Model Based Control of Combustion Timing and Load in HCCI Engines

Ebrahimi, Khashayar

doi:10.7939/r3mw28p0f

Cited by 1 publication

(1 citation statement)

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“…41,70 This in-cylinder temperature was calculated using a zero-dimensional model developed in Ebrahimi. 71 The estimated speed of sound values are being used to calculate the vibration modes using equation (1) to justify the Power Spectral Density (PSD) observations. For the TSIO-520 engine with the configurations listed in Table 1, the oscillation frequencies in kHz for various modes are listed in Table 4.…”

Section: Filter Designmentioning

confidence: 99%

Evaluation of ASTM D6424 standard for knock analysis using unleaded fuel candidates on a six cylinder aircraft engine

Ebrahimi

Gordon

Canteenwalla

et al. 2021

International Journal of Engine Research

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The ASTM D6424 standard is used for general aviation piston engine knock detection and is tested for unleaded fuel candidates. Issues are discussed regarding the identification of knocking cycles, filtering frequency bands, and the effects of down-sampling for this knock detection technique. The knock tests were performed on the Continental TSIO-520-VB engine at 12,000 ft for take-off and cruise conditions using three different fuels, the standard leaded 100LL avgas and two unleaded fuel candidates. The ASTM D6424 knock detection method has its own particular disadvantages, which are detailed and compared to other knock detection methods including the third derivative of pressure signal and discrete wavelet transform. Updates to the standard include a minimum sampling rate of 0.2 CAD. Additionally, the current standard does not contain recommendations for filtering the cylinder pressure which results in over detection of knocking cycles with the two new aviation fuel candidates tested. Recommendations are provided regarding the pressure signal processing prior to ASTM D6424 knock-characterization.

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Section: Filter Designmentioning

confidence: 99%