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Technical Paper

Developing a numerical method for simulating physical and chemical processes that lead to LSPI

2023-09-29
2023-32-0082
All changes that increase the propensity of LSPI. The low speed-high load operation envelope is limited due to LSPI. Hydrogen engines are also being explored, however, with such a low minimum enthalpy of ignition, LSPI is a major limitation to thermal efficiency. ...Low speed pre-ignition (LSPI) is a limiting phenomenon for several of the technologies being pursued as part of the low carbon agenda. ...Hydrogen engines are also being explored, however, with such a low minimum enthalpy of ignition, LSPI is a major limitation to thermal efficiency. Several techniques are utilized in this study to investigate physical and physio-chemical aspects of lubricant initiated LSPI.
Technical Paper

Understanding degradation of engine oil additives and its effect on abnormal combustion in a gasoline engine

2023-09-29
2023-32-0035
Engine oil additives have been found to affect abnormal combustion in turbocharged gasoline direct injection (TGDI) engines, called low speed pre-ignition (LSPI). Some of metal containing additives such as zinc dithiophosphates (ZnDTP) and molybdenum dithiocarbamates (MoDTC) have been found to reduce LSPI events. ...Some of metal containing additives such as zinc dithiophosphates (ZnDTP) and molybdenum dithiocarbamates (MoDTC) have been found to reduce LSPI events. In this study, we investigated degradation of ZnDTP and MoDTC in gasoline engine operation and effects of the degradation on LSPI performance. ...In this study, we investigated degradation of ZnDTP and MoDTC in gasoline engine operation and effects of the degradation on LSPI performance.
Technical Paper

A Technical Review on Low Speed Pre Ignition in Turbocharged Gasoline Direct Injection Engines

2022-10-05
2022-28-0023
The increase of pressure and temperature inside the combustion chamber at high loads also leads to a pre-ignition induced super knock and in severe cases, LSPI leads to broken piston rings, damaged pistons and bent connecting rods. Thus LSPI has become a great concern since it operates in a very common driving pattern of rapidly accelerating the vehicle at lower speed range, thereupon limiting further downsizing of gasoline engines. ...The power lost can be compensated by integrating a turbocharger to the engine to increase the boost pressure however, this again may create an abnormal combustion event known as low-speed pre-ignition (LSPI). The increase of pressure and temperature inside the combustion chamber at high loads also leads to a pre-ignition induced super knock and in severe cases, LSPI leads to broken piston rings, damaged pistons and bent connecting rods. ...The present review paper comprehends the details the conditions for occurrence of LSPI mainly focusing on cause and effect of the local auto ignition taking place inside the cylinder due to formation of contaminants entering from the top land crevice during blow-down and washed from the cylinder walls during direct injection wall impingement, the parameters effecting it and various methods to mitigate the LSPI issue in turbo charged gasoline direct injection engines.
Technical Paper

Effect of Properties and Additives of Gasoline on Low-Speed Pre-Ignition in Turbocharged Engines

2022-08-30
2022-01-1077
There exists a relationship between the particulate number (PN) in the normal combustion and the LSPI frequency. The sensitivity of the PN to the LSPI frequency was approximately 2.0 times greater for the Mn-added gasoline than for the hydrocarbon-based gasoline. ...Gasoline-related factors that affect low-speed pre-ignition (LSPI) include the distillation properties of gasoline, manganese (Mn), ethanol, diesel fuel, detergent for aftermarket, and iron (Fe). ...Therefore, appropriate countermeasures for LSPI have not yet been implemented. To clarify the effect of the gasoline properties and additives on LSPI, engine tests were conducted using gasoline with different “PM Index” values, an indicator of distillation properties, different concentrations of Mn, ethanol, diesel fuel, detergent, Fe, and high-Ca oil.
Technical Paper

Autoignition of Lubricating Oil from Piston Crown and In-Cylinder Condition on Abnormal Combustion of Supercharged SI Engine

2022-01-09
2022-32-0008
It is called the LSPI (Low Speed Pre-Ignition)[1]. This research focuses on one of the source of abnormal combustion which is the autoignition of lubricating oil from piston crown in cylinder, here especially, frequency of autoignition in cylinder[2,3,4]. ...The special behavior of the LSPI has been measured. The autoignition timing is ATDC in the initial stage. When the cycle of autoignition proceed, its timing is advance to BTDC. ...The dangerous activation energy E for the LSPI is under 6452(× 104 J/mol)in this research. The activation energy E would be able to take advantage of the engine design and simulation to prevent from the LSPI.
Technical Paper

Effect of Oil Additives and Fuel Concentration in Lubricating Oil on Abnormal Combustion of Supercharged SI Engine

2022-01-09
2022-32-0007
The spark ignition engine with supercharger which is supplied the fuel directly in cylinder (SI engine) has a phenomenon of abnormal combustion as called Low Speed Pre-Ignition (LSPI). It has been reported that the LSPI would be related with lubricating oil and the ingredients of fuel and oil additives [1] [2]. ...The mechanism of LSPI does not clear sufficiently, especially, relation ignition source of LSPI with the lubricating oil additives and the fuel concentration in lubricating oil. ...This research focuses on the source of LSPI which is autoignition of a lubricating oil droplet in cylinder. The effect of oil additives as Zn, Mo, Mg, Ca and concentration of fuel on autoignition of a lubricating oil droplet has been investigated.
Technical Paper

Lubricant-Oil-Induced Pre-ignition Phenomena in Modern Gasoline Engines: Using Experimental Data and Numerical Chemistry to Develop a Practical Correlation

2021-09-05
2021-24-0052
Low-Speed Pre-Ignition (LSPI) events severely limit the further development of Direct Injection Spark Ignition Engines (DISI), preventing high efficiencies from being achieved. ...However, there is still a lack of knowledge about the fundamental mechanisms leading to LSPI, due to the complex phenomena involved and the interaction between lubricant oil and fuel. ...Understanding how the presence of lubricant oil traces affects gasoline chemical reactivity is an essential step for performing successful numerical simulations aimed at predicting the onset of LSPI phenomena. Reaction mechanisms able to predict oil-fuel interaction have been proposed, but they are computationally demanding.
Journal Article

On Optical Semi-Quantitative Spectral Study of Low-Speed Pre-Ignition Sources in Spark Ignition Engines

2021-04-06
2021-01-0486
The droplet mechanism is typically dominated by the detergent additives present in the lubricant formulation; more specifically calcium and sodium-based detergent additives correlate strongly with the increased LSPI rates. Deposits flaking off the combustion chamber surfaces can also induce LSPI under certain conditions. ...Low-Speed pre-ignition (LSPI) in modern-day, heavily downsized, boosted, and direct-injection spark ignition (SI) engines is a well-known problem. ...A high calcium first-generation Dexos™ 1 compliant oil with moderate LSPI activity was used in this study. The analysis revealed that the precursors contained both the signals for calcium as well as the deposit wavelengths in different proportions.
Journal Article

Market Fuel Effects on Low Speed Pre-Ignition

2021-04-06
2021-01-0487
Conclusions about the effects of fuel on LSPI have been more varied, but as part of a recently completed research consortium, the LSPI tendency of market fuels with a range of properties, including composition, boiling point distribution, ethanol content and particulate matter index (PMI) were evaluated. ...It was found that the PMI and certain boiling points correlated the best with the frequency of LSPI events. In addition, decreased LSPI severity, quantified by the peak-to-peak knock values, was found to correspond with increased octane numbers and higher ethanol content of the market fuels. ...Low-Speed Pre-ignition (LSPI) is an undesirable abnormal combustion phenomenon observed in turbocharged, direct-injection spark-ignition engines and is characterized by early heat release, high cylinder pressures and severe, potentially damaging knock.
Technical Paper

Lubricating Oil Droplets from Piston Crown on Abnormal Combustion in Supercharged SI Engine

2020-11-30
2020-32-2302
However, it has a problem of abnormal combustion which is called Low Speed Pre-ignition (LSPI). It is cleared gradually that the character of lubricating oil effects on LSPI. The lubricating oil which has a tolerance for LSPI has been introduced already in the market nowadays. ...The lubricating oil which has a tolerance for LSPI has been introduced already in the market nowadays. However, cause and mechanism of LSPI occurrence does not clear sufficiently. ...In previous conference SETC 2018, it was reported that the peculiar behavior of LSPI corresponded with behavior of lubricating oil from piston crown [1, 2, 3]. This paper focuses on frequency of lubricating oil scattering from piston crown.
Technical Paper

Autoignition of a Lubricating Oil Droplet with Fuel Ingredients on Abnormal Combustion of Supercharged SI Engine

2020-11-30
2020-32-2318
It is called Low Speed Pre-ignition (LSPI). The lubricating oil which has a tolerance for LSPI has been introduced already in automobile market nowadays. ...However, cause and mechanism of LSPI does not clear sufficiently. It has been reported that the peculiar behavior of LSPI corresponded with behavior of lubricating oil from piston crown [1, 2]. ...This paper focuses on effect of fuel ingredients on autoignition of a lubricating oil droplet about LSPI. On the ignition source point of view, it is important to clear the mechanism of a lubricating oil droplet autoignition in cylinder.
Journal Article

Advanced Methods to Handle LSPI in TGDI Engines

2020-08-18
2020-28-0008
However, TGDI technology is susceptible to an abnormal combustion phenomenon termed as Low Speed Pre-Ignition (LSPI) event. This event happens prior to the intended combustion, which causes the catastrophic engine damage. ...In this paper, advanced methods to handle the LSPI occurrence severity and component level advances in design robustness to avoid the engine damage are reported. ...In overall, the techniques related to engine design to predict the LSPI occurrence in terms of peak cylinder pressure (PCP) and number of events are summarized.
Journal Article

Detailed Analyses and Correlation of Fuel Effects on Stochastic Preignition

2020-04-14
2020-01-0612
Stochastic or Low-Speed Preignition (SPI or LSPI) is an undesirable abnormal combustion phenomenon encountered in spark-ignition engines. It is characterized by very early heat release and high cylinder pressure and can cause knock, noise and ultimately engine damage.
Journal Article

Assessing the Impact of Lubricant and Fuel Composition on LSPI and Emissions in a Turbocharged Gasoline Direct Injection Engine

2020-04-14
2020-01-0610
However, high specific torque levels, especially at low speeds, can lead to abnormal combustion phenomena such as knock or Low-Speed Pre-Ignition (LSPI). LSPI, in particular, can limit further downsizing due to resulting and potentially damaging mega-knock events. ...Herein, we characterize the impacts of lubricant and fuel composition on LSPI frequency in a TGDI engine while specifically exploring the correlation between fuel composition, particulate emissions, and LSPI events. Our research shows that: (1) oil composition has a strong impact on LSPI frequency and that LSPI frequency can be reduced through a carefully focused approach to lubricant formulation. ...Herein, we characterize the impacts of lubricant and fuel composition on LSPI frequency in a TGDI engine while specifically exploring the correlation between fuel composition, particulate emissions, and LSPI events.
Technical Paper

Characteristics of Auto-Ignition for Lubricants and Lubricant/Gasoline Based on an Innovative Single Droplet Test System

2020-04-14
2020-01-1428
However, Low-Speed Pre-Ignition (LSPI) phenomenon observed in these engines restricts their improvement of performance. Some researchers have shown that auto-ignition of lubricant in the combustion chamber has a great effect on the LSPI frequency. ...Some researchers have shown that auto-ignition of lubricant in the combustion chamber has a great effect on the LSPI frequency. To study the auto-ignition characteristics of lubricant, an innovative single droplet auto-ignition test system for lubricant and its mixture is designed and developed, with better accuracy and effectiveness.
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