Influence of Injection and Ambient Conditions on the Nozzle Exit Spray of an Outwardly Opening GDI Injector RWTH Aachen University

Format:

Conference/Event

Author/Creator:

Cordes, Cordes, author.

Contributor:

Kneer, Reinhold

Pischke, Philipp

Conference Name:

SAE 2012 World Congress & Exhibition (2012-04-24 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2012

Summary:

Spray penetration and mixture formation in GDI engines arecrucial to a reliable ignition and the subsequent combustion. Forthe prediction of the mixture formation process, computationalfluid dynamic simulations are applied. Therefore, details about thenozzle exit conditions are essential, either as boundary conditionsto be set, or to validate the numerical results.This paper presents experimental results on the influence ofboundary conditions on the spray structure at the nozzle exit of aGDI injector. The injector investigated is an outwardly openingpiezo injector, generating a hollow cone spray with a stringstructure. The distribution of the strings (the so-called"string structure") is needed for the starting conditionsof the computational fluid dynamic simulations, as the origin ofthe strings is unresolved so far. The experiments are conducted ina constant volume pressure chamber varying the ambient temperaturebetween 300 and 600 K and the ambient pressure between 0.1 and 1.0MPa. Analyzing the impact of the different injection conditions,the injection pressure is varied between 8 and 12 MPa, utilizingenergizing durations between 200 and 600 μs. In addition, theneedle lifts are varied, too. Visualization techniques are used toinvestigate the spray structure and the penetration length.The evaluation of the results is divided into two parts. First,spray images of the nozzle exit flow are compared concentrating ongeneral parameters of the spray such as the penetration length. Inthe second part, the string structure is investigated by extractingthe light intensity profile at certain nozzle distances. Theanalysis of the spray structure shows that the ambient andinjection pressure as well as the ambient temperature influence thecircumferential fuel distribution at the nozzle exit; the needlelift shows no significant influence in the visualization results.Comparing the influence of the different parameters on the stringdistribution shows that the injection pressure and the ambienttemperature have the greatest influence. But even though thegreatest influence can be observed varying the injection pressureand the ambient temperature, these influences are very small

Notes:

Vendor supplied data

Publisher Number:

2012-01-0396

Access Restriction:

Restricted for use by site license