Title: Investigation of the effects of passive pre-chamber nozzle pattern and ignition system on engine performance and emissions

Abstract

The impact of passive pre-chamber (PC) internal volume, nozzle hole pattern (i.e. with and without a central axial nozzle), and PC igniter plug type on performance and emissions was investigated in an optically accessible, single-cylinder, gasoline research engine. The two PC igniter plugs investigated were a conventional inductive coil spark plug and a nanosecond repetitively pulsed (NRP) plasma discharge system previously demonstrated to accelerate early flame propagation. The baseline PC design featured a funnel shaped internal volume with a PC tip that contained six radial nozzles and a larger central axial nozzle. Two additional PC tip geometries were evaluated where either the baseline internal volume was increased or the axial nozzle was removed and the radial nozzle diameters were increased. A sweep of charge equivalence ratios ( ϕ) from nearly stoichiometric to the lean limit was performed for a fixed engine speed (1300 revolutions per minute), and engine load (3.5 bar gross indicated mean effective pressure). Time-resolved PC and main chamber (MC) pressure data as well as MC emissions data were collected to analyze engine performance and emissions characteristics. Combustion in the MC was further investigated using high-speed excited methylidyne radical (CH*) chemiluminescence imaging. Collected results highlighted that while allmore » PC tips and ignition systems exhibited similar performance and emissions down to ϕ = 0.8, relevant differences in thermal efficiency and emissions for leaner charge mixtures were observed, with the results highly dependent on the nozzle pattern and ignition system. Major deviations were correlated to preferential de-pressurization of the PC through the axial nozzle for lean conditions that was not observed for mixture conditions closer to stoichiometric. Results show that a combination of radial and axial nozzle patterns in the PC extended lean-stability limits at the low-load condition evaluated. Further benefits were observed with the use of NRP ignition systems due to faster combustion within the PC volume provided that the volume was sufficiently large.« less

Authors:

Di Sabatino, Francesco  ^[1];

• Search DOE PAGES for author "Di Sabatino, Francesco"
• Search DOE PAGES for ORCID "0000-0003-0038-1395"

Martinez-Hernandiz, Pablo Jose ^[2]; Novella Rosa, Ricardo  ^[2];

• Search DOE PAGES for author "Novella Rosa, Ricardo"
• Search DOE PAGES for ORCID "0000-0002-5123-6924"

Ekoto, Isaac ^[1]

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+ Show Author Affiliations

1. Combustion Research Facility, Sandia National Laboratories, Livermore, CA, USA
2. CMT - Motores Térmicos, Universitat Politècnica de València, Valencia, Spain

Publication Date:

Thu Oct 27 00:00:00 EDT 2022

Sponsoring Org.:

USDOE

OSTI Identifier:

1895189

Resource Type:

Published Article

Journal Name:

International Journal of Engine Research

Additional Journal Information:

Journal Name: International Journal of Engine Research Journal Volume: 24 Journal Issue: 6; Journal ID: ISSN 1468-0874

Publisher:

SAGE Publications

Country of Publication:

United Kingdom

Language:

English