Kumar, Long-Kung Hwang, Xingshi Wang, Fengchao Zhang, Xiaodan Zhang, Liu Yagui, Weiqing Sun, Yan Wang, Wei Cheng, Mingjin Lin
Abstract Various 1D simulation tools (KULI & LMS Amesim) and 3D simulation tools (ANSYS FLUENT®) can be used to size and evaluate truck cooling system design. In this paper, ANSYS FLUENT is used to analyze and validate the design of medium duty truck cooling systems. LMS Amesim is used to verify the quality of heat exchanger input data. This paper discusses design and simulation of parent and derivative trucks. As a first step, the parent truck was modeled in FLUENT (using standard' k - ε model) with detailed fan and underhood geometry. The fan is modeled using Multiple Reference Frame (MRF) method. Detailed geometry of heat exchangers is skipped. The heat exchangers are represented by regular shape cell zones with porous medium and dual cell heat exchanger models to account for their contributions to the entire system in both flow and temperature distribution.
2016-09-27
Technical Paper
2016-01-8139
Santosh Nalanagula, G T Varadharajan
Abstract Aerodynamic drag contributes to 50-60% of fuel consumption in trucks on highways. The limits of conventional wind tunnel testing have forced researchers to study about the drag and ways of reducing it computationally. Due to the stricter norms and eco-friendly approaches, truck manufacturers have begun to invest more for developing truck aerodynamics. This paper evaluates a European vehicle on European conditions. Drag reduction are mostly made by geometric changes. Pressure drag, a major drag for trucks as they run at lower speeds is produced by the shape of the object. Making streamlined bodies as trucks are tougher since it can affect its purpose. Therefore, addition of some components can suffice the needs. The changes in geometry have been implied and analysis for these geometrical changes are done to analyze the better geometry which can provide drag reduction features. The geometrical changes considered are providing side skirts, boattails and roof deflector angle.
2016-09-27
Technical Paper
2016-01-8154
Abhijith Balakrishna, Gang Wang
Abstract The dynamic loading on the skin of a refrigeration unit mounted in the gap between tractor and trailer is studied while another trailer passes by on a freeway using transient computational fluid dynamics. Dynamic Meshing methodology available in Ansys Fluent was used to understand the transient pressure and flow regimes in and around the tractor trailer gap in general and refrigeration unit in particular, at various vehicle speeds. The influences of the lateral distance between the crossing trailers and vehicle speed on the pressure distribution on the refrigeration unit have been studied.
2016-09-27
Technical Paper
2016-01-8155
Devaraj Dasarathan, Jonathan Jilesen, David Croteau, Ray Ayala
Abstract Side window clarity and its effect on side mirror visibility plays a major role in driver comfort. Driving in inclement weather conditions such as rain can be stressful, and having optimal visibility under these conditions is ideal. However, extreme conditions can overwhelm exterior water management devices, resulting in rivulets of water flowing over the a-pillar and onto the vehicle’s side glass. Once on the side glass, these rivulets and the pooling of water they feed, can significantly impair the driver’s ability to see the side mirror and to see outwardly when in situations such as changing lanes. Designing exterior water management features of a vehicle is a challenging exercise, as traditionally, physical testing methods first require a full-scale vehicle for evaluations to be possible. Additionally, common water management devices such as grooves and channels often have undesirable aesthetic, drag, and wind noise implications.
2016-09-27
Technical Paper
2016-01-8070
Prasad Vegendla, Tanju Sofu, Rohit Saha, Mahesh Madurai Kumar, Long-Kung Hwang, Steven Dowding
Abstract Fan and fan-shroud design is critical for underhood air flow management. The objective of this work is to demonstrate a method to optimize fan-shroud shape in order to maximize cooling air mass flow rates through the heat exchangers using the Adjoint Solver in STAR-CCM+®. Such techniques using Computational Fluid Dynamics (CFD) analysis enables the automotive/transport industry to reduce the number of costly experiments that they perform. This work presents the use of CFD as a simulation tool to investigate and assess the various factors that can affect the vehicle thermal performance. In heavy-duty trucks, the cooling package includes heat exchangers, fan-shroud, and fan. In this work, the STAR-CCM+® solver was selected and a java macro built to run the primal flow and the Adjoint solutions sequentially in an automated fashion.
2016-09-27
Technical Paper
2016-01-8140
Devaraj Dasarathan, Ashraf Farag, Matthew Ellis
Abstract Recent regulations on greenhouse gas (GHG) emission standards for heavy-duty vehicles have prompted government agencies to standardize procedures assessing the aerodynamic performance of Class 8 tractor-trailers. The coastdown test procedure is the primary reference method employed to assess vehicle drag currently, while other valid alternatives include constant speed testing, computational fluid dynamics (CFD) simulations, and wind tunnel testing. The main purpose of this paper is to compare CFD simulations with a corresponding 1/8th scale wind tunnel test. Additionally, this paper will highlight the impacts of wind tunnel testing on the total drag coefficient performance as compared to full scale open road analysis with and without real world, upstream turbulence wind conditions. All scale model testing and CFD simulations were performed on a class 8 tractor with a standard 53-foot dry-box trailer.
2016-09-27
Technical Paper
2016-01-8141
Brian R. McAuliffe
Abstract With increasing use of boat-tails on Canadian roads, a concern had been raised regarding the possibility for ice and snow to accumulate and shed from the cavity of a boat-tail affixed to a dry-van trailer, posing a hazard for other road users. This paper describes a preliminary evaluation of the potential for ice and snow accumulation in the cavity of a boat-tail-equipped heavy-duty vehicle. A transient CFD approach was used and combined with a quasi-static particle-tracking simulation to evaluate, firstly, the tendency of various representative ice or snow particles to be entrained in the vehicle wake, and secondly, the potential of such particles to accumulate on the aft end of a dry-van trailer with and without various boat-tail configurations. Results of the particle tracking analyses showed that the greatest numbers of particles impinge on the base of the trailer for the no-boat-tail case, concentrated on the upper surface of the back face of the trailer.
2016-09-27
Technical Paper
2016-01-8008
Hugh Humphreys, David Bevly
Abstract A Computational Fluid Dynamics (CFD) study was completed to characterize the fuel consumption in terms of the separation distance of a Driver-Assistive-Truck-Platooning (DATP). The DATP system considered utilizes radar and GPS for a redundant range measurement, paired with Vehicle to Vehicle (V2V) communications to enable regulation of the longitudinal distance between the pair of trucks without acceleration input from the rear driver. The linkage of information between the trucks promotes increased safety between the following trucks, while improving their fuel economy. The results from this study are compared to previous works. Preliminary analysis of the system indicated that the fuel economy of both trucks increases dramatically as the separation distance diminishes. Additionally, an SAE Type-II fuel economy test complying with the (1986) SAE J1321 standard was completed to correlate the computational studies.
Viewing 1 to 30 of 2142

Filter