Application of Acoustic and Vibration-Based Knock Detection Techniques to a High Speed Engine

Cavina, Nicolò; Businaro, Andrea; Cesare, Matteo De; Monti, Federico; Cerofolini, Alberto

doi:10.4271/2017-01-0786

Cited by 2 publications

(2 citation statements)

References 17 publications

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“…Figure 5, the noisy vibration signals are bandpass-filtered, and knock is determined to occur when the oscillations are above a threshold value. While straightforward, this process can be inaccurate, as discussed by Cavina et al [30], who found that this process was not able to adequately detect knock at high engine speeds. Given that most modern knock sensors use vibration sensing, it is a key signal for knock detection.…”

Section: Vibration Signalsmentioning

confidence: 99%

A Review of Recent Advancements in Knock Detection in Spark Ignition Engines

Mittal

2024

Signals

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In gasoline engines, the combustion process involves a flame’s propagation from the spark plug to the cylinder walls, resulting in the localized heating and pressurization of the cylinder content ahead of the flame, which can lead to the autoignition of the gasoline and air. The energy release from the autoignition event causes the engine cylinder to resonate, causing an unpleasant noise and eventual engine damage. This process is termed as knock. Avoiding knock has resulted in limiting the maximum engine pressures, and hence limiting the maximum efficiencies of the engine. Modern engines employ knock sensors to detect resonances, adjusting the spark plug timing to reduce pressures and temperatures, albeit at the expense of engine performance. This paper sets out to review the different signals that can be measured from an engine to detect the start of knock. These signals traditionally consist of the in-cylinder pressure, the vibrations of the engine block, and acoustic noise. This paper reviews each of these techniques, with a focus on recent advances. A number of novel methods are also presented, including identifying perturbations in the engine speed or exhaust temperature; measuring the ion charge across the spark plug leads; and using artificial intelligence to build models based on engine conditions. Each of these approaches is also reviewed and compared to the more traditional approaches. This review finds that in-cylinder pressure measurements remain as the most accurate for detecting knock in modern engines; however, their usage is limited to research settings. Meanwhile, new sensors and processing techniques for vibration measurements will more accurately detect knock in modern vehicles in the short term. Acoustic measurements and other novel approaches are showing promise in the long term.

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Section: Vibration Signalsmentioning

confidence: 99%

A Review of Recent Advancements in Knock Detection in Spark Ignition Engines

Mittal

2024

Signals

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“…The ionization current is a valid and robust technology for the in-cylinder pressure signal estimation [9]. A third method is that based on the acoustic emissions that can be measured with microphones [10][11][12]. Finally, some low-cost force transducers have been developed for the in-cylinder pressure sensing.…”

Section: Introductionmentioning

confidence: 99%

Development and Experimental Validation of an Adaptive, Piston-Damage-Based Combustion Control System for SI Engines: Part 2—Implementation of Adaptive Strategies

et al. 2021

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This work focuses on the implementation of innovative adaptive strategies and a closed-loop chain in a piston-damage-based combustion controller. In the previous paper (Part 1), implemented models and the open loop algorithm are described and validated by reproducing some vehicle maneuvers at the engine test cell. Such controller is further improved by implementing self-learning algorithms based on the analytical formulations of knock and the combustion model, to update the fuel Research Octane Number (RON) and the relationship between the combustion phase and the spark timing in real-time. These strategies are based on the availability of an on-board indicating system for the estimation of both the knock intensity and the combustion phase index. The equations used to develop the adaptive strategies are described in detail. A closed-loop chain is then added, and the complete controller is finally implemented in a Rapid Control Prototyping (RCP) device. The controller is validated with specific tests defined to verify the robustness and the accuracy of the adaptive strategies. Results of the online validation process are presented in the last part of the paper and the accuracy of the complete controller is finally demonstrated. Indeed, error between the cyclic and the target combustion phase index is within the range ±0.5 Crank Angle degrees (°CA), while the error between the measured and the calculated maximum in-cylinder pressure is included in the range ±5 bar, even when fuel RON or spark advance map is changing.

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Application of Acoustic and Vibration-Based Knock Detection Techniques to a High Speed Engine

Cited by 2 publications

References 17 publications

A Review of Recent Advancements in Knock Detection in Spark Ignition Engines

A Review of Recent Advancements in Knock Detection in Spark Ignition Engines

Development and Experimental Validation of an Adaptive, Piston-Damage-Based Combustion Control System for SI Engines: Part 2—Implementation of Adaptive Strategies

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