Conceptual Design of Small Direct-Injection Spark-Ignition Engine Concepts with Various Injector Positions by Use of CAE-Tools Technische Universitaet Braunschweig

Format:

Conference/Event

Author/Creator:

Schech, Schech, author.

Contributor:

Eilts, Peter

Herbst, Fabian

Siedentop, Arne

Wiebe, Alexander

Conference Name:

2012 Small Engine Technology Conference & Exhibition (2012-10-16 : Madison, Wisconsin, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2012

Summary:

Within a project of a research association(Forschungsver-einigung Verbrennungskraftmaschinen e.V.) a DIspark-ignition engine with small engine displacement was designedat the Institute of Internal Combustion Engines of the TechnischeUniversitat Braunschweig. The objective of the project is toinvestigate the minimum bore diameter which allows the reasonableuse of the advantages of gasoline direct injection.This article outlines the preliminary studies to identifysuitable geometry variants for lateral and central injectorposition concerning effective engine operating data.Under consideration of current production possibilities andgeometries of available injector and spark plug CAD studies werecarried out. All suitable valve concepts, beginning with atwo-valve (2V) concept and up to a four-valve (4V) concept, wereexamined in the CAD studies. The bore diameter was varied in arange from 56 to 62 mm combined with a variation of the stroke/boreratio from 0.9 to 1.2. Further the valve angles, spark plug andinjector position were changed in wide ranges. The selection of themost suitable variant was based on the criteria of intake valveseat ring diameter and the spark plug eccentricity.The effective operating data was calculated by 1D simulations.Due to the unknown net heat release of the engine the combustionprocess was determined by the "turbulent-flame" modelimplemented in the simulation software GT-Power. The influence ofthe stroke/bore ratio on combustion process was adapted in respectto published results. The supercharging system also has asignificant influence on effective operating data. The efficiencyof the exhaust turbocharger was modeled by the scavenging pressuredifference of a VTG turbocharger and variable compressor inletguide vanes presented in [3]. The engine friction was considered byan approach developed in [8]. The influence of the stroke/boreratio, as can be expected from literature, was added to thisapproach. The final assessment of the variants determined by theCAD studies was carried out by the criteria of charging pressure,gas exchange losses, residual gas rate and BSFC at design point andnominal output point.As a result of the preliminary studies an engine displacement of200 cm₃ with a bore diameter of 60 mm and a stroke of 71 mm is themost suitable concept with respect to the boundary conditions.Whereas the 3V concept is most appropriate for the vertical and the4V concept for the horizontal mounted injector position. Bothconcepts were designed at the institute and will be tested onengine test bench

Notes:

Vendor supplied data

Publisher Number:

2012-32-0066

Access Restriction:

Restricted for use by site license