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Viewing 1 to 30 of 33461
2010-10-25
Technical Paper
2010-01-2181
Forrest Jehlik, Eric Rask
Response Surface Methodology (RSM) techniques are applied to develop brake specific fuel consumption (BSFC) maps of a test vehicle over standard drive cycles under various ambient conditions. This technique allows for modeling and predicting fuel consumption of an engine as a function of engine operating conditions. Results will be shown from Federal Test Procedure engine starts of 20°C, and colder conditions of -7°C. Fueling rates under a broad range of engine temperatures are presented. Analysis comparing oil and engine coolant as an input factor of the model is conducted. Analysis comparing the model to experimental datasets, as well as some details into the modeling development, will be presented. Although the methodology was applied to data collected from a vehicle, the same technique could be applied to engines run on dynamometers.
2010-10-25
Technical Paper
2010-01-2185
Alessandro di Gaeta, Veniero Giglio, Giuseppe Police, Fabrizio Reale, Natale Rispoli
In this work the authors present a model to simulate the in-cylinder pressure oscillations due to knock. Pressure oscillations are predicted by the explicit integration of a Partial Differential Wave Equation (PDWE) similar, in its structure, to the so-called “Equation of Telegraphy”. This equation differs mainly from the classical wave formulation for the presence of a loss term. The general solution of such equation is obtained by the Fourier method of variables separation. The integration space is a cylindrical acoustic cavity whose volume is evaluated at the knock onset. The integration constants are derived from the boundary and initial conditions. A novel approach is proposed to derive the initial condition for the derivative of the oscillating component of pressure. It descends, conceptually, from the integration of the linearized relation between the derivative of pressure versus time and the expansion velocity of burned gas.
2010-10-25
Technical Paper
2010-01-2184
Alberto Boretti
Recovery of kinetic energy during driving cycles is the most effective option to improve fuel economy and reduce green house gas (GHG) emissions. Flywheel kinetic energy recovery systems (KERS) may boost this efficiency up to values of about 70%. An engine and vehicle model is developed to simulate the fuel economy of a compact car equipped with a TDI diesel engine and a KERS. Introduction of KERS reduces the fuel used by the 1.6L TDI engine to 3.16 liters per 100 km, corresponding to 82.4 g of CO₂ per km. Downsizing the engine to 1.2 liters as permitted by the torque assistance by KERS, further reduces the fuel consumption to 3.04 liters per 100 km, corresponding to 79.2 g of CO₂ per km. These CO₂ values are 11% better than those of today's most fuel efficient hybrid electric vehicle.
2010-10-25
Technical Paper
2010-01-2182
Markus Wenig, Michael Grill, Michael Bargende
Regarding further development of gasoline engines several new technologies are investigated in order to diminish pollutant emissions and particularly fuel consumption. The Homogeneous Charge Compression Ignition (HCCI) seems to be a promising way to reach these targets. Therefore, in the past years there had been a lot of experimental efforts in this field of combustion system engineering. Negative valve overlap with pilot injection before pumping top dead center (PTDC) and an “intermediate” compression and combustion during PTDC, followed by the main injection after PTDC, is one way to realize and to proper control a HCCI operation. For conventional CI and SI combustion the pressure trace analysis (PTA) is a powerful and widely used tool to analyse, understand and optimize the combustion process.
2010-10-25
Technical Paper
2010-01-2183
Rafael Lugo, Vahid Ebrahimian, Catherine Lefebvre, Chawki Habchi, Jean-Charles de Hemptinne
The adequacy of the fuels with the engines has been often a major goal for the oil industry or car manufacturers. As the formulation of fuels becomes more complex, the use of numerical simulation provides an efficient way to understand and analyze the combustion process. These conclusions become increasingly true with the appearance of second generation biofuels. This paper describes a methodology for the representation of fuels and biofuels using a lumping procedure combined with adequate thermodynamic and thermophysical models. This procedure allows computing different thermodynamic and thermophysical properties for simulation purposes in internal combustion engines. The lumping approach involves reducing analytical data to a few pseudo-components characterized by their molecular weight, critical properties and acentric factor.
2010-10-25
Technical Paper
2010-01-2186
M. Cagri Cevik, Hendrik Hermann, Carl Ritterskamp
Calculating the bearing reliability and behavior is one of the primary tasks which have to be performed to define the main dimensions of the cranktrain of an internal combustion engine. Since the bearing results are essential for the pre-layout of the cranktrain, the conclusion on the bearing safety should be met as early as possible. Therefore detailed simulations like T-EHD or EHD analysis may not be applied to define the dimensions in such an early development phase. In the frame of this study a prediction methodology, based on a HD bearing approach, for bearing reliability of inline-4 crankshafts of passenger cars is proposed. In this way not only the design phase is shortened but also achieving the optimal solution is simplified. Moreover the requirement of a CAD model is eliminated for the preliminary design phase. The influencing parameters on the bearing behavior are first selected and divided into two groups: geometry and loading.
2010-10-25
Technical Paper
2010-01-2199
Leslie Bromberg, Daniel Cohn
Non-petroleum based liquid fuels are essential for reducing oil dependence and greenhouse gas generation. Increased substitution of alcohol fuel for petroleum based fuels could be achieved by 1) use in high efficiency spark ignition engines that are employed for heavy duty as well as light duty operation and 2) use of methanol as well as ethanol. Methanol is the liquid fuel that is most efficiently produced from thermo-chemical gasification of coal, natural gas, waste or biomass. Ethanol can also be produced by this process but at lower efficiency and higher cost. Coal derived methanol is in limited initial use as a transportation fuel in China. Methanol could potentially be produced from natural gas at an economically competitive fuel costs, and with essentially the same greenhouse gas impact as gasoline. Waste derived methanol could also be an affordable low carbon fuel.
2010-10-25
Technical Paper
2010-01-2218
Alberto Boretti
Improvements of vehicle fuel economy are being considered using a mechanically driven flywheel to reduce the amount of mechanical energy produced by the thermal engine recovering the vehicle kinetic energy during braking. A mechanical system having an overall efficiency over a full regenerative cycle of about 70%, about twice the efficiency of battery-based hybrids, is coupled to a naturally aspirated gasoline engine powering a full size sedan. Results of chassis dynamometer experiments and engine and vehicle simulations are used to evaluate the fuel benefits introducing a kinetic energy recovery system and downsizing of the engine. Preliminary results running the new European driving cycle (NEDC) show KERS may reduce fuel consumption by 25% without downsizing, and 33% with downsizing of the 4 litre engine to 3.3 litres.
2010-10-25
Technical Paper
2010-01-2225
Alberto Boretti
Downsizing and Turbo Charging (TC) and Direct Injection (DI) may be combined with Variable Valve Actuation (VVA) to better deal with the challenges of fuel economy enhancement. VVA may control the load without throttle; control the valve directly and quickly; optimize combustion, produce large volumetric efficiency. Benefits lower fuel consumption, lower emissions and better performance and fun to drive. The paper presents an engine model of a 1.6 litre TDI VVA engine specifically designed to run pure ethanol, with computed engine maps for brake specific fuel consumption and efficiency. The paper also presents driving cycle results obtained with a vehicle model for a passenger car powered by this engine and a traditional naturally aspirated gasoline engine. Preliminary results of the VVA system coupled with downsizing, turbo charging and Direct Injection permits significant driving cycle fuel economies.
2010-10-25
Technical Paper
2010-01-2228
Alberto Boretti
Recovery of braking energy during driving cycles is the most effective option to improve fuel economy and reduce green house gas (GHG) emissions. Hybrid electric vehicles suffer the disadvantages of the four efficiency-reducing transformations in each regenerative braking cycle. Flywheel kinetic energy recovery systems (KERS) may boost this efficiency up to almost double values of about 70% avoiding all four of the efficiency-reducing transformations from one form of energy to another and keeping the vehicle's energy in the same form as when the vehicle starts braking when the vehicle is back up to speed. With reference to the baseline configuration with a 1.6 liters engine and no recovery of kinetic energy, introduction of KERS reduces the fuel usage to 3.16 liters per 100 km, corresponding to 82.4 g of CO₂ per km. The 1.6 liters Turbo Direct Injection (TDI) diesel engine without KERS uses 1.37 MJ per km of fuel energy, reducing with KERS to 1.13 MJ per km.
2010-09-28
Journal Article
2010-32-0029
Hiroshi Kuribara, Junya Saito, Hideki Saito, Daisuke Sekiya, Hidenori Arisawa
In motorcycle engines with aluminum crankcases, fatigue fractures at the roots of the internal threads of the fastening bolts used for the cylinder head and crankshaft main bearing often occurs during the durability tests at the prototype stage. A technology that evaluates the fatigue strength of the entire crankcase including the roots of internal threads using a large-scale and nonlinear finite element method (FEM) analysis is established by this research. Parallel process computation by a cluster server enables the evaluation of the fatigue strength of the crankcase in a short time suitable for the development process even when using a model that faithfully reproduces the shape, the contact property, and the elasto-plastic material characteristic of the threads. This technology enables the efficient design of crankcases that are light and durable.
2010-09-28
Technical Paper
2010-32-0021
Shital Shah, Saisankaranarayana Kuppili, Kalyankumar Hatti, Dhananjay Thombare
Exhaust noise from engines is one of component noise pollution to the environment. Exhaust systems are developed to attenuate noise meeting required db (a) levels and sound quality, emissions based on environment norms. Hence this has become an important area of research and development. Most of the advances in theory of acoustic filters and exhaust mufflers have been developed in last two decades. Mufflers are important part of engine system and commonly used in exhaust system to minimize sound transmissions caused by exhaust gases. Design of mufflers is a complex function that affects noise characteristics, emission and fuel efficiency of engine. Therefore muffler design becomes more and more important for noise reduction. Traditionally, muffler design has been an iterative process by trial and error. However, the theories and science that has undergone development in recent years has given a way for an engineer to cut short number of iteration.
2010-09-28
Technical Paper
2010-32-0036
Christoph Dutzler, Gregor Heizinger, Andreas Mair
The continuously increasing product complexity on the one side, and the demand to constantly decrease development times and costs on the other, require new development processes in the automotive industry. This paper describes a product development process which, by intensively and systematically applying computer-aided modeling techniques, makes a significant contribution to the management of this tremendous complexity in a cost- and time- efficient manner. The presented process strives for a widespread usage of modeling techniques (such as physical system modeling and simulation, model-based control system design, rapid prototyping, etc.) over all technical domains involved in the product (mechanics, hydraulics, electrics, electronics, software, etc.) as well as over several stages of the product development process.
2010-09-28
Technical Paper
2010-32-0037
Reza Rezaei, Stefan Pischinger, Jens Ewald, Philipp Adomeit
The fulfillment of the aggravated demands on future small-size High-Speed Direct Injection (HSDI) Diesel engines requires next to the optimization of the injection system and the combustion chamber also the generation of an optimal in-cylinder swirl charge motion. To evaluate different port concepts for modern HSDI Diesel engines, usually quantities as the in-cylinder swirl ratio and the flow coefficient are determined, which are measured on a steady-state flow test bench. It has been shown that different valve lift strategies nominally lead to similar swirl levels. However, significant differences in combustion behavior and engine-out emissions give rise to the assumption that local differences in the in-cylinder flow structure caused by different valve lift strategies have noticeable impact. In this study an additional criterion, the homogeneity of the swirl flow, is introduced and a new approach for a quantitative assessment of swirl flow pattern is presented.
2010-09-28
Technical Paper
2010-32-0034
Michael Steinbatz
The formation of a hydrodynamic lubrication is the essential condition for any friction bearings in combustion engines for optimum performance. The shaft and the bearing are separated by a thin sustainable lubrication film, which prevents a direct metal to metal contact. The resulting fluid friction allows for a low frictional loss and the prevention of wear under normal operating conditions. The hydrodynamic load capacity of the bearings is a result of an oil flow, caused by the rotating shaft and/or bearing within the viscous medium. Depending on the gap geometry (shaft eccentricity) a hydrodynamic pressure is built up in the lubrication film. This pressure separates the surfaces that define the lubrication film and thus equilibrates the external bearing load. However, the local pressure inside the lubrication film will cause local deformations of the shaft and bearing, which again will affect the pressure build-up due to a change of the gap geometry.
2010-09-28
Technical Paper
2010-32-0035
Dalibor Jajcevic, Matthias Fitl, Stephan Schmidt, Karl Glinsner, Raimund Almbauer
The exhaust system design has an important influence on the charge mass and the composition of the charge inside the cylinder, due to its gas dynamic behavior. Therefore the exhaust system determines the characteristics of the indicated mean effective pressure as well. The knowledge of the heat transfer and the post-combustion process of fuel losses inside the exhaust system are important for the thermodynamic analysis of the working process. However, the simulation of the heat transfer over the exhaust pipe wall is time consuming, due to the demand for a transient simulation of many revolutions until a cyclic steady condition is reached. Therefore, the exhaust pipe wall temperature is set to constant in the conventional CFD simulation of 2-stroke engines. This paper covers the discussion of a simulation strategy for the exhaust system of a 2-cylinder 2-stroke engine until cyclic steady condition including the heat transfer over the exhaust pipe wall.
2010-09-28
Technical Paper
2010-32-0032
Claudio Annicchiarico, Renzo Capitani, Riccardo Testi
The paper is focused on the stress field acting on a continuously variable transmission (CVT) mechanism used on the high displacement scooters produced by Piaggio & C. S.p.A. The most important results of the analysis have been extrapolated with the aim of providing the designers with some guidelines useful to reduce the design error occurrence. In detail, in the paper is described the behavior of the belt and of the driven pulley, that are the critical parts of the assembly. The analysis has been conducted with a full MultiBody model of the mechanism combined with the Finite Element analysis of both the belt and the pulley. The output data so obtained have been used in a fatigue analysis in order to define the reliability of these parts. This paper could serve as a base to define a new proportioning method, that should be based on the whole stress history of each part of the assembly, computed with the aid of some numerical tools.
2010-09-28
Technical Paper
2010-32-0033
Om Singh, T. Sreenivasulu, M Kannan, K. Nagaraja
The air-cooled engine surfaces are generally provided with extended surfaces of high conducting materials called fins for enhanced heat transfer. One way to increase the rate of heat transfer is by increasing the fins surface area. However, increase in fin length introduces undesirable vibrations of the fins, which in turn radiate annoying high frequency noise. With the demand of quieter engines increasing, the vehicle manufacturers follow counter measures to minimize the fin vibrations. One trend in the two-wheeler industry is to put rubber dampers between the fins. These rubber dampers damps out the level of vibrations and the level of noise radiated is reduced. However, these rubber dampers have many disadvantages. Apart from the adding extra cost and a parallel manufacture process, these rubbers act as an insulating material, which impede the free flow of cooling air. The engine may get overheated and purpose of providing extended surface would not be satisfied.
2010-09-28
Technical Paper
2010-32-0030
Martin Abart, Stephan Schmidt, Oliver Schoegl, Alexander Trattner, Roland Kirchberger, Helmut Eichlseder, Dalibor Jajcevic
This publication covers investigations on different 3D CFD models for the description of the spray wall and droplet-fluid interaction and the influence of these models on the mixture formation calculation results. Basic experimental investigations in a spray chamber and a flow tunnel as well as the corresponding 3D CFD simulation were conducted in order to clarify the prediction quality of the physical phenomena of spray-wall and spray-fluid interaction by the simulation. Influencing parameters such as the piston top temperature, piston bowl geometry, soot deposits on the piston top as well as flow velocity are investigated. This paper provides a direct link between the underlying simulation models of the mixture formation and actual real world combustion system development processes - underlining the importance of a close interaction of the model calibration and the development process.
2010-09-28
Technical Paper
2010-32-0031
Kenji Nishio
In this paper, the development of a multiaxial fatigue failure criterion is shown, and as an application of the above criterion, a fatigue analysis of a crankcase is conducted. The octahedral shear stress amplitude and the peak value of the maximum principal stress are used in this criterion. The accuracy of the criterion is validated by tension-torsion biaxial fatigue tests. Furthermore, fatigue failure prediction of a crankcase is carried out using static analysis and the criterion. The combination of the static analysis and the criterion enable the prediction of fatigue failure.
2010-09-28
Journal Article
2010-32-0064
Yasuo Moriyoshi, Minoru Iida
In a motorcycle gasoline engine, the port fuel injection system is rapidly spread. Compared to an automotive engine, the injected fuel does not impinge on the intake valve due to space restriction to install the injector. In addition, as the air flow inside the intake pipe may become very fast and has large cycle-to-cycle variation, it is not well found how the injector should be installed in the intake pipe to prepare “good” fuel-air mixture inside the intake pipe. In this study, the formation process of the fuel-air mixture is measured by using ILIDS system that is a 2-D droplets' size and velocity measurement system with high spatial resolution. Experiments with changing conditions such as flow speed and injection direction are carried out.
2010-09-28
Technical Paper
2010-32-0068
Shaiju M. Belsus, Gopi Sankar, Amol Sharma
Reliability has been a complicated domain of vehicle engineering, basically due to the quantum of the authentic data required, and variability of parameters that make real contributions to the subject. Reliability of a vehicle in very generic terms, is not only its functional worthiness and consistency, but also its probability to perform satisfactorily within the intended design life for a particular production batch, application domain, operation duty and customer use. Commercial vehicle industry is driven by returns that a vehicle gives, on the investments made, which depend on parameters like minimum turnaround time, lesser breakdowns, optimized maintenance interval and cost of operation etc. Severe operating conditions, regular customer abuse and higher expectations from products (as expected by Indian customer-base) demand a need to deliver more robust and reliable products.
2010-09-28
Technical Paper
2010-32-0069
Gustavo Fontana, Fabio Bozza, Enzo Galloni, Daniela Siano
In this paper, an experimental and numerical analysis of combustion process and knock occurrence in a small displacement spark-ignition engine is presented. A wide experimental campaign is preliminarily carried out in order to fully characterize the engine behavior in different operating conditions. In particular, the acquisition of a large number of consecutive pressure cycle is realized to analyze the Cyclic Variability (CV) effects in terms of Indicated Mean Effective Pressure (IMEP) Coefficient of Variation (CoV). The spark advance is also changed up to incipient knocking conditions, basing on a proper definition of a knock index. The latter is estimated through the decomposition and the FFT analysis of the instantaneous pressure cycles. Contemporary, a quasi-dimensional combustion and knock model, included within a whole engine one-dimensional (1D) modeling framework, are developed. Combustion and knock models are extended to include the CV effects, too.
2010-09-28
Technical Paper
2010-32-0070
Saharash Khare
The objective of this study is to investigate weight and cost reduction opportunities for a forged steel crankshaft. To optimize the design we need to understand the behavior of the crankshaft when engine is running at high- speed. In past, considerable amount of research effort has gone into the investigation of dynamic characteristics of a spinning shaft with attached discs but there has been less research on the bending behavior of high-speed engine crankshaft. Literature shows that stress and stiffness estimation under static condition is sufficient for engines operating at low-speed but dynamics of crankshaft at high- speed changes stress and stiffness values considerably. Actual engine dynamics simulation and experimental measurement demands huge effort and time. The novelty of this work is to develop simplified testing and simulation methodologies for studying crankshaft behavior in both static and dynamic conditions.
2010-10-19
Technical Paper
2010-01-2323
Keith Lang, Michael Kropinski, Tim Foster
GM's R oad-to- L ab-to- M ath (RLM) initiative is a fundamental engineering strategy leading to higher quality design, reduced structural cost, and improved product development time. GM started the RLM initiative several years ago and the RLM initiative has already provided successful results. The purpose of this paper is to detail the specific RLM efforts at GM related to powertrain controls development and calibration. This paper will focus on the current state of the art but will also examine the history and the future of these related activities. This paper will present a controls development environment and methodology for providing powertrain controls developers with virtual (in the absence of ECU and vehicle hardware) calibration capabilities within their current desktop controls development environment.
2010-10-19
Technical Paper
2010-01-2311
Eric A. Fedewa, Charles Chesbrough
There is a profound sense of urgency among leading industrialized nations: governments recognize that massive reductions in carbon emissions are required if we are to limit climate change in an era of ever-increasing global population growth and increasing affluence. They may also believe that the auto industry can deliver more carbon reduction faster at a lower absolute and political cost than other industries. Continued investment on the part of governments and the auto industry to create a viable model for sustainable mobility and vehicle electrification in the 2010 – 2020 timeframe should help drive transport-related carbon emissions down to the 60-90 grams/kilometer level, from 130-155 grams today, and contribute to an overall 20-30 percent reduction in greenhouse-gas emissions.
2010-10-19
Technical Paper
2010-01-2336
Veerender Kaul, Sarwant Singh, Krishnasami Rajagopalan, Michael Coury
1. ABSTRACT The U.S. National Highway Transportation and Safety Agency's (NHTSA) early estimates of Motor Traffic Fatalities in 2009 in the United States [1] show continuing progress on improving traffic safety on the U.S. roadways. The number of total fatalities and the fatality rate per 100 Million Vehicle Miles (MVM), both show continuing declines. In the 10 year period from 1999 through 2009, the total fatalities have dropped from 41,611 to 33,963 and the fatality rate has dropped from 1.5 fatalities per 100MVM to 1.16 fatalities per 100MVM, a compound annual drop of 2.01% and 2.54% respectively. The large number of traffic fatalities, and the slowing down of the fatality rate decline, compared to the decade before, continues to remain a cause of concern for regulators.
2010-10-19
Journal Article
2010-01-2334
Falke Hendriks, Riné Pelders, Martijn Tideman
Active safety systems are increasingly becoming available in trucks and passenger vehicles. Developments in the field of active safety are shifting from increasing driver comfort towards increasing occupant safety. Furthermore, this shift is seen within active safety systems: safety functions are added to existing comfort systems, rather than adding new safety systems to the vehicle. Comfort systems such as cruise control are extended via ACC to pre-crash braking systems. Testing of active safety systems must follow these developments. Whereas standardized test programs are available for passive safety systems, such test programs are hardly available yet for active safety systems. Furthermore, test programs for passive safety systems consist of only a handful of scenarios. Test programs for active safety systems, however, should consist of much more scenarios, as those systems should function well in many different situations.
2010-10-25
Journal Article
2010-01-2098
Petter Tornehed, Ulf Olofsson
The drive to reduce particle emissions from heavy-duty diesel engines has reached the stage where the contribution from the lubricant can have a major impact on the total amount of particulate matter (PM). This paper proposes a model to predict the survival rate (unburnt oil divided by oil consumption) of the hydrocarbons from the lubricant consumed in the cylinder. The input data are oil consumption and cylinder temperature versus crank angle. The proposed model was tuned to correlate well with data from a six-cylinder heavy-duty diesel engine that meets the Euro 5 legislation without exhaust gas aftertreatment. The measured (and modelled) oil survival shows a strong correlation with engine power. The maximum oil survival rate measured (19%) was at motoring conditions at high speed. For this engine, loads above 100 kW yielded an oil survival rate of nearly zero.
2010-10-25
Technical Paper
2010-01-2092
Maya R. Desai, Monica Tutuianu, Mehrdad Ahmadinejad, Timothy C. Watling, Andrew P.E. York, Joseph W. Stevenson
The aftertreatment challenge in the non-road market is making the same system work and fit not just in one machine, but in hundreds of different machines, some of which can be used for many different purposes. This huge diversity of applications and the relatively small unit numbers for each application, coupled with the rapid introduction of new standards and the very high performance needed from the engines and machines, requires a sophisticated approach to product development. Furthermore, as emissions requirements become ever more stringent, designing a system to meet the legislation subject to packaging and cost constraints becomes progressively more difficult. This is further exacerbated by increasing system complexity, where more than one technology may be required to control all the legislated pollutants and/or an active control strategy is involved. Also a very high degree of component integration is required.
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