A Feedgas HC Emission Model for SI Engines Including Partial Burn Effects

Trinker, Frederick H.; Cheng, James; Davis, George C.

doi:10.4271/932705

Cited by 26 publications

(7 citation statements)

References 9 publications

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“…The most commonly modeled sources of HC in 1D/0D models are the combustion chamber crevices due to their strong contribution to total HC emissions. 31,36,[39][40][41][42][43][44][45][46] Many studies presented the modeling of the fuel adsorption-desorption of the oil-film 31,36,40,41,42,44,[46][47][48][49][50][51][52] based on the 2nd Fick's law, which gave plausible trends of the oil-film HC emissions with engine operating conditions.…”

Section: Unburned Hydrocarbons (Hc)mentioning

confidence: 99%

“…Piston top-land crevice model. For the piston-top land crevice HC emissions, the common approach followed in literature 31,36,[40][41][42][43][44][45][46] of calculating the mixture in a certain volume with the ideal gas law has been adopted. The volume considered corresponds to the piston top-land up to the first compression ring and is approximately 0.2% of the engine displacement and about 2.3% of the compression volume.…”

Section: Unburned Hydrocarbons (Hc) Phenomenological Modelsmentioning

confidence: 99%

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Prediction of gaseous pollutant emissions from a spark-ignition direct-injection engine with gas-exchange simulation

Esposito

Diekhoff²,

Pischinger

2021

International Journal of Engine Research

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With the further tightening of emission regulations and the introduction of real driving emission tests (RDE), the simulative prediction of emissions is becoming increasingly important for the development of future low-emission internal combustion engines. In this context, gas-exchange simulation can be used as a powerful tool for the evaluation of new design concepts. However, the simplified description of the combustion chamber can make the prediction of complex in-cylinder phenomena like emission formation quite challenging. The present work focuses on the prediction of gaseous pollutants from a spark-ignition (SI) direct injection (DI) engine with 1D–0D gas-exchange simulations. The accuracy of the simulative prediction regarding gaseous pollutant emissions is assessed based on the comparison with measurement data obtained with a research single cylinder engine (SCE). Multiple variations of engine operating parameters – for example, load, speed, air-to-fuel ratio, valve timing – are taken into account to verify the predictivity of the simulation toward changing engine operating conditions. Regarding the unburned hydrocarbon (HC) emissions, phenomenological models are used to estimate the contribution of the piston top-land crevice as well as flame wall-quenching and oil-film fuel adsorption-desorption mechanisms. Regarding CO and NO emissions, multiple approaches to describe the burned zone kinetics in combination with a two-zone 0D combustion chamber model are evaluated. In particular, calculations with reduced reaction kinetics are compared with simplified kinetic descriptions. At engine warm operation, the HC models show an accuracy mainly within 20%. The predictions for the NO emissions follow the trend of the measurements with changing engine operating parameters and all modeled results are mainly within ±20%. Regarding CO emissions, the simplified kinetic models are not capable to predict CO at stoichiometric conditions with errors below 30%. With the usage of a reduced kinetic mechanism, a better prediction capability of CO at stoichiometric air-to-fuel ratio could be achieved.

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Section: Unburned Hydrocarbons (Hc)mentioning

confidence: 99%

Section: Unburned Hydrocarbons (Hc) Phenomenological Modelsmentioning

confidence: 99%

Prediction of gaseous pollutant emissions from a spark-ignition direct-injection engine with gas-exchange simulation

Esposito

Diekhoff²,

Pischinger

2021

International Journal of Engine Research

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“…Even if the crevices are very small, the higher density of the mixture in these zones results in a high amount of unburned mixture trapped there (about 7% at part-load are estimated by Alkidas [17] and Eng [22]). Therefore, combustion chamber crevices are considered the main source of HC emissions in many literature sources [15,[23][24][25][26]. Multiple studies [20,[27][28][29][30][31] investigated the contribution of the combustion chamber crevices, with major focus on the piston-ring pack and the effect of its geometry on HC emissions.…”

Section: Piston Top-land Crevicementioning

confidence: 99%

“…At least during warm engine operation, the piston top-land crevice is considered the main source of HC emissions. Therefore, this is the most common modeled source within 1D/0D engine models [6,7,20,24,26,[32][33][34][35][36].…”

Section: Piston Top-land Crevicementioning

confidence: 99%

Development of Phenomenological Models for Engine-Out Hydrocarbon Emissions from an SI DI Engine within a 0D Two-Zone Combustion Chamber Description

Esposito¹,

Diekhoff²,

Pitsch³

et al. 2021

SAE Technical Paper Series

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The increasingly stringent limits on pollutant emissions from internal combustion engine-powered vehicles require the optimization of advanced combustion systems by means of virtual development and simulation tools. Among the gaseous emissions from spark-ignition engines, the unburned hydrocarbon (HC) emissions are the most challenging species to simulate because of the complexity of the multiple physical and chemical mechanisms that contribute to their emission. These mechanisms are mainly three-dimensional (3D) resulting from multi-phase physics -e.g., fuel injection, oil-film layer, etc. -and are difficult to predict even in complex 3D computational fluid-dynamic (CFD) simulations. Phenomenological models describing the relationships between the physical-chemical phenomena are of great interest for the modeling and simplification of such complex mechanisms. In addition, phenomenological models can be applied within simplified simulation environments, e.g., 0D-1D engine simulations, to enable predictions of HC emissions for a wide range of operating conditions. In this work, the development of phenomenological models to account for HC emissions from piston top-land crevices, wall flame quenching, and oil-film adsorption/desorption mechanisms is explained in detail. The model development is based on measurements and models from a single cylinder direct injection (DI) spark ignition (SI) research engine. Common modeling hypotheses and approaches from literature have been verified and further developed with 3D-CFD simulations. In particular, assumptions regarding local temperature and air-fuel ratio, which are necessary for HC modeling, have been developed on the basis of a zone post-processing of the 3D-CFD results. Additionally, a novel approach to describe HC post-oxidation, which is based on 0Dchemistry calculations, has been developed. The HC models have been implemented within a GT-POWER model of the engine in conjunction with a 0D two-zone combustion chamber description. The accuracy of the developed models has been tested against a large experimental database with varying engine load, speed, air to fuel ratio, valve timing, and oil/coolant temperature. The deviation in the HC emission prediction is mainly within 20% at warm engine operation. Higher deviations are observed at cold engine conditions because of the absence of secondary HC models which have not been considered in the present work.

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“…On the other hand, the variation of the S/B ratio has impacts on exhaust emissions. The CO and HC emissions increase with a decreasing S/B ratio, while NO x emissions tended to decrease because of increasing crevice volume and decreasing temperature . Furthermore, turbulence characteristics, detailed heat-transfer analysis, and burned gas temperatures have been investigated in the studies on the effects of the S/B ratio. ,, Effects of the S/B ratio on SI engine performance parameters and exhaust emissions were investigated at various spark-plug configurations .…”

Section: Introductionmentioning

confidence: 99%

Effects of the Stroke/Bore Ratio on the Performance Parameters of a Dual-Spark-Ignition (DSI) Engine

2008

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In this study, the effects of the stroke/bore (S/B) ratio on the performance parameters of an engine having dual-spark ignition (DSI) were investigated theoretically by using a quasi-dimensional thermodynamic cycle model. A range of S/B ratios for various spark-plug locations were examined in the scope of the study. The engine performance parameters, i.e., engine power, indicated mean effective pressure, specific fuel consumption, and thermal efficiency, were computed for various conditions. The obtained results for DSI operation have been compared to those of a single-spark-ignition (SSI) condition. Such comparisons showed that increases in the S/B ratio cause improvements in engine performance parameters. The dual-plug operation also improves the overall engine performance at different percentages for the selected S/B ratios.

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A Feedgas HC Emission Model for SI Engines Including Partial Burn Effects

Cited by 26 publications

References 9 publications

Prediction of gaseous pollutant emissions from a spark-ignition direct-injection engine with gas-exchange simulation

Prediction of gaseous pollutant emissions from a spark-ignition direct-injection engine with gas-exchange simulation

Development of Phenomenological Models for Engine-Out Hydrocarbon Emissions from an SI DI Engine within a 0D Two-Zone Combustion Chamber Description

Effects of the Stroke/Bore Ratio on the Performance Parameters of a Dual-Spark-Ignition (DSI) Engine

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