The article addresses results of the research on the preliminary research on influence of chosen damages of car vehicle engine on noise generated level. The diagnostics experiment was conducted and the noise levels were measured in defined measure points placed outside the vehicle. For the experiments vehicles with damages of the engine and its equipments were chosen. The measures were conducted before and after the repair. The research had preliminary character, so evaluation of the influence of damages of car vehicle engine on noise generated level have had qualitative dimension

Andrzej Wieczorek

Paweł Fabiś

Piotr Folęga

Rafał Burdzik

Łukasz Konieczny

English

Journal of Measurements in Engineering

 164 JOURNAL OF MEASUREMENTS IN ENGINEERING. SEPTEMBER 2013, VOLUME 1, ISSUE 3  
26. Research on influence of damages of car vehicle 
combustion engine on noise level 
Rafał Burdzik1, Piotr Folęga2, Łukasz Konieczny3, Andrzej Wieczorek4, Paweł Fabiś5 
1, 2, 3, 5Silesian University of Technology, Faculty of Transport, Gliwice, Poland 
4Silesian University of Technology, Faculty of Mining and Geology, Gliwice, Poland 
1Corresponding author 
E-mail: 1rafal.burdzik@polsl.pl, 2piotr.folega@polsl.pl, 3lukasz.konieczny@polsl.pl, 
4andrzej.n.wieczorek@polsl.pl, 5pawel.fabis@polsl.pl 
(Received 2 September 2013; accepted 7 September 2013) 
Abstract. The article addresses results of the research on the preliminary research on influence of 
chosen damages of car vehicle engine on noise generated level. The diagnostics experiment was 
conducted and the noise levels were measured in defined measure points placed outside the 
vehicle. For the experiments vehicles with damages of the engine and its equipments were chosen. 
The measures were conducted before and after the repair. The research had preliminary character, 
so evaluation of the influence of damages of car vehicle engine on noise generated level have had 
qualitative dimension. 
Keyword: sound level, noise, combustion engine, diagnostics. 
1. Introduction 
Each exploitation process included situation when technical condition of some elements were 
not proper or even damages have occurred. For the proper services of the technical machines it is 
very important to define and monitor symptoms of the damages. Nowadays it is getting more 
popular to use non-destructive methods during testing and researching on machines health 
monitoring. One of the most popular group of methods is vibroacoustic diagnostics. It is based on 
signals of vibration or acoustics taking from working machine and proper processing. The paper 
presents results of experiments on application of acoustics signal for diagnosis of engine of 
passenger car damages. 
Because of the sound properties, acoustic diagnosis can be considered as one of the very first 
methods. Noise is mostly first symptom of technical condition changes. The perception of those 
symptoms depends on level of increase of the sound. Sound may be defined as any pressure 
variation that the human ear can detect. In terms of sound pressure levels, audible sound ranges 
from the threshold of hearing at 0 dB to the threshold of pain at 130 dB and over. Although an 
increase of 6 dB represents a doubling of the sound pressure, an increase of about 8-10 dB is 
required before the sound subjectively appears to be significantly louder. Similarly, the smallest 
perceptible change is about 1 dB. Perception of the sound increase in dB scale has been depicted 
in Fig. 1. 
 
Fig. 1. Perception of the sound increase in dB scale 
26. RESEARCH ON INFLUENCE OF DAMAGES OF CAR VEHICLE COMBUSTION ENGINE ON NOISE LEVEL.  
RAFAŁ BURDZIK, PIOTR FOLĘGA, ŁUKASZ KONIECZNY, ANDRZEJ WIECZOREK, PAWEŁ FABIŚ 
 © VIRBROENGINEERING. ISSN PRINT 2335-2124, ISSN ONLINE 2424-4635, KAUNAS, LITHUANIA 165 
On the other hand the increase of sound level during damage process causes increase of the 
vehicles noise considered as line source. Road traffic is the most widespread source of noise in all 
countries and the most prevalent cause of annoyance and interference. Therefore, traffic noise 
reduction measures have the highest priority. Road traffic noise accounts for more than 90 % of 
unacceptable noise levels in Europe. From many methods for reduction of road noise, as thin 
noise-reduced surfaces or noise barriers, the acoustics monitoring of vehicle condition can be 
considered as extra alternative method. 
2. Research method 
For the noise measurement the sound level meters can be used. It is common practice to 
calibrate sound level meters using an acoustical calibrator before and after each series of 
measurements. Calibration is to check the instrument’s sensitivity at one specific frequency and 
sound level (usually 1 kHz and 94 dB). During the experiments the sound level meters SON-50 
from SONOPAN company were used. 
a)  
b)  
Fig. 2. Scheme of the test stand and localization of points of the measurement surface:  
a) 1 – vehicle during research, 2 – test stand, 3 – sound level meter; b) 1-5 – measurement points 
26. RESEARCH ON INFLUENCE OF DAMAGES OF CAR VEHICLE COMBUSTION ENGINE ON NOISE LEVEL.  
RAFAŁ BURDZIK, PIOTR FOLĘGA, ŁUKASZ KONIECZNY, ANDRZEJ WIECZOREK, PAWEŁ FABIŚ 
166 JOURNAL OF MEASUREMENTS IN ENGINEERING. SEPTEMBER 2013, VOLUME 1, ISSUE 3  
For the purpose of the analysis of acoustics phenomena the broadband measurements, i. e., 
measurements covering the whole of the audible frequency range, were made using the “A” 
frequency weighting. Noise with distinct tones, for example, noise from fans, compressors is 
generally far more annoying than other types of noise. Spectral analysis may be needed for 
analysis of the dynamics of the noises. During the research the octave filter OF-50 has been used. 
The scope of the research included measurements of the acoustics properties of the vehicles 
with the damages of the engine. Sound levels have been registered on the measurement surface in 
the laboratory with the special position for noise measurement. It is very important to create 
enough free space around the researched vehicle and to maintain the same measurement surface 
in each experiment. 
To compare acoustics properties correlated with the damages the measurements were 
conducted before and after repair of the vehicle. Research set up allows maintaining the same 
measurement points and conditions for every research step. The test stand and localization of 
points of the measurement surface have been depicted in Fig. 2. 
All experimental tests were conducted with the same conditions. The vehicle was standing and 
the engine was working with the idle gear rotational speed of 600 rpm, the temperature of the 
engine was set on ca. 70 ºC. In the laboratory all windows were closed and all different noise 
sources were closed. 
a) 
 
b) 
Fig. 3. View of the measurement and the research on the passenger car 
3. Research results 
The “equivalent continuous sound level”, the ???, is known across the globe as the essential 
averaged parameter. The ??? is the level that, had it been a steady level during the measurement 
period, would represent the amount of energy present in the measured, fluctuating sound pressure 
level. The ??? is measured directly with an integrating sound level meter. ??? is a measure of the 
averaged energy in a varying sound level. 
To complete analysis more estimators of sound level were recorded. For example ?????? – 
maximum A-weighted noise level measured with Slow (S) time weighting. It is the highest level 
of noise occurring during the measurement time. It is often used in conjunction with another noise 
parameter (e. g., ????) to ensure a single noise event does not exceed a limit. It is essential to 
specify the time weighting (F, S or I). Another estimator is ?????? – minimum A-weighted noise 
level measured Slow (S) time weighting. It is the lowest level of noise occurring during the 
measurement time. Interpretation of sound level estimators has been depicted in the Figure 4. 
Before each test the sound level in the laboratory has been measured. Those results were 
compared to sound level in the laboratory during test, when the engine of the vehicle was working. 
For each test the differences were more than 10 dB, so no corrections were needed.  
The paper presents some chosen results of the investigation on vehicle with damages of the 
26. RESEARCH ON INFLUENCE OF DAMAGES OF CAR VEHICLE COMBUSTION ENGINE ON NOISE LEVEL.  
RAFAŁ BURDZIK, PIOTR FOLĘGA, ŁUKASZ KONIECZNY, ANDRZEJ WIECZOREK, PAWEŁ FABIŚ 
 © VIRBROENGINEERING. ISSN PRINT 2335-2124, ISSN ONLINE 2424-4635, KAUNAS, LITHUANIA 167 
water pump and timing belt. The sound levels were measured before and after repair. 
a) 
 
b) 
Fig. 4. Interpretation of some sound level estimators 
a) 
 
b) 
c) 
 
d) 
e) 
 
Fig. 5. Global estimators of sound level 
26. RESEARCH ON INFLUENCE OF DAMAGES OF CAR VEHICLE COMBUSTION ENGINE ON NOISE LEVEL.  
RAFAŁ BURDZIK, PIOTR FOLĘGA, ŁUKASZ KONIECZNY, ANDRZEJ WIECZOREK, PAWEŁ FABIŚ 
168 JOURNAL OF MEASUREMENTS IN ENGINEERING. SEPTEMBER 2013, VOLUME 1, ISSUE 3  
a) measurement point No. 1 
 
b) measurement point No. 2 
c) measurement point No. 3 d) measurement point No. 4 
e) measurement point No. 5 
 
Fig. 6. Octave analysis of sound level 
3.1. Global estimators of the sound level 
During the first step of investigation the global estimators of the sound level were measured, 
such as: 
- ???? equivalent continuous A-weighted noise sound level, 
- ???? peak value C-weighted noise sound level, 
- ??? A-weighted noise level measured with Slow (S) time weighting, 
- ?????? minimum A-weighted noise level measured with Slow (S) time weighting, 
- ?????? maximum A-weighted noise level measured with Slow (S) time weighting. 
The distribution of those estimators in measurement points before and after repair has been 
depicted in Fig. 5. 
26. RESEARCH ON INFLUENCE OF DAMAGES OF CAR VEHICLE COMBUSTION ENGINE ON NOISE LEVEL.  
RAFAŁ BURDZIK, PIOTR FOLĘGA, ŁUKASZ KONIECZNY, ANDRZEJ WIECZOREK, PAWEŁ FABIŚ 
 © VIRBROENGINEERING. ISSN PRINT 2335-2124, ISSN ONLINE 2424-4635, KAUNAS, LITHUANIA 169 
3.2. Frequency analysis of sound level 
To evaluate and compare dynamics of the acoustics phenomena the octave spectrums were 
determined. It can be very helpful for recognition of dominant dynamics components of sound 
level as the symptom of the damages. 
Knowledge of frequency bands can be used for calculation of dynamics (for example rotational 
speed) of the most dominant noise sources. 
4. Conclusions 
Analysis of the results shows that sound level generated by the engine contains mostly the low 
frequency components (octave bands centre frequencies 31.5 and 63). In all researched objects the 
sound level is higher where engine has some damages. After repair the level becomes lower. 
The registered noise is depending on measurement point localization. For the measurement 
point no. 1 the sound level is highest, and the decrease of the noise is most significant in this point. 
The bigest changes of the noise level after and before repair can be observed for frequency band 
from 1000 Hz to 8000 Hz. 
Acoustics phenomenas for working machines are very complicated. It has to be taken into 
consideration that there are many of influences in order to evaluate some diagnostics measures. 
The presented research is preliminary and the results allow to evaluate just in the quality aspect. 
For the quantitative assessment there has to be done many more research. 
References 
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[2] Burdzik R., Konieczny Ł. Research into noise emissions by a car combustion engine exhaust system. 
Scientific Papers of AMW, Vol. 52, Issue 1, 2011, p. 7-12. 
[3] Dąbrowski Z., Dziurdź J., Klekot G. Studies on propagation of vibroacoustic energy and its influence 
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[4] Burdzik R. Material vibration propagation in floor pan. Archives of Materials Science and 
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[5] Burdzik R. Monitoring system of vibration propagation in vehicles and method of analysing vibration 
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[6] Figlus T., Wilk A., Łazarz B. Supporting of diagnosis of combustion engine condition on the basis 
of noise signal analysis. CDMTUR 2012, Žilina - Straža, Slovakia, 2012. 
[7] Dziurdź J. Transformation of nonstationary signals into pseudostationary signals for the needs of 
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Research on influence of damages of car vehicle combustion engine on noise level

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Research on influence of damages of car vehicle combustion engine on noise level

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