Gas Exchange Optimization and the Impact on Emission Reduction for HSDI Diesel Engines

Adolph, Dirk; Rezaei, Reza; Pischinger, Stefan; Adomeit, Philipp; Körfer, Thomas; Kolbeck, Andreas; Lamping, Matthias; Tatur, Marek; Tomazic, Dean

doi:10.4271/2009-01-0653

Cited by 12 publications

(30 citation statements)

References 4 publications

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“…In the LES approach, such small perturbations and fluctuations in flow turbulence are not filtered out as in the RANS model. Furthermore, previous work 6 showed that flow structures predicted by LES approaches exhibit much stronger differences between different valve actuations strategies than RANS. This makes the LES an appropriate model for simulation and analysis of transient phenomena like engine cycle-to-cycle variability.…”

Section: Boundary Conditionsmentioning

confidence: 99%

“…Detailed descriptions of the experimental setup can be found in Adolph et al 6 The gas exchange process is optimized by using an intake port concept consisting of a filling and a tangential port, both with seat swirl chamfers. 6 One important goal of this port concept is to provide a high volumetric efficiency by an optimized flow coefficient. Figure 1 shows the flow measurements of the port design performed on a steady-state flow test bench.…”

Section: Test Enginementioning

confidence: 99%

“…The intake pressure is adjusted at the test bench in order to reach the same in-cylinder filling for both cases. For evaluation and assessment of the in-cylinder flow field in HSDI diesel engines, Adolph et al 6 introduced the homogeneity of the swirl flow as an additional criterion for quantitative assessment of swirl flow pattern and its homogeneity. Here, we will employ the definition of flow in-homogeneity as proposed in Adolph et al 6 The in-homogeneity, I in-hom , is defined as the root mean square of the tangential in-cylinder flow velocity at each cross-section normalized by the absolute value of the flow-velocity component in the same tangential direction, averaged in the complete in-cylinder volume,…”

Section: Evaluation Of In-cylinder Flow and Swirl Qualitymentioning

confidence: 99%

“…Experimental investigations on gas exchange optimization and its impact on emission reduction were presented in previous work. 6 It was shown that increasing the swirl ratio up to a certain optimum level can improve the engine-out emissions and, simultaneously, the fuel consumption. Furthermore, it was observed that the optimum value of the swirl ratio depends on the operating conditions and engine speed.…”

Section: Introductionmentioning

confidence: 99%

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Numerical investigation of the effect of swirl flow in-homogeneity and stability on diesel engine combustion and emissions

Rezaei

Pischinger

Ewald³

et al. 2012

International Journal of Engine Research

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The present study is aimed at numerically investigating the effect of in-cylinder charge motion on mixture preparation, combustion and emission formation in a high-speed direct-injection diesel engine. Previous investigations have shown that different valve-lift strategies nominally lead to similar in-cylinder filling and global swirl levels. However, significant differences in engine-out emissions, especially soot emission, give rise to the assumption that the flow structure and local differences of the swirl motion distribution have a noticeable effect on emission behaviour. In this work, different swirl generation strategies applying different intake valve actuation schemes are numerically investigated by applying transient in-cylinder computational fluid dynamic simulations using both the Reynolds-averaged Navier-Stokes model and the multi-cycle large-eddy simulation approach. Two operating points within the operating range of current diesel passenger cars during federal test procedure 75 and new European driving cycles are simulated. The injection and combustion simulations of different valve strategies show that an in-homogeneity in the in-cylinder flow structure leads to a significant increase in soot emissions, and agree with the observed trends of corresponding experimental investigations.

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Section: Boundary Conditionsmentioning

confidence: 99%

Section: Test Enginementioning

confidence: 99%

Section: Evaluation Of In-cylinder Flow and Swirl Qualitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Numerical investigation of the effect of swirl flow in-homogeneity and stability on diesel engine combustion and emissions

Rezaei

Pischinger

Ewald³

et al. 2012

International Journal of Engine Research

Self Cite

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“…More recently, the Aachen group used LES to study high-speed diesel engines. Adoph et al [159] used single-cycle LES to study the impact of port design on emissions. The study combined PIV measurements and LES to evaluate the impact of port design on in-cylinder flow mixing and homogeneity.…”

Section: Examples Of Les Engine Studiesmentioning

confidence: 99%

Large-eddy simulations for internal combustion engines – a review

Rutland

2011

International Journal of Engine Research

236

150

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A review of using large-eddy simulation (LES) in computational fluid dynamic studies of internal combustion engines is presented. Background material on turbulence modelling, LES approaches, specifically for engines, and the expectations of LES results are discussed. The major modelling approaches for turbulence, combustion, scalars, and liquid sprays are discussed. In each of these areas, a taxonomy is presented for the various types of models appropriate for engines. Advantages, disadvantages, and examples of use in the literature are described for the various types of models. Several recent examples of engine studies using LES are discussed. Recommendations and future prospects are included.

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