Engine-out emissions from a modern high speed diesel engine – The importance of Nozzle Tip Protrusion. (15th September 2018)

• Record Type: Journal Article
• Authors: Leach, Felix; Ismail, Riyaz; Davy, Martin
• Is Part Of: Applied energy. Volume 226(2018)
• Page Start: 340
• Page End: 352
• Publication Date: 2018-09-15
• Subjects: Spray targeting -- Diesel combustion -- NOx -- Soot -- NTP; CA b(a)TDC Crank Angle before (after) Top Dead Centre -- CAD Crank Angle Degrees -- CFD Computational Fluid Dynamics -- DOC Diesel Oxidation Catalyst -- DPF Diesel Particulate Filter -- EGR Exhaust Gas Recirculation -- HSDI High Speed Direct Injection -- IMEP Indicated Mean Effective Pressure -- ISFC Indicated Specific Fuel Consumption -- NOx Indicated Specific Nitrogen Oxides -- LNT Lean NOx Trap -- nIMEP Net Indicated Mean Effective Pressure -- NOx Nitrogen Oxides -- NTP Nozzle Tip Protrusion -- PM Particulate Matter -- SCR Selective Catalytic Reduction -- TDC Top Dead Centre -- TKI Tabulated Kinetic Ignition -- TP Test Point; Power (Mechanics) -- Periodicals; Energy conservation -- Periodicals; Energy conversion -- Periodicals; 621.042
• DOI: 10.1016/j.apenergy.2018.05.117
• Languages: English
• ISSNs: 0306-2619

Abstract

Highlights: The effect of injector Nozzle Tip Protrusion (NTP) is compared in a high speed diesel engine. An excellent experimental-CFD match is observed and used to understand the results. A minor variation (0.5 mm) in NTP is shown to have a statistically significant effect on soot emissions. The effect of in cylinder mixing revealed by the CFD explains this variation. Abstract: Engine out emissions from a diesel engine are highly dependent on the nature of the fuel/air interactions in cylinder, which in turn depend on the detail of the fuel injection process. High temperatures, which promote soot oxidation, also promote NOx formation. Carefully controlling these interactions can lead to cleaner combustion resulting in lower engine-out emissions, thus reducing the burden on the aftertreatment system. In this work a minor (0.5 mm) variation in injector Nozzle Tip Protrusion (NTP) is tested, both experimentally and numerically, at two part-load and four full-load test points. The results indicate that a 0.5 mm variation in NTP can have a significant benefit in reducing soot emissions, across the engine operating map, whilst not having an impact on other emissions or fuel consumption. This paper demonstrates the practical importance of NTP, and demonstrates the sensitivity of engine-out emissions to relatively minor variations of this key element of the combustion system geometry which might occur naturally either in production or in service.