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2016-04-05
Technical Paper
2016-01-1428
Bruce Mehler, Bryan Reimer, Jonathan Dobres, James Foley, Kazutoshi Ebe
This paper presents the results of a study of how people interacted with a production voice-command based interface while driving on public roadways. Tasks included phone contact calling, full address destination entry, and point-of-interest (POI). Baseline driving and driving while engaging in multiple-levels of an auditory-vocal cognitive reference task and manual radio tuning were used as comparison points. Measures included self-reported workload, task performance, physiological arousal, glance behavior, and vehicle control for an analysis sample of 48 participants (gender balanced across ages 21-68). Task analysis and glance measures confirm earlier findings that voice-command interfaces do not always allow the driver to keep their hands on the wheel and eyes on the road, as some assume.
2016-04-05
Technical Paper
2016-01-1425
Thomas McWilliams, Daniel Brown, Bryan Reimer, Bruce Mehler, Jonathan Dobres
Changes in physiological and operational behavior following lane departure warnings are explored in current production automotive systems. Different implementations employing auditory and haptic lane departure warning alerts were recorded in highway driving conditions from the factory installed lane departure warning systems. The lane departure warning events took place during single task driving periods as well as dual task driving. Dual task periods consisted of the driver interacting with the vehicle’s production interface to perform a secondary visual-manual (e.g., radio tuning, contact dialing, etc.) or auditory-vocal (e.g. destination address entry, contact dialing, etc.) tasks. Driver physiology and behavior were recorded and analyzed for pre-event and post-event conditions. To normalize between vehicles, percentage changes between pre-event and post-event measures were calculated.
2016-04-05
Technical Paper
2016-01-1426
Lex Fridman, Joonbum Lee, Bryan Reimer, Bruce Mehler
The challenge of developing a robust, real-time driver gaze classification system is that it has to handle difficult edge cases that arise in real-world driving conditions: extreme lighting variations, eyeglass reflections, sunglasses and other occlusions. We propose a single-camera end-to-end framework for classifying driver gaze into a discrete set of regions. This framework includes data collection, semi-automated annotation, offline classifier training, and an online real-time image processing pipeline that classifies the gaze region of the driver. We evaluate an implementation of each component on various subsets of a large on-road dataset. The key insight of our work is that robust driver gaze classification in real-world conditions is best approached by leveraging the power of supervised learning to generalize over the edge cases present in large annotated on-road datasets.
2016-04-05
Technical Paper
2016-01-1046
Pasquale Pio Totaro, Zachary Westerfield, Tian Tian
The piston’s skirt shape is a critical component in the design of a piston, since it critically influences lateral displacement, tilting movement, oil transport and consequently engine performances. This study proposes an alternative skirt’s profile that aims to reduce frictional losses between piston and cylinder liner. Qualitatively, the proposed profile, so called “Lips” profile for its shape, aims to reduce solid-to-solid contact friction by increasing the total hydrodynamic forces generated on the skirt to balance side forces, and to prevent both side of the skirt to interact with the liner simultaneously. The new skirt’s profile has been first studied and optimized using a piston secondary motion model and then prototyped and tested on a floating liner test bench, showing a 14% average reduction in FMEP.
2016-04-05
Journal Article
2016-01-0495
Tianshi Fang, Tian Tian
In gasoline engines, a scraper ring with a step on the bottom outer edge is widely used as a second ring. However, there lacks a fundamental understanding on the effects of this feature and its dimensions on oil transport. Inspired by observations from visualization experiments, this work combining computational fluid dynamics (CFD) and theoretical analysis shows that oil can be trapped in the space bordered by a second ring step and the chamfer of a piston third land. The trapped oil can be released to a liner when the piston is approaching the top dead center (TDC). This additional oil on the liner becomes a potential source of oil consumption. Such oil transport has been observed at typically less than 1500rpm. Since road vehicles often operate in this speed range, the newly-observed oil trapping and release can be closely associated with oil consumption in gasoline engines. In this work, a comprehensive study on oil trapping and release will be demonstrated.
2016-04-05
Technical Paper
2016-01-0942
Nicholas Custer, Carl Justin Kamp, Alexander Sappok, James Pakko, Christine Lambert, Christoph Boerensen, Victor Wong
The increasing use of gasoline direct injection (GDI) engines coupled with the implementation of new particulate matter (PM) emissions regulations requires new emissions control strategies. Gasoline particulate filters (GPF) present one approach to reduce PM emissions. Although primarily composed of combustible material which may be removed through oxidation, PM also contains incombustible components or ash. Over the service life of the filter the accumulation of ash causes an increase in exhaust backpressure, and limits the useful life of the GPF. In an accelerated aging system, elevated ash levels were created by injecting lubricant oil into a gasoline burner system. GPFs were aged to a series of levels representing filter life up to 150,000 miles. The impact of ash on pressure drop and on its sensitivity to soot accumulation was investigated at specific ash levels.
2016-04-05
Technical Paper
2016-01-1048
Zachary Westerfield, Tian Tian, Yang liu, Dallwoo Kim
The oil control ring (OCR) controls the supply of lubricating oil to the top two rings of the piston ring pack and has a significant contribution to friction of the system. This study investigates the two most prevalent types of OCR in the automotive market: the twin land oil control ring (TLOCR) and three piece oil control ring (TPOCR). First, the basis for TLOCR friction on varying liner roughness is established. Then the effect of changing the land width and spring tension on different liner surfaces for the TLOCR is investigated, and distinct trends are identified. A comparison is then done between the TLOCR and TPOCR on different liner surfaces. Results showed the TPOCR displayed different patterns of friction compared the TLOCR in certain cases.
2016-04-05
Technical Paper
2016-01-0943
Paul Ragaller, Alexander Sappok, Leslie Bromberg, Natarajan Gunasekaran, Jason Warkins, Ryan Wilhelm
Efficient aftertreatment management requires accurate sensing of both particulate filter soot and ash levels for optimized feedback control. Currently a combination of pressure drop measurements and predictive models are used to indirectly estimate the loading state of the filter. Accurate determination of filter soot loading levels is challenging under certain operating conditions, particularly following partial regeneration events and at low flow rate (idle) conditions. This work applied radio frequency (RF)-based sensors to provide a direct measure of the particulate filter soot levels in situ. Direct measurements of the filter loading state enable advanced feedback controls to optimize the combined engine and aftertreatment system for improved DPF management. This study instrumented several cordierite and aluminum titanate diesel particulate filters with RF sensors. The systems were tested on a range of light- and heavy-duty applications, which included on- and off-road engines.
2016-04-05
Journal Article
2016-01-0514
Yan Meng, Yong Xia, Qing Zhou, Shaoting Lin
There has been a rising interest of car manufactures for using plastic materials in interior and exterior trims and safety parts since plastics have quite a few attractive properties: they are light-weight, inexpensive, easy to form, ductile and sustainable. Widely application of thermoplastics drives the demand for reliable and robust methods to modeling structural parts made from plastics. Different from metallic materials, yielding behavior of plastics are pressure dependent and influenced by temperature and strain rate as well. Plastic flow criteria of isotropic polymers has been intensively studied under uniaxial loading. While biaxial tension data is critical in the construction of yielding surface of plastics. However, reliable biaxial tension curve is lacked especially for thermoplastics. The main difficulties consist of two aspects.
2015-09-01
Technical Paper
2015-01-2035
Mathieu Picard, Tian Tian, Takayuki Nishino
The Wankel rotary engine is more compact than conventional piston engines, but its oil and fuel consumption must be reduced to satisfy emission standards and customer expectations. A key step toward this goal is to develop a better understanding of the apex seal lubrication to reduce oil injection while reducing friction and maintaining adequate wear. This paper presents an apex seal dynamics model capable of estimating relative wear and predicting friction, by modeling the gas and oil flows at the seal interfaces with the rotor housing and groove flanks. Model predictions show that a thin oil film can reduce wear and friction, but to a limited extent as the apex seal running face profile is sharp due to the engine kinematics.
2015-06-15
Technical Paper
2015-01-2152
Earle Williams, Michael F. Donovan, David J. Smalley, Robert G. Hallowell, Elaine P. Griffin, Kenta T. Hood, Betty J. Bennett, Mengistu Wolde, Alexei V. Korolev
Abstract MIT Lincoln Laboratory is tasked by the U.S. Federal Aviation Administration to investigate the use of the NEXRAD polarimetric radars* for the remote sensing of icing conditions hazardous to aircraft. A critical aspect of the investigation concerns validation that has relied upon commercial airline icing pilot reports and a dedicated campaign of in situ flights in winter storms. During the month of February in 2012 and 2013, the Convair-580 aircraft operated by the National Research Council of Canada was used for in situ validation of snowstorm characteristics under simultaneous observation by NEXRAD radars in Cleveland, Ohio and Buffalo, New York. The most anisotropic and easily distinguished winter targets to dual pol radar are ice crystals.
2015-04-14
Journal Article
2015-01-0887
J. Felipe Rodriguez, Wai K. Cheng
Abstract The impact of the operating strategy on emissions from the first combustion cycle during cranking was studied quantitatively in a production gasoline direct injection engine. A single injection early in the compression cycle after IVC gives the best tradeoff between HC, particulate mass (PM) and number (PN) emissions and net indicated effective pressure (NIMEP). Retarding the spark timing, it does not materially affect the HC emissions, but lowers the PM/PN emissions substantially. Increasing the injection pressure (at constant fuel mass) increases the NIMEP but also the PM/PN emissions.
2015-04-14
Technical Paper
2015-01-1047
Yujun Wang, Carl Kamp, Amin Saeid, Chris Jackson, Jim Ernstmeyer, Bachir Kharraja, Alexander Sappok, Victor W. Wong
Abstract Sintered metal fiber (SMF) diesel particulate filters (DPF) has more than one order of magnitude lower pressure drop compared to a granular or reaction-born DPF of the same (clean) filtration efficiency. To better understand the filtration process and optimize the filter performance, metal fiber filter models are developed in this study. The major previous theoretical models for clean fibrous filter are summarized and compared with experimental data. Furthermore, a metal fiber DPF soot loading model, using similar concept developed in high efficiency particulate air (HEPA) filter modeling, is built to simulate filter soot loading performance. Compared with experimental results, the soot loading model has relatively good predictions of filter pressure drop and filtration efficiency.
2015-04-14
Technical Paper
2015-01-0274
John Thomas, John Sgueglia, Dajiang Suo, Nancy Leveson, Mark Vernacchia, Padma Sundaram
Abstract The introduction of new safety critical features using software-intensive systems presents a growing challenge to hazard analysis and requirements development. These systems are rich in feature content and can interact with other vehicle systems in complex ways, making the early development of proper requirements critical. Catching potential problems as early as possible is essential because the cost increases exponentially the longer problems remain undetected. However, in practice these problems are often subtle and can remain undetected until integration, testing, production, or even later, when the cost of fixing them is the highest. In this paper, a new technique is demonstrated to perform a hazard analysis in parallel with system and requirements development. The proposed model-based technique begins during early development when design uncertainty is highest and is refined iteratively as development progresses to drive the requirements and necessary design features.
2015-04-14
Journal Article
2015-01-1012
Carl Justin Kamp, Paul Folino, Yujun Wang, Alexander Sappok, Jim Ernstmeyer, Amin Saeid, Rakesh Singh, Bachir Kharraja, Victor W. Wong
Abstract While metal fiber filters have successfully shown a high degree of particle retention functionality for various sizes of diesel engines with a low pressure drop and a relatively high filtration efficiency, little is known about the effects of lubricant-derived ash on the fiber filter systems. Sintered metal fiber filters (SMF-DPF), when used downstream from a diesel engine, effectively trap and oxidize diesel particulate matter via an electrically heated regeneration process where a specific voltage and current are applied to the sintered alloy fibers. In this manner the filter media essentially acts as a resistive heater to generate temperatures high enough to oxidize the carbonaceous particulate matter, which is typically in excess of 600°C.
2014-04-01
Technical Paper
2014-01-1658
Michael J. Plumley, Victor Wong, Mark Molewyk, Soo-Youl Park
Abstract Lubricant viscosity along the engine cylinder liner varies by an order of magnitude due to local temperature variation and vaporization effects. Tremendous potential exists for fuel economy improvement by optimizing local viscosity variations for specific operating conditions. Methods for analytical estimation of friction and wear in the power-cylinder system are reviewed and used to quantify opportunities for improving mechanical efficiency and fuel economy through lubricant formulation tailored specifically to liner temperature distributions. Temperature dependent variations in kinematic viscosity, density, shear thinning, and lubricant composition are investigated. Models incorporating the modified Reynolds equation were used to estimate friction and wear under the top ring and piston skirt of a typical 11.0 liter diesel engine.
2014-04-01
Technical Paper
2014-01-1906
Ashish Vora, Haotian Wu, Chuang Wang, Yili Qian, Gregory Shaver, Vahid Motevalli, Peter Meckl, Oleg Wasynczuk, Haiyan Zhang
Abstract Hybrid powertrains with multiple sources of power have generated new control challenges in the automotive industry. Purdue University's participation in EcoCAR 2, an Advanced Vehicle Technology Competition managed by the Argonne National Laboratories and sponsored by GM and DOE, has provided an exciting opportunity to create a comprehensive test-bench for the development and validation of advanced hybrid powertrain control strategies. As one of 15 competing university teams, the Purdue EcoMakers are re-engineering a donated 2013 Chevrolet Malibu into a plug-in parallel- through-the-road hybrid-electric vehicle, to reduce its environmental impact without compromising performance, safety or consumer acceptability. This paper describes the Purdue team's control development process for the EcoCAR 2 competition.
2014-04-01
Technical Paper
2014-01-1659
Mark Molewyk, Victor W. Wong, Christopher James
Abstract Lowering lubricant viscosity to reduce friction generally carries a side-effect of increased metal-metal contact in mixed or boundary lubrication, for example near top ring reversal along the engine cylinder liner. A strategy to reduce viscosity without increased metal-metal contact involves controlling the local viscosity away from top-ring-reversal locations. This paper discusses the implementation of insulation or thermal barrier coating (TBC) as a means of reducing local oil viscosity and power cylinder friction in internal combustion engines with minimal side-effects of increased wear. TBC is selectively applied to the outside diameter of the cylinder liner to increase the local oil temperature along the liner. Due to the temperature dependence of oil viscosity, the increase in temperature from insulation results in a decrease in the local oil viscosity.
2014-04-01
Journal Article
2014-01-1664
Mathieu Picard, Camille Baelden, Tian Tian, Takayuki Nishino, Eiji Arai, Hiroyuki Hidaka
The rotary engine provides high power density compared to piston engine, but one of its downside is higher oil consumption. A model of the oil seals is developed to calculate internal oil consumption (oil leakage from the crankcase through the oil seals) as a function of engine geometry and operating conditions. The deformation of the oil seals trying to conform to housing distortion is calculated to balance spring force, O-ring and groove friction, and asperity contact and hydrodynamic pressure at the interface. A control volume approach is used to track the oil over a cycle on the seals, the rotor and the housing as the seals are moving following the eccentric rotation of the rotor. The dominant cause of internal oil consumption is the non-conformability of the oil seals to the housing distortion generating net outward scraping, particularly next to the intake and exhaust port where the housing distortion valleys are deep and narrow.
2014-04-01
Journal Article
2014-01-1665
Mathieu Picard, Hiroyuki Hidaka, Tian Tian, Takayuki Nishino, Eiji Arai, Masaki Ohkubo
The rotary engine provides high power density compared to piston engine, but one of its downside is higher oil consumption. In order to better understand oil transport, a laser induced fluorescence technique is used to visualize oil motion on the side of the rotor during engine operation. Oil transport from both metered oil and internal oil is observed. Starting from inside, oil accumulates in the rotor land during inward motion of the rotor created by its eccentric motion. Oil seals are then scraping the oil outward due to seal-housing clearance asymmetry between inward and outward motion. Cut-off seal does not provide an additional barrier to internal oil consumption. Internal oil then mixes with metered oil brought to the side of the rotor by gas leakage. Oil is finally pushed outward by centrifugal force, passes the side seals, and is thrown off in the combustion chamber.
2014-04-01
Journal Article
2014-01-1085
Camille Baelden, Tian Tian
Piston rings are large contributors to friction losses in internal combustion engines. To achieve higher engine efficiency, low friction ring packs that can maintain good sealing performance must be designed. To support this effort, simulation tools have been developed to model the performance of piston rings during engine operation. However, the challenge of predicting oil consumption, blow by, and ring pack friction with sufficient accuracy remains. This is mostly due to the complexity of this system. Ring dynamics, deformation, interaction with liner and piston, gas and lubricant flow must all be studied together to make relevant predictions. In this paper, a new curved beam finite element model of piston rings is proposed. Ring structural deformation and contact with the liner are treated on two separate grids. A comparison with ring models in the literature and analytical solutions shows that it can provide accurate results efficiently.
2014-04-01
Journal Article
2014-01-1368
Justin E. Ketterer, Wai K. Cheng
Abstract Particulate emissions from a production gasoline direct injection spark ignition engine were studied under a typical cold-fast-idle condition (1200 rpm, 2 bar NIMEP). The particle number (PN) density in the 22 to 365 nm range was measured as a function of the injection timing with single pulse injection and with split injection. Very low PN emissions were observed when injection took place in the mid intake stroke because of the fast fuel evaporation and mixing processes which were facilitated by the high turbulent kinetic energy created by the intake charge motion. Under these conditions, substantial liquid fuel film formation on the combustion chamber surfaces was avoided. PN emissions increased when injection took place in the compression stroke, and increased substantially when the fuel spray hit the piston.
2014-04-01
Journal Article
2014-01-1517
Alexander Sappok, Yujun Wang, Ruo-Qian Wang, Carl Kamp, Victor Wong
Ash accumulation in the channels of ceramic, honeycomb-type particulate filters is controlled by several key parameters, which are the focus of this study. Ultimately, it is the formation of ash deposits, their transport, and the manner in which the ash accumulates in the particulate filter, which determines the useful service life of the filter and its resulting impact on engine performance. Although significant variations in ash deposit properties and their spatial distribution within the filter channels have been reported, depending on the filter's application, understanding the key parameters and mechanisms, such as the effects of exhaust flow and temperature conditions, as well as the processes occurring during filter regeneration events (whether passive or active) are critical in developing improved filter ash management strategies.
2014-04-01
Journal Article
2014-01-1486
Carl Justin Kamp, Alexander Sappok, Yujun Wang, William Bryk, Avery Rubin, Victor Wong
Inorganic engine lubricant additives, which have various specific, necessary functions such as anti-wear, leave the combustion chamber bound to soot particles (approximately ≤1% by mass) as ash [13], and accumulate in aftertreatment components. The diesel particulate filter (DPF) is especially susceptible to ash-related issues due to its wall-flow architecture which physically traps most of the soot and ash emissions. Accumulated lubricant-derived ash results in numerous problems including increased filter pressure drop and decreased catalytic functionality. While much progress has been made to understand the macroscopic details and effects of ash accumulation on DPF performance, this study explores the nano- and micron-scale forces which impact particle adhesion and mobility within the particulate filter.
2014-04-01
Technical Paper
2014-01-1206
Young Suk Jo, Raymond Lewis, Leslie Bromberg, John B. Heywood
Abstract 1 Downsizing and turbocharging a spark-ignited engine is becoming an important strategy in the engine industry for improving the efficiency of gasoline engines. Through boosting the air flow, the torque is increased, the engine can thus be downsized, engine friction is reduced in both absolute and relative terms, and engine efficiency is increased. However knock onset with a given octane rating fuel limits both compression ratio and boost levels. This paper explores the operating limits of a turbocharged engine, with various gasoline-ethanol blends, and the interaction between compression ratio, boost levels, and spark retard, to achieve significant increases in maximum engine mean effective pressure and efficiency.
2013-10-14
Journal Article
2013-01-2651
Jongwon Lee, Wai Cheng
The field of automotive engineering has devoted much research to reduce fuel consumption to attain sustainable energy usage. Friction reductions in powertrain components can improve engine fuel economy. Quantitative accounting of friction is complex because it is affected by many physical aspects such as oil viscosity, temperature, surface roughness and component rotation speed. The purpose of this paper is two-fold: first, to develop a useful tool for evaluating the friction in engine and accessories based on test data; second, to exercise the tool to evaluate the fuel economy gain in a drive cycle for several friction reduction technologies.
2013-09-17
Technical Paper
2013-01-2207
Michele Cencetti, Laura Mainini, Paolo Maggiore
A Multi-Objective Optimization (MOO) problem concerning the thermal control problem of Multifunctional Structures (MFSs) is here addressed. In particular the use of Multi-Objective algorithms from an optimization tool and Self-Organizing Maps (SOM) is proposed for the identification of the optimal topological distribution of the heating components for a multifunctional test panel, the Advanced Bread Board (ABB). MFSs are components that conduct many functions within a single piece of hardware, shading the clearly defined boundaries that identify traditional subsystems. Generally speaking, MFSs have already proved to be a disrupting technology, especially in aeronautics and space application fields. The case study exploited in this paper refers to a demonstrator breadboard called ABB. ABB belongs to a particular subset of an extensive family of MFS, that is, of thermo-structural panels with distributed electronics and a health monitoring network.
2013-04-08
Technical Paper
2013-01-1584
Yujun Wang, Victor Wong, Alexander Sappok, Sean Munnis
Ash inside a honeycomb-configured diesel particulate filter (DPF) inlet channel accumulates both as a cake layer along the channel walls and as a “plug” towards the back of the channel. Experimental studies of DPF ash distribution have shown both an axial variation of deposits along channels and accumulation towards the end plugs. This study evaluates the sensitivity of DPF pressure drop on ash axial distribution and the potential to reduce flow restrictions by controlling and optimizing the spatial distribution of ash inside DPF channels. A computational model has been used in conjunction with experimental data to illustrate the sensitivity of ash spatial distribution on DPF performance. The classical constant-thickness DPF one-dimensional models have substantially been updated to include layer thickness axial variations. Material properties, such as ash characteristics, are provided by recent experiments at the authors' laboratory.
2013-04-08
Journal Article
2013-01-0519
Alexander Sappok, Ifran Govani, Carl Kamp, Yujun Wang, Victor Wong
The formation and transport processes governing the build-up of incombustible ash deposits in diesel particulate filters (DPF) are influenced to a large extent by the filter's operating history. More specifically, the regeneration process, whether active, passive, or some variation of the two, has long been assumed to exert significant influence on the resulting ash characteristics. Until recently, only limited circumstantial evidence was available to describe differences in ash properties and distribution impacting DPF performance for filters subjected to different regeneration strategies. This work presents, for the first time, results from a comprehensive series of evaluations with optically-accessible DPF core samples showing the processes controlling the formation, transport, and interaction of the soot and ash deposits over a range of DPF regeneration conditions.
2012-10-22
Journal Article
2012-01-2134
Nancy G. Leveson, Cody Harrison Fleming, Melissa Spencer, John Thomas, Chris Wilkinson
This paper presents a new methodology for the safety assessment of complex software intensive systems such as is envisioned for the coming major upgrade of the air traffic management system known as NextGen. This methodology is based on a new, more inclusive model of accident causation called Systems Theoretic Accident Model and Process (STAMP) [1]. STAMP includes not just the standard component failure mechanisms but also the new ways that software and humans contribute to accidents in complex systems. A new hazard analysis method, called Systems Theoretic Process Analysis (STPA), is built on this theoretical foundation. The STPA is based on systems theory rather than reliability theory; it treats safety as a control problem rather than a failure problem with interactive and possibly nested control loops that may include humans. In this methodology, safety is assured by closed loop control of safety parameters.
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