Experimental Investigation of the Effect of Multiple Injections on Pollutant Formation in a Common-Rail DI Diesel Engine

Vanegas, A.; Won, Hyun Woo; Felsch, C.; Gauding, Michael; Peters, N.

doi:10.4271/2008-01-1191

Cited by 59 publications

(44 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…not directly measured due to the lack of direct velocity or mixing measurements at reacting conditions. A number of studies in the post-injection literature [40][41][42][43] hypothesize that the fuel from the post injection directly adds to the lean mixture near the injector that has reached first-stage, but not second-stage, ignition, allowing it to reach second-stage ignition. However, the mechanism of a post injection directly adding fuel to the mixtures that remain after the main injection does not align with fluid-mechanic processes observed in starting jets.…”

Section: Discussionmentioning

confidence: 98%

Effect of post injections on mixture preparation and unburned hydrocarbon emissions in a heavy-duty diesel engine

O’Connor

Musculus

Pickett

2016

Combustion and Flame

View full text Add to dashboard Cite

a b s t r a c tThis work explores the mechanisms by which a post injection can reduce unburned hydrocarbon (UHC) emissions in heavy-duty diesel engines operating at low-temperature combustion conditions. Post injections, small, close-coupled injections of fuel after the main injection, have been shown to reduce UHC in the authors' previous work. In this work, we analyze optical data from laser-induced fluorescence of both CH 2 O and OH and use chemical reactor modeling to better understand the mechanism by which post injections reduce UHC emissions. The results indicate that post-injection efficacy, or the extent to which a post injection reduces UHC emissions, is a strong function of the cylinder pressure variation during the post injection. However, the data and analysis indicate that the pressure and temperature rise from the post injection combustion cannot solely explain the UHC reduction measured by both engine-out and optical diagnostics. The fluid-mechanic, thermal, and chemical interaction of the post injection with the main-injection mixture is a key part of UHC reduction; the starting action of the post jet and the subsequent entrainment of surrounding gases are likely both important processes in reducing UHC with a post injection.

show abstract

Section: Discussionmentioning

confidence: 98%

Effect of post injections on mixture preparation and unburned hydrocarbon emissions in a heavy-duty diesel engine

O’Connor

Musculus

Pickett

2016

Combustion and Flame

View full text Add to dashboard Cite

show abstract

“…The corresponding injection rates were measured on a Bosch type flow bench. A detailed description of the experimental setup can be found in [20].…”

Section: Methodsmentioning

confidence: 99%

An extended flamelet model for multiple injections in DI Diesel engines

Felsch

Gauding

Hasse

et al. 2009

Proceedings of the Combustion Institute

Self Cite

View full text Add to dashboard Cite

“…Despite many reports on the effects of the multiple-injection strategies, the underlying physics involved in such flow are still not fully understood. In an extensive review, O'Conor et al [3] pointed out a number of remaining research questions, and summarised three main possible effects of multiple-injection: enhanced mixing [7][8][9][10]; increased combustion tempreture [11][12][13][14], and the injection duration effects [1, [15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Jet-jet interaction in multiple injections: A large-eddy simulation study

Hadadpour

Jangi

Bai

2018

Fuel

View full text Add to dashboard Cite

This paper reports on studies of multiple-injection strategies of gaseous fuel in a model combustion chamber and the role of jet-jet interactions on the mixing processes in the chamber using large-eddy simulation (LES). A highpressure non-reacting gas flow injected through a jet with a nozzle diameter of 1.35 mm into a quiescent inert air environment is considered. First, we validate the method and our computational setup by comparing the simulation results of a single injection case with available experimental data. It is shown that the transient ensemble-averaged LES results agree well with the experimental measurements. Second, we simulate and compare fourteen injection strategies in order to understand the effect of the main and the post-injections duration, the dwell time and the mass flow rate of post-injection on the mixing, jet penetration, and near-nozzle mixture. The contribution of each injection in the local mixture composition is quantified by solving transport equations for the mixture fraction of each injection.The results show that the turbulence generated in the main injection is enhanced when the post-injection flow into the main injection flow. The increase of the local turbulence intensity is in favor of increasing the scalar dissipation rate and enhancing the mixing rate. However, the penetration of the post-injection flow into the main injection flow and the level of the gas flow from the interaction of two injections depend on the dwell time and the momentum of the post-injection.The results also show that the post-injection modifies the near-nozzle mixture. The comparison of cases with different mass flow rates in the post-injection indicates that the momentum of the post-injection can be optimized either to push away the near-nozzle remaining gas from the main injection and reduce the near-nozzle residue by more than 25% or enrich this fuel-lean region and increase the near-nozzle gasses by more than 43%. These results are very interesting for optimization of the post-injection to reduce engine-out emissions. Highlights• A high-momentum short post-injection reduces the near-nozzle residue gases.• A low-momentum short post-injection enriches the near-nozzle over-lean mixture.• The longer the dwell time, the lower the peak mass of the fuel-rich mixture.• The cases with shorter dwell time and longer post-injection have more significant jet-jet interaction.

show abstract

Experimental Investigation of the Effect of Multiple Injections on Pollutant Formation in a Common-Rail DI Diesel Engine

Cited by 59 publications

References 4 publications

Effect of post injections on mixture preparation and unburned hydrocarbon emissions in a heavy-duty diesel engine

Effect of post injections on mixture preparation and unburned hydrocarbon emissions in a heavy-duty diesel engine

An extended flamelet model for multiple injections in DI Diesel engines

Jet-jet interaction in multiple injections: A large-eddy simulation study

Contact Info

Product

Resources

About