Weak knock characterization and detection for knock control

Nilsson, Ylva; Frisk, Erik; Nielsen, Lars

doi:10.1243/09544070jauto871

Cited by 20 publications

(11 citation statements)

References 32 publications

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“…A wide variety of different knock intensity metrics have been proposed, based on different knock sensors and signal processing/detection algorithms. [12][13][14][15][16][17][18][19][20] The precise details of these metrics do not seem to be critical, providing they reflect the properties of the underlying knock process that they are intended to measure. This work, for example, is based on a prior experimental analysis of a large database of recorded knock intensity data derived from an accelerometer-based knock sensor mounted on a Ford 5.4 L V8 gasoline engine.…”

Section: Knock Characterizationmentioning

confidence: 99%

A dual-threshold knock controller

Jones

Shayestehmanesh

Frey

2016

International Journal of Engine Research

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The use of a knock intensity threshold set at a relatively high level is effective for identifying knocking cycles, but results in high Type II (false negative) classification errors. Many cycles, although classified as non-knocking cycles (i.e. below the threshold), are actually operating in an undesirably high knock rate region. A traditional controller is therefore likely to advance the spark further into this region, when the correct response would be to retard the spark. In this article, a new dual-threshold knock controller is presented in which a second threshold is introduced in order to identify non-knocking cycles more clearly. This enables the advance gain to be increased without adversely affecting other aspects of the response, thereby improving the transient and steady-state performance characteristics of the controller. The threshold values can also be optimized so as to minimize the total Type I and Type II misclassification errors, resulting in a significant improvement in most aspects of the controller response.

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Section: Knock Characterizationmentioning

confidence: 99%

A dual-threshold knock controller

Jones

Shayestehmanesh

Frey

2016

International Journal of Engine Research

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“…A rich amount of literature has focused on processing the in-cylinder pressure oscillations, knock formations, and knock detection methods. 1–10 The characterization and modeling of the abovementioned focuses are deeply analyzed and formulated by Spelina et al 11,12 Regarding knock probability control, various methods have been developed to regulate spark timing in deterministic and statistic-based ways. The target of knock probability control via the SA is to keep the SA as close to the limit as possible.…”

Section: Introductionmentioning

confidence: 99%

Beta distribution-based knock probability map learning and spark timing control for SI engines

Zhao

Shen

2021

Proceedings of the Institution of Mechanical Engineers, Part D:

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In gasoline engines, the spark timing is often advanced to increase fuel economy under certain heavy load engine operating conditions. As a compromise between the risk of knock and the power output, spark timing is regulated at the boundary where a low knock probability is tolerated. Due to the stochasticity of binary knock events, it is necessary to have a large number of engine cycles for probability estimations, which can slow down the response speed of a controller to operating condition changes. To speed up the spark timing regulation and to reduce the spark timing variance, in this article, a knock probability feedforward map learning method and a spark timing control method are proposed under a unified framework. A learning method that applies the beta distribution is the key contribution of this work. The beta distribution in the map learning part is used to describe knock probabilities with uncertainties and to determine the next engine operating condition for sampling and map learning. In the spark timing method, the beta distribution is applied in the conventional control method to adjust the control gains. The proposed methods are experimentally validated on a test bench equipped with a production Toyota 1.8 L, 4-cylinder SI engine.

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“…On the other hand, the requirement of consumers in noise comfort and intension of automotive market competition also promote further engine noise suppression. 15,16 Noise due to high-pressure fuel pump is one of the major causes for consumer complains, and much greater emphasis has been given on its noise performance improvement. However, the reduction of radiated noise from other engine components, benefiting from engine miniaturization and new acoustic damping materials using, makes the high-pressure fuel pump induced noise more highlighted.…”

Section: Introductionmentioning

confidence: 99%

An experimental study for effect factors of the roller tappet induced impact noise in high-pressure fuel system of GDi engine

Shen

Tang²,

Lian

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part D:

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With the wide application of gasoline direct injection system, its noise problem is becoming increasingly prominent under serious competitive environment. As the primary noise source of the engine in idle condition, the significant noise generated by the low-to-high pressure transmission part of high-pressure fuel pump becomes more and more serious. This paper focuses on the driving component of high-pressure fuel pump, the roller tappet, and experimentally studies effect factors of impact noise induced by it at engine idle. Both the impact occurrence time and position are analyzed from the combined vibration acceleration and crankshaft/camshaft rotation angle signals in the time domain according to the structure and kinematic mechanism of the roller tappet. The influences of the axial clearance between roller and tappet shell, the engine rotation speed and the lubrication conditions are investigated by experiments. The experimental results show that the lubrication is the primary factor for the roller tappet induced impact noise reduction. A significant improvement about 83% can be achieved under pressure lubrication.

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Weak knock characterization and detection for knock control

Cited by 20 publications

References 32 publications

A dual-threshold knock controller

A dual-threshold knock controller

Beta distribution-based knock probability map learning and spark timing control for SI engines

An experimental study for effect factors of the roller tappet induced impact noise in high-pressure fuel system of GDi engine

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