The Effect of NOx on Knock in Spark-ignition Engines

Kawabata, Yusuke; Sakonji, Tatsuo; Amano, Tadaaki

doi:10.4271/1999-01-0572

Cited by 22 publications

(7 citation statements)

References 2 publications

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“…The intake NO2 has the stronger impact on acceleration of the ignition. A possible explanation is that NO2 produces reactive radicals in the C1-C2 chemistry as follows [16]:…”

Section: Effects Of Nitrogen Oxide Addition On Ignitionmentioning

confidence: 99%

“…In spark-ignition engines, it is known that NOx enhances the ignition, leading to knocking issues [16]. Sjöberg et al suggested the possibility that such autoignition was influenced by the presence of unburned or only partially-oxidized hydrocarbons and nitrogen monoxide (NO) in a homogeneous charge compression ignition (HCCI) engine fueled with gasoline and primary reference fuels [17], and Kawasaki et al demonstrated that the ignition was enhanced with either NO and nitrogen dioxide (NO2) in a HCCI engine fueled with natural gas [18].…”

Section: Introductionmentioning

confidence: 99%

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EGR gas composition effects on ignition delays in diesel combustion

Kobashi

Todokoro

Shibata

et al. 2020

Fuel

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“…The intake NO2 has the stronger impact on acceleration of the ignition. A possible explanation is that NO2 produces reactive radicals in the C1-C2 chemistry as follows [16]:…”

Section: Effects Of Nitrogen Oxide Addition On Ignitionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

EGR gas composition effects on ignition delays in diesel combustion

Kobashi

Todokoro

Shibata

et al. 2020

Fuel

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“…The correction vector, shown in equation (11), consists of several parameters with a total dimension of ½n 3 m. The size of this map is based on the chosen discretization for engine speed ½m and EGR mass flow rate ½n. Each correction parameter corresponds to a different set of these variables.…”

Section: Adaptation Algorithmmentioning

confidence: 99%

“…[1][2][3] Also, when compared to high-pressure EGR configurations, LP systems prove to be more suitable for downsized turbocharged SI engines. [4][5][6][7][8][9][10][11] Aiming to fully exploit those benefits, new challenges are introduced that require more complex, precise, and robust control systems. The long air-paths and significant transport delays between the EGR valve and the cylinders are the main drawbacks of LP-cEGR systems.…”

Section: Introductionmentioning

confidence: 99%

Short-term and long-term adaptation algorithm for low-pressure exhaust gas recirculation estimation in spark-ignition engines

Siokos

Koli

Prucka

2018

International Journal of Engine Research

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Low-pressure exhaust gas recirculation systems are capable of increasing fuel efficiency of spark-ignition engines; however, they introduce control challenges. The low available pressure differential that drives exhaust gas recirculation flow, along with the significant pressure pulsations in the exhaust environment of a turbocharged engine hamper the accuracy of feed-forward estimation models. For that reason, feedback measurements are required in an effort to increase prediction accuracy. Additionally, the accumulation of deposits in the exhaust gas recirculation system and the aging of the valve, change the flow characteristics over time. Under these considerations, an adaptation algorithm is developed which handles both short-term (operating-point-dependent errors) and long-term (system aging) corrections for exhaust gas recirculation flow estimation. The algorithm is based on an extended Kalman filter for joint state and parameter estimation and uses the output of an intake oxygen sensor to adjust the feed-forward prediction by creating an online adaptation map. Two different exhaust gas recirculation estimation models are developed and coupled with the adaptation algorithm. The performance of the algorithm for both estimation models is evaluated in real-time through transient experiments with a turbocharged spark-ignition engine. It is demonstrated that this methodology is capable of creating an adaptation map which captures system aging, while also reduces the estimation bias by more than four times resulting in a prediction error of less than 1%. Finally, this approach proves to be a valuable tool that can significantly reduce offline calibration efforts for such models.

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“…A clean low-pressure cooled external EGR system was implemented on the Miller cycle engine, as it reduces the NO x in the recirculated exhaust gas and suppresses knock. 14 Specifically, exhaust gas was transported from downstream of the closed-coupled three-way catalytic converter (TWC) to a location upstream of the inlet of the turbocharger compressor, as illustrated in Figure 1. In order to evaluate the EGR benefits without flow limitation, a dual-leg EGR system was designed to maximize the EGR flow, where each leg consists of an EGR cooler and an EGR valve.…”

Section: Experimental Set-upmentioning

confidence: 99%

Development of a Miller cycle engine with single-stage boosting and cooled external exhaust gas recirculation

Liu

Zhu

Sun

2016

Proceedings of the Institution of Mechanical Engineers, Part D:

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In this paper, the development of a Miller cycle gasoline engine which has a high compression ratio from 11.5:1 to 12.5:1, single-stage turbocharging and external cooled exhaust gas recirculation is described. The improvement in the fuel economy by adding external cooled exhaust gas recirculation to the Miller cycle engine at different geometric compression ratios were experimentally evaluated in part-load operating conditions. The potential of adding external cooled exhaust gas recirculation in full-load conditions to mitigate pre-ignition in order to allow higher geometric compression ratios to be utilized was also assessed. An average of 3.2% additional improvement in the fuel economy was achieved by adding external cooled exhaust gas recirculation to the Miller cycle engine at a geometric compression ratio of 11.5:1. It was also demonstrated that the fuel consumption of the engine with external cooled exhaust gas recirculation was reduced by 3-7% in a wide range of part-load operating conditions and that the engine output of the Miller cycle engine at a geometric compression ratio of 12.5:1 increased at 2000 r/min in the full-load condition. The Miller cycle engine with external cooled exhaust gas recirculation at a geometric compression ratio of 12.5:1 achieved a broad brake specific fuel consumption range of 220 g/kW h or lower, with the lowest brake specific fuel consumption of 215 g/kW h. While there are still challenges in implementing external cooled exhaust gas recirculation, the Miller cycle engine with single-stage turbocharging and external cooled exhaust gas recirculation showed its potential for substantial improvement in the fuel economy as one of the technical pathways to meet future requirements in reducing carbon dioxide emissions.

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The Effect of NOx on Knock in Spark-ignition Engines

Cited by 22 publications

References 2 publications

EGR gas composition effects on ignition delays in diesel combustion

EGR gas composition effects on ignition delays in diesel combustion

Short-term and long-term adaptation algorithm for low-pressure exhaust gas recirculation estimation in spark-ignition engines

Development of a Miller cycle engine with single-stage boosting and cooled external exhaust gas recirculation

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