1D Numerical and Experimental Investigations of an Ultralean Pre-Chamber Engine

Bozza, Fabio; Bellis, Vincenzo De; Tufano, Daniela; Malfi, Enrica; Müller, Christoph; Habermann, Knut

doi:10.4271/03-13-02-0012

Cited by 12 publications

(13 citation statements)

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“…As experimentally and numerically demonstrated [18][19][20], the introduction of a pre-chamber allows to strongly extend the lean burn limit of a conventional SI engine. This engine is designed to operate with very lean air/fuel mixtures to improve the engine efficiency and reduce the NO X emission in a zone as wide as possible for the operating domain.…”

Section: E-compmentioning

confidence: 99%

“…An empirical correlation is used for the estimation of the mechanical friction losses, dependent on engine speed, combustion phasing, and in-cylinder pressure peak. The steady-state flow coefficients for both the intake and the exhaust valves have been measured on a similar single-cylinder research engine and are here assigned to predict the flow permeability through the cylinder head [19,20,22]. A standard map-based approach is employed to reproduce the boosting system.…”

Section: Engine Model Description and Validationmentioning

confidence: 99%

“…An "in-house" developed phenomenological K-k-T turbulence sub-model is employed to estimate those quantities [29]. The turbulence model takes into account the energy flux transferred from the mean flow kinetic energy, K, to the turbulent one, k. The model includes proper balance equations for tumble and swirl angular momentum, T and S. The model is applied to both PC and MC, and also considers the turbulence production induced by the incoming/outcoming flow through the orifices [20].…”

Section: Engine Model Description and Validationmentioning

confidence: 99%

“…The quasi-dimensional combustion model was tuned with reference to a research engine [19,20], having geometrical and architectural characteristics similar to the four-cylinder engine under study for which experimental data are not yet available. The model was tuned by a trial-and-error procedure aiming to obtain the best agreement with pressure signals in both PC and MC.…”

Section: Engine Model Description and Validationmentioning

confidence: 99%

“…An "in-house" quasi-dimensional model is employed to reproduce the main in-cylinder phenomena, such as mixture formation, combustion, turbulence, and emissions. Its reliability has been validated in a prototype single-cylinder unit in previous activities [19,20]. Here, the same model, with few enhancements, is applied to foresee the behavior of the multi-cylinder engine as well.…”

Section: Introductionmentioning

confidence: 99%

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Optimal Calibration Strategy of a Hybrid Electric Vehicle Equipped with an Ultra-Lean Pre-Chamber SI Engine for the Minimization of CO2 and Pollutant Emissions

et al. 2020

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The complexity of modern hybrid powertrains poses new challenges for the optimal control concerning, on one hand, the thermal engine to maximize its efficiency, and, on the other hand, the vehicle to minimize the noxious emissions and CO2. In this context, the engine calibration has to be conducted by considering simultaneously the powertrain management, the vehicle characteristics, and the driving mission. In this work, a calibration methodology for a two-stage boosted ultra-lean pre-chamber spark ignition (SI) engine is proposed, aiming at minimizing its CO2 and pollutant emissions. The engine features a flexible variable valve timing (VVT) control of the valves and an E-compressor, coupled in series to a turbocharger, to guarantee an adequate boost level needed for ultra-lean operation. The engine is simulated in a refined 1D model. A simplified methodology, based on a network of proportional integral derivative (PID) controllers, is presented for the calibration over the whole operating domain. Two calibration variants are proposed and compared, characterized by different fuel and electric consumptions: the first one aims to exclusively maximize the brake thermal efficiency, and the second one additionally considers the electric energy absorbed by the E-compressor and drained from the battery. After a verification against the outcomes of an automatic optimizer, the calibration strategies are assessed based on pollutant and CO2 emissions along representative driving cycles by vehicle simulations. The results highlight slightly lower CO2 emissions with the calibration approach that minimizes the E-compressor consumption, thus revealing the importance of considering the engine calibration phase, the powertrain management, the vehicle characteristics, and its mission.

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Section: E-compmentioning

confidence: 99%

Section: Engine Model Description and Validationmentioning

confidence: 99%