scholarly journals Adder Box Used in the Heavy Trucks Transmission Noise Reduction

Symmetry ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2165
Author(s):  
Andrei Bencze ◽  
Maria Luminița Scutaru ◽  
Marin Marin ◽  
Sorin Vlase ◽  
Ana Toderiță
Keyword(s):  
Noise Reduction ◽  
Mechanical Impedance ◽  
Noise Spectrum ◽  
Experimental Setup ◽  
Heavy Vehicles ◽  
Symmetrical Structure ◽  
Heavy Trucks ◽  
Experimental Assembly

The paper aims to analyze the vibrations of a summing box, used in heavy vehicles. An experimental setup is proposed and used for the analysis of these vibrations transmitted by the box housing, based on the measurement of the mechanical impedance. It is then shown that a simpler measurement, namely that of the generated noise spectrum, can provide equally useful results, with less effort and in a shorter time. The experimental setup is much simpler, involving a sonometer arranged in the experimental assembly. The symmetry of the box allows us to facilitate the execution of the experimental assembly, and the use of the symmetrical structure to facilitate the calculation of vibrations. The results obtained using this method in the case of a redesigned adder box are presented in the paper.

scholarly journals Reduction of Aerodynamic Drag of Heavy Vehicles using CFD

2021 ◽  
Vol 9 (8) ◽  
pp. 2670-2678
Author(s):  
Priyank Kothari
Keyword(s):  
Fuel Economy ◽  
Aerodynamic Drag ◽  
Fuel Efficiency ◽  
Heavy Vehicles ◽  
Heavy Trucks ◽  
Air Resistance

Abstract: Aerodynamic drag is the force that opposes an object’s motion. When a vehicle no matter the size, is designed to allow air to move fluidly over its body, aerodynamic drag will have less of an impact on its performance and fuel economy. Heavy trucks burn a significant amount of fuel as to overcome the air resistance. More than 50% of an 18-wheeler’s fuel is spent reducing aerodynamic drag on the highways. Keywords: Aerodynamics, Heavy vehicles, ANSYS, Aerodynamic Drag, Fuel efficiency.

scholarly journals Numerical and experimental analyses of intake silencer and its effects on turbocharger compressor performance

2019 ◽  
Vol 11 (3) ◽  
pp. 168781401982667 ◽  
Author(s):  
Chen Liu ◽  
Yipeng Cao ◽  
Yang Liu ◽  
Wenping Zhang ◽  
Pingjian Ming ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Transmission Loss ◽  
Pressure Ratio ◽  
Pressure Fluctuations ◽  
Noise Spectrum ◽  
Acoustic Mode ◽  
Frequency Noise ◽  
Reduced Pressure ◽  
Compressor Rotor ◽  
Compressor Performance

Numerical studies of a marine diesel engine intake silencer are conducted to evaluate its performance, and effects of the silencer on the turbocharger compressor performance are also discussed. The results show that the duct acoustic mode method can be used in the silencer transmission loss prediction, and the predicted noise reduction and main frequency range agree with the measurements fairly well. However, it is found that the silencer compromises the compressor performance by shortening its operating range. It is found that the static pressure on the compressor blade surface is decreased, thus the compressor total-to-total pressure ratio and isentropic efficiency are reduced. Pressure fluctuations at compressor rotor and stator inlets enhanced when a silencer is installed, which means the trend of pressure spectrum in the rotor and stator passage is changed. Compared with the results of a compressor in natural aspiration, it is found that the silencer can significantly reduce high-frequency noise. In particular, it is quite effective in tonal noise reduction. In addition, the compressor inlet noise spectrum indicates that noise radiation characteristics are different with a silencer installed.

Spring Load Restrictions in Finland: Current Policy and Research Implications

1998 ◽  
Vol 1615 (1) ◽  
pp. 29-31
Author(s):  
Jukka Isotalo
Keyword(s):  
Research Programme ◽  
Road Maintenance ◽  
Current Policy ◽  
Heavy Vehicles ◽  
Minimum Standard ◽  
Maximum Weight ◽  
Frost Action ◽  
Heavy Trucks ◽  
Restriction Policy ◽  
National Road

Roads in Finland are exposed to seasonal strength variation. Because of industrial policy, the maximum weight of heavy trucks is 60 metric tons all year. The policies applied by the Finnish National Road Administration (Finnra) to mitigate the effects of seasonal road strength variations on public roads, and the current research on the topic in Finland, are investigated. It has been estimated that the annual cost of road repairs because of spring damages is about $10 million under the present load restriction policy. The costs for road repairs would be $35 million without restrictions. The annual additional cost for all heavy transport is estimated at $15 million. An internal Finnra survey revealed that $80 million to $100 million is needed to repair all known frost-susceptible road sections. Finnra load restrictions are intended to prevent damage to roads by heavy vehicles during spring thaw. The restrictions will reduce and possibly eliminate increases in annual road maintenance costs. On the other hand, the restrictions will allow a minimum standard for vital transport. Finnra’s Road Structures Research Programme (TPPT) studies improvements in the durability, strength, and economy of road structures. A key part of the TPPT project concerns problems associated with frost, especially durability against frost action. The most important factors of frost action on roads are the freezing index, duration of frost and thaw seasons, surface temperature, and ground water level. Methods for testing and calculating frost effects are discussed, as are the questions that must be answered before more precise models can be published.

Noise Evaluation of Concrete Pavement

2013 ◽  
Vol 368-370 ◽  
pp. 1985-1989
Author(s):  
Ya Min Liu ◽  
Rao Rao Han ◽  
Zhi Jin Tao ◽  
Jie Chen
Keyword(s):  
Noise Reduction ◽  
Noise Level ◽  
Noise Spectrum ◽  
Concrete Pavement ◽  
Noise Characteristic ◽  
Groove Width ◽  
Concrete Pavements ◽  
Frequency Range ◽  
Porous Concrete ◽  
Noise Evaluation

In order to evaluate noise characteristic of concrete pavements with different texture, specimens were prepared carefully by varying groove parameters, such as groove width and space between grooves. Employing tire impact method, the noise level and noise spectrum of different pavements were analyzed. The results indicate that the noise level of transverse grooved concrete pavement is the greatest, and the followings are glossy concrete pavement and longitudinal grooved concrete pavement, porous concrete pavement has the lowest noise level. For grooved pavement, the noise level is promoted with increasing the space between grooves. Besides that, the noise level of transverse grooved concrete pavement becomes greater as the groove width increases. For longitudinal grooved pavement, there is a contrary tendency. It is porous concrete pavement for a frequency larger than 1600HZ. In the whole frequency range, the noise-reduction ability of transverse grooved concrete pavement is the worst.

Study on Surface Radiation Noise of a Diesel Engine Based on FEM

2013 ◽  
Vol 774-776 ◽  
pp. 17-20 ◽  
Author(s):  
Ye Miao Zhao ◽  
Xiao Hui Cao ◽  
Chen Hai Guo ◽  
Qing Zhen Ma
Keyword(s):  
Diesel Engine ◽  
Noise Reduction ◽  
Sound Pressure ◽  
Combustion Engine ◽  
Element Model ◽  
Noise Spectrum ◽  
Surface Radiation ◽  
Vibration Velocity ◽  
Finite Element Software ◽  
Radiation Noise

To evaluate the noise of a diesel engine and provide the basis for the next step for noise reduction, a boundary element model of the diesel engine has been built and finite element software is used to analyze the noise of the engine. Surface vibration velocity distribution, radiation noise spectrum, sound pressure distribution and total noise level are calculated. The calculation results obtained show that the most representative three points of the peak of SPL (sound pressure level) are 500Hz, 1200Hz and 1950Hz; total SPL is 108.99dB; the main sources of the noise of the diesel engine are oil pan, gear chamber cover and flywheel housing, these three parts should be prior; the noise of the lower part and left and right part (the gear chamber cover side and flywheel housing side) of the engine is greater than the upper part and front and rear part; improving the suspension mechanism of the internal combustion engine, optimizing the oil sump, flywheel housing and gear chamber cover and strengthening the rigidity of the skirt of the engine body can be used as the primary means of noise reduction.

scholarly journals Performance of Rear Under-Ride Protection Device (RUPD) During Car to Heavy Truck Rear Impact

2019 ◽  
Vol 8 (6) ◽  
pp. 3367-3375
Keyword(s):  
Experimental Tests ◽  
Structure Design ◽  
Design Stage ◽  
Protection Device ◽  
Heavy Vehicles ◽  
Passenger Vehicles ◽  
Rear Impact ◽  
Heavy Trucks ◽  
Heavy Truck ◽  
Crash Tests

Passenger vehicles crashes with Under-ride rear end of heavy vehicles result in fatal injuries due to sliding of passenger car beneath heavy trucks frames. This is related to an improper structure design of rear under-ride protection device (RUPD) that is mounted to the rear of the heavy vehicles. The design of effective RUPD must be taken into consideration during the design stage of truck chassis frame. There are two types of analyses used to investigate the performance of trucks RUPDs such as experimental tests and numerical analysis or simulation. This review aims to discuss the available research methods on the performance of RUPDs during car to heavy truck rear impact, and record their lack and potential areas. Moreover various crash velocities will be discussed for the car-to-heavy truck rear impact tests, as well as different scales of car frontal crash tests are included. Furthermore energy absorption capability of different truck RUPDs designs will be presented in this paper.

Aeroacoustic Characteristics of Cavity and Effect Study of Mesh on Noise Suppression

2013 ◽  
Vol 421 ◽  
pp. 104-109
Author(s):  
Jing Sun ◽  
Guang Jun Yang ◽  
Jian Jun Liu
Keyword(s):  
Noise Reduction ◽  
Noise Suppression ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Cavity Flow ◽  
Noise Spectrum ◽  
Effect Study ◽  
Suppression Effect ◽  
Reduction Effect ◽  
Suppression Effects

To explore the noise suppression effect of mesh on cavity, the wind tunnel experiment is carried out based on the analysis of clean cavity flow characteristics. The meshes are arranged both in the cavity and at the leading edge of the cavity. Through the analysis of pressure distribution on the cavity bottom and the noise spectrum monitored at front and rear walls respectively, noise suppression effects of mesh programs relative to the clean cavity and changes in the flow field are studied, the results show that the mesh inside the cavity has a better noise reduction effect. The work in this paper provides an effective way for cavity noise reduction.

scholarly journals Portable Low-Frequency Noise Reduction Device for Both Small Open and Closed Spaces

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Chao Wang ◽  
Haiyang Gao ◽  
Liyao Yu ◽  
Tiantian Yu ◽  
Wenhui Yan ◽  
...  
Keyword(s):  
Noise Reduction ◽  
Open Space ◽  
Active Noise Control ◽  
Low Frequency ◽  
Noise Pollution ◽  
Noise Spectrum ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Pollution Problem ◽  
Negative Impacts

Noise pollution has been given more attention due to its negative impacts on human health and disease. The portable low-frequency noise reduction device we developed in this research can provide an effective way for solving low-frequency noise pollution problem in the small space. This work describes the design principle and the prototype structures for two versions of V1.5 and V2.0 and builds the noise test systems for small spaces, respectively. These devices, installed on the outer surface of the small spaces, can automatically identify the noise spectrum and implement noise reduction by means of the active noise control (ANC) technology. The testing results indicate that the noise can be reduced 12 dB in the range of 250 Hz~400 Hz for the small closed space while, for the small open space, the best effect of 5.88 dB occurs in the optimal frequency of 450 Hz. These effects will be weakened with the increasing distance away from the source and show the obvious axisymmetric distribution in the inverted cone space.

Road Traffic Noise Status in Dhanbad, An Industrial Town of the Coal Belt in India

2002 ◽  
Vol 33 (10) ◽  
pp. 10-23
Author(s):  
A K Pal ◽  
R Samanta
Keyword(s):  
High Speed ◽  
Road Traffic ◽  
Traffic Noise ◽  
Noise Spectrum ◽  
Firing Frequency ◽  
Road Traffic Noise ◽  
Heavy Vehicles ◽  
Contributing Factors ◽  
Industrial Town ◽  
Peak Value

The increase in fast moving traffic and narrow roads are causing vehicle congestion which results in vehicles moving in low gears, accelerating, stopping and horn blowing, etc. All these are the contributing factors for considerable noise in industrial towns in India. The percentage of heavy vehicles in the traffic stream is also a major factor contributing to high noise levels. This paper delineates the systematic noise investigation in Dhanbad, an industrial town in the coal belt. Out of the six monitoring stations within Dhanbad town – Bank More, Shramik Chawk and Court More stations show maximum LAeq levels [79.0 to 84.1 dB] due to higher number of vehicles. On the other hand, at G.T. Road at Govindpur free flowing traffic outside Dhanbad town registers maximum LAeq[81.0 dB] during evening hour (7.00p.m to 8.00p.m) due to the greater number of heavy vehicles (189). The noise generated within Dhanbad town is more than that of the free flowing highway at Govindpur G.T. Road. A car in general generates 15 -dB (A) less noise than a heavy commercial vehicle. It has also been observed that sudden braking followed by gearing acceleration leads to an increase of 10– 15 dB (A) noise level. The frequency spectrum analysis reveals that the highway (G.T. Road) noise has a well-defined sound pressure level (SPL) at 63 Hz., representing the firing frequency of the vehicles at high speed. Again, a comparatively less alarming frequency at about 1 kHz may be due to the combined effect of tyres and wind. The alarming SPL for the traffic inside town has been in the range of 63 Hz to 125 Hz due to the lower speed of the vehicles. After that, there is no peak at higher frequency range, indicating that at relatively low speed tyres and wind make a negligible contribution to the noise spectrum. The Noise Ratings (NR), which represent the annoyance factor, are observed varying from morning to evening. In most of places, NR during the morning session show peak value due to prevalence of dominant high frequency. Statistical models / relationships between LAeq, total traffic volume per hour (Q) and percentage of heavy vehicles over total vehicles (P) are developed which can be used for the prediction of traffic noise in similar situations. The authors stress the need of curbing the traffic noise by taking appropriate steps to bring about a smoother traffic flow at moderate speeds and minimum horn blowing. The necessary steps will include widening of roads, diverting the traffic by means of some bypass roads, making traffic one-way, removing the business congestion in the roadway, avoiding or removing inter sections at near by places, etc. Besides, provision of suitable barriers in the sensitive zone of the roadways can go a long war way to reducing the noise situation.

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