scholarly journals IMPROVEMENT OF MUFFLER S DESIGN FOR REDUCTION OF THE LEVEL OF SOUND PRESSURE ON SMALL TRACTORS OPERATORS

2021 ◽  
Author(s):  
M. I. Podolsky ◽  
◽  
I. Y. Lilevman ◽  
O. Y. Lilevman ◽  
O. Y. Kedrovsky ◽  
...  
Keyword(s):  
Internal Combustion Engines ◽  
Gas Flow ◽  
Sound Pressure ◽  
Internal Combustion ◽  
Pressure Level ◽  
Combustion Engines ◽  
Sound Waves ◽  
Exhaust Gases ◽  
Noise Absorption ◽  
Made In

Noise background, as an important factor in the working conditions of agricultural operators, has a direct impact on human health and productivity. This topic is especially relevant for small tractors, which in most cases are not equipped with cabs. One of the main means of reducing the sound pressure on the operator are the mufflers of exhaust gases, which mainly have a labyrinth-absorbing type of action. The paper proposes a fundamental approach to the design of the muffler by the criterion of reflection and scattering of sound waves with the verification of efficiency by computer simulation. The purpose of research: - to improve the working conditions of operators of small tractors that are not equipped with cabs, by reducing the sound pressure level from internal combustion engines; - to improve the noise-absorbing properties of mufflers of exhaust gases of engines with observance of requirements to manufacturability of process of their manufacturing; - to develop a structural scheme of the exhaust gases muffler based on the results of preliminary modeling and analysis of the trajectory of the gas flow in the cavity of its working part. Methods. Determination of the sound pressure level of the engine of a small tractor by mathematical (computer) modeling of the behavior of the exhaust gas flow in the muffler cavity in different frequency ranges. Results. The article analyzes the main sources of noise during the operation of agricultural machinery with internal combustion engines (ICE). On the basis of literature sources and methods, their separate degree of influence on the complex picture of noise pollution of the working space of the operator of a small tractor is established. A comparative analysis of the efficiency of mufflers, created on the generally accepted principles and approaches to the design of such devices. According to the results of previous tests, shortcomings and limitations in the application of design concepts were identified, an additional analysis of external causes and factors was made, and adjustments were made to the method of creating muffler designs. An alternative design approach to the creation of internal combustion engine mufflers of small tractors is proposed and computer modeling of the processes of sound pressure distribution and sound waves in their cavity is performed. Conclusions. 1. A layout diagram of the design of the exhaust muffler, containing a resonator chamber and a shell module, which is made in the form of a three-stage ribbed diffuser of oscillations of the exhaust flow pulses with an additional surface layer of the vibration absorber. The parameters of the exhaust flow of exhaust gases of a typical diesel engine of a small tractor with a capacity of 24 hp are calculated. (pressure - 11652 Pa, acceleration – 90-105 m / s2, frequency - 1950-3300 Hz), which performed computer simulations of the process of gas movement in the muffler cavity of the proposed layout. Optimal design parameters were selected to ensure the maximum possible noise absorption with a body diameter of 150 mm and a length of 600 mm. The calculated sound pressure when working at the crankshaft speed (1700-2000) rpm does not exceed 72 dB. At the same time, the design of the muffler is made in compliance with the requirements for economic feasibility, manufacturability and in accordance with the capabilities of industrial production. A further direction of research is the manufacture of an experimental sample of the muffler and testing for the efficiency of its noise absorption in the conditions of operation of small tractors.

IMPROVEMENT OF NOISE SILENCER ARMORED VEHICLE KRAZ “BASTION” APPLICATION OF THE GAS SCREEN

2019 ◽  
pp. 11-16
Author(s):  
Volodymyr Fedorov ◽  
Vasyl Yanovsky ◽  
E. M. Mazur
Keyword(s):  
Internal Combustion Engines ◽  
Gas Flow ◽  
Visual Masking ◽  
Internal Combustion ◽  
External Noise ◽  
Angle Of Incidence ◽  
Combustion Engines ◽  
Sound Waves ◽  
Armored Vehicle ◽  
Gas Screen

Ukraine has been fighting for five years in the east with the Northern Neighbor and for much more time striving for NATO membership. Under these circumstances, the ongoing improvement of military technology. Creation of modern armored cars is topical. One of the important requirements for them – high masking properties. In addition to visual masking there is also sound. In this case, it means reducing the external noise of armored cars. The source of noise and ways to reduce them is a lot. One of the most powerful sources of armored car noise is the noise of the release system, the noise of the bedroom. This type of noise is reduced by means of silencers. The latter are diverse in terms of designs, principles of operation, frequency characteristics and acoustic efficiency. The increase of the acoustic efficiency of silencer noise of the car internal combustion engines was proposed using a gas screen, which until now was used only in aircraft engineering. The essence of the proposal is to create around the outlet branch muffler gas flow, the speed of which is higher than the speed of the outflow of bedrooms. Due to this, the sound waves contained in the sleeping bags will not be able to go into the environment, passing through an additional gas stream, and they will fall onto a special sound absorbing plate. Correspondingly, the sponges will be reflected from this plate and will go to the environment. In this work, for example, the KrAZ Armored Vehicle “Bastion” shows the projected increase in the acoustic efficiency of the existing silencer through the use of a gas screen for the speed of the armored vehicle 45, 50, 75 and 85 km / h. At the same time, the dependence of the difference in speeds of artificially created gas flow and the beds in the muffler of noise from the angle of incidence of sound waves in the flow of bedrooms was calculated. Also shown is the dependence of the angle of incidence of sound waves on the frequency of the latter. Improvement of the existing muffler noise of the internal combustion engines through the use of a gas screen is projected to reduce the external noise of the KrAZ “Bastion” car at 4-6 dB in the range of 45-85 km / h. Keywords: armored vehicle, internal combustion engine, silencer, exhaust gases, noise, noise source, acoustic efficiency, gas screen.

Science in Relation to Regulating and Promoting Civil Aviation

1929 ◽  
Vol 33 (228) ◽  
pp. 1139-1166
Keyword(s):  
Similar Condition ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Air Transport ◽  
Civil Aviation ◽  
Combustion Engines ◽  
The Past ◽  
Mechanical Devices ◽  
Physical Laws ◽  
Made In

During the past quarter of a century great strides have been made in perfecting the science of aviation. Too much credit cannot be given to the men who have laboured untiringly in the laboratories in an endeavour to determine with mathematical certainty the physical laws that govern the mechanical devices which mankind is using in his conquest of the air.Science has done more for civil aviation, however, than unravel the mysteries of aerodynamics and internal combustion engines. It has provided many important aids to air navigation, such as improved lighting facilities for airways and airports, wireless as a means of communication between ground and aeroplane, and also as a beacon to guide the pilot on his course, and numerous instruments which now adorn the cockpit of every aeroplane.While at times the development of air transport may suffer because of lack of co–ordination between the laboratory and the factory, it will suffer far more should a similar condition exist between the scientists and those charged with the duty of regulating and promoting civil aviation.

scholarly journals Comparative Parameters Evaluation of Internal Combustion Engines Naturally Aspired and Supercharged With Hybrid Turbocharger

2020 ◽  
Author(s):  
Chiriac Rares ◽  
Anghel Chiru
Keyword(s):  
Internal Combustion Engine ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Energy Performance ◽  
Operating Efficiency ◽  
Combustion Engines ◽  
Exhaust Gases ◽  
Electric Generator ◽  
Technical Solutions

Abstract Internal combustion engines have an operating efficiency that can be exploited to increase their performance. Some of the waste gases can be recovered through technical solutions such as turbocharging. The turbocharging solution is one of the most popular technical solutions for increasing the energy performance of internal combustion engines. This requires an analysis of the energy balance of the internal combustion engine. This shows that there is a significant reserve of energy in the exhaust gases, which can be used to increase the engine efficiency. One solution is to use this energy to drive a turbine coupled with an electric generator. This article aims to present the result of the experimental research of the hybrid turbocharger, simulating and validating the new solutions for increasing the energy performance of internal combustion engines through hybrid turbochargers using a coupled electric generator. The simulations will be performed using AMESim software developed by Siemens to demonstrate through calculations the efficiency of new solutions, such as a hybrid turbocharger. The tests will be performed using an diesel internal combustion engine with a cylinder capacity of 1.9 liters which is also simulated with AMESim software. The residual exhaust gases of the internal combustion engine will drive the hybrid turbocharger turbine and generate electricity. Electricity can then be used for storage in the car battery or for consumption by the car's electrical system. The article also includes a comparative study between the power and torque of the naturally aspirated internal combustion engine equipped with a hybrid turbocharger.

scholarly journals INCREASING THE EFFICIENCY OF TECHNOLOGIES AND TECHNICAL MEANS OF QUALITY CONTROL RESTORATION OF SMALL-SIZED ENGINES

2021 ◽  
pp. 137-151
Author(s):  
Yuriy Paladiychuk ◽  
Inna Telyatnuk
Keyword(s):  
Internal Combustion Engine ◽  
Crop Production ◽  
Internal Combustion Engines ◽  
Light Transmission ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Combustion Engines ◽  
Agricultural Machinery ◽  
Exhaust Gases ◽  
Functional Scheme

Mechanization of labor on small farms and individual farms is a very important issue of modern agriculture. The use of small agricultural machinery with a capacity of up to 16 kW is quite relevant today. Small-sized machinery is divided into: small 4-wheeled tractors, 2-wheeled motoblocks, cultivators, machines and equipment. With the help of this technique perform various agricultural and other types of work in crop production, horticulture, gardening on small plots, livestock and more. Despite its rather small size, small equipment also has various mechanisms that fail over time. Most often, the parts of the internal combustion engine fail. In general, the cost of repairing the internal combustion engine during operation may exceed the total cost of the engine by 5-6 times. Thus, there is a question of improving the system of technical service of engines of small tractors. This article considers the issue of increasing the efficiency of operation of internal combustion engines for small tractors, due to the effective conduct of after-sales or post-repair running-in and improving the maintenance system. Types of small-sized equipment are presented. The analysis of possible loading and speed modes of cold and hot running-in of internal combustion engines and means for their realization is carried out. Technical means for running-in and testing of internal combustion engines are analyzed. The following formulas are given for determination: smoke of exhaust gases at running-in of engines; light transmission of exhaust gases; speed control range; load torque; the content of harmful substances (Q) in the exhaust gases on the j-th components. The necessity of bench running-in of engines of small-sized agricultural machinery is substantiated. The functional scheme of the stand for running-in and testing of internal combustion engines is considered. The stages of cold and hot running-in of small-sized engines are described. With the help of the received information, the results are made and the analysis of methods of running-in of internal combustion engines of small-sized agricultural machinery is carried out.

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