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Viewing 151 to 180 of 9785
Technical Paper
2014-04-01
Jiri Hvezda
Abstract The paper introduces a recently developed toolset to be implemented into the complex simulation codes for internal combustion engines to treat the calculations dealing with a high-pressure part of the thermodynamic cycle in a four-stroke spark ignition engine. This multi-zone simulating tool works on the basis of a simple quasi-dimensional method reflecting the real combustion chamber geometry and uses a specific approach to describe the species chemical transformation during combustion. Here a standard kinetic scheme is combined adaptively with a flexible method for chemical equilibrium in the cases of abnormally fast chemical reactions to improve the numerical performance of the equation system. Real 3-D combustion chamber geometry is taken into account by means of geometrical characteristics created in advance. A newly generalized tool providing these data is presented here. The new code is also able to work in predictive or inverse mode. The selected results regarding these two algorithms are mentioned at the end.
Technical Paper
2014-04-01
Sebastian Salbrechter, Markus Krenn, Gerhard Pirker, Andreas Wimmer, Michael Nöst
Abstract Optimization of engine warm-up behavior has traditionally made use of experimental investigations. However, thermal engine models are a more cost-effective alternative and allow evaluation of the fuel saving potential of thermal management measures in different driving cycles. To simulate the thermal behavior of engines in general and engine warm-up in particular, knowledge of heat distribution throughout all engine components is essential. To this end, gas-side heat transfer inside the combustion chamber and in the exhaust port must be modeled as accurately as possible. Up to now, map-based models have been used to simulate heat transfer and fuel consumption; these two values are calculated as a function of engine speed and load. To extend the scope of these models, it is increasingly desirable to calculate gas-side heat transfer and fuel consumption as a function of engine operating parameters in order to evaluate different ECU databases. This paper describes the creation of a parameter-based heat transfer model using a statistical approach.
Technical Paper
2014-04-01
Jugurtha Benouali, Christophe Petitjean, Isabelle Citti, Regis Beauvis, Laurent Delaforge
Abstract The development of Electrical and Hybrid cars led to the introduction of reversible heat pump systems in order to reduce the energy consumption and increase the car autonomy during the Zero Emission Mode. One of the most important components in the heat pump system, is the evaporator condenser that “pumps the heat” from the ambient air. Moreover, this heat exchanger has to work in both modes: A/C (condenser mode) and heat pump (evaporator mode). This paper will explain the main steps of the development of this heat exchanger: circuiting (refrigerant side) in order to improve the homogeneity and the performances fins (air side) in order to reduce icing impact. We will also present system tests results that illustrate the impact of those evolutions on loop performances (heating capacity and COP).
Technical Paper
2014-04-01
Namwook Kim, Aymeric Rousseau, Daeheung Lee, Henning Lohse-Busch
Abstract This paper introduces control strategy analysis and performance degradation for the 2010 Toyota Prius under different thermal conditions. The goal was to understand, in as much detail as possible, the impact of thermal conditions on component and vehicle performances by analyzing a number of test data obtained under different thermal conditions in the Advanced Powertrain Research Facility (APRF) at Argonne National Laboratory. A previous study analyzed the control behavior and performance under a normal ambient temperature; thus the first step in this study was to focus on the impact when the ambient temperature is cold or hot. Based on the analyzed results, thermal component models were developed in which the vehicle controller in the simulation was designed to mimic the control behavior when temperatures of the components are cold or hot. Further, the performance degradation of the components was applied to the mathematical models based on analysis of the test data. All the thermal component models were integrated into a vehicle system with the redesigned supervisory controller, and the vehicle model was validated with the test data.
Technical Paper
2014-04-01
Abhijit Nitin Khare, Henning Lohse-Busch, Douglas Nelson
Abstract Ambient temperature plays an important role in the operational behavior of a vehicle. Temperature variances from 20 F to 72 F to 95 F produce different operation from different HEVs, as prescribed by their respective energy management strategies. The extra variable of Climate Control causes these behaviors to change again. There have been studies conducted on the differences in operational behavior of conventional vehicles as against HEVs, with and without climate control. Lohse-Bush et al conclude that operational behavior of conventional vehicles is much more robust as compared to HEVs and that the effect of ambient temperature is felt more prominently in HEVs (1). However, HEVs cover a broad range of powertrain architectures, climate control systems, vehicle weights etc.The objective of this paper is to examine three different HEVs under three different temperature conditions, both with or without climate control, and come up with observations and trends on their energy usage and operational behavior.
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
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
Nicolas F. Ponchaut, Francesco Colella, Ryan Spray, Quinn Horn
Abstract The emergence of Plug-in hybrid electric vehicles (PHEVs) and electric vehicles (EVs) as a viable means of transportation has been coincident with the development of lithium-ion battery technology and electronics that have enabled the storage and use of large amounts of energy that were previously only possible with internal combustion engines. However, the safety aspects of using these large energy storage battery packs are a significant challenge to address. For example an unintentional sudden release of energy, such as through a thermal runaway event, is a common concern. Developing thermal management systems for upset conditions in battery packs requires a clear understanding of the heat generation mechanisms and kinetics associated with the failures of Li-ion batteries. Although every effort is made to avoid thermal runaway situations, there can still be upset and unforeseen instances where a cell or a pack would reach a sufficiently high temperature to initiate exothermic reaction(s) that often are initially slow to develop.
Technical Paper
2014-04-01
Ludwig Brabetz, Mohamed Ayeb
For the prevention of technical risks and the optimum design of an electrical distribution system, considerable efforts have been made to implement thermal models of wires, bundles, and electromechanical components in order to improve thermal analysis. Unfortunately, in most cases, important input parameters such as the position of a wire within a bundle or the profiles of the currents are unknown. This leads to the use of worst-case scenarios, frequently providing unrealistic results and uneconomic over-dimensioning. The proposed approach is based on the thermal simulation of a large number of randomly-generated bundle configurations for given profiles of currents. Thus one gets a temperature distribution, allowing a much more precise analysis compared to a simple worst-case calculation. By applying the same method to various current profiles, one gets temperature distributions for each wire as a function of a normalized total bundle current. The finding is that statistics allow a very good thermal assessment despite unknown bundle configurations and current profiles.
Technical Paper
2014-04-01
Jason Lisseman, Lisa Diwischek, Stefanie Essers, David Andrews
The last years have seen an increasing amount of innovations in the functionality of car electronics (e.g. advanced driver assistant systems (ADAS) and in-vehicle infotainment systems (IVIS)). These electrical systems are not reserved for premium cars anymore, but additionally reach mid-size, compact, and subcompact cars. The growing number of functionalities in these cars entails increasing amount of interfaces, which may confuse, overload, or annoy the driver. Accompanying this, there is a trend towards the integration of capacitive touchscreens as user interfaces. These touchscreens were implemented first in consumer electronics and had a substantial impact on the way in which users interact with technology. This in turn has led to an increased user driven demand for the technology to be implemented in other domains, even in safety-critical ones like the automotive area. Capacitive touchscreens have certain drawbacks in their distraction potential and their usability, leading to safety-critical situations and negative user feedback.
Technical Paper
2014-04-01
Scott Peck, Aditya Velivelli, Wilko Jansen
Integration of advanced battery systems into the next generation of hybrid and electric vehicles will require significant design, analysis, and test efforts. One major design issue is the thermal management of the battery pack. Analysis tools are being developed that can assist in the development of battery pack thermal design and system integration. However, the breadth of thermal design issues that must be addressed requires that there are a variety of analysis tools to address them efficiently and effectively. A set of battery modeling tools has been implemented in the thermal modeling software code PowerTHERM. These tools are coupled thermal-electric models of battery behavior during current charge and discharge. In this paper we describe the three models in terms of the physics they capture, and their input data requirements. We discuss where the capabilities and limitations of each model best align with the different issues needed to be addressed by analysis. Model outputs are compared with measured data for various analysis scenarios, including simulation of constant current charge/discharge, and response to charge/discharge profiles derived from a standard drive cycle, for both single cell and multi-cell pack configurations.
Technical Paper
2014-04-01
Mirko Schulze, Rashad Mustafa, Benjamin Tilch, Peter Eilts, Ferit Küçükay
Hybrid electric vehicles (HEVs) are facing increased challenges of optimizing the energy flow through a vehicle system, to enhance both the fuel economy and emissions. Energy management of HEVs is a difficult task due to complexity of total system, considering the electrical, mechanical and thermal behavior. Innovative thermal management is one of the solutions for reaching these targets. In this paper, the potential of thermal management for a parallel HEV with a baseline control strategy under different driving cycles and ambient temperatures is presented. The focus of the investigations is on reducing fuel consumption and increasing comfort for passengers. In the first part of this paper, the developed HEV-model including the validation with measurements is presented. In the second part, the combined thermal management measures, for example the recuperation of exhaust-gas energy, engine compartment encapsulation and the effect on the target functions are discussed. Simulation results show potential of reduction fuel consumption together with increasing the comfort for the passenger cabin.
Technical Paper
2014-04-01
Lijun Zhang, Hongzheng Cheng, Kun Diao, Cheng Ruan
To accurately and efficiently predict the temperature fields inside a lithium-ion battery is key technology for the enhancement of battery thermal management and the improvement of battery performances. The dimensional analysis method is applied to derive similarity criterions and the similarity coefficients of battery interior temperature fields, based on the governing partial differential equations describing the three dimensional transient temperature field. To verify the correctness of similarity criterions and the similarity coefficients, 3D finite element models of battery temperature field are established with a prototype and scale model, on the assumption that the battery cell has single-layer structure and multi-layers structure separately. The simulation results show that the similarity criterions and the similarity coefficients are correct. The calculation efficiency is checked to be much more efficient compared with FEM model based on the original cell structure in aspect of amount of resources occupied.
Technical Paper
2014-04-01
Xueyu Zhang, Andrej Ivanco, Xinran Tao, John Wagner, Zoran Filipi
This paper investigates the impact of battery cooling ancillary losses on fuel economy, and optimal control strategy for a series hybrid electric truck with consideration of cooling losses. Battery thermal model and its refrigeration-based cooling system are integrated into vehicle model, and the parasitic power consumption from cooling auxiliaries is considered in power management problem. Two supervisory control strategies are compared. First, a rule-based control strategy is coupled with a thermal management strategy; it controls power system and cooling system separately. The second is optimal control strategy developed using Dynamic Programming; it optimizes power flow with consideration of both propulsion and cooling requirement. The result shows that battery cooling consumption could cause fuel economy loss as high as 5%. When dynamic programming coordinates control of the powertrain and the cooling system in an optimal way, the fuel consumption penalty due to cooling losses is reduced to 3.7%, and battery duty cycle becomes milder.
Technical Paper
2014-04-01
Vijay Somandepalli, Kevin Marr, Quinn Horn
As lithium-ion cells and systems become larger and more ubiquitous in automotive applications, fire and explosion hazards that are rare or non-existent in smaller systems may exist in these larger systems. One potential hazard can occur when flammable gases emitted from a lithium-ion cell failure accumulate in or around automobiles and are ignited by electrical activity or by the cells themselves and result in a fire or explosion. In some instances, the safety aspects related to fires and explosions protection of electric vehicles and hybrid vehicles using these large energy storage battery packs are a significant challenge to address. This paper describes and characterizes the combustion and explosion hazards that can occur when a lithium ion battery pack fails and goes into thermal runaway in an enclosed space. Metrics such as gas composition, maximum overpressure, rate of pressure rise, and flammability limits are described. This information can be helpful to battery and pack designers, vehicle designers, first responders and emergency personnel in developing strategies to mitigate and prevent explosion hazards from the use of battery packs in automobiles and other fields where large battery packs are used.
Technical Paper
2014-04-01
Alessandro Naddeo, Nicola Cappetti, Orlando Ippolito
Abstract General comfort may be defined as the “level of well-being” perceived by humans in a working environment. The state-of-the-art about evaluation of comfort/discomfort shows the need for an objective method to evaluate the “effect in the internal body” and “perceived effects” in main systems of comfort perception. In the early phases of automotive design, the seating and dashboard command can be virtually prototyped, and, using Digital Human Modeling (DHM) software, several kinds of interactions can me modeled to evaluate the ergonomics and comfort of designed solutions. Several studies demonstrated that DHM approaches are favorable in virtual reachability and usability tests as well as in macro-ergonomics evaluations, but they appear insufficient in terms of evaluating comfort. Comfort level is extremely difficult to detect and measure; in fact, it is affected by individual perceptions and always depends on the biomechanical, physiological, and psychological state of the tester during task execution.
Technical Paper
2014-04-01
Saiful Bari, Shekh Rubaiyat
Abstract The heat from the exhaust gas of diesel engines can be an important heat source to provide additional power using a separate Rankine Cycle (RC) or an Organic Rankine Cycle (ORC). Water is the best working fluid for this type of applications in terms of efficiency of the RC system, availability and environmental friendliness. However, for small engines and also at part load operations, the exhaust gas temperature is not sufficient enough to heat the steam to be in superheated zone, which after expansion in the turbine needs to be in superheated zone. Ammonia was found to be an alternate working fluid for these types of applications which can run at low exhaust temperatures. Computer simulation was carried out with an optimized heat exchanger to estimate additional power with water and ammonia as the working fluids. ANSYS 14.0 CFX software was used for the simulation. It was found that at full load 23.7% and 10.9% additional power were achieved by using water and ammonia as the working fluids respectively.
Technical Paper
2014-04-01
Charles Sprouse III, Christopher Depcik
Abstract Significant progress towards reducing diesel engine fuel consumption and emissions is possible through the simultaneous Waste Heat Recovery (WHR) and Particulate Matter (PM) filtration in a novel device described here as a Diesel Particulate Filter Heat Exchanger (DPFHX). This original device concept is based on the shell-and-tube heat exchanger geometry, where enlarged tubes contain DPF cores, allowing waste heat recovery from engine exhaust and allowing further energy capture from the exothermic PM regeneration event. The heat transferred to the working fluid on the shell side of the DPFHX becomes available for use in a secondary power cycle, which is an increasingly attractive method of boosting powertrain efficiency due to fuel savings of around 10 to 15%. Moreover, these fuel savings are proportional to the associated emissions reduction after a short warm-up period, with startup emissions relatively unchanged when implementing a WHR system. Due to the absence of prior DPFHX research and the unique heat transfer process present, this effort describes construction of a prototype DPFHX and subsequent WHR experiments in a single cylinder diesel engine test cell with a comparison between heat exchanger performance with and without DPF cores installed.
Technical Paper
2014-04-01
Dimitrios Angelos Mitakos, Christopher Blomberg, Yuri M. Wright, Peter Obrecht, Bruno Schneider, Konstantinos Boulouchos
Abstract The heat release of the low temperature reactions (LTR or cool-flame) under Homogeneous Charge Compression Ignition (HCCI) combustion has been quantified for five candidate fuels in an optically accessible Rapid Compression Expansion Machine (RCEM). Two technical fuels (Naphthas) and three primary reference fuels (PRF), (n-heptane, PRF25 and PRF50) were examined. The Cetane Numbers (CN) of the fuels range from 35 to 56. Variation of the operating parameters has been performed, in regard to initial charge temperature of 383, 408, and 433K, exhaust gas recirculation (EGR) rate of 0%, 25%, and 50%, and equivalence ratio of 0.29, 0.38, 0.4, 0.53, 0.57, and 0.8. Pressure indication measurements, OH-chemiluminescence imaging, and passive spectroscopy were simultaneously implemented. In our previous work, an empirical, three-stage, Arrhenius-type ignition delay model, parameterized on shock tube data, was found to be applicable also in a transient, engine-relevant environment. The pressure rise due to cool-flame heat release, which is crucial for the induction of main ignition, was included in the experimental pressure traces that have been used.
Technical Paper
2014-04-01
Tetsu Yamada, Shouji Adachi, Koichi Nakata, Takashi Kurauchi, Isao Takagi
From the time the first Hybrid Vehicle (HV) was launched, 17 years have past, and HV vehicles have boosted the global CO2 reduction trend. In order to maximize their merit, many HV engines focused on the best fuel consumption value namely thermal efficiency. This was because HV systems can control the operating area of engine and get merit. However, considering climate change and energy issues, it is important to focus conventional vehicle as well as HV vehicle progress. The Atkinson cycle with a high compression ratio is the typical approach that HV engines use to enhance thermal efficiency. However, the drawback of the high compression ratio is a reduction of engine torque. Thermal efficiency at low load areas is relatively more important with conventional engines than with HV engines and how to overcome these issues is significantly important with conventional engines. The engines which have technologies contributing to lower the vehicle fuel economy are described as ESTEC (Economy with Superior Thermal Efficient Combustion) engines.
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
Francisco Payri, Pablo Olmeda, Jaime Martin, Ricardo Carreño
The generalization of exhaust aftertreatment systems along with the growing awareness about climate change is leading to an increasing importance of the efficiency over other criteria during the design of reciprocating engines. Using experimental and theoretical tools to perform detailed global energy balance (GEB) of the engine is a key issue for assessing the potential of different strategies to reduce consumption. With the objective of improving the analysis of GEB, this paper describes a tool that allows calculating the detailed internal repartition of the fuel energy in DI Diesel engines. Starting from the instantaneous in-cylinder pressure, the tool is able to describe the different energy paths thanks to specific submodels for all the relevant subsystems. Hence, the heat transfer from gases to engine walls is obtained with convective and radiative models in the chamber and ports; the repartition of the heat flux throughout the engine metal elements towards the oil and coolant is estimated with a lumped capacitance model; finally, the auxiliary systems and friction losses are obtained through specific semiempirical submodels.
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.
Technical Paper
2014-04-01
Akira Kikusato, Kusaka Jin, Yasuhiro Daisho
The first objective of this work is to develop a numerical simulation model of the spark ignited (SI) engine combustion, taking into account knock avoidance and heat transfer between in-cylinder gas and combustion chamber wall. Secondly, the model was utilized to investigate the potential of reducing heat losses by applying a heat insulation coating to the combustion chamber wall, thereby improving engine thermal efficiency. A reduction in heat losses is related to important operating factors of improving SI engine thermal efficiency. However, reducing heat losses tends to accompany increased combustion chamber wall temperatures, resulting in the onset of knock in SI engines. Thus, the numerical model was intended to make it possible to investigate the interaction of the heat losses and knock occurrence. The present paper consists of Part 1 and 2. Part 1 deals with the description of the numerical model and the fundamental characteristics of instantaneous temperature swings in the combustion chamber wall.
Technical Paper
2014-04-01
Simon Huber, Thomas Indinger, Nikolaus Adams, Thomas Schuetz
The optimization of the flow field around new vehicle concepts is driven by aerodynamic and thermal demands. Even though aerodynamics and thermodynamics interact, the corresponding design processes are still decoupled. Objective of this study is to include a thermal model into the aerodynamic design process. Thus, thermal concepts can be evaluated at a considerably earlier design stage of new vehicles, resulting in earlier market entry. In a first step, an incompressible CFD code is extended with a passive scalar transport equation for temperature. The next step also accounts for buoyancy effects. The simulated development of the thermal boundary layer is validated on a hot flat plate without pressure gradient. Subsequently, the solvers are validated for a heated block with ground clearance: The flow pattern in the wake and integral heat transfer coefficients are compared to wind tunnel simulations. The main section of this report covers the validation on a full-scale production car. A specially developed heated electronic component dummy mounted to the underbody of the car introduces heat into the flow field.
Technical Paper
2014-04-01
Saeed Asgari, Xiao Hu, Michael Tsuk, Shailendra Kaushik
The thermal behavior of a fluid-cooled battery can be modeled using computational fluid dynamics (CFD). Depending on the size and complexity of the battery module and the available computing hardware, the simulation can take days or weeks to run. This work introduces a reduced-order model that combines proper orthogonal decomposition, capturing the variation of the temperature field in the spatial domain, and linear time-invariant system techniques exploiting the linear relationship between the resulting proper orthogonal decomposition coefficients and the uniform heat source considered here as the input to the system. After completing an initial CFD run to establish the reduction, the reduced-order model runs much faster than the CFD model. This work will focus on thermal modeling of a single prismatic battery cell with one adjacent cooling channel. The extension to the multiple input multiple output case such as a battery module will be discussed in another paper.
Technical Paper
2014-04-01
Peter Eilts, Claude-Pascal Stoeber-Schmidt
A model for the calculation of heat release in direct injection Diesel engines is presented. It needs only one engine-specific experimental parameter. In the form the model is presented here it is limited to the medium and upper load range, where Diesel combustion is mainly mixing controlled. The development of the model is based on data from medium speed engines. The applicability to automotive engines is shown in some examples. The model is based on the theory of single phase turbulent jets. Starting from the balance of momentum and fuel mass flow the stationary part of the jet can be calculated. The propagation of the front of the unsteady jet is determined from a continuity consideration. Heat release is calculated based on the assumptions of the Simple Chemically Reacting System (SCRS). Fuel that is mixed with air is assumed to be burnt instantaneously. Adjustment of the model to a good correspondence of measured and calculated heat release results in an experimental parameter which is in the same range as the figures published for turbulent jet flames.
Technical Paper
2014-04-01
Johann C. Wurzenberger, Tomaz Katrasnik
This works presents a real-time capable simulation model for dual fuel operated engines. The computational performance is reached by an optimized filling and emptying modeling approach applying tailored models for in-cylinder combustion and species transport in the gas path. The highly complex phenomena taking place during Diesel and gasoline type combustion are covered by explicit approaches supported by testbed data. The impact of the thermodynamic characteristics induced by the different fuels is described by an appropriate set of transport equations in combination with specifically prepared property databases. A thermodynamic highly accurate 6-species approach is presented. Additionally, a 3-species and a 1-species transport approach relying on the assumption of a lumped fuel are investigated regarding accuracy and computational performance. The comparison of measured and simulated pressure and temperature traces shows very good agreement. The real-time factor of a 6 cylinder medium speed engine is in the range of 0.2 for all species transport approaches, enabling the support of HiL based function development and calibration.
Technical Paper
2014-04-01
Arnon Poran, Moris Artoul, Moshe Sheintuch, Leonid Tartakovsky
This paper describes a model for the simulation of the joint operation of internal combustion engine (ICE) with methanol reformer when the ICE is fed by the methanol steam reforming (SRM) products and the energy of the exhaust gases is utilized to sustain endothermic SRM reactions. This approach enables ICE feeding by a gaseous fuel with very favorable properties, thus leading to increase in the overall energy efficiency of the vehicle and emissions reduction. Previous modeling attempts were focused either on the performance of ICE fueled with SRM products or on the reforming process simulation and reactor design. It is clear that the engine performance is affected by the composition of the reforming products and the reforming products are affected by the exhaust gas temperature, composition and flow rate. Due to the tight interrelations between the two main parts of the considered ICE-reformer system, it is desirable to create a single model that simulates joint operation of the ICE and the SRM reactor.
Technical Paper
2014-04-01
Owais Iqbal, Kunal Arora, Manyam Sanka
Accurate numerical prediction of an engine thermal map at a wide range of engine operating conditions can help tune engine performance parameters at an early development stage. This study documents the correlation of an engine thermal simulation using the conjugate heat transfer (CHT) methodology with thermocouple data from an engine operating in a dynamometer and a vehicle drive cell. Three different operating conditions are matched with the simulation data. Temperatures predicted by simulation at specific sections, both at the intake and the exhaust sides of the engine are compared with the measured temperatures in the same location on the operating engine.
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