Title: A phenomenological rate of injection model for predicting fuel injection with application to mixture formation in light-duty diesel engines

Abstract

Fuel injection rate laws are one of the most important pieces of information needed when modeling engine combustion with computational fluid dynamics. In this study, a simple phenomenological model of a common-rail injector was developed and calibrated for the Bosch CRI2.2 platform. The model requires three tunable parameter fits, making it relatively easy to calibrate and suitable for injector modeling when high-fidelity information about the internal injector’s geometry and electrical circuit details are not available. Each injection pulse is modeled as a sequence of up to four stages: an injection needle mechanical opening transient, a full-lift viscous flow inertial transient, a Bernoulli steady-state stage, and a needle descent transient. Parameters for each stage are obtained as polynomial fits from measured injection rate properties. The model enforces total injected mass, and the intermediate stages are only introduced if the injection pulse duration is long enough. Experimental rates of injection from two separate campaigns on the same injector were used to calibrate the model. The model was first validated against measured injection rate laws featuring pilot injections, short partially premixed combustion pulses, and conventional diesel combustion injection strategies. Then, it was employed as an input to engine computational fluid dynamics simulations, whichmore » were run to simulate experiments of mixture formation in an optically accessible light-duty diesel engine. It was found that, though simple, this model is capable of predicting both pilot and main injection pulse mass flow rates well: the simulations yielded accurate predictions of in-cylinder equivalence ratio distributions from injection strategies for both partially premixed combustion and pilot injections. Also, once calibrated, the model produced appropriate results for a wide range of injected mass and rail pressure values. Finally, it was observed that usage of such a relatively simple model can be a good choice when high-fidelity injection rate input and highly detailed information of the injector’s geometry and operation are not available, particularly as noticeable discrepancies can be present also among different experimental campaigns on similar hardware.« less

Authors:

Perini, Federico  ^[1];

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Busch, Stephen ^[2]; Reitz, Rolf Deneys ^[1]

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+ Show Author Affiliations

1. Wisconsin Engine Research Consultants, LLC, Madison, WI, USA
2. Sandia National Laboratories, Livermore, CA, USA

Publication Date:

2020-01-31

Sponsoring Org.:

USDOE

OSTI Identifier:

1596381

Grant/Contract Number:  

Sandia Subcontract 1890589, 1

Resource Type:

Published Article

Journal Name:

Proceedings of the Institution of Mechanical Engineers. Part D, Journal of Automobile Engineering

Additional Journal Information:

Journal Name: Proceedings of the Institution of Mechanical Engineers. Part D, Journal of Automobile Engineering; Journal ID: ISSN 0954-4070

Publisher:

SAGE Publications

Country of Publication:

United Kingdom

Language:

English