Limits on downsizing in spark ignition engines due to pre-ignition

Willand, Jürgen; Daniel, Marc; Montefrancesco, Emanuela; Geringer, Bernhard; Hofmann, Peter; Kieberger, Markus

doi:10.1007/bf03226955

Cited by 56 publications

(19 citation statements)

References 2 publications

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“…In numerous technical publications potential root cause sources have been discussed [2,3,4,5,6,7,8]. Some track pre-ignition back to oil droplets and combustion chamber deposits as possible root cause [1, 5,12].…”

Section: Figure 1 -Illustration Of Operation Area Where Pre-ignition mentioning

confidence: 99%

Systematic Approach to Analyze and Characterize Pre-ignition Events in Turbocharged Direct-injected Gasoline Engines

Haenel¹,

Seyfried²,

Kleeberg³

et al. 2011

SAE Technical Paper Series

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Downsized direct-injected boosted gasoline engines with high specific power and torque output are leading the way to reduce fuel consumption in passenger car vehicles while maintaining the same performance when compared to applications with larger naturally aspirated engines. These downsized engines reach brake mean effective pressure levels which are in excess of 20 bar. When targeting high output levels at low engine speeds, undesired combustion events called pre-ignition can occur. These pre-ignition events are typically accompanied by very high cylinder peak pressures which can lead to severe damage if the engine is not designed to withstand these high cylinder pressures. Although these pre-ignition events have been reported by numerous other authors, it seems that their occurrence is rather erratic which makes it difficult to investigate or reliably exclude them. This paper describes a systematic engine dyno testing approach to force the engine into pre-ignition in order to study and characterize these events. A sensitivity study of various parameters shows that pre-ignition can occur repeatedly at the same load levels if boundary conditions are controlled sufficiently, meaning pre-ignition occurrence is less erratic than previously thought. Several hundred pre-ignition events have been recorded and analyzed in this study. A post-processing tool was developed and applied to analyze and characterize all recorded pre-ignition events. The knowledge gained out of these investigations will help to better understand the pre-ignition phenomena and what combustion development activities need to be applied in order to avoid or counteract pre-ignition during an engine development program or afterwards during customer usage in a passenger car.

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Section: Figure 1 -Illustration Of Operation Area Where Pre-ignition mentioning

confidence: 99%

Systematic Approach to Analyze and Characterize Pre-ignition Events in Turbocharged Direct-injected Gasoline Engines

Haenel¹,

Seyfried²,

Kleeberg³

et al. 2011

SAE Technical Paper Series

View full text Add to dashboard Cite

show abstract

“…Recent developments, especially in highly boosted Spark Ignition (SI), gasoline-fueled engines with direct injection in the low-speed and high-load operating regime, have however been challenged by the occurrence of a new mode of engine knock [1], which has been variously termed as superknock, unwanted pre-ignition [2], mega knock [3], LSPI (low-speed pre-ignition) [4], Deto-knock [5], developing detonation [6,7] or subsequent front propagation [8]. It is significant to note that such a single super-knock event can instantaneously and severely damage the engine due to the extremely high peak pressure and the associated pressure oscillations developed.…”

Section: Introductionmentioning

confidence: 99%

Analysis of pre-ignition to super-knock: Hotspot-induced deflagration to detonation

Wang

et al. 2015

Fuel

190

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“…In some papers super-knock is regarded as pre-ignition. Willand et al 4 combined visualization and thermodynamics to analyze the cause of pre-ignition. They concluded that hot spots, deposits, oil droplets, residual gas, auto-ignition of the air/fuel mixture, valve timing, and intake pressure wave are all potential causes of pre-ignition.…”

Section: Introductionmentioning

confidence: 99%

3D simulation study on the influence of lubricant oil droplets on pre-ignition in turbocharged DISI engines

Huang

Zhang

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part D:

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A skeletal chemical kinetic model for the simulation of auto-ignition and flame propagation characteristics of primary reference fuel (PRF) was developed. Coupled with this model, 3D simulations were applied to investigate the influence of lubricant oil droplets on pre-ignition in a turbocharged direct-injection spark-ignition (DISI) engine at low-speed high-load operating conditions. First, a simulation study on the influence of a lubricant oil droplet on auto-ignition of gasoline substitute and air mixture was performed in a constant-volume chamber. The results revealed that with an increase of the lubricant oil droplet diameter, the ignition delay time for the air/fuel mixture initially decreased and then increased. The ignition delay time was further shortened with the increase of the temperature of the lubricant oil droplet and the temperature and pressure of the mixture. Moreover, it was found that when n-heptane (n-C7H16) was used as a substitute for the direct evaporation product of the lubricant oil droplet, the shortening of the ignition delay time for the air/fuel mixture caused by lubricant oil evaporation was not enough to initiate pre-ignition. When octyl hydrogen peroxide ketone (C8KET) was chosen as a representative of the accumulated stable reactive radicals, the ignition delay time was significantly shortened and was short enough to trigger pre-ignition. Therefore, pre-ignition may not be induced by the direct evaporation product of an lubricant oil droplet but by the accumulated stable reactive radicals. A simulation study on auto-ignition and flame propagation of the air/fuel mixture with the presence of a lubricant oil droplet was then conducted in a turbocharged DISI engine. The results successfully predicted the auto-ignition of the air/fuel mixture near the lubricant oil droplet before the spark ignition timing. Finally, a more convincing mechanism for pre-ignition induced by lubricant oil droplets is proposed to provide some clues for further investigation.

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Limits on downsizing in spark ignition engines due to pre-ignition

Cited by 56 publications

References 2 publications

Systematic Approach to Analyze and Characterize Pre-ignition Events in Turbocharged Direct-injected Gasoline Engines

Systematic Approach to Analyze and Characterize Pre-ignition Events in Turbocharged Direct-injected Gasoline Engines

Analysis of pre-ignition to super-knock: Hotspot-induced deflagration to detonation

3D simulation study on the influence of lubricant oil droplets on pre-ignition in turbocharged DISI engines

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