Quasi-Dimensional Modeling of CI-Combustion with Multiple Pilot- and Post Injections

Rether, Dominik; Grill, Michael; Schmid, Andreas; Bargende, Michael

doi:10.4271/2010-01-0150

Cited by 25 publications

(4 citation statements)

References 8 publications

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“…At part-load conditions, the combustion process becomes more complex, since a large proportion of the fuel is burnt during a pre-mixed reaction [22,23,26,28,29]. Lower rail pressures and in-cylinder temperatures cause autoignition to be delayed, meaning more fuel is mixed with air before combustion occurs, to a higher proportion of combustion being pre-mixed.…”

Section: Pre-mixed Combustion Modelmentioning

confidence: 99%

“…Therefore, the pilot combustion event is modelled as a fully pre-mixed reaction, since the fuel injection quantities are small and Burke 14 GTP-17-1057 the fuel air mixture is assumed to be fully mixed prior to combustion [26]. The effect on main injection ignition delay can be modelled by modifying the Arrhenius rate, as proposed by Rether et al [28]: (21) In this case, an additional term is added to the denominator of the exponent proportional to the energy released from the pilot combustion, 𝑄 𝑝𝑖𝑙𝑜𝑡 .…”

Section: Pilot Combustion Modelmentioning

confidence: 99%

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An Improved Rate of Heat Release Model for Modern High-Speed Diesel Engines

Dowell

Akehurst

Burke

2017

Journal of Engineering for Gas Turbines and Power

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To meet the increasingly stringent emissions standards, diesel engines need to include more active technologies with their associated control systems. Hardware-in-the-loop (HiL) approaches are becoming popular where the engine system is represented as a real-time capable model to allow development of the controller hardware and software without the need for the real engine system. This paper focusses on the engine model required in such approaches. A number of semi-physical, zero-dimensional combustion modeling techniques are enhanced and combined into a complete model, these include—ignition delay, premixed and diffusion combustion and wall impingement. In addition, a fuel injection model was used to provide fuel injection rate from solenoid energizing signals. The model was parameterized using a small set of experimental data from an engine dynamometer test facility and validated against a complete data set covering the full engine speed and torque range. The model was shown to characterize the rate of heat release (RoHR) well over the engine speed and load range. Critically, the wall impingement model improved R2 value for maximum RoHR from 0.89 to 0.96. This was reflected in the model's ability to match both pilot and main combustion phasing, and peak heat release rates derived from measured data. The model predicted indicated mean effective pressure and maximum pressure with R2 values of 0.99 across the engine map. The worst prediction was for the angle of maximum pressure which had an R2 of 0.74. The results demonstrate the predictive ability of the model, with only a small set of empirical data for training—this is a key advantage over conventional methods. The fuel injection model yielded good results for predicted injection quantity (R2 = 0.99) and enabled the use of the RoHR model without the need for measured rate of injection.

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Section: Pre-mixed Combustion Modelmentioning

confidence: 99%

Section: Pilot Combustion Modelmentioning

confidence: 99%

An Improved Rate of Heat Release Model for Modern High-Speed Diesel Engines

Dowell

Akehurst

Burke

2017

Journal of Engineering for Gas Turbines and Power

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“…Obviously, the most important simplifying assumption for these cases, which may affect the accuracy of the results, lies in considering noninteracting zones. As far as zone mixing and interaction of fuel jets are concerned, CFD obviously offers much more insight into the phenomenon; nevertheless, from a quasi-dimensional point of view, a unique attempt at differentiating between them has been published in the recent literature [49], although it considers a special treatment for pilot fuel injections, by assuming them as single zones, and computes separate ignition delay times for each of the injection pulses. In the present model, this kind of treatment was embedded, as each of the spray parcels, into which each injection pulse is subdivided, evolves according to its own ignition delay time.…”

Section: Spray Model Calibrationmentioning

confidence: 99%

Development and calibration of an enhanced quasi-dimensional combustion model for HSDI diesel engines

Perini

Mattarelli

2011

International Journal of Engine Research

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The paper describes the development and validation of a quasi-dimensional combustion model, applicable to any type of high-speed direct-injection (HSDI) diesel engines. In this model, the fundamental in-cylinder processes are taken into account, including turbulence, fuel injection, spray dynamics, ignition, and combustion. In comparison with similar models presented in the literature, a more physical description of average in-cylinder turbulence properties and their interaction with spray dynamics is introduced, as well as a detailed modelling of fuel jet wall impingement. Some experimental measures available in the literature and three-dimensional computational fluid dynamics simulations were considered to calibrate the modelling parameters. These improved sub-models make results accuracy less dependent on the calibration carried out on each engine, so that the same parameter setting can be successfully applied to different combustion chamber configurations. The model was first applied to a small HSDI turbocharged diesel engine. The specific calibration was supported by both experimental and simulation results, the latest being obtained from the threedimensional computational fluid dynamics analyses. Then, a different diesel engine was simulated, adopting the same set-up of the model parameters. For both engines, the comparison between experiments and simulation showed a very good agreement in terms of in-cylinder pressures and heat release rates, as well as of average in-cylinder turbulence properties. It is worth mentioning that the two engines had a quite different unit displacement, i.e. 312 and 697 cm 3 , respectively. As a conclusion, this model was demonstrated to be a reliable tool for addressing the optimization of the main engine design parameters, such as injection rates and timings, combustion chamber base geometry, and so forth.

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“…There are two types of quasi-dimensional diesel combustion models depending on the formulation. Phenomenological combustion models 10–13 are extension of single-zone empirical models by expanding the fuel evaporation model into a spray model, where a number of zones with different composition and temperature but the same pressure are used and an air zone is used to account for air entrainment, leading to accurate predictions of heat release rate, pressure, and NOx emissions. However, the burn rate is still calculated empirically; thus, an ignition delay model is required for these models.…”

Section: Introductionmentioning

confidence: 99%

Multi-zone reaction-based modeling of combustion for multiple-injection diesel engines

Men

Haskara

Zhu

2018

International Journal of Engine Research

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As the requirements for performance and restrictions on emissions become stringent, diesel engines are equipped with advanced air, fuel, exhaust gas recirculation techniques, and associated control strategies, making them incredibly complex systems. To enable model-based engine control, control-oriented combustion models, including Wiebe-based and single-zone reaction-based models, have been developed to predict engine burn rate or in-cylinder pressure. Despite model simplicity, they are not suitable for engines operating outside the normal range because of the large error beyond calibrated region with extremely high calibration effort. The purpose of this article is to obtain a parametric understanding of diesel combustion by developing a physics-based model which can predict the combustion metrics, such as in-cylinder pressure, burn rate, and indicated mean effective pressure accurately, over a wide range of operating conditions, especially with multiple injections. In the proposed model, it is assumed that engine cylinder is divided into three zones: a fuel zone, a reaction zone, and an unmixed zone. The formulation of reaction and unmixed zones is based on the reaction-based modeling methodology, where the interaction between them is governed by Fick’s law of diffusion. The fuel zone is formulated as a virtual zone, which only accounts for mass and heat transfer associated with fuel injection and evaporation. The model is validated using test data under different speed and load conditions, with multiple injections and exhaust gas recirculation rates. It is shown that the multi-zone model outperformed the single-zone model in in-cylinder pressure prediction and calibration effort with a mild penalty in computational time.

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Quasi-Dimensional Modeling of CI-Combustion with Multiple Pilot- and Post Injections

Cited by 25 publications

References 8 publications

An Improved Rate of Heat Release Model for Modern High-Speed Diesel Engines

An Improved Rate of Heat Release Model for Modern High-Speed Diesel Engines

Development and calibration of an enhanced quasi-dimensional combustion model for HSDI diesel engines

Multi-zone reaction-based modeling of combustion for multiple-injection diesel engines

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