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Technical Keynote - Introduction to EcoCAR The NeXt Challenge Year Three: Vehicle Refinement and Testing

This presentation will introduce the overall goals of the EcoCAR competition in brief, and will go into the third and final year of the competition in detail. The final year of competition saw teams refining and testing their student-built advanced technology vehicles including hybrids, plug-in hybrids, hydrogen fuel cell PHEVs and one battery electric. Important events, such as the Spring Workshop chassis dynamometer testing event at the U.S. Environmental Protection agency, as well as significant competition results, such as vehicle performance, consumer acceptability and efficiency will be presented. Presenter Patrick Walsh

Impact of Supervisory Control on Criteria Tailpipe Emissions for an Extended-Range Electric Vehicle

The Hybrid Electric Vehicle Team of Virginia Tech participated in the three-year EcoCAR Advanced Vehicle Technology Competition organized by Argonne National Laboratory, and sponsored by General Motors and the U.S. Department of Energy. The team established goals for the design of a plug-in, range-extended hybrid electric vehicle that meets or exceeds the competition requirements for EcoCAR. The challenge involved designing a crossover SUV powertrain to reduce fuel consumption, petroleum energy use, regulated tailpipe emissions, and well-to-wheel greenhouse gas emissions. To interface with and control the hybrid powertrain, the team added a Hybrid Vehicle Supervisory Controller, which enacts a torque split control strategy. This paper builds on an earlier paper [1] that evaluated the petroleum energy use, criteria tailpipe emissions, and greenhouse gas emissions of the Virginia Tech EcoCAR vehicle and control strategy from the 2nd year of the competition.
Technical Paper

Nanofluids for Vehicle Thermal Management

Applying nanotechnology to thermal engineering, ANL has addressed the interesting and timely topic of nanofluids. We have developed methods for producing both oxide and metal nanofluids, studied their thermal conductivity, and obtained promising results: (1) Stable suspensions of nanoparticles can be achieved. (2) Nanofluids have significantly higher thermal conductivities than their base liquids. (3) Measured thermal conductivities of nanofluids are much greater than predicted. For these reasons, nanofluids show promise for improving the design and performance of vehicle thermal management systems. However, critical barriers to further development and application of nanofluid technology are agglomeration of nanoparticles and oxidation of metallic nanoparticles. Therefore, methods to prevent particle agglomeration and degradation are required.
Technical Paper

Effect of Soot Loading on the Thermal Characteristics of Diesel Engine Oils

When compared with new oil, used diesel engine oils exhibited thermal conductivity that increases as the concentration of soot increases. The magnitude of the effect depends on the oil composition, and on the size and dispersion of the soot particles. Although soot in engine oil is generally deleterious to engine performance from the standpoint of wear and deposits, no negative effects were observed on the thermal performance of the oil itself; indeed, even slight positive effects are expected for oils that maintain soot in stable dispersion. Therefore, the thermal challenge for engine oils in diesel engines that use exhaust gas recirculation will be to prevent soot deposition on engine surfaces.
Technical Paper

Effects of Ethanol Additives on Diesel Particulate and NOx Emissions

Particulate and nitrogen oxide emissions from a 1.9-liter Volkswagen diesel engine were measured for three different fuels: neat diesel fuel, a blend of diesel fuel with 10% ethanol, and a blend of diesel fuel with 15% ethanol. Engine-out emissions were measured on an engine dynamometer for five different speeds and five different torques using the standard engine-control unit. Results show that particulate emissions can be significantly reduced over approximately two-thirds of the engine map by using a diesel-ethanol blend. Nitrogen oxide emissions can also be significantly reduced over a smaller portion of the engine map by using a diesel-ethanol blend. Moreover, there is an overlap between the regions where particulate emissions can be reduced by up to 75% and nitrogen oxide emissions are reduced by up to 84% compared with neat diesel fuel.
Technical Paper

Challenges in Reforming Gasoline: All Components are Not Created Equal

Gasoline is a complex fuel. Many of the constituents of gasoline that are beneficial for the internal combustion engine (ICE) are expected to be challenging for on-board reformers in fuel-cell vehicles. To address these issues, the autothermal reforming of gasoline and individual components of gasoline has been investigated. The results indicate that aromatic components require higher temperatures and longer contact times to reform than paraffinic components. Napthenic components require higher temperatures to reform, but can be reformed at higher space velocities than paraffinic components. The effects of sulfur are dependent on the catalyst. These results suggest that further evolution of gasoline could reduce the demands on the reformer and provide a better fuel for a fuel-cell vehicle.
Technical Paper

An Assessment of Electric Vehicle Life Cycle Costs to Consumers

A methodology for evaluating life cycle cost of electric vehicles (EVs) to their buyers is presented. The methodology is based on an analysis of conventional vehicle costs, costs of drivetrain and auxiliary components unique to EVs, and battery costs. The conventional vehicle's costs are allocated to such subsystems as body, chassis, and powertrain. In electric vehicles, an electric drive is substituted for the conventional powertrain. The current status of the electric drive components and battery costs is evaluated. Battery costs are estimated by evaluating the material requirements and production costs at different production levels; battery costs are also collected from other sources. Costs of auxiliary components, such as those for heating and cooling the passenger compartment, are also estimated. Here, the methodology is applied to two vehicle types: subcompact car and minivan.
Technical Paper

Lifecycle Analysis for Freight Transport

This paper evaluates the total lifecycle impacts for hauling freight long distances over land in the United States. The dominant modes of surface freight transport in the United States are large motor trucks (tractor-semitrailer combinations) and trains. These vehicles account for a significant portion of the transportation sector's petroleum usage and atmospheric emissions (among which nitrogen oxides and particulate matter are especially important). The objective of this paper is to evaluate the potential for reductions in energy use (in particular, petroleum use) and atmospheric emissions that result from freight transport, possibly as the result of research and development on improved technology or alternative fuels, such as Fischer-Tropsch diesel and natural gas, or from mode shifts in competitive markets. The impacts examined include energy use, both in toto and the petroleum fraction, and emissions of greenhouse gases and nitrogen oxides and particulate matter.
Technical Paper

Exhaust Emissions of a Vehicle with a Gasoline Direct-Injection Engine

Their high fuel economy is making light-duty vehicles with spark-ignition direct-injection (SIDI) engines attractive. However, the implications for exhaust emissions and the effects of fuel quality on emissions are not clear for this type of engine. A Mitsubishi Legnum with a 1.8-L GDI™ engine was tested on federal test procedure (FTP) and highway fuel economy cycles. The results were compared with those for a production Dodge Neon vehicle with a 2.0-L port fuel-injection (PFI) engine. The Mitsubishi was tested with Indolene, Amoco Premium Ultimate, and a low-sulfur gasoline. The Neon was tested only with Indolene. Both engine-out and tailpipe emissions were measured. Second-by-second emissions and hydrocarbon speciation were also evaluated. The SIDI engine provided up to 24% better fuel economy than the PFI engine on the highway cycle. Tailpipe emissions of oxides of nitrogen (NOx) from the SIDI vehicle using low-sulfur fuel were 40% less than those when using Indolene.
Technical Paper

Variable Air Composition with Polymer Membrane - A New Low Emissions Tool

Air can be enriched with oxygen and/or nitrogen by selective permeation through a nonporous polymer membrane; this concept offers numerous potential benefits for piston engines. The use of oxygen-enriched intake air can significantly reduce exhaust emissions (except NOx), improve power density, lessen ignition delay, and allow the use of lower-grade fuels. The use of nitrogen-enriched air as a diluent can lessen NOx emissions and may be considered an alternative to exhaust gas recirculation (EGR). Nitrogen-enriched air can also be used to generate a monatomic-nitrogen stream, with nonthermal plasma, to treat exhaust NOx. With such synergistic use of variable air composition from an on-board polymer membrane, many emissions problems can be solved effectively. This paper presents an overview of different applications of air separation membranes for diesel and spark-ignition engines. Membrane characteristics and operating requirements are examined for use in automotive engines.
Technical Paper

Cylinder Pressure Analysis of a Diesel Engine Using Oxygen-Enriched Air and Emulsified Fuels

Analytical studies of oxygen-enriched diesel engine combustion have indicated the various benefits as well as the need for using cheaper fuels with water addition. To verify analytical results, a series of single-cylinder diesel engine tests were conducted to investigate the concepts of oxygen enriched air (OEA) for combustion with water emulsified fuels. Cylinder pressure traces were obtained for inlet oxygen levels of 21% to 35% and fuel emulsions with water contents of 0% to 20%. Data for emulsified fuels included no. 2 and no. 4 diesel fuels. The excess oxygen for the tests was supplied from compressed bottled oxygen connected to the intake manifold. The cylinder pressure data was collected with an AVL pressure transducer and a personal computer-based data logging system. The crank angle was measured with an optical encoder. In each data run, 30 consecutive cycles were recorded and later averaged for analysis.
Technical Paper

Analysis of Life Cycle Costs for Electric Vans with Advanced Battery Systems

The performance of advanced Zn/Br2, LiAl/FeS, Na/S, Ni/Fe, and Fe/Air batteries in electric vans was compared to that of tubular lead-acid technology. The MARVEL computer analysis system evaluated these batteries for the G-Van and IDSEP vehicles over two driving schedules. Each of the advanced batteries exhibited the potential for major improvements in both range and life cycle cost compared with tubular lead-acid. A sensitivity analysis revealed specific energy, battery initial cost, and cycle life to be the dominant factors in reducing life cycle cost for the case of vans powered by tubular lead-acid batteries.
Technical Paper

Comparison of In-Nozzle Flow Characteristics of Naphtha and N-Dodecane Fuels

It is well known that in-nozzle flow behavior can significantly influence the near-nozzle spray formation and mixing that in turn affect engine performance and emissions. This in-nozzle flow behavior can, in turn, be significantly influenced by fuel properties. The goal of this study is to characterize the behavior of two different fuels, namely, a straight-run naphtha that has an anti-knock index of 58 (denoted as “Full-Range Naphtha”) and n-dodecane, in a simulated multi-hole common-rail diesel fuel injector. Simulations were carried out using a fully compressible multi-phase flow representation based on the mixture model assumption with the Volume of Fluid method. Our previous studies have shown that the characteristics of internal and near-nozzle flow are strongly related to needle motion in both the along- and off-axis directions.
Technical Paper

Energy Efficiency Benefits of Active Transmission Warm-up under Real-World Operating Conditions

Active transmission warm-up systems are used by automotive manufacturers in effort to increase powertrain efficiency and decrease fuel consumption. These systems vary from one manufacturer to another, but their main goal is to capture waste heat from the powertrain and accelerate transmission fluid warm-up. In this study, the fuel consumption benefit from the active transmission warm-up system in a 2013 Ford Taurus 2.0 L EcoBoost is quantified on a cold start UDDS drive cycle at ambient temperatures of −7 and 21 °C. In addition to this, the fuel consumption and greenhouse gas emissions impact on the EPA 5-cycle test, hot start HWY drive cycle, and a cold start, constant speed drive cycle is also quantified. An extra effort to determine the maximum possible benefit of active transmission warm-up is made by modifying the test vehicle to provide external heating to pre-heat and further accelerate the transmission fluid warm-up.
Technical Paper

In-Cylinder Oxygen Mass Fraction Estimation Method for Minimizing Cylinder-to-Cylinder Variations

Recent developments in advanced combustion engines have demonstrated the potential increases in efficiency and reductions in emissions through low temperature combustion (LTC). These combustion modes often rely on high exhaust gas recirculation (EGR), early fuel injection systems, and in some cases a combination of fuels with different reactivities. Despite the advantages of LTC, such operations are highly sensitive to the in-cylinder pre-combustion conditions and face significant challenges in multi-cylinder operation due to cylinder-to-cylinder variations of the combustion process. The cause of cylinder-to-cylinder variations is strongly tied to non-uniform trapped mass. In particular, in-cylinder oxygen concentration plays a critical role in the combustion process of each cylinder and can be leveraged to predict combustion characteristics and to develop control algorithms that mitigate cylinder-to-cylinder variation.
Technical Paper

Achieving Stable Engine Operation of Gasoline Compression Ignition Using 87 AKI Gasoline Down to Idle

For several years there has been a great deal of effort made in researching ways to run a compression ignition engine with simultaneously high efficiency and low emissions. Recently much of this focus has been dedicated to using gasoline-like fuels that are more volatile and less reactive than conventional diesel fuel to allow the combustion to be more premixed. One of the key challenges to using fuels with such properties in a compression ignition engine is stable engine operation at low loads. This paper provides an analysis of how stable gasoline compression ignition (GCI) engine operation was achieved down to idle speed and load on a multi-cylinder compression ignition engine using only 87 anti-knock index (AKI) gasoline. The variables explored to extend stable engine operation to idle included: uncooled exhaust gas recirculation (EGR), injection timing, injection pressure, and injector nozzle geometry.
Technical Paper

Characterization of Oxidation Behaviors and Chemical-Kinetics Parameters of Diesel Particulates Relevant to DPF Regeneration

At the current stage of engine technology, diesel engines typically require diesel particulate filter (DPF) systems to meet recent particulate emissions standards. To assure the performance and reliability of DPF systems, profound understanding of filtration and regeneration mechanisms is required. Among extensive efforts for developing advanced DPF systems, the development of effective thermal management strategies, which control the thermal runaway taking place in oxidation of an excess amount of soot deposit in DPF, is quite challenging. This difficulty stems mainly from lack of sufficient knowledge and understanding about DPF regeneration mechanisms, which need detailed information about oxidation of diesel particulate matter (PM). Therefore, this work carried out a series of oxidation experiments of diesel particulates collected from a DPF on a diesel engine, and evaluated the oxidation rates of the samples using a thermo-gravimetric analyzer (TGA).
Technical Paper

Efficiency Improved Combustion System for Hydrogen Direct Injection Operation

This paper reports on research activities aiming to improve the efficiency of direct injected, hydrogen powered internal combustion engines. In a recent major change in the experimental setup the hydrogen single cylinder research engine at Argonne National Laboratory was upgraded to a new engine geometry providing increased compression ratio and a longer piston stroke compared to its predecessor. The higher compression ratio and the more advantageous volume to surface ratio of the combustion chamber are both intended to improve the overall efficiency of the experimental setup. Additionally, a new series of faster acting, piezo-activated injectors is used with the new engine providing increased flexibility for the optimization of DI injection strategies. This study focuses on the comparison of experimental data of the baseline versus the improved single cylinder research engine for similar engine operating conditions.
Technical Paper

Accurate Measurements of Heat Release, Oxidation Rates, and Soluble Organic Compounds of Diesel Particulates through Thermal Reactions

In an effort of providing better understanding of regeneration mechanisms of diesel particulate matter (PM), this experimental investigation focused on evaluating the amount of heat release generated during the thermal reaction of diesel PM and the concentrations of soluble organic compounds (SOCs) dissolved in PM emissions. Differences in oxidation behaviors were observed for two different diesel PM samples: a SOC-containing PM sample and a dry soot sample with no SOCs. Both samples were collected from a cordierite particulate filter membrane in a thermal reactor connected to the exhaust pipe of a light-duty diesel engine. A differential scanning calorimeter (DSC) and a thermogravimetric analyzer (TGA) were used to measure the amount of heat release during oxidation, along with subsequent oxidation rates and the concentrations of SOCs dissolved in particulate samples, respectively.
Technical Paper

Study of Regulated and Non-Regulated Emissions from Combustion of Gasoline, Alcohol Fuels and their Blends in a DI-SI Engine

Alternative fuels for internal combustion engines have been the subject of numerous studies. The new U.S. Renewable Fuel Standard has made it a requirement to increase the production of ethanol and advanced biofuels to 36 billion gallons by 2022. Because corn-based ethanol will be capped at 15 billion gallons, 21 billion gallons must come from the advanced biofuels category. A potential source to fill the gap may be butanol and its isomers as they possess fuel properties superior to ethanol. Recently, concerns have been raised about emission of currently non-regulated constituents, aldehydes in particular, from alcohol-based fuels. In an effort to assess the relative impact of the U.S. Renewable Fuel Standards on emissions from a modern gasoline engine, both regulated and non-regulated gas constituents were measured from the combustion of three different alcohol isomers in a modern direct-injected (DI) spark ignition (SI) gasoline engine.