Increasing knock detection sensitivity by combining knock sensor signal with a control oriented combustion model

Plá, Benjamín; Bares, Pau; Jiménez, Irina; Guardiola, Carlos

doi:10.1016/j.ymssp.2021.108665

Cited by 7 publications

(2 citation statements)

References 14 publications

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“…Aramburu et al [28] used a knock limit of MAPO = 4 bar in their study of a six-cylinder engine with a displacement of 5883 cm 3 . The same MAPO limit was used by Pla et al [29], even though the displacement of the direct-injection engine was only 1300 cm 3 . For engines with larger cylinder capacity (5 dm 3 /cyl.…”

Section: Gasoline-fueled Knock Combustion Tests In Pre-chamber Systemsmentioning

confidence: 99%

Experimental Investigation on Knock Characteristics from Pre-Chamber Gas Engine Fueled by Hydrogen

Pielecha,

Szwajca,

Skobiej

2024

Energies

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Hydrogen-fueled engines require large values of the excess air ratio in order to achieve high thermal efficiency. A low value of this coefficient promotes knocking combustion. This paper analyzes the conditions for the occurrence of knocking combustion in an engine with a turbulent jet ignition (TJI) system with a passive pre-chamber. A single-cylinder engine equipped with a TJI system was running with an air-to-fuel equivalence ratio λ in the range of 1.25–2.00, and the center of combustion (CoC) was regulated in the range of 2–14 deg aTDC (top dead center). Such process conditions made it possible to fully analyze the ascension of knock combustion until its disappearance with the increase in lambda and CoC. Measures of knock in the form of maximum amplitude pressure oscillation (MAPO) and integral modulus of pressure oscillation (IMPO) were used. The absolute values of these indices were pointed out, which can provide the basis for the definition of knock combustion. Based on our own work, the MAPO index > 1 bar was defined, determining the occurrence of knocking (without indicating its quality). In addition, taking into account MAPO, it was concluded that IMPO > 0.13 bar·deg is the quantity responsible for knocking combustion.

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Section: Gasoline-fueled Knock Combustion Tests In Pre-chamber Systemsmentioning

confidence: 99%

Experimental Investigation on Knock Characteristics from Pre-Chamber Gas Engine Fueled by Hydrogen

Pielecha,

Szwajca,

Skobiej

2024

Energies

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“…Pla et al [32] proposed a novel knock recognition method that uses a combustion model to estimate the mass fraction that is burned when vibrations are sensed by a knock sensor. The amplitude of the vibration wave depends on the amount of fuel and air that autoignite.…”

Section: Processing Of 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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