Simulation of Catalytic Oxidation and Selective Catalytic NOx Reduction in Lean-Exhaust Hybrid Vehicles

Smith

Energy Conversion and Management

et al. 2015

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We present fuel savings estimates resulting from the combined implementation of multiple advanced energy management technologies in both conventional and parallel hybrid class 8 diesel trucks. The energy management technologies considered here have been specifically targeted by the 21 st Century Truck Partnership (21 CTP) between the U.S. Department of Energy and U.S. industry and include advanced combustion engines, waste heat recovery, and reductions in auxiliary loads, rolling resistance, aerodynamic drag, and gross vehicle weight. We estimate that combined use of all these technologies in hybrid trucks has the potential to improve fuel economy by more than 60% compared to current conventional trucks, but this requires careful system integration to avoid nonoptimal interactions. Major factors to be considered in system integration are discussed.

Section: Potential Benefits Of Class 8 Hd Truck Hybridizationmentioning

confidence: 99%

The evaluation of developing vehicle technologies on the fuel economy of long-haul trucks

Smith

Energy Conversion and Management

et al. 2015

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“…32 Details of the simplified DOC model used here are provided in a previous publication. 24 Briefly, three global one-step reactions are considered, including CO oxidation, HC oxidation, and NO oxidation (see equations (1)-( 3)). We assume that the global performance of the DOC device can be approximated by a single, representative one-dimensional channel with transient plug flow.…”

Section: The Doc Modelmentioning

confidence: 99%

“…Instead, it is necessary to utilize new lean exhaust technologies such as lean NO x traps (LNTs), selective catalytic reduction (SCR), and diesel particulate filters (DPFs). [24][25][26] These emission control technologies can directly impact fuel consumption and also are sensitive to engine exhaust transients, especially temperature. Thus utilizing PCCI technology in combination with lean exhaust emissions controls requires sophisticated models and control strategies to accurately predict and control the performance of both the engine and after-treatment system in response to fluctuating engine power demands.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, the engine and aftertreatment models need to faithfully capture the transient responses of devices based on the most recent technology. For simulating both conventional and hybrid vehicles, we have developed physically-based models for current lean exhaust NO x and PM controls 24,26,27 and also a methodology that makes it possible to account for the unsteady exhaust emissions and temperature from representative engines. 28 These models and methodology have been implemented into the Powertrain Systems Analysis Toolkit (PSAT) vehicle simulation platform developed by Argonne National Laboratory 29 in order to study the impact of PCCI on fuel economy and emissions reduction in conventional and HEVs.…”

Section: Introductionmentioning

confidence: 99%

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Simulating the impact of premixed charge compression ignition on light-duty diesel fuel economy and emissions of particulates and NO_x

Proceedings of the Institution of Mechanical Engineers, Part D:

Wagner

et al. 2012

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We report results from urban drive cycle simulations of a light-duty conventional vehicle and a similar hybrid electric vehicle, both of which are equipped with diesel engines capable of operating in either conventional diesel combustion mode or in premixed charge compression ignition mode. Both simulated vehicles include lean exhaust after-treatment trains for controlling hydrocarbon, carbon monoxide, nitrogen oxide, and particulate matter emissions. Our results indicate that, in the simulated conventional vehicle, premixed charge compression ignition can significantly reduce fuel consumption and emissions by reducing the need for lean nitrogen oxide traps and diesel particulate filter regeneration. However, the opportunity for utilizing premixed charge compression ignition in the simulated hybrid electric vehicle is limited because the engine typically experiences higher loads and multiple stop–start transients that are outside the allowable premixed charge compression ignition operating range. This suggests that developing ways of extending the premixed charge compression ignition operating range combined with improved control strategies for engine and emissions control management will be especially important for realizing the potential benefits of premixed charge compression ignition in hybrid electric vehicles.

“…Catalyzed diesel particulate filters remove particulate matter from the engine exhaust by mechanical filtration; the trapped solid carbon including adsorbed residual HCs is subsequently oxidized. The particulate oxidation can occur during normal operation via oxidation by NO 2 at moderate exhaust temperatures (∼300° to 350°C) (22,23). The SCR model was fitted to laboratory bench-reactor measurements of a commercial chabazite copper-zeolite SCR catalyst commonly sold on diesel vehicles (14).…”

Section: Aftertreatment System Modelmentioning

confidence: 99%

Comparison of Parallel and Series Hybrid Power Trains for Transit Bus Applications

Transportation Research Record

Smith

et al. 2016

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The fuel economy and emissions of conventional and hybrid buses equipped with emissions aftertreatment were evaluated via computational simulation for six representative city bus drive cycles. Both series and parallel configurations for the hybrid case were studied. The simulation results indicated that series hybrid buses have the greatest overall advantage in fuel economy. The series and parallel hybrid buses were predicted to produce similar carbon monoxide and hydrocarbon tailpipe emissions but were also predicted to have reduced tailpipe emissions of nitrogen oxides compared with the conventional bus in higher speed cycles. For the New York bus cycle, which has the lowest average speed among the cycles evaluated, the series bus tailpipe emissions were somewhat higher than they were for the conventional bus; the parallel hybrid bus had significantly lower tailpipe emissions. All three bus power trains were found to require periodic active diesel particulate filter regeneration to maintain control of particulate matter. Plug-in operation of series hybrid buses appears to offer significant fuel economy benefits and is easily employed because of the relatively large battery capacity that is typical of the series hybrid configuration.