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. As shown here, 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 fluidmore » dynamics simulations, which 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

Research Org.:

Sandia National Lab. (SNL-CA), Livermore, CA (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE), Transportation Office. Vehicle Technologies Office; USDOE National Nuclear Security Administration (NNSA)

OSTI Identifier:

1596381

Alternate Identifier(s):

OSTI ID: 1770794

Report Number(s):

SAND-2021-2539J
Journal ID: ISSN 0954-4070

Grant/Contract Number:  

AC04-94AL85000; 1890589; NA-0003525

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 Volume: 234 Journal Issue: 7; Journal ID: ISSN 0954-4070

Publisher:

SAGE

Country of Publication:

United Kingdom

Language:

English

Subject:

42 ENGINEERING; diesel fuel injection; diesel engine combustion; light-duty diesel engines; mixture distribution: engines; computational fluid dynamics