Improving ion current of sparkplug ion sensors in HCCI combustion using sodium, potassium, and cesium acetates: Experimental and numerical modeling

Butt, Ryan H.; Chen, Yinwei; Mack, J. Hunter; Saxena, Samveg; Dibble, Robert W.; Chen, J.-Y.

doi:10.1016/j.proci.2014.06.084

Cited by 17 publications

(7 citation statements)

References 9 publications

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“…The optimization of signal-to-noise ratio can be achieved with fuel additive, even under the condition of k > 3 [28]. With better signal-to-noise ratio, the relation between IC signal and NO X emissions will be more obvious than Fig.…”

Section: Resultsmentioning

confidence: 99%

Numerical simulation study on correlation between ion current signal and NO X emissions in controlled auto-ignition engine

Liu

et al. 2015

Applied Energy

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Section: Resultsmentioning

confidence: 99%

Numerical simulation study on correlation between ion current signal and NO X emissions in controlled auto-ignition engine

Liu

et al. 2015

Applied Energy

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“…The DC voltage ion current sensors suffer from low signal-to-noise ratio SNR [13,14]. As noted earlier, with low SNR, a false ion signal from noise, instead of a flame front passing the ion sensor gap, may be detected.…”

Section: Ms It Is Remarkable That Even With the Long Delay Fuel Injection Still Reduces Ki Exploration #3: Ac-voltage Based Ion Current Smentioning

confidence: 98%

“…Melby (1953) used as many as 17 ion sensors on the cylinder head to track a pre-ignition event's flame front propagation [12]. Ion sensors were employed in combustion diagnostics (to detect knock and combustion phasing) by several researchers [13,14]. More recently, ion sensors are being investigated again for pre-ignition detection [15][16][17][18].…”

mentioning

confidence: 99%

Pre-ignition Detection Followed by Immediate Damage Mitigation in a Spark-Ignited Engine

Singh

Dibble

2021

SAE Technical Paper Series

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Pre-ignition remains a significant bottleneck to further downsizing and downspeeding technologies employed for reducing CO2 emissions in modern turbocharged spark-ignited engines. Pre-ignition, which occurs rarely, may lead to high peak pressures that auto-ignite the entire charge before TDC. The resulting high-pressure oscillations are known as super-knock, leading to sudden and permanent hardware damage to the engine. Over the years, numerous researchers have investigated the stochastic phenomenon's source and concluded that there is a role of lubricant additives, deposits, gasoline properties, and hot surfaces in triggering pre-ignition. No single source has been identified; the research continues. Here, we take a different approach; rather than continue the search for the source(s) of super-knock, we explore mitigating super-knock by detecting pre-ignition early enough to take immediate evasive action. Such evasive action is expected to suppress knock intensity, thereby saving the engine from any permanent damage.In this regard, the current work offers ways to detect pre-ignition (using ion sensors) and then mitigate engine damage by using immediate fuel enrichment. We present three related explorations.In exploration #1, we explore if the occurrence of ions products from the exhaust can warn that the next cycle has a high probability of preignition. For this next cycle, the intake fuel injection can be suspended or increased to operate engine fuel-rich. We find strong ion activity on every cycle. However, there is a weak correlation between the ion signal and pre-ignition occurrence.In exploration #2, an in-cylinder ion-current sensor is used to discover pre-ignition event unfolding during the compression stroke. When such a rare event is detected, more fuel is immediately injected, making the end gas far less reactive and avoiding autoignition and knock. These explorations #1 and #2 were conducted with a DC-based ion sensor. These explorations showed exciting and promising findings. However, our DC-based ion sensors are prone to low signal-to-noise ratio SNR, leading to false positives (unacceptably high number of false positives.)In Exploration #3, the signal-to-noise ratio improvement is explored by replacing the DC-based system with a novel AC-based system. We find the bandpass filtering of the ion signal is key to improved SNR.

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“…By conducting the sensitivity analysis, the C0-C2 section in this work is compared with the detailed primary reference fuel mechanism (M LLNL ) developed by Lawrence Livermore National Laboratory (LLNL) [23] . The M LLNL was successfully used for ion current signal phasing and amplitude analysis by Dibble et al [12] . Thus, the ion concentrations can be well predicted in the proposed flame ionization mechanism since the CH producing rate is accurately reproduced.…”

Section: Base Gasoline Fuel Oxidation Mechanismmentioning

confidence: 99%

“…Recently, several technical solutions including ionic sensor location optimization [11] , alkali metal based ionization enhancement additives [12] and high frequency AC power source [13] , are proposed for improvement of the ion current sensing system. Optimization of any of these proposals will be strongly aided by a chemical kinetic simulation of the in-cylinder flame ionization process.…”

Section: Introductionmentioning

confidence: 99%

A skeletal gasoline flame ionization mechanism for combustion timing prediction on HCCI engines

Dong

Chen

et al. 2017

Proceedings of the Combustion Institute

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Ion current sensing technology has the potential to be a low cost and real time combustion phasing solution for HCCI or HCCI-like engine control. Based on a primary reference fuel oxidation mechanism and a C1-C4 hydrocarbon flame ionization mechanism, a skeletal mechanism for gasoline flame ionization process prediction on HCCI engines was developed in this paper. Since the ion concentrations significantly affect the aroused ion current signals, the mechanism is targeted on accurately predicting both the ion production concentrations and other key combustion characteristics. Through the comparison with the results from the detailed gasoline flame ionization mechanism and experimental results, the predicted maximum hydronium (H 3 O + ) ion concentration and the concentration variation tendency are validated. Additionally, the auto-ignition delay time ( t ign ) accurately predicted under HCCI engine conditions. Through coupling with a 3D-CFD engine model, the skeletal mechanism was applied to predict the important information of incylinder ion species, which are validated by the experimental ion current amplitudes and phases. The results show that the ion current phase (Ion50) matches well with the positions where the predicted ion concentration reaches its maximum, and the ion current amplitudes are well predicted under the conditions of different equivalence ratios ( ) and fuel injection ratios ( Inj ratio ).

show abstract

Improving ion current of sparkplug ion sensors in HCCI combustion using sodium, potassium, and cesium acetates: Experimental and numerical modeling

Cited by 17 publications

References 9 publications

Numerical simulation study on correlation between ion current signal and NO X emissions in controlled auto-ignition engine

Numerical simulation study on correlation between ion current signal and NO X emissions in controlled auto-ignition engine

Pre-ignition Detection Followed by Immediate Damage Mitigation in a Spark-Ignited Engine

A skeletal gasoline flame ionization mechanism for combustion timing prediction on HCCI engines

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