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Viewing 1 to 30 of 2234
2010-10-25
Journal Article
2010-01-2196
William P. Attard, Patrick Parsons
Turbulent Jet Ignition is an advanced spark-initiated pre-chamber combustion system for an otherwise standard spark ignition engine found in current on-road vehicles. This next-generation pre-chamber design simply replaces the spark plug in a conventional spark ignition engine. Turbulent Jet Ignition enables very fast burn rates due to the ignition system producing multiple, widely distributed ignition sites, which consume the main charge rapidly. This high energy ignition system results from the partially combusted (reacting) prechamber products initiating main chamber combustion. The fast burn rates allow for increased levels of dilution (lean burn and/or EGR) when compared to conventional spark ignition combustion, with dilution levels being comparable to other low temperature combustion technologies (HCCI) without the complex control drawbacks.
2010-10-25
Technical Paper
2010-01-2198
Vittorio Manente, Claes-Goeran Zander, Bengt Johansson, Per Tunestal, William Cannella
A Scania 13 1 engine modified for single cylinder operations was run using nine fuels in the boiling point range of gasoline, but very different octane number, together with PRF20 and MK1-diesel. The eleven fuels were tested in a load sweep between 5 and 26 bar gross IMEP at 1250 rpm and also at idle (2.5 bar IMEP, 600 rpm). The boost level was proportional to the load while the inlet temperature was held constant at 303 K. For each fuel the load sweep was terminated if the ignitibility limit was reached. A lower load limit of 15 and 10 bar gross IMEP was found with fuels having an octane number range of 93-100 and 80-89 respectively, while fuels with an octane number below 70 were able to run through the whole load range including idle. A careful selection of boost pressure and EGR in the previously specified load range allowed achieving a gross indicated efficiency between 52 and 55% while NOx ranged between 0.1 and 0.5 g/kWh.
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
2010-01-2202
Umut Uysal, Ozgen Akalin
A timing drive model was developed based on computer-aided simulation methods and used to calculate the contribution of each system component to the overall timing drive friction loss at various engine operating conditions. Combining the analytical results and statistical methods, an optimization study was performed to calculate the ideal system design parameters such as hydraulic tensioner spring force and flow rate, sprocket tooth profiles and circularity, and oil supply pressure. The simulation results revealed that while the plastic guide - timing chain friction is responsible for the most part of the frictional losses, the contribution of timing chain friction increases with increasing speed. It was found that the tensioner guide is the key element in the guiding system that causes friction losses. Furthermore, tensioner spring force and engine oil pressure were identified as major design parameters that influence the efficiency of the timing drive.
2010-10-25
Technical Paper
2010-01-2205
Thomas Edward Briggs, Robert Wagner, K. Dean Edwards, Scott Curran, Eric Nafziger
In order to achieve proposed fuel economy requirements, engines must make better use of the available fuel energy. Regardless of how efficient the engine is, there will still be a significant fraction of the fuel energy that is rejected in the exhaust and coolant streams. One viable technology for recovering this waste heat is an Organic Rankine Cycle. This cycle heats a working fluid using these heat streams and expands the fluid through a turbine to produce shaft power. The present work was the development of such a system applied to a light duty diesel engine. This lab demonstration was designed to maximize the peak brake thermal efficiency of the engine, and the combined system achieved an efficiency of 45%. The design of the system is discussed, as are the experimental performance results. The system potential at typical operating conditions was evaluated to determine the practicality of installing such a system in a vehicle.
2010-10-25
Technical Paper
2010-01-2206
Scott Curran, Vitaly Prikhodko, Kukwon Cho, C. Scott Sluder, James Parks, Robert Wagner, Sage Kokjohn, Rolf D. Reitz
In-cylinder fuel blending of gasoline with diesel fuel is investigated on a multi-cylinder light-duty diesel engine as a strategy to control in-cylinder fuel reactivity for improved efficiency and lowest possible emissions. This approach was developed and demonstrated at the University of Wisconsin through modeling and single-cylinder engine experiments. The objective of this study is to better understand the potential and challenges of this method on a multi-cylinder engine. More specifically, the effect of cylinder-to-cylinder imbalances and in-cylinder charge motion as well as the potential limitations imposed by real-world turbo-machinery were investigated on a 1.9-liter four-cylinder engine. This investigation focused on one engine condition, 2300 rpm, 5.5 bar net mean effective pressure (NMEP). Gasoline was introduced with a port-fuel-injection system.
2010-10-25
Technical Paper
2010-01-2209
K. Dean Edwards, Robert Wagner, Thomas Briggs
Modern diesel engines used in light-duty transportation applications have peak brake thermal efficiencies in the range of 40-42% for high-load operation with substantially lower efficiencies at realistic road-load conditions. Thermodynamic energy and exergy analysis reveals that the largest losses from these engines are due to combustion irreversibility and heat loss to the coolant, through the exhaust, and by direct convection and radiation to the environment. Substantial improvement in overall engine efficiency requires reducing or recovering these losses. Unfortunately, much of the heat transfer either occurs at relatively low temperatures resulting in large entropy generation (such as in the air-charge cooler), is transferred to low-exergy flow streams (such as the oil and engine coolant), or is radiated or convected directly to the environment.
2010-10-05
Technical Paper
2010-01-2033
Gergis W. William
Currently, the chassis assembly contributes about 73 percent of the overall weight of a 14.63 m long haul trailer. This paper presents alternative design concepts for the structural floor of a van trailer utilizing sandwich panels with various material and geometric characteristics of the core layer in order to reduce its weight significantly below that of the current design configuration. The main objective of the new designs is to achieve optimal tradeoffs between the overall structural weight and the flexural stiffness of the floor. Various preliminary design concepts of the core designs were compared on the basis of a single section of the core structure. Six different designs were analyzed by weight, maximum displacement and maximum stress under bending and torsion loads. Each concept was kept uniform by length, thickness, loading and boundary conditions. Each design concept was examined through testing of scaled model for floor assemblies.
2010-10-05
Technical Paper
2010-01-2036
Gergis W. William
Recent advances in Metal Matrix Composites have made them ready for transition to large-volume production and commercialization. Such new materials seem to allow the fabrication of higher quality parts at less than 50 percent of the weight as compared to steel. The increasing requirements of weight savings and extended durability motivated the potential application of MMC technology into the heavy vehicle market. However, significant technical barriers such as joining are likely to hinder the broad applications of MMC materials in heavy vehicles. The focus of this paper is to examine the feasibility of manufacturing and the behavior of bolted joint connections made from aluminum matrix reinforced with Silicon Carbide (SiC) particles. Two reinforcement ratios: 20% and 45% were considered in this study. The first part of the paper concentrates on experimental evaluation of bolted MMC joints.
2010-04-12
Technical Paper
2010-01-0589
Michele Kaiser, Uwe Krueger, Roderick Harris, Luke Cruff
Due to the rising costs of fuel and increasingly stringent regulations, auto makers are in need of technology to enable more fuel-efficient powertrain technologies to be introduced to the marketplace. Such powertrains must not sacrifice performance, safety or driver comfort. Today's engine and powertrain manufacturers must, therefore, do more with less by achieving acceptable vehicle performance while reducing fuel consumption. One effective method to achieve this is the extreme downsizing of current direct injection spark ignited (DISI) engines through the use of high levels of boosting and cooled exhaust gas recirculation (EGR). Key challenges to highly downsized gasoline engines are retarded combustion to prevent engine knocking and the necessity to operate at air/fuel ratios that are significantly richer than the stoichiometric ratio.
2011-04-12
Technical Paper
2011-01-0345
Suresh Gopalakrishnan, Chandra Namuduri, Michael Reynolds
In this paper, a low-cost means to improve fuel economy in conventional vehicles by employing ultracapacitor based Active Energy Recovery Buffer (AERB) scheme will be presented. The kinetic energy of the vehicle during the coast down events is utilized to charge the ultracapacitor either directly or through a dc-dc converter, allowing the voltage to increase up to the maximum permissible level. When the vehicle starts after a Stop event, the energy stored in the capacitor is discharged to power the accessory loads until the capacitor voltage falls below a minimum threshold. The use of stored capacitor energy to power the accessory loads relieves the generator torque load on the engine resulting in reduced fuel consumption. Two different topologies are considered for implementing the AERB system. The first topology, which is a simple add-on to the conventional vehicle electrical system, comprises of the ultracapacitor bank and the dc-dc converter connected across the dc bus.
2011-04-12
Technical Paper
2011-01-0664
William P. Attard, Michael Bassett, Patrick Parsons, Hugh Blaxill
Turbulent Jet Ignition is an advanced spark initiated pre-chamber combustion system for otherwise standard spark ignition engines found in current passenger vehicles. This next generation pre-chamber design simply replaces the spark plug in a conventional spark ignition engine. Turbulent Jet Ignition enables very fast burn rates due to the ignition system producing multiple, widely distributed ignition sites, which consume the main charge rapidly. This high energy ignition results from the partially combusted (reacting) pre-chamber products initiating combustion in the main chamber. The distributed ignition sites enable relatively small flame travel distances enabling short combustion durations and high burn rates. Multiple benefits include extending the knock limit and initiating combustion in very dilute mixtures (excess air and or EGR), with dilution levels being comparable to other low temperature combustion technologies (HCCI), without the complex control drawbacks.
2011-04-12
Technical Paper
2011-01-0231
YoungJae Jung, Yeongwoo Yoo
In recent years, many automotive companies have been striving to reduce costs and shorten new vehicle development cycle time. To develop a new vehicle costs a tremendous amount especially at the prototype phase. So currently vehicle simulation on the powertrain bench is an attractive alternative at the development phase to reduce the quantity of proto vehicles. This test method moves the test site from the road to the bench without the need for real chassis parts. This paper deals with the method and strategy for moving testing from road to bench, specifically emission and fuel economy test for vehicles equipped with manual transmission. To execute vehicle type tests on the bench requires correlation and simulation of many parameters - for example gear shifting, throttle position, clutch travel and related driver characteristics, temperature and driving road load resistance, etc.
2011-04-12
Journal Article
2011-01-0146
Darrell Robinette, Michael Grimmer, Jeremy Horgan, Jevon Kennell, Richard Vykydal
The torque converter and torque converter clutch are critical devices governing overall power transfer efficiency in automatic transmission powertrains. With calibrations becoming more aggressive to meet increasing fuel economy standards, the torque converter clutch is being applied over a wider range of driving conditions. At low engine speed and high engine torque, noise and vibration concerns originating from the driveline, powertrain or vehicle structure can supersede aggressive torque converter clutch scheduling. Understanding the torsional characteristics of the torque converter clutch and its interaction with the drivetrain can lead to a more robust design, operation in regions otherwise restricted by noise and vibration, and potential fuel economy improvement.
2011-04-12
Journal Article
2011-01-0618
Zhenhong Lin, David Greene
To make informed decisions about travel and vehicle purchase, consumers need unbiased and accurate information of the fuel economy they will actually obtain. In the past, the EPA fuel economy estimates based on its 1984 rules have been widely criticized for overestimating on-road fuel economy. In 2008, EPA adopted a new estimation rule. This study compares the usefulness of the EPA's 1984 and 2008 estimates based on their prediction bias and accuracy and attempts to improve the prediction of on-road fuel economies based on consumer and vehicle attributes. We examine the usefulness of the EPA fuel economy estimates using a large sample of self-reported on-road fuel economy data and develop an Individualized Model for more accurately predicting an individual driver's on-road fuel economy based on easily determined vehicle and driver attributes. Accuracy rather than bias appears to have limited the usefulness of the EPA 1984 estimates in predicting on-road MPG.
2013-04-08
Technical Paper
2013-01-1392
Frank Bayerl, Sigrid ter Heide, Cedric A. Ball
The automotive industry is looking for options to reduce weight and increase engine efficiency to comply with new CO₂ emission and fuel economy regulations. Increasingly, automakers are examining their use of materials for even the smallest components. Engineering thermosets are an effective lightweighting alternative to heavier conventional steel and aluminum die cast products. They combine outstanding temperature stability, long-term mechanical strength, dimensional stability and high chemical resistance. This paper focuses on two recent projects where (BAKELITE™) phenolic-based engineering thermosets have successfully replaced traditional metals in automotive under-the-hood applications and outperformed engineering thermoplastics also considered for the applications. First, a water pump housing made with engineering thermoset material is shown to have good chemical resistance to coolants without additional corrosion protection and to maintain its mechanical properties.
2013-04-08
Journal Article
2013-01-1300
Douglas Ball, David Moser, Yonghong Yang, David Lewis
The Environmental Protection Agency (EPA) and Department of Transportation's National Highway Traffic Safety Administration (NHTSA) have finalized regulation that will reduce greenhouse gases and increase fuel economy for model year (MY) 2012-2016 light-duty vehicles. This ruling not only includes a CO₂ standard that will require vehicles to achieve fleet average 35 mpg by MY 2016, but will apply a cap on nitrous oxide (N₂O) and methane emissions to 10 and 30 mg/mile, respectively, however CO₂ emission reductions can be exchanged for either N₂O or methane credit. The work outlined investigates the N₂O emissions of a variety of low emission vehicles per the Federal Test Procedure (FTP). Fourier Transform Infrared Spectroscopy (FTIR) was used to measure both bag and modal N₂O emissions. N₂O emissions were less than 1 mg/mile for three SULEV vehicles with 6,400 km-aged catalysts.
2004-03-08
Technical Paper
2004-01-0576
Zhang Han, Zhu Yuan, Tian Guangyu, Chen Quanshi, Chen Yaobin
This paper presents a preliminary design and analysis of an optimal energy management and control system for a power-split hybrid electric vehicle (HEV) using hybrid dynamical control system theory and design tools. The hybrid dynamical system theory is applied to formulate HEV powertrain dynamical system in which the interactions of discrete and continuous dynamics are involved. The Sequential Quadratic Programming (SQP) method is applied to optimize power distribution. An improved dynamic programming method is employed to determine the optimal power distribution and the vehicle operating mode transitions.
2004-03-08
Technical Paper
2004-01-0575
Daxing Wang, Xin Zhang
In this paper the hardware of PCU based on digital signal processor (DSP) is developed and the software of PCU control with a nested structure is created. The control algorithm is programmed in C language, and the signal collection and communication are realized by assembly language with a high system performance. The electromagnetic interference in PHEV is serious, so the hardware and software anti-interference treatments for the PCU are studied in this paper. Besides, the hardware in the loop simulation system (HILSS) is set up and used as a main test instrument to check the PCU's performance. Also the simulation results of PCU control are shown in this paper.
2004-03-08
Technical Paper
2004-01-0573
Sujit Das
The affordability of today's and future advanced technology vehicles (i.e., diesel, hybrid, and fuel cell) developed for improved fuel economy remains a concern with respect to final consumer acceptance. The automotive system cost model (ASCM) developed for the production cost estimates at a level of five major subsystems and 35+ components, has been used here to address the affordability issue of advanced technology vehicles. Scenarios encompassing five alternative powertrain and three body options for a mid-size vehicle under two different timeframes (i.e., 2002 and 2010) were considered to determine the cost-effectiveness of among the competing technology options within the same timeframe and between the two timeframes.
2004-03-08
Technical Paper
2004-01-0572
Feng An, Danilo J. Santini
The strong correlation between vehicle weight and fuel economy for conventional vehicles (CVs) is considered common knowledge, and the relationship of mass reduction to fuel consumption reduction for conventional vehicles (CVs) is often cited without separating effects of powertrain vs. vehicle body (glider), nor on the ground of equivalent vehicle performance level. This paper challenges the assumption that this relationship is easily summarized. Further, for hybrid electric vehicles (HEVs) the relationship between mass, performance and fuel consumption is not the same as for CVs, and vary with hybrid types. For fully functioning (all wheel regeneration) hybrid vehicles, where battery pack and motor(s) have enough power and energy storage, a very large fraction of kinetic energy is recovered and engine idling is effectively eliminated.
2004-03-08
Technical Paper
2004-01-0571
Miguel M. Gomez, Victor H. Mucino, Nigel Clark, James E. Smith
Continuously variable transmissions (CVTs) are usually used in small vehicles due to power limitations on the variable elements. Continuously variable power-split transmissions (CVPST) were developed in order to reduce the fraction of power passing through the variable elements [1,2]. The configuration presented in this paper includes a planetary gear train (PGT), which in combination with the CVT allows the power to be split and therefore increase the power envelope of the system. The PGT also provides a branch that can be used in a hybrid electric vehicle (HEV) operation through an electric motor. A conceptual design of a CVPST for a HEV is presented in this paper. The objectives are to show the different operational modes, with diagrams, perform a power analysis, develop the velocity and force equations and finally show the performance of the system with an example application.
2004-03-08
Technical Paper
2004-01-0569
Peter J. Wezenbeek, David G. Evans, David P. Sczomak, John P. Absmeier, Gerald T. Fattic
Implementation of engine turnoff at idle is desirable to gain improvements in vehicle fuel economy. There are a number of alternatives for implementation of the restarting function, including the existing cranking motor, a 12V or 36V belt-starter, a crankshaft integrated-starter-generator (ISG), and other, more complex hybrid powertrain architectures. Of these options, the 12V belt-alternator-starter (BAS) offers strong potential for fast, quiet starting at a lower system cost and complexity than higher-power 36V alternatives. Two challenges are 1) the need to accelerate a large engine to idle speed quickly, and 2) dynamic torque control during the start for smoothness. In the absence of a higher power electrical machine to accomplish these tasks, combustion-assisted starting has been studied as a potential method of aiding a 12V accessory drive belt-alternator-starter in the starting process on larger engines.
2004-03-08
Technical Paper
2004-01-0568
P. H. Mellor, S. G. Burrow, R. Ong
The paper considers the implications of typical faults on the operation and control of a permanent magnet (PM) traction drive. The discussion is illustrated with analyses and test results taken from a vector controlled, imbedded magnet design of PM motor that has been prototyped for a future fuel cell powered mid size car. In particular the paper describes the outcome of an experimental investigation where a series of representative faults have been imposed on the prototype machine. The impact of the various faults and the subsequent fault control on the drive system are presented in terms of braking torque, and maximum current requirements.
2004-03-08
Technical Paper
2004-01-0567
Hiroyuki Satoh, Shigemitsu Akutsu, Tomoya Miyamura, Hiroaki Shinoki
This motor adopted a salient pole type surface permanent magnet rotor, which enables it both to produce reluctance torque and to minimize the use of magnets. The inductance value is set at the limit value enabling output at the maximum rotor speed, which suppresses field-weakening current. The utilization of the magnets enables continuous operation at the maximum rotor speed by suppressing eddy current loss by means of magnet surface insulation and magnet segmentation. Strength reliability at high rotor speeds has been assured by applying the Weibull-theory as a method of evaluating the strength of magnets.
2004-03-08
Technical Paper
2004-01-0566
James E. Walters, Ronald J. Krefta, Gabriel Gallegos-Lopez, Gerald T. Fattic
Due to the need for improving fuel economy, reducing tailpipe emissions and the trend towards increasing electrical content in automobiles, hybrid drivetrains are being considered by the automotive industry. In the foreseeable future, in order to address the drive towards hybridization, vehicle manufacturers will begin to use a 42 volt-based architecture in conjunction with an integrated starter and generator system. Depending on the desired power level and allowable changes to the vehicle drivetrain, either an Integrated Starter Generator which mounts between the engine and the transmission or a Belt Alternator Starter (BAS) system which mounts on the accessory belt can be used. This paper will examine the impact of choosing either a Permanent Magnet (PM) machine or an Induction machine for a BAS application. The impact of the technology on the electric machine design process, power stage implementation, control strategy and overall system design philosophy will be discussed.
2004-03-08
Technical Paper
2004-01-0565
Paul Turnbull, John Kuo, Roy Schultz, Bruce Turner
A twenty-five kilowatt (peak power for one minute), permanent magnet electric machine for a hybrid electric vehicle application was designed and tested. The electric machine is located in the clutch housing of an automatically shifted manual transmission and is subjected to 120 °C continuous ambient temperatures. The package constraints and duty cycle requirements resulted in an extremely challenging thermal design for an electric machine. The losses in the machine were predicted using models based on first principles and the heat transfer in the machine was modeled using computational fluid dynamics. The simulations were compared to test results over a variety of operating conditions and the results were used to validate the models. Parametric studies were conducted to evaluate the performance of potting materials and cooling topologies.
2004-03-08
Technical Paper
2004-01-0550
Claudia O. Iyer, Zhiyu Han, Jianwen Yi
This paper describes the CFD modeling work conducted for the development and research of a Vortex Induced Stratification Combustion (VISC) system that demonstrated superior fuel economy benefits. The Ford in-house CFD code and simulation methodology were employed. In the VISC concept a vortex forms on the outside of the wide cone angle spray and transports fuel vapor from the spray to the spark plug gap. A spray model for an outward-opening pintle injector used in the engine was developed, tested, and implemented in the code. Modeling proved to be effective for design optimization and analysis. The CFD simulations revealed important physical phenomena associated with the spray-guided combustion system mixing preparation.
2004-03-08
Technical Paper
2004-01-0549
Terry Alger, Jeff McGee, Steven Wooldridge
The influence of mixture preparation on misfires at idle in a Direct Injection Spark Ignition (DISI) engine was investigated. A wall-guided DISI engine was run at idle conditions in a stratified charge mode (750 rpm / 90 kPa MAP). Images of the mixture composition at the spark plug were taken at spark timing using Planar Laser Induced Fluorescence (PLIF) for several different End-of-Injection (EOI) timings and spark timings. Cylinder pressure data were acquired simultaneously with the images to identify misfire cycles. The misfire rate was found to increase as the EOI timing was advanced from the optimal timing, defined by maximum stability and lowest ISFC. Images show that the misfire rate at a particular operating condition can be correlated to the fuel distribution and the location of the stratified charge in the engine. Cycles that showed a lower amount of stratification (overmixing) and/or high gradients in fuel concentration near the spark plug were the least stable.
2004-03-08
Technical Paper
2004-01-0548
Jeff McGee, Terry Alger, Erica Blobaum, Steve Wooldridge
A PLIF measurement system was designed and applied for imaging direct-injected stratified charge fuel preparation. An extensive measurement plane was achieved through novel design features in the system. Measurement and processing uncertainties were assessed at ±15% for the semi-quantitative fuel density. Tracer selection among suggested iso-octane candidates was found not to have a significant effect on PLIF results under the conditions tested. Stratified charge fuel distribution images were acquired for three piston and fuel injector combinations. The effect of piston design in guiding the fuel mixture position was most notable. Fuel distribution features correlated reasonably well with measured data from a thermodynamic engine of similar design.
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