Impact of the Injection Strategy on Soot Reactivity and Particle Properties of a GDI Engine

Koch, Sergej; Kubach, Heiko; Velji, Amin; Koch, Thomas; Hagen, Fabian P.; Bockhorn, Henning; Loukou, A.; Trimis, D.; Suntz, Rainer

doi:10.4271/2020-01-0392

Cited by 8 publications

(4 citation statements)

References 40 publications

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“…Sample A22_1 is obtained from the GDI engine operated with a modified injection pressure (87.5 bar compared to 100 bar for sample A22). Engine conditions are given in detail in Koch et al (2020). The ICE soot was complemented by samples from a commercial Diesel Direct Injection engine at injection pressures of 2200 bar, 1600 bar and 1200 bar (C50_2200, C50_1600, C50_1200).…”

Section: Methodsmentioning

confidence: 99%

“…The oxidation rates of the soot samples were measured through temperature programmed oxidation (TPO) employing thermogravimetric analysis (TGA) (Koch et al 2020;Hagen et al 2020). Dynamic, non-isothermal measurements were performed with a TG 209 F1 Libra thermo balance (Netzsch Gerätebau GmbH, Germany) at a heating rate of 5 K min −1 .…”

Section: Oxidation Ratesmentioning

confidence: 99%

“…The single steps of the procedure used in this work are depicted in Fig. 4, see also Koch et al (2020). The single computing steps are given in the left part of the figure and illustrated with the help of corresponding HRTEM images (right part).…”

Section: Hrtem Image Preparation and Processingmentioning

confidence: 99%

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Why Soot is not Alike Soot: A Molecular/Nanostructural Approach to Low Temperature Soot Oxidation

Hagen

Hardock

Koch

et al. 2020

Flow Turbulence Combust

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Due to worldwide increasingly sharpened emission regulations, the development of Gasoline Direct Injection and Diesel Direct Injection engines not only aims at the reduction of the emission of nitrogen oxides but also at the reduction of particulate emissions. Regarding present regulations, both tasks can be achieved solely with the help of exhaust after treatment systems. For the reduction of the emission of particulates, Gasoline (GPF) and diesel Particulate Filters (DPF) offer a solution and their implementation is intensely promoted. Under optimal conditions particulates retained on particulate filters are continuously oxidized with the exhaust residual oxygen so that the particulate filter (PF) is regenerated possibly without any additional intervention into the engine operating parameters. The regeneration behavior of PF depends on the reaction rates of soot particles with oxidative reactants at exhaust gas temperatures. The reaction rates of soot particles from internal combustion engines (ICE) often are discussed in terms of order/disorder on the particle nanoscale, the concentration and kind of functional groups on the particle surfaces, and the content of (mostly polycyclic aromatic) hydrocarbons in the soot. In this work the reactivity of different kinds of soot (soot from flames, soot from ICE, carbon black) under oxidation conditions representative for PF regeneration is investigated. Soot reactivity is determined in dynamic Temperature Programmed Oxidation (TPO) experiments and the soot primary particle morphology and nanostructure is investigated by High-Resolution Transmission Electron Microscopy (HRTEM). An image analysis method based on known methods from the literature and improving some infirmities is used to evaluate morphology and nanostructural characteristics. From this, primary particle size distributions, length and separation distance distributions as well as tortuosities of fringes within the primary particle structures are obtained. Further, UV-visible spectroscopy and Raman scattering and other diagnostic techniques are used to study the properties connected to the reactivity of soot and to corroborate the experimental findings. It is found that nanostructural characteristics predominantly affect reactivity. Oxidation rates are derived from TPO and interpreted on a molecular basis from quantum chemistry calculations revealing a replication/activation oxidation mechanism.

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Section: Methodsmentioning

confidence: 99%

Section: Oxidation Ratesmentioning

confidence: 99%

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Why Soot is not Alike Soot: A Molecular/Nanostructural Approach to Low Temperature Soot Oxidation

Hagen

Hardock

Koch

et al. 2020

Flow Turbulence Combust

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“…It is known that the engine system needs to be optimally designed and to be adjusted adequate engine operating parameters to ensuring engine performance [12][13][14][15] . And reducing the cylinder-tocylinder variation should be basically secured to realize the optimized engine performance for a multi-cylinder engine.…”

Section: Introductionmentioning

confidence: 99%

Effect of Intake Manifold Geometry on Cylinder-to-Cylinder Variation and Tumble Enhancement in Gasoline Direct Injection Engine

Shin

Kim

Son

et al. 2022

Preprint

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In order to improve the performance of the gasoline direct injection engine system, it is fundamentally important to reduce the cylinder-to-cylinder variation which affected by the intake manifold geometry. Furthermore, the early tumble development which influences the characteristics of the mixture as followed by the atomization and evaporation of the fuel, also greatly affects engine performance. Thus, in this study, the cylinder-to-cylinder variation in volumetric efficiency and tumble for two different type of intake manifold (curved type and straight type) was investigated using computational fluid dynamic program, CONVERE v2.4. And influence of the intake manifold curve radius to the early flow intensity and tumble development was analyzed. As a result, it was advantageous for cylinder-to-cylinder variation in the straight intake manifold compared to the curved intake manifold. When the intake manifold curve radius was increased in the straight intake manifold, it was effective in strengthening the early flow and tumble intensity. At 3000 rpm, the distance from the intake manifold inlet to the port also had an effect. Therefore, it is possible to improve the intake manifold performance by increasing the intake manifold curve radius and adapting turbocharging at engine speeds above 3000 rpm.

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Influence of Global Operating Parameters on the Reactivity of Soot Particles from Direct Injection Gasoline Engines

Koch

Hagen

Büttner

et al. 2022

Emiss. Control Sci. Technol.

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The aim of this study is to investigate the impact of global operating parameters, e.g., engine speed, brake mean effective pressure, and air–fuel ratio, of a turbocharged 4-cylinder GDI engine on the reactivity of soot particles against oxidation. The knowledge of soot reactivity is crucial for optimizing gasoline particulate filter regeneration strategies and is, consequently, a key parameter for reducing fuel consumption and CO2 emissions. In this work, time-resolved in-cylinder soot concentrations and exhaust particle size distributions are measured by using two-color pyrometry, engine exhaust particle sizer and smoke meter, respectively. Reactivity against oxidation by molecular oxygen is determined by temperature programmed oxidation analysis. To derive a physicochemical explanation for varying soot reactivity, the morphological and nanostructural primary particle structure of collected samples is analyzed using high-resolution electron microscopy and image analysis algorithms. The results reveal that engine operating parameters affect soot reactivity differently. While engine speed has only a slight effect, a reduction of air/fuel ratio (λ < 1.0) or an increase of BMEP > 10 bar significantly reduces the soot oxidation reactivity. These findings give evidence, that the quality of the fuel/air mixture is a significant parameter influencing soot reactivity. Measured soot concentrations substantiate the hypothesis that low-sooty homogeneous premixed combustion of a homogeneous fuel/air mixture favors formation of high-reactive soot particle fractions. Reactive soot particle aggregates are composed of multiple soot fractions of different reactivity. Reactive primary particles are composed of short graphene-like layers and vice versa, providing a physicochemical explanation for varying soot reactivity depending on engine operating conditions.

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Impact of the Injection Strategy on Soot Reactivity and Particle Properties of a GDI Engine

Cited by 8 publications

References 40 publications

Why Soot is not Alike Soot: A Molecular/Nanostructural Approach to Low Temperature Soot Oxidation

Why Soot is not Alike Soot: A Molecular/Nanostructural Approach to Low Temperature Soot Oxidation

Effect of Intake Manifold Geometry on Cylinder-to-Cylinder Variation and Tumble Enhancement in Gasoline Direct Injection Engine

Influence of Global Operating Parameters on the Reactivity of Soot Particles from Direct Injection Gasoline Engines

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