Investigating Water Injection in Single-Cylinder Gasoline Spark-Ignited Engines at Fixed Speed

Singh, Eshan; Hlaing, Ponnya; Dibble, Robert W.

doi:10.1021/acs.energyfuels.0c03057

Cited by 14 publications

(2 citation statements)

References 49 publications

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“…In previous work, we direct-injected water late in the exhaust stroke to cool/quench only the residual exhaust without impacting the fresh incoming mixture (by finishing water injection before intake valve opening time) [23,24]. Such strategy significantly suppressed preignition frequency, supporting the idea that reactive debris in the residual gas is the cause for triggering pre-ignition in the subsequent cycle.…”

Section: Results and Discussion: Exploration #1: Pre-ignition Prediction From Exhaust Cycle Ion Signal And Mitigation Strategymentioning

confidence: 60%

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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Section: Results and Discussion: Exploration #1: Pre-ignition Prediction From Exhaust Cycle Ion Signal And Mitigation Strategymentioning

confidence: 60%

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

Singh

Dibble

2021

SAE Technical Paper Series

Self Cite

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“…(2) Shared memory, where each RDD is read-only and can be created by batch operations on other RDDs, and variables are shared between tasks and between tasks and drivers in parallel operations. RDDs provide four important operators that enable the Spark platform to provide richer interfaces and operations based on MR [30].…”

Section: Intelligent Evaluation Process Of Adaboost-ls-wsvm Based On ...mentioning

confidence: 99%

Smart Evaluation of Sustainability of Photovoltaic Projects in the Context of Carbon Neutrality Target

et al. 2022

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To support the sustainable development of photovoltaic (PV) projects in the context of the carbon neutrality aim, a scientific and reliable evaluation technique is crucial. In this research, an AdaBoost-LS-WSVM intelligent evaluation model built on the Spark platform is suggested to increase evaluation accuracy and timeliness. Firstly, the sustainability evaluation index system of PV projects is constructed from five levels: geographic resource sustainability, technical sustainability, economic sustainability, social sustainability, and environmental sustainability in the context of the carbon neutrality target. Then, the AdaBoost-LS-WSVM intelligent evaluation model with Spark as the platform is constructed, and the wavelet kernel function is applied to the LSSVM model to form the LS-WSVM regression model with stronger nonlinear fitting ability. The learning and training of training samples are completed by the AdaBoost model, and multiple weak LS-WSVM regressors are weighted to get a strong LS-WSVM regressor. The regression model is used for assessing the sustainability of PV projects on Spark Big Data runtime platform. Lastly, the scientific accuracy and reliability of the proposed model is confirmed by a case study, which facilitates a timely and effective assessment of the sustainability of PV projects in the context of carbon neutrality target and can provide scientific and reasonable decision support for the construction of a sustainable development model of PV projects.

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The Effect of Water Injection on a Naturally Aspirated Spark-Ignited Engine

Kim,

Chung,

Kim

et al. 2024

Int.J Automot. Technol.

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Water injection (WI) is a well-known technique to mitigate knocking phenomena, reducing the in-cylinder gas temperature with a high heat of vaporization and specific heat of water. In this study, the effect of WI directly into the cylinder on fuel efficiency was investigated using a 2.0 L naturally aspirated (NA), four-cylinder, port fuel injection (PFI)-spark-ignited (SI) engine. Spray visualization of water injection by a commercial gasoline direct-injection (GDI) injector was performed to elucidate the water evaporation characteristics. In engine experiments, combustion characteristics were analyzed by adjusting the WI timing and amount. Synergistic effects with other gas dilution techniques, such as EGR and Lean burn, were also investigated. The spray image of WI showed poor evaporation of water compared to gasoline, even at high fuel temperatures. The optimal timing of WI was advanced up to the early intake stroke due to the harsh conditions of NA engines for water evaporation compared to turbocharged engines. With the combination of EGR, the optimal WI timing was advanced by the compression stroke, and further fuel efficiency improvement was achieved. In lean combustion, WI can improve both combustion stability and fuel efficiency.

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Investigating Water Injection in Single-Cylinder Gasoline Spark-Ignited Engines at Fixed Speed

Cited by 14 publications

References 49 publications

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

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

Smart Evaluation of Sustainability of Photovoltaic Projects in the Context of Carbon Neutrality Target

The Effect of Water Injection on a Naturally Aspirated Spark-Ignited Engine

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