CN110375989B - Diesel engine combustion noise detection system - Google Patents
Diesel engine combustion noise detection system Download PDFInfo
- Publication number
- CN110375989B CN110375989B CN201910665953.2A CN201910665953A CN110375989B CN 110375989 B CN110375989 B CN 110375989B CN 201910665953 A CN201910665953 A CN 201910665953A CN 110375989 B CN110375989 B CN 110375989B
- Authority
- CN
- China
- Prior art keywords
- signal
- combustion
- excitation source
- diesel engine
- source sub
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H17/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves, not provided for in the preceding groups
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M15/00—Testing of engines
- G01M15/04—Testing internal-combustion engines
- G01M15/10—Testing internal-combustion engines by monitoring exhaust gases or combustion flame
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M15/00—Testing of engines
- G01M15/04—Testing internal-combustion engines
- G01M15/12—Testing internal-combustion engines by monitoring vibrations
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
- Testing Of Engines (AREA)
Abstract
The invention provides a diesel engine combustion noise detection system, which comprises a signal acquisition module and a signal processing module, wherein the signal acquisition module is used for acquiring a diesel engine cylinder pressure signal, the signal acquisition module is connected with the signal processing module, and the signal processing module executes the following steps: step one, processing the diesel engine cylinder pressure signal measured by the signal acquisition module by using a variational modal decomposition method, and respectively extracting different excitation source sub-signals from the diesel engine cylinder pressure signal; processing the excitation source sub-signal by using fast Fourier transform, and extracting a combustion signal and a combustion resonance signal from the excitation source sub-signal; and step three, calculating the combustion signal and the combustion resonance signal in the step two by utilizing an envelope derivative energy operator, and acquiring the instantaneous combustion noise frequency weighting energy of the combustion signal and the combustion resonance signal. The invention can be widely applied to the field of diesel engine combustion noise detection.
Description
Technical Field
The invention relates to a technology for detecting combustion noise of a diesel engine, in particular to a technology for acquiring noise source energy based on a diesel engine cylinder pressure signal.
Background
Diesel engines have been extensively studied as the core power plant of transportation vehicles such as heavy trucks and ships. The problem of vibration and noise of diesel engines has been a major factor limiting the development of diesel engines. Therefore, vibration and noise reduction of the diesel engine becomes a research hotspot of scholars in the related field. The noise generated by the diesel engine is mainly divided into three parts: mechanical noise, intake and exhaust noise, and combustion noise. The combustion noise is related to combustion, and occupies a great proportion in the overall noise of the diesel engine, so that the effective reduction of the combustion noise becomes the key for reducing vibration and noise of the diesel engine.
FPayri finds two excitation sources generating combustion noise, one being a combustion signal (corresponding to a middle frequency band) and the other being a combustion resonance signal (corresponding to a high frequency band), by decomposing a cylinder pressure signal in a paper "New method for in-cylinder pressure analysis in direct injection direction to combustion noise". In order to effectively reduce the combustion noise generated by these two excitation sources, it is first necessary to accurately estimate the combustion noise based on the cylinder pressure signal. The pressure rise rate and the heat release rate can reflect the change of combustion noise to a certain extent, but can be evaluated only visually, and the accuracy is poor.
Disclosure of Invention
In order to solve the problem of low accuracy of the existing diesel engine combustion noise detection, the invention provides a diesel engine combustion noise detection system which can weight combustion noise energy according to the acquired frequency generated by a combustion noise excitation source so as to accurately detect the combustion noise source of a diesel engine.
The technical scheme of the invention is as follows.
The utility model provides a diesel engine combustion noise detecting system, is including the signal acquisition module who obtains diesel engine cylinder pressure signal, and signal processing module, the signal acquisition module with signal processing module connects, signal processing module carries out following step:
step one, processing the diesel engine cylinder pressure signal measured by the signal acquisition module by using a variational modal decomposition method, and respectively extracting different excitation source sub-signals from the diesel engine cylinder pressure signal; the excitation source sub-signals comprise a combustion excitation signal and a combustion resonance excitation signal;
processing the excitation source sub-signal by using fast Fourier transform to obtain a frequency spectrum of the excitation source sub-signal, and converting the frequency spectrum into power spectral density; acquiring frequency spectrums corresponding to the combustion excitation signal and the combustion resonance excitation signal from the power spectrum density, and performing Fourier inversion on the frequency spectrums to obtain a combustion signal and a combustion resonance signal;
and step three, calculating the combustion signal and the combustion resonance signal in the step two by utilizing an envelope derivative energy operator, and acquiring the instantaneous combustion noise frequency weighting energy of the combustion signal and the combustion resonance signal.
In step one, the excitation source sub-signal further comprises: a back-off signal and a high-frequency oscillation signal.
Processing the excitation source sub-signal by using fast Fourier transform, wherein the processing of the excitation source sub-signal comprises the following steps:
PSD(ω)＝X(ω)2/Fs·N
x (omega) is the fast Fourier transform of the excitation source sub-signal, Fs is the sampling frequency, N is the signal length, PSD (omega) is the power spectral density, and omega represents the frequency.
The envelope derivative energy operator in step three:
Γ[x(t)]＝diff(x(t))2+H[diff(x(t))]2
wherein Γ [ x (t) ] represents the envelope derivative energy operator, x (t) is the combustion signal or the combustion resonance signal, and H [ · ] represents a Hilbert transform; diff (·) denotes the derivative.
The invention has the technical effects that:
according to the diesel engine combustion noise detection system, the variational modal decomposition method adopted in the signal processing module execution step can effectively reduce frequency aliasing among decomposed sub-signals, so that a combustion noise excitation source is accurately extracted. The envelope derivative method realizes the accurate calculation of the frequency weighting energy and accurately obtains the combustion noise energy generated by each excitation source. Compared with the existing combustion noise evaluation method, the method has the advantages of intuition and accuracy, and achieves the purpose of the invention.
Drawings
FIG. 1 is a block diagram of a diesel combustion noise detection system of the present invention.
Fig. 2 is a diagram of sub-signals obtained by metamorphic mode decomposition.
Fig. 3 is a power spectral density map.
FIG. 4 is a graph of an extracted combustion signal and a combustion resonance signal.
FIG. 5 is a combustion noise energy plot of a combustion signal versus a combustion resonance signal.
Detailed Description
The technical solution of the present invention will be described in detail below with reference to the embodiments shown in the drawings.
FIG. 1 shows the main components of the diesel combustion noise detection system of the present invention, namely, a signal acquisition module and a signal processing module. The signal acquisition module is connected with the signal processing module, and the connection refers to wired or wireless connection capable of carrying out signal transmission between the signal acquisition module and the signal processing module.
The signal acquisition module is used for measuring a pressure signal (namely a cylinder pressure signal) in a diesel cylinder, and the signal processing module executes the following steps for processing after receiving the pressure signal in the diesel cylinder.
Step one, processing the diesel engine cylinder pressure signal measured in the signal acquisition module by using a variational modal decomposition method, and respectively extracting different excitation source sub-signals from the diesel engine cylinder pressure signal; the excitation source sub-signals include a combustion excitation signal and a combustion resonance excitation signal.
There are many sources of excitation that generate noise during in-cylinder combustion in diesel engines, and these sources generate sub-signals that include a drag signal, a combustion excitation signal, a combustion resonance excitation signal, and a high frequency oscillation signal. These signals are distributed over different frequency bands. Since the variational modal decomposition method has good anti-aliasing performance, each excitation source sub-signal can be accurately extracted, and therefore, each excitation source sub-signal is separated by using the variational modal decomposition method.
[x1(t)，x2(t)，x3(t)，x4(t)]＝VMD(p(t)) (1)
Wherein xi (t) is the ith decomposed sub-signal, i represents one of numbers 1, 2, 3 and 4; and p (t) is a cylinder pressure signal measured by the signal acquisition module. VMD represents the variational modal decomposition process, and the number of decomposed sub-signals is 4. The resulting subsignals are shown in fig. 2.
Processing the excitation source sub-signal by using fast Fourier transform to obtain a frequency spectrum of the excitation source sub-signal, and converting the frequency spectrum into power spectral density; and acquiring frequency spectrums corresponding to the combustion excitation signal and the combustion resonance excitation signal from the power spectrum density, and performing Fourier inversion on the frequency spectrums to obtain a combustion signal and a combustion resonance signal.
Performing fast Fourier transform on each excitation source subsignal obtained in the step one to obtain a frequency spectrum of each excitation source subsignal, and performing corresponding processing on the frequency spectrum to convert the frequency spectrum into power spectral density, wherein the specific method comprises the following steps:
PSD(ω)＝X(ω)2/Fs·N (2)
wherein, X (ω) is the fast fourier transform of the excitation source sub-signal, Fs is the sampling frequency, N is the signal length, PSD (ω) is the power spectral density, ω represents the frequency. The power spectral density obtained is shown in fig. 3. The sub-signals are screened according to power spectral density, and a combustion excitation signal and a combustion resonance excitation signal directly related to combustion noise are selected. Wherein the combustion excitation signal is located substantially in the mid-frequency band and the combustion resonance excitation signal is located in the high-frequency band. The two are subjected to Fourier transformation, so that a combustion signal and a combustion resonance signal can be obtained, as shown in FIG. 4, wherein the excitation source 2 represents a combustion resonance excitation source, and the excitation source 4 represents a combustion excitation source.
And step three, calculating the combustion signal and the combustion resonance signal in the step two by utilizing an envelope derivative energy operator, and acquiring the instantaneous combustion noise frequency weighting energy of the combustion signal and the combustion resonance signal.
Because the sub-signals obtained in the second step are all in a pressure fluctuation mode, the amplitude change of the sub-signals is difficult to observe, and therefore the sub-signals are converted into a signal energy mode.
The traditional method for calculating signal energy is to sum the squares of the signal amplitudes with the signal y (t) ═ Acos (ω)0t + φ), where A is the amplitude, ω is0Phi is frequency and phi is phase. The energy of y (t) can be expressed as:
S[y(t)]＝|Acos(ω0t+φ)|2＝A2 (3)
obviously, the conventional signal energy calculation method does not involve frequency.
The invention utilizes signal envelope combined with weighting filtering to calculate the frequency weighting instantaneous energy of the signal. The envelope of the random signal z (t) can be expressed as
S[z(t)]＝|z(t)+jH[z(t)]|2 (4)
Where H [. cndot. ] represents the Hilbert transform, and the weighting filter is selected as the derivative of the signal. Taking the random signal z (t) as an example, the envelope derivative energy operator used in the present invention can be expressed as:
Γ[z(t)]＝|diff(z(t))+jH[diff(z(t))]|2＝diff(z(t))2+H[diff(z(t))]2 (5)
where diff (·) denotes the derivative. The envelope derivative energy of the signal y (t) can be calculated according to equation (5) as
Γ[y(t)]＝A2ω0 2 (6)
By comparing the formula (6) and the formula (3), the envelope derivative energy of the signal contains frequency weighting information, i.e. ω0。
When applied to discrete signals, equation (6) needs to be discretized, where the discrete form of the first derivative is
diff(z(n))＝[z(n+1)-z(n-1)]/2 (7)
n represents the current time step, brought into (5), and obtained
Wherein H (n) ═ H (z (n)). Accordingly, the combustion signal and the combustion resonance signal obtained in the second step are applied to the formula (8), i.e. z (n) in the formula is replaced, so that the instantaneous combustion noise frequency weighted energy change of the combustion signal and the combustion resonance signal is shown in fig. 5.
It should be noted that the above-mentioned embodiments are only examples of the present invention, and do not limit the scope of the invention, and the invention may be replaced by other equivalent techniques. Therefore, all equivalent changes, direct or indirect applications, made by using the description and drawings of the present invention, or other related technical fields are all included in the scope of the present invention.
Claims (4)
1. The utility model provides a diesel engine combustion noise detecting system, is including the signal acquisition module who obtains diesel engine cylinder pressure signal, and signal processing module, the signal acquisition module with signal processing module connects its characterized in that: the signal processing module executes the following steps:
step one, processing the diesel engine cylinder pressure signal measured by the signal acquisition module by using a variational modal decomposition method, and respectively extracting different excitation source sub-signals from the diesel engine cylinder pressure signal; the excitation source sub-signals comprise a combustion excitation signal and a combustion resonance excitation signal;
processing the excitation source sub-signal by using fast Fourier transform to obtain a frequency spectrum of the excitation source sub-signal, and converting the frequency spectrum into power spectral density; acquiring frequency spectrums corresponding to the combustion excitation signal and the combustion resonance excitation signal from the power spectrum density, and performing Fourier inversion on the frequency spectrums to obtain a combustion signal and a combustion resonance signal;
and step three, calculating the combustion signal and the combustion resonance signal in the step two by utilizing an envelope derivative energy operator, and acquiring the instantaneous combustion noise frequency weighting energy of the combustion signal and the combustion resonance signal.
2. The diesel combustion noise detection system of claim 1, wherein: in step one, the excitation source sub-signal further comprises: a back-off signal and a high-frequency oscillation signal.
3. The diesel combustion noise detection system of claim 1, wherein: processing the excitation source sub-signal by using fast Fourier transform, wherein the processing of the excitation source sub-signal comprises the following steps:
PSD(ω)＝X(ω)2/Fs·N
x (omega) is the fast Fourier transform of the excitation source sub-signal, Fs is the sampling frequency, N is the signal length, PSD (omega) is the power spectral density, and omega represents the frequency.
4. The diesel combustion noise detection system of claim 1, wherein: the envelope derivative energy operator in step three:
Γ[x(t)]＝diff(x(t))2+H[diff(x(t))]2
wherein Γ [ x (t) ] represents the envelope derivative energy operator, x (t) is the combustion signal or the combustion resonance signal, and H [ · ] represents a Hilbert transform; diff (·) denotes the derivative.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910665953.2A CN110375989B (en) | 2019-07-23 | 2019-07-23 | Diesel engine combustion noise detection system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910665953.2A CN110375989B (en) | 2019-07-23 | 2019-07-23 | Diesel engine combustion noise detection system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110375989A CN110375989A (en) | 2019-10-25 |
| CN110375989B true CN110375989B (en) | 2021-02-02 |
Family
ID=68255031
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910665953.2A Active CN110375989B (en) | 2019-07-23 | 2019-07-23 | Diesel engine combustion noise detection system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110375989B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112377305B (en) * | 2020-10-17 | 2021-11-19 | 哈尔滨工程大学 | Combustion phase identification method and system for marine compression ignition diesel engine |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105260549A (en) * | 2015-10-22 | 2016-01-20 | 中国汽车工程研究院股份有限公司 | Determination method of internal combustion engine combustion noise |
| JP2016121592A (en) * | 2014-12-24 | 2016-07-07 | トヨタ自動車株式会社 | Failure detection device of in-cylinder pressure sensor |
| JP2018003780A (en) * | 2016-07-06 | 2018-01-11 | トヨタ自動車株式会社 | Control device of internal combustion engine |
| CN108871791A (en) * | 2018-06-28 | 2018-11-23 | 奇瑞汽车股份有限公司 | A kind of automobile starting noise-measuring system and test method |
| CN108985188A (en) * | 2018-06-28 | 2018-12-11 | 哈尔滨工程大学 | A kind of signal processing method based on analysis combustion noise under the conditions of multi-injection |
-
2019
- 2019-07-23 CN CN201910665953.2A patent/CN110375989B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2016121592A (en) * | 2014-12-24 | 2016-07-07 | トヨタ自動車株式会社 | Failure detection device of in-cylinder pressure sensor |
| CN105260549A (en) * | 2015-10-22 | 2016-01-20 | 中国汽车工程研究院股份有限公司 | Determination method of internal combustion engine combustion noise |
| JP2018003780A (en) * | 2016-07-06 | 2018-01-11 | トヨタ自動車株式会社 | Control device of internal combustion engine |
| CN108871791A (en) * | 2018-06-28 | 2018-11-23 | 奇瑞汽车股份有限公司 | A kind of automobile starting noise-measuring system and test method |
| CN108985188A (en) * | 2018-06-28 | 2018-12-11 | 哈尔滨工程大学 | A kind of signal processing method based on analysis combustion noise under the conditions of multi-injection |
Non-Patent Citations (3)
| Title |
|---|
| New methodology for in-cylinder pressure analysis in direct injection diesel engines-application to combustion noise;F Payri 等;《MEASUREMENT SCIENCE AND TECHNOLOGY》;20050121;第16卷;第540-547页 * |
| 基于改进VMD与包络导数能量算子的滚动轴承早期故障诊断;任学平 等;《振动与冲击》;20181231;第37卷(第15期);第6-13页 * |
| 基于试验缸压曲线的船用柴油机燃烧噪声分析;毛金龙 等;《柴油机》;20190331;第41卷(第2期);第8-13页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110375989A (en) | 2019-10-25 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Yao et al. | Noise source identification of diesel engine based on variational mode decomposition and robust independent component analysis | |
| Bi et al. | Development of a novel knock characteristic detection method for gasoline engines based on wavelet-denoising and EMD decomposition | |
| CN101782464B (en) | Method and instrument thereof for acoustic diagnosis of automobile engine | |
| CN110375989B (en) | Diesel engine combustion noise detection system | |
| CN109271936A (en) | The building of aircraft vehicle vibrations Mishap Database and search method based on perceptual hash algorithm | |
| CN109446552B (en) | Time domain calculation method for structural fatigue life under multi-axis related random excitation | |
| Li et al. | Instantaneous angular speed-based fault diagnosis of multicylinder marine diesel engine using intrinsic multiscale dispersion entropy | |
| CN111353415B (en) | Method for detecting harmonic component in impulse response | |
| Albarbar | An investigation into diesel engine air-borne acoustics using continuous wavelet transform | |
| Xu et al. | A novel method for extracting maximum kurtosis component and its applications in rolling bearing fault diagnosis | |
| Li et al. | Determination of knock characteristics in spark ignition engines: An approach based on ensemble empirical mode decomposition | |
| CN201622112U (en) | Automobile engine acoustics diagnosis instrument | |
| Xu et al. | Analysis of the time-frequency characteristics of internal combustion engine vibration signal based on Hilbert-Huang transform | |
| Liu et al. | Application of wavelet packet transform in the knock detection of gasoline engines | |
| CN112162235B (en) | Smooth segmented stochastic resonance enhanced acoustic vector signal orientation method | |
| CN114838924A (en) | Structural damping ratio identification method based on wind-induced vibration non-stationary response | |
| CN110344960B (en) | Engine rotating speed estimation method and system | |
| Zhang et al. | Knock threshold detection in turbocharged gasoline engine using EEMD and bispectrum | |
| Zhen et al. | Calculate engine crankshaft angular acceleration based on original flywheel data | |
| CN114659791B (en) | Turbine fault detection method, system, device and storage medium | |
| Yang et al. | A New Time-frequency Combined Method Based on Improved Complete Ensemble EMD and Affine Smooth Pseudo Wigner-Ville Distribution | |
| CN116046893B (en) | Ultrasonic guided wave signal enhancement method and system based on multi-mode recognition-fusion | |
| Wang | Harmonic analysis of electrified railway based on improved HHT | |
| CN110389037B (en) | Diesel engine air intake measuring system | |
| Yang et al. | Noise Source Identification of a Gasoline Engine Based on Parameters Optimized Variational Mode Decomposition and Robust Independent Component Analysis |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |