Development of a Heavy Duty Nozzle Coking Test

Risberg, Per; Adlercreutz, Ludvig; Aguilera, Miguel Gómez; Johansson, Tobias; Stensiö, Lars; Ångström, Hans-Erik

doi:10.4271/2013-01-2674

Cited by 11 publications

(5 citation statements)

References 9 publications

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“…The key challenge facing these methods is the high temporal resolution required to capture the highly transient thermal evolution of in-engine surfaces across the cycle, compounded with the hostile environment found inside a combustion chamber and the difficulty accessing the internal surfaces either physically or optically. One such method used to overcome this is to modify a fuel injector nozzle to allow a thermocouple to be fitted beneath the injector surface, as close to the injector tip as possible without compromising the internal injector geometry [11,12]. However, embedding thermocouples inside injector tips remains a complex and risky approach due to the machining process weakening the nozzle tips, potentially leading to a mechanical failure of the injector nozzle and catastrophic engine damage.…”

Section: Introductionmentioning

confidence: 99%

High-Speed Thermographic Analysis of Diesel Injector Nozzle Tip Temperature

Gander¹,

Crua²,

Sykes³

et al. 2022

SAE Int. J. Adv. & Curr. Prac. in Mobility

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The temperature of fuel injectors can affect the flow inside nozzles and the subsequent spray and liquid films on the injector tips. These processes are known to impact fuel mixing, combustion and the formation of deposits that can cause engines to go off calibration. However, there is a lack of experimental data for the transient evolution of nozzle temperature throughout engine cycles and the effect of operating conditions on injector tip temperature. Although some measurements of engine surface temperature exist, they have relatively low temporal resolutions and cannot be applied to production injectors due to the requirement for a specialist coating which can interfere with the orifice geometry. To address this knowledge gap, we have developed a high-speed infrared imaging approach to measure the temperature of the nozzle surface inside an optical diesel engine. We investigated ways of increasing the emissivity of the nozzle surface with minimal intrusion by applying thin carbon coatings. We compare our measurements with those from a production injector that was instrumented with internal thermocouples. Our steady-state off-engine investigation showed that nozzle surface temperature measured by infrared imaging could yield data at 1200 fps with uncertainties of +20 K to -1 K compared to simultaneous thermocouple measurements. We applied this approach to an optical diesel engine to investigate the effect of injection duration and increased swirl ratio on injector nozzle temperature and surface homogeneity.

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Section: Introductionmentioning

confidence: 99%

High-Speed Thermographic Analysis of Diesel Injector Nozzle Tip Temperature

Gander¹,

Crua²,

Sykes³

et al. 2022

SAE Int. J. Adv. & Curr. Prac. in Mobility

View full text Add to dashboard Cite

show abstract

“…These challenges reside in the high acquisition rates required for the largely transient temperature profiles, the extreme conditions found within a reacting engine cylinder, and the complications imposed when accessing the injector nozzle surface, both optically and physically. One approach is to embed a thermocouple under the injector nozzle surface, positioning its probe as close to the orifices as possible [17,28,29]. Nevertheless, the technique is considerably restricted to an acquisition rate lower than one reading per cycle [26] due to the slow time constants of thermocouples.…”

Section: Introductionmentioning

confidence: 99%

High-Speed Infrared Measurement of Injector Tip Temperature during Diesel Engine Operation

et al. 2021

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Pre-catalyst engine emissions and detrimental injector deposits have been widely associated with the near-nozzle fluid dynamics during and after the injection events. Although the heating and evaporation of fuel films on the nozzle surface directly affects some of these processes, there are no experimental data for the transient evolution of nozzle surface temperature during typical engine conditions. In order to address this gap in knowledge, we present a non-intrusive approach for the full-cycle time resolved measurement of the surface temperature of production nozzles in an optical engine. A mid-wave infrared high-speed camera was calibrated against controlled conditions, both out of engine and in-engine to account for non-ideal in surface emissivity and optical transmissivity. A custom-modified injector with a thermocouple embedded below the nozzle surface was used to validate the approach under running engine conditions. Calibrated infrared thermography was then applied to characterise the nozzle temperature at 1200 frames per second, during motored and fired engine operation, thus revealing for the first time the effect of transient operating conditions on the temperature of the injector nozzle’s surface.

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“…The sediment amounts formed on the new generation diesel injectors are much more than gasoline injectors because of diesel fuel nature and high temperature operating mode of the diesel engines and smaller holes of their injectors. In most studies (Arpaia et al 2009;Mancaruso et al 2013;Risberg et al 2013;Smith and Williams 2015;Tang et al 2009;Williams et al 2013), some techniques for accelerating the injector deposition (such as adding zinc to diesel fuel) have been used in order to investigate its destructive effects.…”

Section: Introductionmentioning

confidence: 99%

“…As mentioned earlier, in most studies, the researchers developed a sediment deposition in diesel injector nozzle by adding zinc and using accelerator techniques (Arpaia et al 2009;Mancaruso et al 2013;Risberg et al 2013;Smith and Williams 2015;Tang et al 2009;Williams et al 2013). As in these works the fuel specification is not the same as the standard diesel fuel, in the present work, in order to properly investigate the deposition phenomenon, the test conditions are selected in normal engine operation with standard fuel.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of the Coking Phenomenon Effects on Spray Characteristics of the High Pressure Diesel Injector

Sheykhvazayefi¹,

Gorji-Bandpy²,

Hajialimohammadi³

et al. 2020

JAFM

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The novel diesel engines with advanced fuel injection systems are equipped with solenoid injectors comprising multiple small nozzle orifices which makes considerable improvement in fuel spray characteristics and engine performance along with providing high pressure fuel injection system. On the other hand, poor fuel quality, impurities and heavy metal elements in the diesel fuel, and high temperature medium in the diesel engines combustion chamber lead to remarkable deposits formation in the small holes of the nozzle. In addition, it results in partial or complete nozzle hole obstruction which is called injector nozzle coking having detrimental effects on discharged spray ideal behavior and proper engine performance. In this work, the analysis of coking phenomenon influences on diesel spray macroscopic characteristics have been done. Initially, the coked injectors with different time operation and deposit amounts are prepared under experimental and specific operating conditions. Then, the images recorded from the spatial and temporal evolution of a diesel spray in various injection and chamber pressures, are processed through the extended code in MATLAB software in order to analyze discharged fuel spray characteristics. The SCHLIEREN Imaging Method with high speed camera has been utilized in a CVC (constant volume chamber) without combustion. Non-Destructive Electron Microscopy Method of SEM (Scanning Electron Microscope) imaging was utilized in order to analyze sediments quantity and construction changes during injector working in the real engine conditions. The results show that, sediments occupy 20, 40, 75 and 90% of the total hole opening surface, respectively in the injectors with 300, 700, 800 and 900 hours operating time. By increasing the injector operation time and accumulated sediment amount on the nozzle, the discharged injector spray exhibits a more inappropriate behavior. Moreover, The Results revealed that coking has considerable effects on the spray tip penetration at low injection pressures. As injection pressure increases, the decreasing rate of the penetration length alleviates gently. In other words, at high injection pressures (1500 bar and higher) the penetration length has minor drop compared with non-utilized injectors even at 900 hours operating time, but the spray projected area can be reduced up to 28% in high chamber pressures.

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Development of a Heavy Duty Nozzle Coking Test

Cited by 11 publications

References 9 publications

High-Speed Thermographic Analysis of Diesel Injector Nozzle Tip Temperature

High-Speed Thermographic Analysis of Diesel Injector Nozzle Tip Temperature

High-Speed Infrared Measurement of Injector Tip Temperature during Diesel Engine Operation

Experimental Study of the Coking Phenomenon Effects on Spray Characteristics of the High Pressure Diesel Injector

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