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Numerical investigation on the effects of fueling the Turbulent Jet Ignition gas engine with methane and hydrogen

Pielecha Ireneusz, Szwajca Filip, Skobiej Kinga

Pojazdy Szynowe

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2023

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Nr 1-2

46--57

EN

The modern solution of two-stage combustion, namely the Turbulent Jet Ignition (TJI), enables the combustion of ultra-lean mixtures. Thanks to this solution, it became possible to reduce fuel consumption and, at the same time, to increase the combustion process indicators (including the overall combustion system efficiency). The article presents the results of numerical tests of a heavy-duty engine equipped with the TJI system running on gas fuels. The AVL BOOST software was used to analyze the effects of different fuel injection rates into the pre-chamber and various ignition timing angles, while maintaining a constant global excess air ratio. Increasing the proportion of hydrogen in the prechamber resulted in its reduction in the main chamber (the fuel dose was kept constant with different excess air coefficients in each of the chambers). The maximum combustion pressure values in both chambers were investigated. Changes in the amount of heat released and its release rate were determined. As a result of the simulations, different ignition and combustion conditions were presented for the tested fuels. Based on this, maps of fuel dose to prechamber vs. ignition advance angle were drawn up, showing selected thermodynamic indicators of the combustion process.

2

Two-zone simulation of an axial vane rotary engine cycle

Mirzaei M., Hashemi S. M., Saranjam B., Binesh A.

International Journal of Applied Mechanics and Engineering

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2021

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Vol. 26, no. 2

143--159

EN

An axial vane rotary engine (AVRE) is a novel type of rotary engines. The engine is a positive displacement mechanism that permits the four “stroke” action to occur in one revolution of the shaft with a minimum number of moving components in comparison to reciprocating engines. In this paper, a two-zone combustion model is developed for a spark ignition AVRE. The combustion chamber is divided into burned and unburned zones and differential equations are developed for the change in pressure and change in temperature in each zone. The modelling is based on equations for energy and mass conservation, equation of state, and burned mass fraction. The assumption is made that both zones are at the same pressure P, and the ignition temperature is the adiabatic flame temperature based on the mixture enthalpy at the onset of combustion. The developed code for engine simulation in MATLAB is applied to another engine and there is a good agreement between results of this code and results related to the engine chosen for validation, so the modelling is independent of configuration.

3

Effects of combustion products composition models on the exergetic analysis of spark-ignition engine fuelled with ethanol

Rufino Caio H., de Lima Alessandro J. T. B., Mattos Ana P., Allah Fazal U. M., Ferreir Janito V., Gallo Waldyr L. R.

Archives of Thermodynamics

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2019

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Vol. 40, no 3

27--42

EN

The engine simulations have become an integral part of engine design and development. They are based on approximations and assumptions. The precision of the results depends on the accuracy of these hypotheses. The simplified models of frozen composition, chemical equilibrium and chemical kinetics provide the compositions of combustion products for engine cycle simulations. This paper evaluates the effects of different operating conditions and hypotheses on the exergetic analysis of a spark-ignition engine. The Brazilian automotive market has the highest number of flex-fuel vehicles. Therefore, a flex-fuel engine is considered for simulations in order to demonstrate the effects of these different hypotheses. The stroke length and bore diameter have the same value of 80 mm. The in-cylinder irreversibility is calculated for each case at the closed part of the engine cycle. A comparative analysis of these hypotheses provides a comprehensive evaluation of their effects on exergetic analysis. Higher values of accumulated irreversibility are observed for the oversimplified hypothesis.

4

Comparison of flow performance in one- and three-dimensional software for modelling opposed piston engines

Opaliński M., Mazuro P., Wyszyński M.

Archivum Combustionis

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2015

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Vol. 35 nr 1

29--40

EN

Simulating a full engine that includes a turbocharging system is time consuming and demands high power computing capabilities. Simplification of the engine model was considered indispensable to verify different boosting system concepts in reasonable timeframes. An attempt was made to reduce the computing time demand using the one-dimensional Ricardo WAVE software. Comparison of results of selected inlet and exhaust gas parameters of models created in 3D software (Ansys FLUENT) and Ricardo WAVE showed differences between 1 and 12%. Those discrepancies may be acceptable for initial verification of different boosting system concepts. In order to obtain more accurate results it is recommended to link the engine FLUENT model with Ricardo WAVE boosting model.