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Technical Paper
2014-10-13
John Thomas
Vehicle manufacturers among others are putting great emphasis on improving fuel economy (FE) of light-duty vehicles in the U.S. market, with significant FE gains being realized in recent years. The U.S. Environmental Protection Agency (EPA) data indicates that the aggregate FE of vehicles produced for the U.S. market has improved by 20% from model year (MY) 2005 to 2013. This steep climb in FE includes changes in vehicle choice, improvements in engine and transmission technology, and reducing aerodynamic drag, rolling resistance, and parasitic losses. The powertrain related improvements focus on optimizing in-use efficiency of the transmission and engine as a system, and may make use of what is termed downsizing and/or downspeeding. This study explores quantifying recent improvements in powertrain efficiency, viewed separately from other vehicle alterations and attributes (noting that most vehicle changes are not completely independent). A methodology is outlined to estimate powertrain efficiency for the U.S city and highway cycle tests using data from the EPA vehicle database.
Technical Paper
2014-10-13
Brian C. Kaul, Benjamin J. Lawler, Charles E.A. Finney, Michelle L. Edwards, Robert M. Wagner
Advances in engine controls and sensor technology are making advanced, direct, high-speed control of engine combustion more feasible. Control of combustion rate and phasing in low-temperature combustion regimes and active control of cyclic variability in dilute SI combustion are being pursued in laboratory environments with high-quality data acquisition systems, using metrics calculated from in-cylinder pressure. In order to implement these advanced combustion controls in production, lower-quality data will need to be tolerated even if indicated pressure sensors are made available. This paper examines the effects of several data quality issues, including phase shifting (incorrect TDC location), reduced data resolution, pressure pegging errors, and random noise on calculated combustion metrics that are used for control feedback. Combustion phasing, mean effective pressure, and cycle-total heat release are considered. Symbolic data analysis has been shown to be an effective technique for identifying underlying patterns in noisy data, and has been applied to cyclic variability of dilute SI combustion, identifying deterministic effects that underlie the stochastic variations that are present.
Technical Paper
2014-09-30
Zhiming Gao, Charles Finney, Charles Daw, Tim J. LaClair, David Smith
Two hybrid powertrain configurations, including parallel and series hybrids, were simulated for fuel economy, component energy loss, and emissions control in Class 8 trucks over both city and highway driving conditions. A comprehensive set of component models describing engine fuel consumption, emissions control, battery energy, and accessory power demand interactions was developed and integrated with the simulated hybrid trucks to identify heavy-duty (HD) hybrid technology barriers. The results show that series hybrid is absolutely negative for fuel-economy improvement of long-haul trucks due to an efficiency penalty associated with the dual-step conversions of energy (i.e. mechanical to electric to mechanical). The current parallel hybrid technology combined with 50% auxiliary load reduction could improve fuel economy by 5-7% in long-haul trucks, but a profound improvement of long-haul truck fuel economy requires innovative technologies for reducing aerodynamic drag and rolling resistance.
Article
2014-06-26
The Department of Energy’s Oak Ridge National Laboratory (ORNL) has launched its new Institute for Functional Imaging of Materials, which aims to accelerate discovery, design, and deployment of new materials, according to a release from the laboratory.
Article
2014-05-04
A new electrolyte developed the U.S. Department of Energy's Oak Ridge National Laboratory (ORNL) serves not only as an ion conductor, but also as a cathode supplement in batteries. Potential uses of the technology include remote keyless entry systems, cardiac pacemakers, sensors, and other applications "where replacing or recharging a battery is not possible or desirable."
Technical Paper
2014-04-01
Adam Dempsey, Scott Curran, John Storey, Mary Eibl, Josh Pihl, Vitaly Prikhodko, Robert Wagner, James Parks
Abstract Low temperature combustion (LTC) has been shown to yield higher brake thermal efficiencies with lower NOx and soot emissions, relative to conventional diesel combustion (CDC). However, while demonstrating low soot carbon emissions it has been shown that LTC operation does produce particulate matter whose composition appears to be much different than CDC. The particulate matter emissions from dual-fuel reactivity controlled compression ignition (RCCI) using gasoline and diesel fuel were investigated in this study. A four cylinder General Motors 1.9L ZDTH engine was modified with a port-fuel injection system while maintaining the stock direct injection fuel system. The pistons were modified for highly premixed operation and feature an open shallow bowl design. RCCI operation was carried out using a certification grade 97 research octane gasoline and a certification grade diesel fuel. To study the particulate matter emissions from RCCI operation, particle size distributions were measured with a Scanning Mobility Particle Sizer (SMPS) and total particulate concentration in the exhaust was determined using membrane filters.
Technical Paper
2014-04-01
Zhenhong Lin, Jan-Mou Li, Jing Dong
Abstract This study attempts to establish a quantitative linkage between deployment of dynamic wireless power transfer (DWPT) and the market adoption of plug-in electric vehicles (PEV). This linkage can be useful for analyzing the societal benefits of DWPT and justifying investments in its research, development, demonstration and deployment. Spatial relationships between charging opportunity and DWPT availability are estimated for four metropolitan areas. The consumer value of DWPT is formulated as a function of key DWPT deployment parameters and then integrated into an existing validated consumer choice model, where sales of PEVs are endogenous. Results indicate significant impacts on PEV sales of DWPT deployment, even only at 0.5% of road length by 2050. Significant impact heterogeneity is observed. Larger impacts appear to be on battery electric vehicles (BEV) as opposed to plug-in hybrid electric vehicles (PHEV), on short-range BEVs as opposed to long-range ones, and on consumers with charging challenges, such as consumers without adequate home or workplace charging and consumers with high driving intensity.
Technical Paper
2014-04-01
Krishna Kamasamudram, Ashok Kumar, Jinyong Luo, Neal Currier, Aleksey Yezerets, Thomas Watkins, Larry Allard
Abstract An operational challenge associated with SCR catalysts is the NH3 slip control, particularly for commercial small pore Cu-zeolite formulations as a consequence of their significant ammonia storage capacity. The desorption of NH3 during increasing temperature transients is one example of this challenge. Ammonia slipping from SCR catalyst typically passes through a platinum based ammonia oxidation catalyst (AMOx), leading to the formation of the undesired byproducts NOx and N2O. We have discovered a distinctive characteristic, an overlapping NH3 desorption and oxidation, in a state-of-the-art Cu-zeolite SCR catalyst that can minimize NH3 slip during temperature transients encountered in real-world operation of a vehicle. In this work we show new insights, gained from NH3 temperature programmed desorption and oxidation experiments, into the Cu-zeolite catalyst functions responsible for the overlap of NH3 desorption and oxidation characteristics and the impact of hydrothermal treatment on these functions.
Technical Paper
2014-04-01
Jan-Mou Li, David Smith
Abstract Driver is a key component in vehicle simulation. An ideal driver model simulates driving patterns a human driver may perform to negotiate road profiles. There are simulation packages having the capability to simulate driver behavior. However, it is rarely documented how they work with road profiles. This paper proposes a new truck driver model for vehicle simulation to imitate actual driving behavior in negotiating road grade and curvature. The proposed model is developed based upon Gipps' car-following model. Road grade and curvature were not considered in the original Gipps' model although it is based directly on driver behavior and expectancy for vehicles in a stream of traffic. New parameters are introduced to capture drivers' choice of desired speeds that they intend to use in order to negotiating road grade and curvature simultaneously. With the new parameters, the proposed model can emulate behaviors like uphill preparation for different truck drivers. Speed variation while cruising can be explained by the empirical model and therefore facilitating a better estimation of performance in vehicle simulation.
Technical Paper
2014-04-01
Jing Dong, Zhenhong Lin, Changzheng Liu, Yanghe Liu
Abstract This paper utilizes GPS tracked multiday travel activities to estimate the temporal distribution of electricity loads and assess battery electric vehicle (BEV) grid impacts at a significant market penetration level. The BEV load and non-PEV load vary by time of the day and day of the week. We consider two charging preferences: home priority assumes BEV drivers prefer charging at home and would not charge at public charging stations unless the state of charge (SOC) of the battery is not sufficient to cover the way back to home; and charging priority does not require drivers to defer charging to home and assumes drivers will utilize the first available charging opportunity. Both home and charging priority scenarios show an evening peak demand. Charging priority scenario also shows a morning peak on weekdays, possibly due to workplace charging. Assuming a significant percentage of the vehicle population in Seattle is displaced by BEVs, the BEV electricity demand is added to the non-PEV load.
Technical Paper
2014-04-01
Michael D. Kass, Mark W. Noakes, Brian Kaul, Dean Edwards, Timothy Theiss, Lonnie Love, Ryan Dehoff, John Thomas
Abstract The performance of a 4cc two-stroke single cylinder glow plug engine was assessed at wide open throttle for speeds ranging from 2000 to 7000RPM. The engine performance was mapped for the stock aluminum head and one composed of titanium, which was printed using additive manufacturing. The engine was mounted to a motoring dynamometer and the maximum torque was determined by adjusting the fuel flow. Maximum torque occurred around 3000 to 3500RPM and tended to be higher when using the aluminum head. At slower speeds, the titanium head produced slightly higher torque. For each test condition, maximum torque occurred at leaner conditions for the titanium head compared to the stock aluminum one. Higher efficiencies were observed with the aluminum head for speeds greater than 3000RPM, but the titanium heads provided better efficiency at the lower speed points. The titanium head was equipped with an in-cylinder pressure sensor and the combustion performance was assessed at maximum torque for speeds of 4000, 6000, and 7000RPM.
Technical Paper
2014-04-01
Zhiming Gao, Tim J. LaClair, C. Stuart Daw, David E. Smith, Oscar Franzese
We present simulated fuel economy and emissions of city transit buses powered by conventional diesel engines and diesel-hybrid electric powertrains of varying size. Six representative city drive cycles were included in the study. In addition, we included previously published aftertreatment device models for control of CO, HC, NOx, and particulate matter (PM) emissions. Our results reveal that bus hybridization can significantly enhance fuel economy by reducing engine idling time, reducing demands for accessory loads, exploiting regenerative braking, and shifting engine operation to speeds and loads with higher fuel efficiency. Increased hybridization also tends to monotonically reduce engine-out emissions, but tailpipe (post-aftertreatment) emissions are affected by complex interactions between engine load and the transient catalyst temperatures, and the emissions results were found to depend significantly on motor size and details of each drive cycle.
Technical Paper
2014-04-01
Sujit Das
Advanced lightweight materials are increasingly being incorporated into new vehicle designs by automakers to enhance performance and assist in complying with increasing requirements of corporate average fuel economy standards. To assess the primary energy and carbon dioxide equivalent (CO2e) implications of vehicle designs utilizing these materials, this study examines the potential life cycle impacts of two lightweight material alternative vehicle designs, i.e., steel and aluminum of a typical passenger vehicle operated today in North America. LCA for three common alternative lightweight vehicle designs are evaluated: current production (“Baseline”), an advanced high strength steel and aluminum design (“LWSV”), and an aluminum-intensive design (AIV). This study focuses on body-in-white and closures since these are the largest automotive systems by weight accounting for approximately 40% of total curb weight of a typical passenger vehicle. Secondary mass savings resulting from body lightweighting are considered for the vehicles' engine, driveline and suspension.
Technical Paper
2014-04-01
Forrest Jehlik, Tim Laclair
Response surface methodology (RSM) techniques were applied to develop a predictive model of electric vehicle (EV) energy consumption over the Environmental Protection Agency's (EPA) standardized drive cycles. The model is based on measurements from a synthetic composite drive cycle. The synthetic drive cycle is a minimized statistical composite of the standardized urban (UDDS), highway (HWFET), and US06 cycles. The composite synthetic drive cycle is 20 minutes in length thereby reducing testing time of the three standard EPA cycles by over 55%. Vehicle speed and acceleration were used as model inputs for a third order least squared regression model predicting vehicle battery power output as a function of the drive cycle. The approach reduced three cycles and 46 minutes of drive time to a single test of 20 minutes. Application of response surface modeling to the synthetic drive cycle is shown to predict energy consumption of the three EPA cycles within 2.6% of the actual measured values.
Technical Paper
2014-04-01
Vitaly Y. Prikhodko, James E. Parks, Josh A. Pihl, Todd J. Toops
A commercial three-way catalyst (TWC) was evaluated for ammonia (NH3) generation on a 2.0-liter BMW lean burn gasoline direct injection engine as a component in a passive ammonia selective catalytic reduction (SCR) system. The passive NH3 SCR system is a potential low cost approach for controlling nitrogen oxides (NOX) emissions from lean burn gasoline engines. In this system, NH3 is generated over a close-coupled TWC during periodic slightly rich engine operation and subsequently stored on an underfloor SCR catalyst. Upon switching to lean, NOX passes through the TWC and is reduced by the stored NH3 on the SCR catalyst. NH3 generation was evaluated at different air-fuel equivalence ratios at multiple engine speed and load conditions. Near complete conversion of NOX to NH3 was achieved at λ=0.96 for nearly all conditions studied. At the λ=0.96 condition, HC emissions were relatively minimal, but CO emissions were significant. Operation at AFRs richer than λ=0.96 did not provide more NH3 yield and led to higher HC and CO emissions.
Technical Paper
2014-04-01
John Thomas, Shean Huff, Brian West
To quantify the fuel economy (FE) effect of some common vehicle accessories or alterations, a compact passenger sedan and a sport utility vehicle (SUV) were subjected to SAE J2263 coastdown procedures. Coastdowns were conducted with low tire pressure, all windows open, with a roof top or hitch-mounted cargo carrier, and with the SUV pulling an enclosed cargo trailer. From these coastdowns, vehicle dynamometer coefficients were developed which enabled the execution of vehicle dynamometer experiments to determine the effect of these changes on vehicle FE and emissions over standard drive cycles and at steady highway speeds. In addition, two minivans were subjected to coastdowns to examine the similarity in derived coefficients for two duplicate vehicles of the same model. The FE penalty associated with the rooftop cargo box mounted on the compact sedan was as high as 25-27% at higher speeds, where the aerodynamic drag is most pronounced. For both vehicles, use of a hitch mounted cargo tray carrying a similar load resulted in very small FE penalties, unlike the rooftop cargo box.
Technical Paper
2014-04-01
Michael D. Kass, Timothy Theiss, Steve Pawel, James Baustian, Les Wolf, Wolf Koch, Chris Janke
The compatibility of elastomeric materials used in fuel storage and dispensing applications was determined for test fuels representing neat gasoline and gasoline blends containing 10 and 17 vol.% ethanol, and 16 and 24 vol.% isobutanol. The actual test fuel chemistries were based on the aggressive formulations described in SAE J1681 for oxygenated gasoline. Elastomer specimens of fluorocarbon, fluorosilicone, acrylonitrile rubber (NBR), polyurethane, neoprene, styrene butadiene rubber (SBR) and silicone were exposed to the test fuels for 4 weeks at 60°C. After measuring the wetted volume and hardness, the specimens were dried for 20 hours at 60°C and then remeasured for volume and hardness. Dynamic mechanical analysis (DMA) was also performed to determine the glass transition temperature (Tg). Comparison to the original values showed that all elastomer materials experienced volume expansion and softening when wetted by the test fuels. The fluorocarbons underwent the least amount of swelling (<25 %) while the SBR and silicone samples exhibited the highest level of expansion (>100%).
Technical Paper
2014-04-01
Michael D. Kass, Chris Janke, Timothy Theiss, Steve Pawel, James Baustian, Les Wolf, Wolf Koch
The compatibility of plastic materials used in gasoline storage and dispensing applications was determined for test fuels representing neat gasoline (Fuel C), and blends containing 25% ethanol (CE25a), 16% isobutanol (CiBu16a), and 24% isobutanol (CiBu24a). A solubility analysis was also performed and compared to the volume swell results obtained from the test fuel exposures. The plastic specimens were exposed to each test fuel for16 weeks at 60°C. After measuring the wetted volume and hardness, the specimens were dried for 65 hours at 60°C and then remeasured for volume and hardness. Dynamic mechanical analysis (DMA), which measures the storage modulus as a function of temperature, was also performed on the dried specimens to determine the temperature associated with the onset of the glass-to-rubber transition (Tg). For many of the plastic materials, the solubility analysis was able to predict the relative volume swell for each test fuel. Those plastic materials commonly used as permeation barriers exhibited the least amount of volume and hardness change (<5%) when exposed to the test fuels.
Technical Paper
2014-04-01
Aaron Williams, Robert McCormick, Michael Lance, Chao Xie, Todd Toops, Rasto Brezny
Small impurities in the fuel can have a significant impact on the emissions control system performance over the lifetime of the vehicle. Of particular interest in recent studies has been the impact of sodium, potassium, and calcium that can be introduced either through fuel constituents, such as biodiesel, or as lubricant additives. In a collaboration between the National Renewable Energy Laboratory and the Oak Ridge National Laboratory, a series of accelerated aging studies have been performed to understand the potential impact of these metals on the emissions control system. This paper explores the effect of the rate of accelerated aging on the capture of fuel-borne metal impurities in the emission control devices and the subsequent impact on performance. Aging was accelerated by doping the fuel with high levels of the metals of interest. Three separate evaluations were performed, each with a different rate of accelerated aging. The aged emissions control systems were evaluated through vehicle testing and then dissected for a more complete analysis of the devices.
Technical Paper
2014-04-01
C. Scott Sluder, Brian H. West, Aron D. Butler, Arvon L. Mitcham, William J. Ruona
During the 1980s, the U.S. Environmental Protection Agency (EPA) incorporated the R factor into fuel economy calculations in order to address concerns about the impacts of test fuel property variations on corporate average fuel economy (CAFE) compliance, which is determined using the Federal Test Procedure (FTP) and Highway Fuel Economy Test (HFET) cycles. The R factor is defined as the ratio of the percent change in fuel economy to the percent change in volumetric heating value for tests conducted using two differing fuels. At the time the R-factor was devised, tests using representative vehicles initially indicated that an appropriate value for the R factor was 0.6. Reassessing the R factor has recently come under renewed interest after EPA's March 2013 proposal to adjust the properties of certification gasoline to contain significant amounts of ethanol. This proposed change will likely result in a significant deviation from the CAFE baseline test fuel heating value, and thus increased importance of the R factor.
Technical Paper
2014-04-01
John M. Storey, Sam Lewis, James Szybist, John Thomas, Teresa Barone, Mary Eibl, Eric Nafziger, Brian Kaul
Gasoline direct injection (GDI) engines can offer improved fuel economy and higher performance over their port fuel-injected (PFI) counterparts, and are now appearing in increasingly more U.S. and European vehicles. Small displacement, turbocharged GDI engines are replacing large displacement engines, particularly in light-duty trucks and sport utility vehicles, in order for manufacturers to meet more stringent fuel economy standards. GDI engines typically emit the most particulate matter (PM) during periods of rich operation such as start-up and acceleration, and emissions of air toxics are also more likely during this condition. A 2.0 L GDI engine was operated at lambda of 0.91 at typical loads for acceleration (2600 rpm, 8 bar BMEP) on three different fuels; an 87 anti-knock index (AKI) gasoline (E0), 30% ethanol blended with the 87 AKI fuel (E30), and 48% isobutanol blended with the 87 AKI fuel. E30 was chosen to maximize octane enhancement while minimizing ethanol-blend level and iBu48 was chosen to match the same fuel oxygen level as E30.
Technical Paper
2014-01-15
Matthew Langholtz, Mark Downing, Robin Graham, Fred Baker, Alicia Compere, William Griffith, Raymond Boeman, Martin Keller
Lignin by-products from biorefineries has the potential to provide a low-cost alternative to petroleum-based precursors to manufacture carbon fiber, which can be combined with a binding matrix to produce a structural material with much greater specific strength and specific stiffness than conventional materials such as steel and aluminum. The market for carbon fiber is universally projected to grow exponentially to fill the needs of clean energy technologies such as wind turbines and to improve the fuel economies in vehicles through lightweighting. In addition to cellulosic biofuel production, lignin-based carbon fiber production coupled with biorefineries may provide $2,400 to $3,600 added value dry Mg−1 of biomass for vehicle applications. Compared to producing ethanol alone, the addition of lignin-derived carbon fiber could increase biorefinery gross revenue by 30% to 300%. Using lignin-derived carbon fiber in 15 million vehicles per year in the US could reduce fossil fuel consumption by 2-5 billion liters year−1, reduce CO2 emissions by about 6.7 million Mg year−1, and realize fuel savings through vehicle lightweighting of $700 to $1,600 per Mg biomass processed.
Article
2013-08-29
Scientists at the U.S. Department of Energy's Oak Ridge National Laboratory have developed a new oxygen "sponge" that can easily absorb or shed oxygen atoms at low temperatures. Materials with these novel characteristics would be useful in devices such as rechargeable batteries, sensors, gas converters, and fuel cells.
Article
2013-06-10
Oak Ridge National Laboratory (ORNL) is preparing to open a Vehicle Systems Integration Laboratory in July, with a focus on powertrain. Manufacturers will be able to test different designs under real-world conditions, which helps save time and cost. 
Article
2013-04-17
The lab runs fuel-economy tests with A/C on maximum vs. A/C "comfort level," A/C-off and with windows open and closed. Some results are surprising, including an unexpected "crossover" point in testing on a Toyota Corolla.
Technical Paper
2013-04-08
Scott Curran, Reed Hanson, Robert Wagner, Rolf D. Reitz
In-cylinder blending of gasoline and diesel to achieve Reactivity Controlled Compression Ignition (RCCI) has been shown to reduce NOX and particulate matter (PM) emissions while maintaining or improving brake thermal efficiency as compared to conventional diesel combustion (CDC). The RCCI concept has an advantage over many advanced combustion strategies in that the fuel reactivity can be tailored to the engine speed and load allowing stable low-temperature combustion to be extended over more of the light-duty drive cycle load range. Varying the premixed gasoline fraction changes the fuel reactivity stratification in the cylinder providing further control of combustion phasing and pressure rise rate than the use of EGR alone. This added control over the combustion process has been shown to allow rapid engine operating point exploration without direct modeling guidance. This paper explores the efficiency, emissions and combustion characteristics of RCCI with gasoline and ultra-low sulfur diesel fuel over a wide speed and load range in a light-duty multi-cylinder diesel engine leading to the creation of an RCCI engine map.
Technical Paper
2013-04-08
John Thomas, Brian West, Shean Huff
Proper maintenance can help vehicles perform as designed, positively affecting fuel economy, emissions, and overall driveability. This paper addresses the issue of whether air filter replacement improves fuel economy. Described are measured results for increasing air filter pressure drop in turbocharged diesel-engine-powered vehicles, with primary focus on changes in vehicle fuel economy but also including emissions and performance. Older studies of carbureted gasoline vehicles have indicated that replacing a clogged or dirty air filter can improve vehicle fuel economy and, conversely, that a dirty air filter can be significantly detrimental to fuel economy. In contrast, a recent study showed that the fuel economy of modern gasoline vehicles is virtually unaffected by filter clogging due to the closed loop control and throttled operation of these engines. Because modern diesel engines operate without throttling (or with minimal throttling), a different result could be anticipated. The effects of clogged air filters on the fuel economy, acceleration, and emissions of three late model turbocharged diesel-powered vehicles were examined.
Technical Paper
2013-04-08
Brian Kaul, Robert Wagner, Johney Green
Operation of spark-ignition (SI) engines with high levels of charge dilution through exhaust gas recirculation (EGR) achieves significant engine efficiency gains while maintaining stoichiometric operation for compatibility with three-way catalysts. Dilution levels, however, are limited by cyclic variability - including significant numbers of misfires - that becomes more pronounced with increasing dilution. This variability has been shown to have both stochastic and deterministic components. Stochastic effects include turbulence, mixing variations, and the like, while the deterministic effect is primarily due to the nonlinear dependence of flame propagation rates and ignition characteristics on the charge composition, which is influenced by the composition of residual gases from prior cycles. The presence of determinism implies that an increased understanding of the dynamics of such systems could lead to effective control approaches that allow operation near the edge of stability, effectively extending the dilution limit.
Technical Paper
2013-04-08
Shean Huff, Brian West, John Thomas
On-road and laboratory experiments with a 2009 Ford Explorer and a 2009 Toyota Corolla were conducted to assess the fuel consumption penalty associated with air conditioner (A/C) use at idle and highway cruise conditions. Vehicle data were acquired on-road and on a chassis dynamometer. Data were gathered for various A/C settings and with the A/C off and the windows open. At steady speeds between 64.4 and 113 kph (40 and 70 mph), both vehicles consumed more fuel with the A/C on at maximum cooling load (compressor at 100% duty cycle) than when driving with the windows down. The Explorer maintained this trend beyond 113 kph (70 mph), while the Corolla fuel consumption with the windows down matched that of running the A/C at 121 kph (75 mph), and exceeded it at 129 kph (80 mph). The incremental fuel consumption rate penalty due to air conditioner use was nearly constant with a slight trend of increasing consumption with increasing vehicle (and compressor) speed. A lower fuel penalty due to A/C operation is observed at idle for both vehicles, likely due to the low compressor speed at this operating point, although the percentage increase due to A/C use is highest at idle.
Technical Paper
2013-04-08
Vitaly Y. Prikhodko, Scott J. Curran, James E. Parks, Robert M. Wagner
Reactivity Controlled Compression Ignition (RCCI) has demonstrated diesel-like or better brake thermal efficiency with significant reductions in nitrogen oxide (NOX) and particulate matter (PM) emissions. Hydrocarbon (HC) and carbon monoxide (CO) emission levels, on the other hand, are higher and similar to those of port-fuel-injected (PFI) gasoline engines. The higher HC and CO emissions combined with the lower exhaust temperatures during RCCI operation present a challenge for current exhaust aftertreatment technologies. The reduction of HC and CO emissions in a lean environment is typically achieved with an oxidation catalyst. In this work, several diesel oxidation catalysts (DOC) with different precious metal loadings were evaluated for effectiveness to control HC and CO emissions from RCCI combustion in a light-duty multi-cylinder engine operating on gasoline and diesel fuels. Each catalyst was evaluated under steady-state engine operation with temperatures ranging from 160 to 260°C.
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