Diesel Additive Technology Effects on Injector Hole Erosion/Corrosion, Injector Fouling and Particulate Traps

Caprotti, Rinaldo; Fowler, William J.; Lepperhoff, Gerhard; Houben, Michaël

doi:10.4271/932739

Cited by 23 publications

(14 citation statements)

References 10 publications

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“…A mechanism for the formation of deposits in injector nozzles was described by Caprotti [2] and is shown in Figure 1. The resulting deposits have the potential to restrict the hydraulic flow in the nozzle holes, thereby reducing maximum flow rate and engine power.…”

Section: Introductionmentioning

confidence: 99%

Investigations on Deposit Formation in the Holes of Diesel Injector Nozzles

Birgel¹,

Ladommatos²,

Aleiferis³

et al. 2011

SAE Int. J. Fuels Lubr.

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Current developments in fuels and emissions regulations are resulting in an increasingly severe operating environment for diesel fuel injection systems. The formation of deposits within the holes or on the outside of the injector nozzle can affect the overall system performance. The rate of deposit formation is affected by a number of parameters, including operating conditions and fuel composition. For the work reported here an accelerated test procedure was developed to evaluate the relative importance of some of these parameters in a high pressure common rail fuel injection system. The resulting methodology produced measurable deposits in a custom made injector nozzle on a single cylinder engine. The results indicate that fuels containing 30%v/v and 100% Fatty Acid Methyl Ester (FAME), that does not meet EN 14214 produced more deposit than an EN590 petroleum diesel fuel. Overall, the addition of zinc to the fuel had the biggest effect on deposit formation and resulted in a 12.2% decrease in Indicated Mean Effective Pressure (IMEP). The effects of zinc were unexpectedly reduced when it was added to fuel containing 30%v/v biodiesel. Reducing the common-rail pressure with 30%v/v biodiesel (no added zinc) increased the loss in IMEP. Raising the air and fuel temperatures by 40°C and 30°C respectively showed no bigger loss in IMEP. The results indicate that deposit formation may continue after engine shut down.

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Section: Introductionmentioning

confidence: 99%

Investigations on Deposit Formation in the Holes of Diesel Injector Nozzles

Birgel¹,

Ladommatos²,

Aleiferis³

et al. 2011

SAE Int. J. Fuels Lubr.

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“…This reduction in performance is known to manifest in a variety of ways including increased acoustic and pollutant emissions [1][2][3]. The deposits can also reduce the hydraulic diameter of the nozzle hole, resulting in a reduction in the quantity of injected fuel and reduced quality and consistency of injection [3][4][5]; all of which cause a reduction in engine power [6].…”

Section: Introductionmentioning

confidence: 99%

A quantitative analysis of nozzle surface bound fuel for diesel injectors

Turner

Sykes

Sercey

et al. 2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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In a fuel injector at the end of the injection, the needle descent and the rapid pressure drop in the nozzle leads to discharge of large, slow-moving liquid structures. This unwanted discharge is often referred as fuel 'dribble' and results in near-nozzle surface wetting, creating fuel-rich regions that are believed to contribute to unburnt hydrocarbon emissions. Subsequent fluid overspill occurs during the pressure drop in the expansion stroke when residual fluid inside the nozzle is displaced by the expansion of trapped gases as the pressure through the orifices is equalised, leading to further surface wetting. There have been several recent advancements in the characterisation of these near nozzle fluid processes, yet there is a lack of quantitative data relating the operating conditions and hardware parameters to the quantity of overspill and surface-bound fuel. In this study, methods for quantifying nozzle tip wetting after the end of injection were developed, to gain a better understanding of the underlying processes and to study the influence of engine operating conditions. A high-speed camera with a longdistance microscope was used to visualise fluid behaviour at the microscopic scale during, and after, the end of injection. In order to measure the nozzle tip temperature, a production injector was used which was instrumented with a type K thermocouple near one of the orifices. Image post-processing techniques were developed to track both the initial fuel coverage area on the nozzle surface, as well as the temporal evolution and spreading rate of surface-bound fluid. The conclusion presents an analysis of the area of fuel coverage and the rate of spreading and how these depend on injection pressure, in-cylinder pressure and in-cylinder temperature. It was observed that for this VCO injector, the rate of spreading correlates with the initial area of fuel coverage measured after the end of injection, suggesting that the main mechanism for nozzle wetting is through the impingement of dribble onto the nozzle. However, occasional observations of the expansion of orifice-trapped gas were made that lead to a significant increase in nozzle wetting. KeywordsDiesel; end of injection; dribble; surface wetting; image processing Introduction Increasingly strict emissions standards place considerable pressure on the automotive industry to increase the efficiency of, and reduce the emissions of the engine. This is primarily done by optimising the fuel-air mixing processes that occur inside the combustion chamber. Since the fuel air mixing is affected by the fuel injection equipment (FIE), much of the research efforts have been in improving the injector design and spray characteristics. This has resulted in the numbers of holes in the injector tip increasing with subsequent designs, as well as increases in the operating pressure, with typical systems operating with common rail pressures of over 200 MPa. These increasingly harsh conditions are believed to accelerate the formation and growth of deposits in and arou...

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“…al. [43] from 1993 a possible physical mechanism for deposits in an in-line injection system is described with several references (Figure 23). …”

Section: Possible Physical Mechanismmentioning

confidence: 99%

“…The description, given by [43], is that after "closing of the nozzle in the high pressure part of the combustion process, liquid fuel is stored in the injector holes. This fuel expands during the expansion stroke due to temperature increase of the injector body.…”

Section: Possible Physical Mechanismmentioning

confidence: 99%

Deposit Formation in the Holes of Diesel Injector Nozzles: A Critical Review

Birgel¹,

Ladommatos²,

Aleiferis³

et al. 2008

SAE Technical Paper Series

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Current developments in fuels and emissions regulations are resulting in increasingly severe operating environment for the injection system. Formation of deposits within the holes of the injector nozzle or on the outside of the injector tip may have an adverse effect on overall system performance. This paper provides a critical review of the current understanding of the main factors affecting deposit formation.Two main types of engine test cycles, which attempt to simulate field conditions, are described in the literature. The first type involves cycling between high and low load. The second involves steady state operation at constant speed either at medium or high load.

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Diesel Additive Technology Effects on Injector Hole Erosion/Corrosion, Injector Fouling and Particulate Traps

Cited by 23 publications

References 10 publications

Investigations on Deposit Formation in the Holes of Diesel Injector Nozzles

Investigations on Deposit Formation in the Holes of Diesel Injector Nozzles

A quantitative analysis of nozzle surface bound fuel for diesel injectors

Deposit Formation in the Holes of Diesel Injector Nozzles: A Critical Review

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