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Technical Paper

Development of a Standardized Test to Evaluate the Effect of Gasoline Engine Oil on the Occurrence of Low Speed Pre-Ignition - The Sequence IX Test

2018-09-10
2018-01-1808
The study described in this paper covers the development of the Sequence IX Low Speed Pre-Ignition (LSPI) test for the new engine oil category, ILSAC GF-6. The purpose of the Sequence IX test is to evaluate a lubricant’s ability to protect against LSPI events which are prevalent when operating a highly boosted/downsized gasoline direct-injected engine. ...The purpose of the Sequence IX test is to evaluate a lubricant’s ability to protect against LSPI events which are prevalent when operating a highly boosted/downsized gasoline direct-injected engine. ...The purpose of the Sequence IX test is to evaluate a lubricant’s ability to protect against LSPI events which are prevalent when operating a highly boosted/downsized gasoline direct-injected engine. LSPI is characterized as a combustion event that starts before ignition spark, typically followed by excessive in-cylinder pressures and heavy knock, which can cause severe engine damage and failure.
Journal Article

Study of Low-Speed Pre-Ignition in Boosted Spark Ignition Engine

2014-04-01
2014-01-1218
This paper analyzes low-speed pre-ignition (LSPI), a sudden pre-ignition phenomenon that occurs in downsized boosted gasoline engines in low engine speed high-load operation regions. ...This research visualized the in-cylinder state before the start of LSPI combustion and observed the behavior of particles, which are thought to be the ignition source. ...Additionally, results also suggested that the well-known phenomenon in which the LSPI frequency rises in accordance with greater oil dilution may also be explained by an increase in deposit generation.
Journal Article

Experimental Studies on the Occurrence of Low-Speed Pre-Ignition in Turbocharged GDI Engines

2015-04-14
2015-01-0753
In the present paper the results of a set of experimental investigations on LSPI are discussed. The ignition system of a test engine was modified to enable random spark advance in one of the four cylinders. ...The ignition system of a test engine was modified to enable random spark advance in one of the four cylinders. LSPI sequences were successfully triggered and exhibited similar characteristics compared to regularly occurring pre-ignition. ...In a second engine the influence of the physical properties of the considered lubricant on the LSPI frequency was analyzed. In addition different piston ring assemblies have been tested. Moreover an online acquisition of the unburned hydrocarbon emissions in the exhaust gas was performed.
Journal Article

Investigation of Engine Oil Base Stock Effects on Low Speed Pre-Ignition in a Turbocharged Direct Injection SI Engine

2016-03-14
2016-01-9071
Low speed pre-ignition (LSPI) is a type of engine knocking specific to turbocharged direct injection engines. There are numerous factors that affect the amount of LSPI produced by an engine. ...There are numerous factors that affect the amount of LSPI produced by an engine. Some of these factors are related to engine hardware; others are specific to the fuel and engine oil. ...In this paper we focus on the effect of the engine oil base stock on LSPI. We conducted experiments in a stationary engine operating at conditions chosen to accentuate pre-ignition.
Technical Paper

An Introduction to How Low Speed Pre Ignition Affects Engine Components

2017-03-28
2017-01-1042
This phenomenon has the potential to catastrophically damage the power cylinder unit (PCU); therefore, engine manufacturers and suppliers are working to eliminate LSPI or design components to survive LSPI events if they occur. This paper is the first of a series of papers that will discuss MAHLE’s LSPI research, focused on power cylinder unit (PCU) components and systems designed to withstand LSPI events, as well as minimizing or eliminating the propensity of LSPI to occur. ...This paper is the first of a series of papers that will discuss MAHLE’s LSPI research, focused on power cylinder unit (PCU) components and systems designed to withstand LSPI events, as well as minimizing or eliminating the propensity of LSPI to occur....This operating condition results in an environment within the combustion chamber which has the propensity to experience a disruptive abnormal combustion event known as low speed pre-ignition (LSPI). This phenomenon has the potential to catastrophically damage the power cylinder unit (PCU); therefore, engine manufacturers and suppliers are working to eliminate LSPI or design components to survive LSPI events if they occur.
Technical Paper

Understanding Low Speed Pre-Ignition Phenomena across Turbo-Charged GDI Engines and Impact on Future Engine Oil Design

2015-09-01
2015-01-2028
Of particular interest for upcoming engine oil development is the phenomenon of low speed pre-ignition (LSPI). LSPI is an abnormal combustion event in which lubricating oil has been observed to play a role. ...Currently there are a number of different LSPI engine tests, using different hardware, operating conditions, and criteria to determine when LSPI events have occurred. In this presentation, a comparison of different LSPI tests will be made based on Oronite's extensive research work in this area. ...Smaller displacement engines, often with turbochargers, developed to meet higher fuel economy standards demand higher performance engine oils in conventional areas (oxidation and deposit control, fuel economy), and completely new areas (Low-Speed Pre-ignition [LSPI], turbocharger performance). Formulating engine oils which can simultaneously meet these competing demands will become more complex with increasing performance requirements.
Journal Article

Engine Oil Development for Preventing Pre-Ignition in Turbocharged Gasoline Engine

2014-10-13
2014-01-2785
According to recent technical reports, auto-ignition of an engine oil droplet in a combustion chamber is believed to be one of major contributing factors of LSPI and its formulations have a significant effect on LSPI frequency. Toyota has reported that the oxidation stability of engine oil can be a dominant factor of its auto-ignition, which is a function of its base oil and additive components, of which an example was found that calcium-based detergents significantly increase LSPI frequency. ...However abnormal combustion referred to as Low-Speed Pre-ignition (LSPI) is known to be able to occur in low-speed and high-torque conditions. It is a potential restriction to maximize the engine performance and its benefit, therefore prevention of LSPI is strongly desired for long-term durability of engine performance. ...It is a potential restriction to maximize the engine performance and its benefit, therefore prevention of LSPI is strongly desired for long-term durability of engine performance. According to recent technical reports, auto-ignition of an engine oil droplet in a combustion chamber is believed to be one of major contributing factors of LSPI and its formulations have a significant effect on LSPI frequency.
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

The Effect of Gasoline Metallic Additives on Low Speed Pre-Ignition

2018-04-03
2018-01-0936
As mentioned in several papers, metallic additives of engine oil such as calcium cause an abnormal combustion phenomenon called low-speed pre-ignition (LSPI) in turbocharged spark ignition engines. In contrast, the effect of metallic additives of gasoline such as MMT on LSPI has not been studied. ...In contrast, the effect of metallic additives of gasoline such as MMT on LSPI has not been studied. In this study, it was confirmed that manganese in gasoline increased the possibility of LSPI, and that lower volatile gasoline which contains heavy aromatic components tended to show higher sensitivity to manganese concentration in turbocharged spark ignition engines. ...In this study, it was confirmed that manganese in gasoline increased the possibility of LSPI, and that lower volatile gasoline which contains heavy aromatic components tended to show higher sensitivity to manganese concentration in turbocharged spark ignition engines.
Technical Paper

Characteristics of Abnormal Combustion in the Scavenging Zone for a Highly-Boosted Gasoline Direct Injection Engine

2017-03-28
2017-01-1721
It was demonstrated that with proper mixture enrichment, intensities and frequencies of superknock induced by LSPI could be reduced; when the mixture was enriched sufficiently, LSPI events occurred without leading to superknock. ...The low-speed pre-ignition (LSPI) events observed in the engine tests fell mainly in the scavenging zone. The most representative LSPI pattern observed was a sequence of the events, with the event number varying from one to 10 in the sequence. ...The most representative LSPI pattern observed was a sequence of the events, with the event number varying from one to 10 in the sequence.
Technical Paper

Investigations of Smoke Emission, Fuel Dilution and Pre-Ignition in a 2.0L Turbo-Charged GDI Engine

2016-04-05
2016-01-0698
The effect of the injection timing and injection strategy on fuel dilution and smoke emission, and LSPI are the focus of the experimental study. Dyno test results show that early fuel injection induces severe piston wetting and results in high smoke emission, reversely, retarding injection too far produces higher fuel dilution and increases smoke emission too due to the fuel spray impinging on the liner..There is a short time for evaporation and mixing of the fuel based on the constrained injection timing window, particularly in the higher load operation. ...Test results on this engine show that using the double injection can effectively reduce LSPI occurrence, by reducing the liner impingement. This indicates that the higher fuel dilution on cylinder wall is likely one of the key mechanism for the occurrence of LSPI events in this engine. ...This indicates that the higher fuel dilution on cylinder wall is likely one of the key mechanism for the occurrence of LSPI events in this engine.
Journal Article

0W-16 Fuel Economy Gasoline Engine Oil Compatible with Low Speed Pre-Ignition Performance

2017-10-08
2017-01-2346
The development of low viscosity gasoline engine oils should not only focus on fuel economy improvement, but also on the low speed pre-ignition (LSPI) prevention property. In previous LSPI prevention literatures, the necessity of applying Ca/Mg-based detergents system in the engine oil formulations was proposed. ...This newly developed engine oil also passed LSPI test and all of the bench and engine tests required by GF-5, which implied that this oil could provide good protection for engines.
Technical Paper

Cycle Resolved Combustion and Pre-Ignition Diagnostic Employing Ion Current in a PFI Boosted SI Engine

2015-04-14
2015-01-0881
An ion current sensor is employed in a 4 cylinder production SI engine for combustion diagnosis during combustion process, knock, and low speed pre-ignition (LSPI) detection. The results show that the ion current peak value and ion current peak phase have strong correlation with the cylinder pressure and pressure peak phase respectively. ...Importantly, the ion sensor successfully detected the low speed pre-ignition (LSPI) about more than 20 °CA before spark ignition.
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.
Journal Article

An Investigation on the Ignition Characteristics of Lubricant Component Containing Fuel Droplets Using Rapid Compression and Expansion Machine

2016-10-17
2016-01-2168
With the development of downsized spark ignition (SI) engines, low-speed pre-ignition (LSPI) has been observed more frequently as an abnormal combustion phenomenon, and there is a critical need to solve this issue. ...It has been acknowledged that LSPI is not directly triggered by autoignition of the fuel, but by some other material with a short ignition delay time. ...It was previously reported that LSPI can be caused by droplets of lubricant oil intermixed with the fuel. In this work, the ignition behavior of lubricant component containing fuel droplets was experimentally investigated by using a constant volume chamber (CVC) and a rapid compression and expansion machine (RCEM), which enable visualization of the combustion process in the cylinder.
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.
Technical Paper

Modeling the Evolution of Fuel and Lubricant Interactions on the Liner in Internal Combustion Engines

2018-04-03
2018-01-0279
Studies have shown that this mechanism is possibly a leading cause for low-speed pre-ignition (LSPI) as the droplets contain oil that has a much lower self-ignition temperature than pure fuel. ...In this interest, this work aims to study the oil-fuel interactions on the liner during an engine cycle, addressing molecular diffusion (in the liquid film) and vaporization (at the liquid-gas interface) to quantify the amount of fuel and oil that are subject to scraping by the top ring, thereby exploring their implications on LSPI and friction. An analytical model is developed by coupling multi-component heat and mass transfer using an implicit, adaptive-time and fixed-space numerical scheme.
Technical Paper

Influence of Fuel Dilution of Crankcase Oil on Ignitability of Oil Particles in a Highly Boosted Gasoline Direct Injection Engine

2015-09-29
2015-01-2811
The relationship between fuel dilution of the crankcase oil and low-speed pre-ignition (LSPI) was studied experimentally with a highly-boosted 1.8L turbocharged gasoline direct injection (TGDI) engine fueled with RON93 gasoline. ...It was demonstrated that frequency of LSPI is linked strongly to the minimum auto ignition temperature of the oil particles.
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