Review of Vehicle Engine Efficiency and Emissions

Joshi, Ameya

doi:10.4271/2017-01-0907

Cited by 107 publications

(34 citation statements)

References 46 publications

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“…To meet the soot emission regulation becomes the bottle neck of modern engine development, especially for the diesel engines. Diesel particulate filter (DPF) has been extensively used in modern diesel engine, which traps many engine-out soot particles (Johnson and Joshi, 2017;Johnson, 2009). Gasoline particulate filter (GPF) (Chan et al, 2012;Fischer et al, 2017) is being considered as a very important solution for PM emission of gasoline direct-injection engines.…”

Section: Introductionmentioning

confidence: 99%

Raman spectroscopy of diesel and gasoline engine-out soot using different laser power

2019

Journal of Environmental Sciences

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We studied engine-out soot samples collected from a heavy-duty direct-injection diesel engine and a port-fuel injection gasoline spark-ignition engine. The two types of soot samples were characterized using Raman spectroscopy with different laser power. A Matlab program using least-square-method with trust-region-reflective algorithm was developed for curve fitting. We used a DOE (design of experiments) method to avoid local convergence. This method was used for two-band fitting and three-band fitting. The fitting results were used to determine the intensity ratio of D and G Raman bands. We find that high laser power may cause oxidation of soot samples, which gives higher D/G intensity ratio. Diesel soot has consistently higher amorphous/graphitic carbon ratio and thus higher oxidation reactivity, in comparison to gasoline soot, which is revealed by the higher D/G intensity ratio in Raman spectra measured under the same laser power. Keywords:Raman spectroscopy diesel engine gasoline engine soot emission particulate matter ---

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Section: Introductionmentioning

confidence: 99%

Raman spectroscopy of diesel and gasoline engine-out soot using different laser power

2019

Journal of Environmental Sciences

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“…"Three-way" catalysts, although being successfully employed for NO x abatement in gasoline-powered vehicles, are not sufficiently effective in the O 2 -rich exhaust environment typically in "lean-burn" engines (e.g., diesel engines). In this case, one of the leading strategies for NO x emission control (DeNO x ) is the selective catalytic reduction with ammonia as reducing agent (NH 3 -SCR) [3]. In NH 3 -SCR systems, an aqueous urea solution (AdBlue TM , VDA, Berlin, Germany) is injected into the hot exhaust gas mixture and it subsequently decomposes to form gaseous NH 3 [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

“…In this case, one of the leading strategies for NO x emission control (DeNO x ) is the selective catalytic reduction with ammonia as reducing agent (NH 3 -SCR) [3]. In NH 3 -SCR systems, an aqueous urea solution (AdBlue TM , VDA, Berlin, Germany) is injected into the hot exhaust gas mixture and it subsequently decomposes to form gaseous NH 3 [3][4][5]. Depending on the NO to NO 2 ratio, different SCR reactions may occur and the most important one is the so-called "standard SCR" [2,4,6]:…”

Section: Introductionmentioning

confidence: 99%

“…Particularly, Cu-zeolites show outstanding low-temperature performance and low sensitivity to NO 2 concentration in the exhaust flow [4,5]. Due to their better performance (in terms of both activity and hydrothermal stability) when compared to large-and medium-pore zeolite materials, Cu-exchanged small-pore chabazite (CHA) zeolites (e.g., Cu-SSZ-13 and Cu-SAPO-34) are now the most common choice for NH 3 -SCR [2][3][4][5][6]8,9]. Nevertheless, a deeper mechanistic understanding of Cu-zeolite catalyzed NH 3 -SCR is still needed in order to develop even more efficient catalysts for meeting the increasingly stringent NO x emission legislation [1,3,4].…”

Section: Introductionmentioning

confidence: 99%

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Mobility of NH3-Solvated CuII Ions in Cu-SSZ-13 and Cu-ZSM-5 NH3-SCR Catalysts: A Comparative Impedance Spectroscopy Study

2018

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The mobility of NH 3 -solvated Cu ions within the zeolite framework has been recently identified as a key factor for the kinetics of the selective catalytic reduction of NO x with NH 3 (NH 3 -SCR) over Cu-zeolite catalysts at low temperatures. Here, we utilize in situ impedance spectroscopy to explore the mobility of NH 3 -solvated Cu II ions, i.e., Cu II (NH 3 ) n , in Cu-SSZ-13 and Cu-ZSM-5 zeolites with varied Cu ion exchange levels, and observed that both the zeolite framework (CHA or MFI) and the Cu exchange level influence the high-frequency dielectric relaxation processes that are associated with the short-range (local) motion of Cu II (NH 3 ) n . Our results suggest that the local motion of Cu II (NH 3 ) n species is favored within the CHA framework due to the unique cage structure, and thereby contribute to the overall ion conductivity at high frequencies, which, on the contrary, is not observed for ZSM-5, where NH 3 -solvated Cu 2+ ions do not experience a comparable constrained space for local motion. This study sheds new light on the mobility of Cu active sites under NH 3 -SCR related reaction conditions and may contribute to an advanced understanding of the underlying mechanism.

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“…Therefore, increasing the volumetric efficiency and reducing the loss caused by friction and pumping for the maximum output according to each operating condition improves the power performance. During this optimization process, the optimum intake and exhaust flow rate and timing are adjusted according to the operating conditions without lowering the torque stability and the maximum output [3]. For instance, early exhaust valve opening (EEVO) and cylinder deactivation are implemented to raise the exhaust gas temperatures for DOC activation [4].…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Effects of Internal EGR by Variable Exhaust Valve Actuation with Post Injection on Auto-ignited Combustion and Emission Performance

Cho

Lee

2018

Applied Sciences

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Variable valve mechanisms are usually applied to a gasoline combustion engine to improve its power performance by controlling the amount of intake air according to the operating load. These mechanisms offer one possibility of resolving the conflict of objectives between a further reduction of raw emissions and an improvement in fuel efficiency. In recent years, variable valve control systems have become extremely important in the diesel combustion engine. Importantly, it has been shown that there are several potential benefits of applying variable valve timing (VVT) to a compression ignition engine. Valve train variability could offer one option to achieve the reduction goals of engine-out emissions and fuel consumption. The aim of this study was to investigate the effects on part load combustion and emission performance of internal exhaust gas recirculation (EGR) by variable exhaust valve lift actuation using a cam-in-cam system, which is an electronically variable valve device with a variable inside cam retarded to about 30 degrees. Numerical simulation based on GT-POWER has been performed to predict the NO x reduction strategy at the part load operating point of 1200 rpm in a four-valve diesel engine. A GT-POWER model of a common-rail direct injection engine with internal EGR was built and verified with experimental data. As a result, large potential for reducing NO x emissions through the use of exhaust valve control has been identified. Namely, it is possible to utilize heat efficiently as recompression of retarded post injection with downscaled specification of the exhaust valve rather than the intake valve, even if the CIC V1 condition with a reduction of the exhaust valve has a higher internal EGR rate of about 2% compared to that of the CIC V2 condition.

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Review of Vehicle Engine Efficiency and Emissions

Cited by 107 publications

References 46 publications

Raman spectroscopy of diesel and gasoline engine-out soot using different laser power

Raman spectroscopy of diesel and gasoline engine-out soot using different laser power

Mobility of NH3-Solvated CuII Ions in Cu-SSZ-13 and Cu-ZSM-5 NH3-SCR Catalysts: A Comparative Impedance Spectroscopy Study

Investigation on the Effects of Internal EGR by Variable Exhaust Valve Actuation with Post Injection on Auto-ignited Combustion and Emission Performance

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