Detection and identification of illegal-modified private cars through frequency band analysis

2021 ◽  
Vol 263 (5) ◽  
pp. 1765-1772
Author(s):  
Hok Man Joyce Chow ◽  
Sau Cheong Cheung ◽  
Kit Wing Cheng ◽  
Chee Kwan Lee ◽  
Terence Tsang ◽  
...  
Keyword(s):  
Exhaust System ◽  
Noise Spectrum ◽  
Sound Level ◽  
Vehicle Exhaust ◽  
Late Night ◽  
Detection And Identification ◽  
Single Vehicle ◽  
Level Meter ◽  
Post Purchase ◽  
Exhaust Systems

Post-purchase-illegal-modification of road vehicles' exhaust systems by vehicle fanatics for loudness has caused an upsurge in nuisances to local residences when driven and rallied during late night and early mornings. Traditional enforcement measures rely on setting up roadblocks by the Police at rallying hotspots. These measures involve the judgement of individual police officer and can be subjective. With the aid of noise monitoring equipment, the accuracy and efficiency of on-site exhaust system-modified vehicle detection can be enhanced. Since the sound profile of a single-vehicle exhaust cannot be captured by simple roadside noise level measurements alone, segregation and analysis of the noise spectrum are employed to identify vehicles with modified exhaust systems. The paper presents the findings of investigating the feasibility and accuracy of off-the-shelf devices for detecting vehicles fitted with modified exhaust systems, with private cars being the primary target. A pilot test by roadside noise monitoring has been conducted with a sound level meter and an acoustic camera and revealed an on-site accuracy of up to 75%. Data collected during the tests were further used to explore the applicability of integrating artificial intelligence with traditional noise monitoring devices.

scholarly journals KAJIAN PENERAPAN SENSOR MIC-CONDENSER DALAM RANCANG BANGUN SOUND LEVEL METER DIGITAL.

JURNAL ELTEK ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 86
Author(s):  
Achmad Komarudin ◽  
Hariyadi Singgih ◽  
Moh. Luqman
Keyword(s):  
Data Processing ◽  
Sound Pressure ◽  
Motor Vehicle ◽  
Sound Level ◽  
Motor Vehicles ◽  
Sound Level Meter ◽  
Vehicle Exhaust ◽  
Sound Sources ◽  
Level Meter ◽  
Digital Sound

Noise levels in the industrial and urban streets have a threshold value that has been determined by the Regulation of the State Minister of the Environment Number 07 Year 2009 for motor vehicles. And Minister of Manpower Number: KEP-51 / MEN / 1999 for industrial environment. To know the value of noise is required a Digital Level Sound Meter gauge that can be used as a measuring instrument of sound intensity noise value of motor vehicle exhaust and other sound sources. This tool can change the amount of sound pressure converted in LCD display. This Digital Sound Level Meter is used to measure the feasibility of thresholds on exhaust and other sound sources. The purpose of this research is to study the application of Mic-condenser sensors in Digital Sound Level Meter design The research method is to design and design the system, using mic condenser sensor, designing signal conditioner using op-amp with series of Absolute Value Modulus (MAV), which can rectify AC voltage into DC using Microkontroller ATMega 8535 as data processing result of data processing which has become the quantity sound pressure with decibels (dBA) is presented in LCD devices The results of the system test show that this Digital Sound Level Meter can run and can display the sound pressure level captured by the mic condenser sensor, and from the result of the Digital Sound Level Meter test compared to the comparison tool obtained an error of 2.94%.

scholarly journals Design and evaluating efficiency of gas exhaust system silencer of outboard motor SEA PRO 2.5

2021 ◽  
Vol 2021 (1) ◽  
pp. 81-87
Author(s):  
Mikhail Nikolaevich Pokusaev ◽  
Konstantin Evgenievich Khmelnitsky ◽  
Alexei Alekseevich Kadin ◽  
Alexei Viktorovich Sergeev
Keyword(s):  
Noise Reduction ◽  
Noise Level ◽  
Aerodynamic Drag ◽  
Exhaust System ◽  
Water Layer ◽  
Sound Level ◽  
Low Frequencies ◽  
Full Speed ◽  
Made In China ◽  
Exhaust Systems

The article presents the results of developing and evaluating the effectiveness of the silencer of outboard motor SEA PRO 2.5 made in China. The experiments were carried out in a large experimental pool of Astrakhan State Technical University, with the use of a noise meter-spectrum analyzer Ecophysics-110 of the first class, with the software Signal+3G Light. In the theoretical analysis of the development, it has been suggested that the efficiency of silencers of exhaust systems of outboard motors could have a smaller effect than with cars, since at underwater exhaust the noise reduction will occur from the water layer when the motor is submerged. It has been proved that using a silencer in underwater exhaust systems of outboard motors can increase the aerodynamic drag for gases and reduce power. To test the theoretical assumptions, there was made a silencer for the gas exhaust system of the outboard motor SEA PRO 2.5 from stainless steel perforated sponge. It was determined that the net effect of the silencer (excluding water silencing) could be heard at low frequencies (up to 125 Hz) and makes up to 12.7 dba at full speed of the motor. The average equivalent sound level is reduced up to 4.5 dba at low speed, and at full speed of the outboard motor is practically not evident. In addition, the outboard motor noise level was reduced by water and made at full speed up to 22 dba for frequencies over 2000 Hz; for average equivalent noise level it made 15 dba. The combination of noise reduction by water and by a silencer helps to reduce noise at low and high sound frequencies, which is a positive effect of the developed device.

scholarly journals MODERN VEHICLE EXHAUST SYSTEM DESIGN DYNAMIC ANALYSIS

Akustika ◽  
2019 ◽  
Vol 32 ◽  
pp. 351-354 ◽  
Author(s):  
R.I. Rakhmatov ◽  
G.G: Nadareishvili ◽  
S.I. Yudin
Keyword(s):  
Dynamic Analysis ◽  
System Design ◽  
Exhaust System ◽  
Vehicle Exhaust ◽  
Oscillation Modes ◽  
Eigen Frequencies ◽  
Exhaust Systems

The article considers the procedure and results of calculation of the natural (eigen) frequencies and waveforms (oscillation modes or forms) of modern vehicle exhaust systems. The maximum values of exhaust system vibratory displacements are calculated.

Measurement of Noise inside the Compartment and Vibration on both Sides of Elastomeric Powertrain Mounts of Passenger Car

2013 ◽  
Vol 471 ◽  
pp. 59-63
Author(s):  
Mohd Noor Arib Rejab ◽  
Roslan Abd Rahman ◽  
Raja Ishak Raja Hamzah ◽  
Jawaid Iqbal Inayat Hussain ◽  
Nazirah Ahmad ◽  
...  
Keyword(s):  
Fast Response ◽  
Sound Level ◽  
Measurement Noise ◽  
The Other ◽  
Vibration Level ◽  
Test Conditions ◽  
Exhaust Noise ◽  
Run Up ◽  
Level Meter ◽  
High Level

This paper presents an evaluation on elastomeric mount used to isolate vibration from powertrain to chassis or structure vehicle. The assessments started with measurement of noise inside compartment, and exhaust noise. This is followed by the measurement of vibration on both sides of elastomeric mounts. The noise in the compartment and exhaust noise is measured according to BS 6086: 1981 and BS ISO 5130: 2007. The noise in the compartment and vibration is tested in three conditions. Firstly, engine is run-up with load (driving at second gear); secondly, without load; and thirdly, without load but hanging. A microphone is fixed at the ear of the mannequin. The fast response and A weighting sound level meter were used for measurement noise in the compartment and exhaust noise. The vibration is measured in terms of acceleration on both sides of each elastomeric powertrain mounts. Two accelerometer transducers are fixed on both sides of powertrain elastomeric mounts. One side was identified as a source of vibration and the other as receiver of vibrations. The results showed that the pattern of overall vibration level on source and receiver increased from 1050 RPM (idling) to 4000 RPM on all test conditions. Vibration transmitted to chassis or receiver structure was analyzed using transmissibility concept. By evaluating test condition of engine run-up without load, informed that the front and rear mounts showed a high level transmissibility contributing to structure-borne noise.

Testing of Sonic-Absorbent Panels’ Behavior in Open-Air Environment

2012 ◽  
Author(s):  
Petru A. Pop ◽  
Patricia A. Ungur ◽  
Liviu Lazar ◽  
Mircea Gordan ◽  
Florin M. Marcu
Keyword(s):  
High Frequency ◽  
Noise Pollution ◽  
Sound Level ◽  
Sound Level Meter ◽  
Data Logger ◽  
Public Buildings ◽  
Gypsum Plaster ◽  
Level Meter ◽  
And Control

One wildly used method to reduce and control the noise pollution in green city’s buildings is using sonic-absorbent panels. Their applications can be multiple, such as the insulation of buildings, acoustic barriers and fences along the highway or in front of supermarkets, hospitals and other public buildings. This paper presents a method for testing the behavior of sonic-absorbent panels in open-air environment. The work represents a carrying on of previous research about absorbent materials from gypsum family, tested in lab conditions. The experiment setup used a dynamic installation and as a sample a stand formed by six sonic-absorbent panels from special modeling alpha-gypsum plaster. This installation has been composed of two loudspeakers for emitting the sound at a well-defined frequency by the first laptop, the microphone for detecting and transmitting the signal to the second laptop for analyzing and processing the data. All operations were performed using MATLAB Programs, while a Data Logger Sound Level Meter type CENTER 332 was put on near the microphone to compare both results. The first experiment of acoustic stand has been realized by setting up the installation at a frequency from 50 Hz to 1250 Hz and altering the distance between loudspeakers and stand at 0.5m to 1m and 1.5m, respectively. The second experiment kept the same test’s conditions, while two and three layers of sonic-absorbent panels formed the stand, respectively, but at same distance from source of 0.5 m. In both tests, the results underlined the good sonic-absorbent properties of these panels, especially at medium and high frequency, which can recommend using the panels for multiple outside applications.

Pemetaan Dan Perhitungan Pemaparan Tingkat Kebisingan Pada Industri Pengolahan Kayu Di Kecamatan Siak, Provinsi Riau

2021 ◽  
Vol 6 (2) ◽  
pp. 68-76
Author(s):  
Aryo Sasmita ◽  
Muhammad Reza ◽  
Rodesia Mustika Rozi
Keyword(s):  
Sound Level ◽  
Sound Level Meter ◽  
Noise Mapping ◽  
Level Meter

Dalam kegiatan operasionalnya CV. X yang bergerak pada pengolahan kayu, berpotensi menimbulkan kebisingan yang berasal dari mesin-mesin yang digunakan dalam proses produksi pallet. Kebisingan di perusahaan ini dapat berpengaruh terhadap kesehatan dan kenyamanan pekerja. Penelitian ini bertujuan untuk mengetahui intensitas kebisingan yang dihasilkan oleh mesin produksi, lama waktu pemaparan, pemetaan kebisingan dan upaya pengendalian kebisingan. Metode pengukuran kebisingan mengacu pada metode noise mapping dan alat yang digunakan adalah Sound Level Meter. Data yang diperoleh kemudian diolah menjadi peta kontur dengan variasi warna biru, hijau, kuning, ungu dan merah. Hasil penelitian menunjukkan tingkat kebisingan tertinggi sebesar 99,4 dB dan tingkat kebisingan terendah sebesar 67,3 dB. Berdasarkan hasil perhitungan menggunakan persamaan NIOSH dari 128 titik pengukuran metode noise mapping terdapat 38 titik dengan tingkat kebisingan >85 dB yang menunjukkan waktu pemaparan di atas standar yang sudah direkomendasikan NIOSH. Tingkat kebisingan tertinggi sebesar 99,4 dB dengan lama pemaparan selama 0,3 jam dan tingkat kebisingan terendah sebesar 67,3 dB dengan lama pemaparan selama 475 jam. Upaya pengendalian yang dapat dilakukan untuk mengurangi kebisingan seperti pengendalian dari sumber, jalur transmisi, dan penerima.

A Sound Level Meter featured with automatic estimation of the measurement uncertainty

Measurement ◽  
2021 ◽  
pp. 110409
Author(s):  
Marco Carratù ◽  
Consolatina Liguori ◽  
Vincenzo Paciello ◽  
Antonio Pietrosanto ◽  
Domenico Russo ◽  
...  
Keyword(s):  
Measurement Uncertainty ◽  
Sound Level ◽  
Sound Level Meter ◽  
Automatic Estimation ◽  
Level Meter

Methods to Improve Combustion Stability, Efficiency, and Power Density of a Small, Port-Injected, Spark-Ignited, Two-Stroke Natural Gas Engine

2017 ◽  
Author(s):  
Derek Johnson ◽  
Mahdi Darzi ◽  
Chris Ulishney ◽  
Mehar Bade ◽  
Nima Zamani
Keyword(s):  
Natural Gas ◽  
Power Density ◽  
Low Cost ◽  
Exhaust System ◽  
Combustion Stability ◽  
Liquid Fuels ◽  
Delivery Ratio ◽  
Resonance Theory ◽  
Indicated Mean Effective Pressure ◽  
Exhaust Systems

Two-stroke engines are often used for their low cost, simplicity, and power density. However, these engines suffer efficiency penalties due to fuel short-circuiting. Increasing power density has previously been an area of focus for performance two-stroke engines — such as in dirt bikes. Smaller-displacement engines have also been used to power remote controlled cars, boats, and aircraft. These engines typically rely on gasoline or higher-octane liquid fuels. However, natural gas is an inherently knock-resistant fuel and small natural gas engines and generators could see increased market penetration. Power generators typically operate at a fixed frequency with varied load, which can take advantage of intake and exhaust system tuning. In addition, stationary engines may not be subject to size restrictions of optimal intake and exhaust systems. This paper examines methods to improve combustion stability, efficiency, and power density of a 29cc air-cooled two-stroke engine converted to operate on natural gas. Initial conversion showed significant penalties on delivery ratio, which lowered power density and efficiency. To overcome these issues a tuned intake pipe, two exhaust resonators, and a combustion dome were designed and tested. The engine was operated at 5400 RPM and fueling was adjusted to yield maximum brake-torque (MBT). All tests were conducted under wide-open throttle conditions. The intake and exhaust systems were designed based on Helmholtz resonance theory and empirical data. The engine utilized a two-piece cylinder head with removable combustion dome. The combustion dome was modified for optimal compression ratio while decreasing squish area and volume. With all designs incorporated, power increased from 0.22 kW to 1.07 kW — a factor of 4.86. Efficiency also increased from 7% to 12%. In addition to these performance gains, the coefficient of variation (COV) of indicated mean effective pressure (IMEP) decreased from just above 11% to less than 4%.

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