Investigation of Lubricant Oil influence on Ignition of Gasoline-like Fuels by a Detailed Reaction Mechanism

Distaso, Elia; Amirante, Riccardo; Calò, G.; Palma, P. De; Tamburrano, Paolo; Reitz, Rolf D.

doi:10.1016/j.egypro.2018.08.155

Cited by 24 publications

(8 citation statements)

References 41 publications

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“…Previously, Ohtomo et al used hexadecane as one of the components for their lubricant oil droplet. Similarly, Distaso et al also showed that C16-C18 hydrocarbons could be considered as a surrogate for commercial lubricant oil. Moreover, Kuti et al have also reported that hexadecane can reproduce the chemical ignition delay of large alkanes present in lubricant oils.…”

Section: Introductionmentioning

confidence: 97%

Auto-Ignition of a Hexadecane Droplet Mixed with Different Octane Number Fuels at Elevated Pressures To Investigate the Pre-Ignition Behavior

et al. 2019

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Pre-ignition is an abnormal combustion event that may occur in boosted direct injection gasoline engines, where one or more auto-ignition events are observed before spark ignition. Due to the direct injection of fuel into the cylinder, some liquid fuel may splash off the walls, pulling lubricating oil with it. The auto-ignition of liquid fuel/lubricant droplets is considered as one of the possible sources of pre-ignition. To assess this stochastic phenomenon in a controlled way, the autoignition of a single droplet of a hexadecane-fuel mixture was investigated, with hexadecane serving as a surrogate for the lubricating oil. This experiment included suspending a single hexadecane-fuel mixture droplet on a thermocouple bead in preheated air, at a temperature of 300 ± 4°C, in a constant volume chamber over a wide range of pressures (4−30 bar). Four different fuels with a range of research octane number (RON) between 70 and 120 were mixed with hexadecane at a volume percentage of 75% hexadecane to 25% fuel to investigate the time to ignition of the droplet, designated as TI. The TI was measured by recording the droplet temperature history simultaneously with high-speed droplet imaging. The droplet ignition is triggered by the auto-ignition of the combustible mixture formed by the hexadecane-fuel mixture's vapor that mixes with the hot ambient air around the droplet. An empirical model was proposed to predict the TI in terms of pressure and the mixture's RON.At constant pressure, the rate of evaporation of the mixture's droplet increases with increasing RON. The time to ignition is seen to increase exponentially as the fuel's RON used in the mixture increases. On the other hand, for a given fuel RON, the time to ignition decreases with increasing ambient pressure. The empirical model shows that at pressures above 20 bar, the dilution of hexadecane by the different fuels has no significant effect on delaying the auto-ignition of the droplet.

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Section: Introductionmentioning

confidence: 97%

Auto-Ignition of a Hexadecane Droplet Mixed with Different Octane Number Fuels at Elevated Pressures To Investigate the Pre-Ignition Behavior

et al. 2019

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“…Therefore, a constant volume combustion chamber (CVCC), where temperature and pressure could be controlled independently, is used to study the effect of RON on the auto-ignition of the lubricant oil surrogate. Previous studies have shown hexadecane to be a suitable surrogate for lubricant oil as it shows similar ignition characteristics. ,, Hence, hexadecane has been considered as a surrogate for lubricant oil in this study. Previously, Mitsudharmadi et al investigated the effect of RON of different fuels by mixing FACE I, PRF91, PRF95, and toluene with hexadecane by 25 vol % in pre-ignition occurrences.…”

Section: Introductionmentioning

confidence: 99%

Study of the Effect of Research Octane Number on the Auto-Ignition of Lubricant Oil Surrogates (n-Hexadecane)

2022

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Engine oil is considered one of the sources for pre-ignition in downsized boosted direct injection spark-ignited engines. When interacting with fuel sprayed in the combustion chamber, engine oil forms an ignitable mixture and can cause an ignition event before firing the spark plug. Because high research octane number (RON) fuels are difficult to auto-ignite and tend to suppress the knock in an internal combustion engine, studying their interaction with engine oil is essential. Hence, in the current study, a suitable lubricant oil surrogate, namely, n-hexadecane, is mixed with iso-octane and n-heptane at different concentrations to investigate the auto-ignition behavior at elevated pressures. Five sets of fuels (PRF0, PRF20, PRF50, PRF80, and PRF100) were prepared to get a wide range of RONs and blended with n-hexadecane at 15, 25, 35, and 45% mixture concentrations (vol %). These experiments were conducted in a constant volume combustion chamber, keeping the initial temperature constant at 300 °C. A single droplet of the mixture was suspended on a thermocouple bead to record the droplet’s lifetime temperature. It was observed that hexadecane mixed with PRF0, PRF20, PRF50, and PRF80 showed similar auto-ignition behaviors. The time of ignition (TI) for these mixtures initially increased until 25% concentration of the fuel in n-hexadecane, and further addition of fuels to 35% and higher concentrations showed a gradual decrease in TI. Ignition of mixtures with 35% and 45% fuel concentrations is attributed to n-heptane, as its low temperature chemistry is the dominant factor in its high reactivity compared to iso-octane. TI increased with the increasing concentration of PRF100 mixtures in hexadecane, unlike other PRF fuels tested in this study. This is because iso-octane is a high RON fuel with a higher auto-ignition temperature, making it challenging to auto-ignite.

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“…Lubricant oil can either directly reach the combustion chamber or can be released into the exhaust and the intake manifolds, contributing differently to the shape of particle size distribution (PSD), as demonstrated in a recent work [38]. The long hydrocarbon chains constituting lubricant oil can enhance soot precursor formation in the combustion chamber and can undergo pyrolysis or partial oxidation in the exhaust gases [55,56]. These findings suggest that soot emissions recorded after the exhaust gases have been discharged from the engine can differ substantially from those generated in the combustion chamber.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, the devices with which the exhaust gases interact before being discharged from the engine can alter the PSD function, affecting the final particle number (PN) and particle mass (PM). It is well known that exhaust after-treatment systems have non-negligible effects on soot particles [56][57][58][59][60]. A three-way catalytic converter (TWC) reduces gaseous emissions at an acceptable level, but dedicated research is still needed for better understanding its effects on soot emissions, since contradictory results have been reported [57][58][59][60][61].…”

Section: Introductionmentioning

confidence: 99%

Evolution of Soot Particle Number, Mass and Size Distribution along the Exhaust Line of a Heavy-Duty Engine Fueled with Compressed Natural Gas

et al. 2020

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An experimental study has been conducted to provide a characterization of the transformations that particle size distributions and the number density of soot particles can encounter along the exhaust line of a modern EURO VI compliant heavy-duty engine, fueled with compressed natural gas. Being aware of the particles history in the exhausts can be of utmost importance to understand soot formation and oxidation dynamics, so that, new strategies for further reducing these emissions can be formulated and present and future regulations met. To this purpose, particle samples were collected from several points along the exhaust pipe, namely upstream and downstream of each device the exhaust gases interact with. The engine was turbocharged and equipped with a two-stage after-treatment system. The measurements were carried out in steady conditions while the engine operated in stoichiometric conditions. Particle emissions were measured using a fast-response particle size spectrometer (DMS500) so that size information was analyzed in the range between 5 and 1000 nm. Particle mass information was derived from size distribution data using a correlation available in the literature. The reported results provide more insight on the particle emission process related to natural gas engines and, in particular, point out the effects that the turbine and the after-treatment devices produce on soot particles. Furthermore, the reported observations suggest that soot particles might not derive only from the fuel, namely, external sources, such as lubricant oil, might have a relevant role in soot formation.

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Investigation of Lubricant Oil influence on Ignition of Gasoline-like Fuels by a Detailed Reaction Mechanism

Cited by 24 publications

References 41 publications

Auto-Ignition of a Hexadecane Droplet Mixed with Different Octane Number Fuels at Elevated Pressures To Investigate the Pre-Ignition Behavior

Auto-Ignition of a Hexadecane Droplet Mixed with Different Octane Number Fuels at Elevated Pressures To Investigate the Pre-Ignition Behavior

Study of the Effect of Research Octane Number on the Auto-Ignition of Lubricant Oil Surrogates (n-Hexadecane)

Evolution of Soot Particle Number, Mass and Size Distribution along the Exhaust Line of a Heavy-Duty Engine Fueled with Compressed Natural Gas

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