Statistical study on engine knock oscillation and heat release using multiple spark plugs and pressure sensors

Shi, Hao; Uddeen, Kalim; An, Yanzhao; Pei, Yiqiang; Johansson, Bengt

doi:10.1016/j.fuel.2021.120746

Cited by 23 publications

(15 citation statements)

References 40 publications

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“…In-cylinder pressure is one of the most essential parameters of the combustion process. 6 A high band pass filter (>4 kHz) was applied to process the recorded pressure data, estimate knock intensity, and observe frequencies in a specific range. 5,6 In order to differentiate between normal and knocking combustion, the pressure trace and filter pressure graphs are shown in Figure 4 by firing spark plug (1) at CR 10.5, with the data recorded by the top sensor due to its higher sensitivity.…”

Section: Resultsmentioning

confidence: 99%

“…21 When auto-ignition occurs, the pressure inside the chamber oscillates strongly, and an installed pressure sensor can detect the oscillation response, and a high pass band filter can then be used to differentiate the knocking combustion versus normal combustion; therefore this analysis is highly accurate in monitoring knock. 5,6,21 However, this method is limited by transducer reliability and cost. 22 Additionally, the noise sensing method uses a noise frequency spectrum of the combustion, and analyzes the power of knock by estimating the sound pressure level in a specific frequency range.…”

Section: Introductionmentioning

confidence: 99%

“…They also reported that knock intensity could be reduced if the spark location was chosen near to the position where autoignition could occur. In our previous studies, 5,6,33 we have triggered multiple spark plug strategies at lower CR to distinguished the knock mechanism, and perceived that knock propensity and intensity increased by firing double and triple spark plugs, but that operation with four spark plugs could suppress the knock occurrence.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The effects of compression ratio and combustion initiation location on knock emergence by using multiple pressure sensing devices

Uddeen

Shi

Tang

et al. 2022

International Journal of Engine Research

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Knock research is an essential study because knock limits spark-ignition (SI) engine power output, durability, noise, fuel consumption, and emission performance. The thermal efficiency of an engine can be improved by increasing the compression ratio, but at the same time it leads to the possibility of end gas autoignition inside the chamber. The objective of this work was to show the effect of three different compression ratios (CRs) 8.5, 9.5, and 10.5 on the mechanism of knock. In order to achieve this four equispaced spark plugs were fitted around the circumference of a special metal liner to initiate flame fronts from those plugs by firing with different spark approaches (e.g. spark timing, number, and location). In addition, six pressure sensors were installed at various locations to precisely record the autoignition event by monitoring pressure oscillations, combustion characteristics, and knock intensity. In-cylinder pressure and heat release rate (HRR) analyses were applied to distinguish the knocking combustion for the three different CRs. The results showed that a greater number of spark plugs produced more stable combustion even for a delayed spark timing (ST) than a single spark plug, but also increased pressure oscillations, HRR and knock propensity with higher CRs due to an increase in pressure and temperature inside the cylinder. The maximum amplitude of pressure oscillation (MAPO) method was used to determine the knock intensity, and it was observed that at the lowest CR of 8.5 three spark plugs gave higher MAPO values compared to four spark plugs for the same operating conditions. However, four spark plugs instigated higher MAPO values than three spark plugs for the higher CRs of 9.5 and 10.5 because, with the increase of CR and spark plug numbers, the pressure and temperature were increased during the combustion event, which was coupled with the compression effect on the unburned end gas mixture. Additionally, Fast Fourier transform (FFT) and wavelet methods were implemented to observe the frequencies induced during knock. It was found that sparking four plugs provoked various vibration modes in different amplitude ranges with the different CRs.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The effects of compression ratio and combustion initiation location on knock emergence by using multiple pressure sensing devices

Uddeen

Shi

Tang

et al. 2022

International Journal of Engine Research

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“…In order to differentiate normal combustion from knocking combustion, pressure trace and high band pass filtration analysis with a frequency range of 4 to 25 kHz were performed [18]. In addition, the maximum amplitude of pressure oscillation (MAPO) was used to quantify the knock intensity [5,7].…”

Section: Pressure and Heat Release Rate Evaluationmentioning

confidence: 99%

“…The key factors involved in knock studies are the parameters affecting knock, detection techniques and suppression methodologies [1,5]. There are several parameters that can be used to mitigate the knock such as fuel property [12,13], compression ratio [14,15], airfuel equivalence ratio (λ) [16], boundary conditions [17], and the number of ignition sites and timing [18,19], etc. Increasing the octane number (ON) of the fuel can reduce the knock occurrence, and decreasing the coolant boundary temperature can also help to reduce the knock [12,17].…”

Section: Introductionmentioning

confidence: 99%

Using Multiple Ignition Sites and Pressure Sensing Devices to Determine the Effect of Air-Fuel Equivalence Ratio on the Morphology of Knocking Combustion

Uddeen¹,

Shi²,

Tang³

et al. 2022

SAE Technical Paper Series

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In spark-ignition combustion, knocking combustion inherently presents an interaction between the main flame front and end gas autoignition. Conventionally, it generates a high amplitude pressure wave traveling across the chamber that can be responsible for reducing the performance of the engine, and can cause heavy damage to engine components. In order to study the phenomenon in a controllable way, experiments were performed on a specialized single-cylinder research engine fitted with a liner equipped with four equi-spaced spark plugs in the side so as to propagate various flame topologies from those locations, and hence achieve more controlled knock events. In addition, six pressure transducers were employed at distinct locations to precisely record details of the autoignition event by monitoring the pressure oscillations, and with them the combustion characteristics and knock intensity. Various spark ignition approaches such as the spark timing (ST), the number of ignition sites, and the location of the active spark plugs were applied to analyze the knock attributes for different ignition strategies. It has been observed that the knock intensity of single spark ignition is normally weak, while increasing the activated plug number from one to three could remarkably increase the maximum amplitude of pressure oscillation (MAPO) and knock cycle numbers. However, four spark ignition mitigates the steep pressure spikes caused by knock, and reduces the MAPO to a lower level than triple spark ignition. . Since knock occurrence depends on the relative air-fuel ratio (λ), this paper also described the effect of rich and lean conditions (λ = 0.7, 0.9, 1.0, and 1.3), on knock instigation coupled with firing multiple spark ignition sites. The experimental results revealed that λ = 0.9 case shows the maximum knock propensity along with various high frequency acoustics modes due to higher heat release rate with faster flame propagation inside the chamber. However, for the same operating conditions λ = 0.7 and 1.0 gave slight to moderate knock.

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Knock probability determination in a turbocharged gasoline engine through exhaust gas temperature and artificial neural network

Hosseini

Chitsaz

2023

Applied Thermal Engineering

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Statistical study on engine knock oscillation and heat release using multiple spark plugs and pressure sensors

Cited by 23 publications

References 40 publications

The effects of compression ratio and combustion initiation location on knock emergence by using multiple pressure sensing devices

The effects of compression ratio and combustion initiation location on knock emergence by using multiple pressure sensing devices

Using Multiple Ignition Sites and Pressure Sensing Devices to Determine the Effect of Air-Fuel Equivalence Ratio on the Morphology of Knocking Combustion

Knock probability determination in a turbocharged gasoline engine through exhaust gas temperature and artificial neural network

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