Model-based optimization of multi-hole injector spray targeting for gasoline direct injection

Gawlica, Tobias; Samenfink, Wolfgang; Schünemann, Erik; Koch, Thomas

doi:10.1007/978-3-658-23181-1_14

Cited by 9 publications

(6 citation statements)

References 14 publications

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“…The results partly agree with this analysis, indicating other mechanisms are contributing to PN emissions at higher loads. The results are also partly in agreement with the literature described previously 14,18,20 In the other studies, the size difference between the main-and pre-holes was much greater than for the injector variants used in this study. This would indicate that there is an optimal difference in diameters that can result in lower tip wetting PN.…”

Section: Discussion-correlation Of Pn With Tip Wetting and Tip Drying Mechanismssupporting

confidence: 93%

“…However, when tested in an engine, higher PN emissions were observed for larger pre-holes at all engine loads, although the researchers attributed the increase in PN to flash boiling rather than the increase in injector pre-hole diameter. Finally, Gawlica et al 14 stated in their modeling study that tip wetting is more likely at lower loads and late SOI which agrees with the data presented here. The results of the current work and these other studies indicate that there is an optimal pre-hole diameter for different load/operating conditions.…”

Section: Effects Of Injector Geometrysupporting

confidence: 91%

“…[7][8][9][10] Pool fires can be created when liquidphase fuel impinges on surfaces, including the piston crown, intake and exhaust valves, and cylinder walls. [11][12][13] Some operating strategies and design criteria 14 can help reduce and sometimes eliminate fuel-rich zones, such as late fuel injection or multiple fuel injection events. 12,15,16 However, one surface wetting mechanism that cannot be avoided by injection strategy and is not well understood is injector tip wetting.…”

Section: Introductionmentioning

confidence: 99%

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Mechanisms of fuel injector tip wetting and tip drying based on experimental measurements of engine-out particulate emissions from gasoline direct-injection engines

Medina

Alzahrani

Fatouraie

et al. 2020

International Journal of Engine Research

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Gasoline fuel deposited on the fuel injector tip has been identified as a significant source of particulate emissions at some operating conditions of gasoline direct-injection engines. This work proposes simplified conceptual understanding for mechanisms controlling injector tip wetting and tip drying in gasoline direct-injection engines. The objective of the work was to identify which physical mechanisms of tip wetting and drying were most important for the operating conditions and hardware considered and to relate the mechanisms to measurements of particulate number emissions. Trends for each of the physical processes were evaluated as a function of engine operating conditions such as engine speed, start of injection timing, engine load, fuel rail pressure, and coolant temperature. The effects of fuel injector geometries on the tip wetting and drying mechanisms were also considered. Several mechanisms of injector tip wetting were represented with the conceptual understanding including wide plume wetting, vortex droplet wetting, fuel dribble wetting, and fuel condensation wetting. The main tip drying mechanism considered was single-phase evaporation. Using the conceptual understanding for tip wetting and drying mechanisms that were created in this work, the effects of engine operating conditions and fuel injector geometries on the mechanisms were compared with experimental results for particulate number. The results indicate that measured particulate number was increased by increasing injected fuel mass. Increasing injected fuel mass was suspected to increase tip wetting via wide plume wetting and vortex droplet wetting mechanisms. Particulate number was also observed to increase with hole length. Longer hole length was suspected to result in higher tip wetting via vortex droplet and fuel dribble wetting mechanisms. Longer timescale was found to decrease particulate number emissions. Lower speeds and early injection timings increased the timescale. Similarly, higher coolant temperature decreased particulate number. The coolant temperature influenced tip temperature resulting in higher tip drying.

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Section: Discussion-correlation Of Pn With Tip Wetting and Tip Drying Mechanismssupporting

confidence: 93%

Section: Effects Of Injector Geometrysupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mechanisms of fuel injector tip wetting and tip drying based on experimental measurements of engine-out particulate emissions from gasoline direct-injection engines

Medina

Alzahrani

Fatouraie

et al. 2020

International Journal of Engine Research

View full text Add to dashboard Cite

show abstract

“…The OBD can, apart from measurements of the circuit continuity, determine the faulty operation of the injector by detecting incorrect dosage (incorrect parameters of exhaust gas as determined by the sensors controlling the mixture). Despite the highly restrictive standards required by the legislator for the content of toxic substances in the exhaust [9,20], the OBD system can detect only critical injector damage, such as: the discontinuity in the powering circuit or coil, or the total blockage of the needle closing the nozzle. In the course of operation, the injector, as an element susceptible to high load conditions (temperature, pressure, and frequency of work), may be subject to partial damage causing deterioration of its work parameters [5].…”

Section: Introductionmentioning

confidence: 99%

New approach of model based detection of early stages of fuel injector failures

Mączak¹,

Więcławski²,

Szczurowski³

2023

Eksploatacja i Niezawodność – Maintenance and Reliability

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The aim of the work was to develop a method of real time diagnosing electromagnetic fuel injectors using the observation of electric current parameters available in the engine control unit. Performing this task required finding a precise criterion for assessing the correct operation of an electromagnetic injector. For this purpose, a mathematical model describing the individual phases of the injector's operation was used, allowing the simulation of the occurrence of typical failures. On its basis, symptoms of particular failures were determined based on the observation of electric current parameters in the control circuit. Observation of voltage and current waveforms allows to locate both electrical and mechanical damages to the injectors and to assess the correctness of the power system components. The presented diagnostic method allows the detection of the described damages in the early stages of their development, which prevents damage to the catalytic converter and other engine systems (valves, piston rings or cylinder surfaces), i.e. damages resulting from an incorrect fuel mixture.

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“…Typically, these regions are formed in either the gas phase because of the poor mixing process of fuel and air or due to the fuel impingement on chamber walls during spray leading to liquid films forming on these surfaces. 5,8–10 Some injection strategies, such as late fuel injection or multi-injection, 2,11–13 may help or in many cases eliminate the liquid films created by the injection process on surfaces like the piston, cylinder liner, engine head, and/or the valves. However, the one surface wetting that could not be completely eliminated by operating strategy is injector tip wetting.…”

Section: Introductionmentioning

confidence: 99%

Analytical model for liquid film evaporation on fuel injector tip for the mitigation of injector tip wetting and the resulting particulate emissions in gasoline direct-injection engines

Alzahrani

Fatouraie

Sick

2020

International Journal of Engine Research

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Unevaporated fuel films forming on the fuel injector tip of gasoline direct-injection engines burn in a diffusion flame at the time of spark, producing particulates and at some operating conditions, these films have been identified as the dominating source of particulate emissions. This work developed an analytical model for liquid film evaporation on the injector tip, that is, injector tip drying, for the mitigation of injector tip wetting and the resulting particulate emissions. The model explains theoretically how fuel films on the injector tip evaporate with time from the end of injection to the spark. The model takes into consideration engine operating conditions, including engine load and speed, tip and fuel temperatures, gas temperature and pressure, and fuel properties. The model explains the observed trends in particulate number (PN) emissions due to injector tip wetting. Engine experiments were used to validate the model by correlating the predicted film mass at the time of spark to measurements of PN emissions at different conditions. A tip drying time constant was also defined and was found to correlate well with the measured PN for all conditions tested. This time constant is a deterministic factor for mitigating tip wetting. In general, the results indicate that the liquid film evaporation on the injector tip follows a first order, asymptotic behavior. Furthermore, the tip drying physics causes the observed increasing and decreasing non-linear trends in PN emissions with the engine load and the available time for tip drying, respectively. Additionally, the liquid film evaporation on the injector tip is highly sensitive to most of the injector initial and boundary conditions, including the initial film mass after the end of injection, the wetted surface area, the available time for tip drying and the injector tip temperature. The initial film temperature has the least effect on film mass evaporation.

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Model-based optimization of multi-hole injector spray targeting for gasoline direct injection

Cited by 9 publications

References 14 publications

Mechanisms of fuel injector tip wetting and tip drying based on experimental measurements of engine-out particulate emissions from gasoline direct-injection engines

Mechanisms of fuel injector tip wetting and tip drying based on experimental measurements of engine-out particulate emissions from gasoline direct-injection engines

New approach of model based detection of early stages of fuel injector failures

Analytical model for liquid film evaporation on fuel injector tip for the mitigation of injector tip wetting and the resulting particulate emissions in gasoline direct-injection engines

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