Methodology for processing pressure traces used as inputs for combustion analyses in diesel engines

Rašić, Davor (author), Vihar, Rok (author), Žvar Baškovič, Urban (author), Katrašnik, Tomaž (author)

This study proposes a novel methodology for designing an optimum equiripple finite impulse response (FIR) filter for processing in-cylinder pressure traces of a diesel internal combustion engine, which serve as inputs for high-precision combustion analyses. The proposed automated workflow is based on an innovative approach of determining the transition band frequencies and optimum filter order. The methodology is based on discrete Fourier transform analysis, which is the first step to estimate the location of the pass-band and stop-band frequencies. The second step uses short-time Fourier transform analysis to refine the estimated aforementioned frequencies. These pass-band and stop-band frequencies are further used to determine the most appropriate FIR filter order. The most widely used existing methods for estimating the FIR filter order are not effective in suppressing the oscillations in the rate-of-heat-release (ROHR) trace, thus hindering the accuracy of combustion analyses. To address this problem, an innovative method for determining the order of an FIR filter is proposed in this study. This method is based on the minimization of the integral of normalized signal-to-noise differences between the stop-band frequency and the Nyquist frequency. Developed filters were validated using spectral analysis and calculation of the ROHR. The validation results showed that the filters designed using the proposed innovative method were superior compared with those using the existing methods for all analyzed cases.

• Language: English
• Keywords: diesel engines, FIR filters, harmonics, spectral analyses
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Author Accepted Manuscript
• Year: 2017
• Number of pages: Str. 1-22
• Numbering: Vol. 28, iss. 5
• PID: 20.500.12556/RUL-106226
• UDC: 621.43(045)
• ISSN on article: 0957-0233
• DOI: 10.1088/1361-6501/aa5f9e
• COBISS.SI-ID: 15304475
• Publication date in RUL: 13.02.2019

Record is a part of a journal

• Title: Measurement science & technology
• Shortened title: Meas. sci. technol.
• Publisher: IOP Publishing
• ISSN: 0957-0233
• COBISS.SI-ID: 6000901

Secondary language

• Language: Slovenian
• Keywords: dizelski motorji, FIR filtri, harmoniki, spektralna analiza

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0401
• Name: Energetsko strojništvo