Effects of Fuel Properties on SIDI Fuel Injector Deposit

Ashida, Tsuyoshi; Takei, Yasunori; Hosi, Hirohoko

doi:10.4271/2001-01-3694

Cited by 25 publications

(23 citation statements)

References 6 publications

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“…Depending on the detergent type, they were able to reverse or avoid any injector flow loss caused by fouling. Analogous effects of fuel additives were also reported by other groups [13,14,20,21]. These publications all show a decrease of injector performance caused by fouling and illustrate potential benefits of fuel additives.…”

supporting

confidence: 78%

Injector Fouling and Its Impact on Engine Emissions and Spray Characteristics in Gasoline Direct Injection Engines

Henkel

Hardalupas

Taylor

et al. 2017

SAE Int. J. Fuels Lubr.

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Unlike in port fuel injection (PFI) systems, gasoline direct injection (GDI) engines deliver fuel directly into the combustion chamber. This opens up the possibility of new injection strategies and can improve efficiency and fuel consumption, especially under partial load [1,2,3]. An additional advantage is the so-called stratified charge operation, which allows adjustment of the injection and ignition timings of the engine, to further optimise engine operation [4]. In addition, the charge cooling effect observed during fuel injection allows for the use of higher compression ratios, with reduced risk of knocking. These benefits are gaining more attention with the continuing trend of downsizing and super-or turbocharging of engines, due to increasingly strict emissions regulations [5,6,7]. Additional benefits of GDI are the option to completely shut-off fuel supply while coasting [8] and improved cold start behaviour compared to PFI engines [9,10].One major challenge of the GDI concept, however, is the potential for increased formation of particulate emissions. Recent emissions legislations such as EURO 6 in Europe and LEV III (Low Emissions Vehicle Program) in the US pose very strict limitations on particle number and mass (PM) concentrations [11,12]. Methods to control particulate emissions from GDI engines are therefore important.Introduction of an injector into the combustion chamber of a GDI engine results in direct exposure of the injector tip to the harsh conditions occurring during combustion. Because the flame directly interacts with the nozzle, combustion products can be deposited on the surface and inside cavities. This is usually referred to as injector fouling or coking and can have an adverse effect on fuel consumption, engine performance and both hydrocarbons and particulate emissions. Formation of deposits on the injector tip can result in alteration of spray pattern leading to increased spray impingement and therefore increased particulate emissions [13,14,15,16].The phenomenon of injector fouling and how it is influenced by fuel and engine parameters was the focus of a number of studies. Aradi et al. [17] investigated different fuel blends under several conditions in a four cylinder engine. They used rich fuel-to-air ratios in order to promote fouling. By measuring the temperature of the injector tip with an internal sensor, they saw that with increasing temperature Injector Fouling and Its Impact on Engine Emissions and Spray Characteristics in Gasoline Direct Injection Engines ABSTRACTIn Gasoline Direct Injection engines, direct exposure of the injector to the flame can cause combustion products to accumulate on the nozzle, which can result in increased particulate emissions. This research observes the impact of injector fouling on particulate emissions and the associated injector spray pattern and shows how both can be reversed by utilising fuel detergency. For this purpose multi-hole injectors were deliberately fouled in a four-cylinder test engine with two different base fuels. During a fo...

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supporting

confidence: 78%

Injector Fouling and Its Impact on Engine Emissions and Spray Characteristics in Gasoline Direct Injection Engines

Henkel

Hardalupas

Taylor

et al. 2017

SAE Int. J. Fuels Lubr.

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“…The wave length of electrons are shorter than that of the visible light; therefore resolutions of 0.2 to 0.5 nm can be achieved [49]. Many researchers have taken SEM images of injector deposits [14,22,25,26,37,[45][46][47].…”

Section: Deposit Visualizationmentioning

confidence: 99%

“…The key parameters controlled are the injector tip temperature, fuel injection pressure, coolant temperature, and soak period; all of which are also used in the PFI injector fouling test [36,51,61]. Several researchers have developed injector tip temperature maps and use those maps to determine the number of engine cycles required for accelerated tests [47,51]. Vehicle tests are often related back to field or standard driving cycles [23,26,37].…”

Section: Compositional Analysismentioning

confidence: 99%

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Fuel injector deposits in direct-injection spark-ignition engines

Wang

et al. 2015

Progress in Energy and Combustion Science

151

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Controlling fuel injector deposits is recognised as a challenge for advanced direct-injection sparkignition (DISI) engines. This paper gives a comprehensive overview of the research on formation, measurement, effect, and mitigation of injector deposits in DISI engines. Methodologies for the injector deposit studies include visual and compositional analysis. It is shown that injector deposits will reduce injector fuel flow rates, and lead to changes in spray characteristics. Consequently, spray angle and envelope are likely to be affected, and spray penetration distance as well as droplet diameter can be increased. Injector deposits are revealed to be primarily fuel-derived and created by two distinct free radical pathways, i.e., low temperature auto-oxidation and high temperature pyrolysis. Fuel compositions (olefins, aromatics, and sulphur), as well as T90 parameter, are significant factors in injector deposit formation. The worst consequences of injector fouling are pre-ignition, and engine misfiring and malfunction. Emissions, especially particulates, dramatically increase as the fuel injector becomes fouled. It appears that fuel detergent is the most effective method in controlling injector deposit formation if its chemistry and dosage rate are optimized. Outward opening piezo-driven injector configuration with a good surface finish, a sharp nozzle inlet, and a counter bore design, is useful in preventing injector deposit formation. Reducing injector nozzle temperature by methods such as designing special injector cooling passages, and improving engine design are also proven to be 2 helpful in reducing injector fouling. Anti-deposit coatings only delay the onset of injector deposit formation.

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“…When DCAs are not included, ethanol has been found to reduce injector deposits in comparison to gasoline (Ashida et al 2001). Whether this is because ethanol leads to lower injector nozzle temperatures compared to gasoline, 4 because it has a detergent effect, or because it is a source of fewer deposit-forming precursors is not clear.…”

Section: A2 Testing Resultsmentioning

confidence: 99%