scholarly journals ANALYSIS OF THE ENGINE STRUCTURAL AND THERMAL STRESS

2021 ◽  
Vol 2021 (2) ◽  
pp. 55-64
Author(s):  
LIVIU CONSTANTIN STAN
Keyword(s):  
Working Conditions ◽  
Elastic Limit ◽  
Inertial Force ◽  
Final Conclusion ◽  
Maximum Pressure ◽  
Axial Deformation ◽  
Pressure Force ◽  
Piston Head ◽  
Engine Cylinder ◽  
Engine Power

The paper aims to analyse the demands of four-stroke naval pistons. To begin with, a brief analysis of the evolution of shipbuilding was made. Mechanical requests are produced by the gas pressure force and inertial force of the alternate moving masses. Under its action the piston suffers an axial deformation. The thermal demands appearing in the engine are all the more important as the engine power is higher. The possibility of calculating them is more difficult due to the complexity of the thermogazodynamic phenomena in the engine cylinder. Thus, in the piston head, which comes in contact with both the hot gases and the fresh (much cooler) load, a non-stationary heat flow is installed which leads to a certain thermal regime of the engine. Considering the demands outlined in the last chapter, they lead to the final conclusion that although the most unfavourable loading situation was considered as the maximum pressure during the processes and even exaggerated in establishing the working conditions, the piston is still close to the elastic limit. This demonstrates that the way of calculating the dimensions of the piston is correct and safe, as long as its constructive dimensions are not oversized.

A New Concept of Externally Heated Engine—Comparisons with the Stirling Engine

1996 ◽  
Vol 210 (5) ◽  
pp. 363-371 ◽  
Author(s):  
L Brzeski ◽  
Z Kazimierski
Keyword(s):  
Low Power ◽  
Power Density ◽  
Internal Combustion Engines ◽  
Thermodynamic Cycle ◽  
Rotational Frequency ◽  
Stirling Engine ◽  
Maximum Pressure ◽  
Combustion Engines ◽  
Working Medium ◽  
Engine Cylinder

This paper presents a new concept of the externally heated valve (EHV) engine. Air can be used as a working medium in the closed cycle of this engine. Heat delivered to the working air can come from a combustion chamber or another heat generator of an arbitrary type. The engine construction and the thermodynamic cycle performed by it are original and entirely different from the well-known Stirling engine. The main disadvantage of the Stirling engine is its low power density, that is the low power obtained per litre of the engine cylinder volume. In the case of the engine presented here it is possible to achieve power density and efficiency similar to those typical of advanced internal combustion engines. Comparisons between the power of the Stirling engine and the power of the new engine have been performed for the same engine capacity, rotational frequency and maximum and minimum temperatures of the cycle. At the same minimum pressure of the working gas in both engines, the power of the EHV engine is several times higher than that of the Stirling engine, while, on the other hand, at the same maximum pressure of the working gas in both engines, the power of the EHV engine is 20 per cent higher than that of the Stirling engine power. The efficiencies of both engines do not differ significantly from each other.

scholarly journals A Computational Approach for Cam Size Optimization of Disc Cam-Follower Mechanisms With Translating Roller Followers

2013 ◽  
Vol 5 (4) ◽  
Author(s):  
Paulo Flores
Keyword(s):  
Objective Function ◽  
Design Optimization ◽  
Working Conditions ◽  
Computational Approach ◽  
Geometric Constraints ◽  
Size Optimization ◽  
Radius Of Curvature ◽  
Maximum Pressure ◽  
Cam Follower ◽  
Base Circle

The main objective of this work is to present a computational approach for design optimization of disc cam mechanisms with eccentric translating roller followers. For this purpose, the objective function defined here takes into account the three major parameters that influence the final cam size, namely, the base circle radius of the cam, the radius of the roller and the offset of the follower. Furthermore, geometric constraints related to the maximum pressure angle and minimum radius of curvature are included to ensure good working conditions of the system. Finally, an application example is presented and used to discuss the main assumptions and procedure adopted throughout this work.

scholarly journals INVESTIGATION OF TRACTOR ENGINE POWER AND ECONOMICAL WORKING CONDITIONS UTILIZATION DURING TRANSPORT OPERATION

Transport ◽  
2008 ◽  
Vol 23 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Antanas Juostas ◽  
Algirdas Janulevičius
Keyword(s):  
Working Conditions ◽  
Driving Force ◽  
Engine Speed ◽  
Traction Force ◽  
Rolling Resistance ◽  
Point Of View ◽  
Utilization Coefficient ◽  
Driving Speed ◽  
Tractor Engine ◽  
Engine Power

Article analyzes tractor working and its engine conditions from economical point of view. Overview of tractor wheel slippage reliance on the traction force and weight utilization coefficient is given. Tractor maximum driving force according to road and field conditions, and driving speed are submitted. Literature and theoretical investigation analysis is done, where interaction between tractor wheels made‐up driving force and grip is analysed. Driving speed and driving force dependence on rolling resistance and total aggregate weight using nominal power is described. In the present experimental research reduction in fuel consumption of tractor transport aggregate by reducing engine speed and by keeping the same work speed, was determined.

scholarly journals Pressure measurement in the cylinder of four-stroke marine engine – simulation analysis

2019 ◽  
Vol 177 (2) ◽  
pp. 36-39
Author(s):  
Dominika CUPER-PRZYBYLSKA
Keyword(s):  
Simulation Analysis ◽  
Measuring Channel ◽  
Measurement Channel ◽  
Maximum Pressure ◽  
Marine Engine ◽  
Combustion Pressure ◽  
Engine Simulation ◽  
Engine Cylinder ◽  
Different Diameters ◽  
Combustion Processes

The measurement of combustion pressure relies on connecting a pressure sensor to a four-stroke marine engine cylinder by a channel led out from the engine cylinder. The geometry of the channel distorts the results of combustion pressure measurements. The purpose of the work is to create a model of combustion processes in engine cylinders. The model uses a mathematical description of the indicator channel on one of the engine cylinders. The input data to the model and the data necessary for its verification came from the direct measurements on the research facility. The test object was a four-stroke Sulzer 3AL25/30 engine loaded by an electric power generator. During calculations, different diameters and lengths of measurement channel were simulated. The obtained results allowed to formulate the conclusion that the geometry of the measurement channel has a significant impact on the measurement results. The increase of the length of the measuring channel as well as the diameter of the channel causes disturbances in the measurement of the maximum pressure.

3D HUMAN LIFTING MOTION PREDICTION WITH DIFFERENT PERFORMANCE MEASURES

2012 ◽  
Vol 09 (02) ◽  
pp. 1250012 ◽  
Author(s):  
YUJIANG XIANG ◽  
JASBIR S. ARORA ◽  
KARIM ABDEL-MALEK
Keyword(s):  
Performance Measures ◽  
Shear Force ◽  
Degrees Of Freedom ◽  
Human Performance ◽  
Three Dimensional ◽  
Optimal Solution ◽  
Performance Measure ◽  
Maximum Pressure ◽  
Pressure Force ◽  
Digital Human

This paper presents an optimization-based method for predicting a human dynamic lifting task. The three-dimensional digital human skeletal model has 55 degrees of freedom. Lifting motion is generated by minimizing an objective function (human performance measure) subjected to basic physical and kinematical constraints. Four objective functions are investigated in the formulation: the dynamic effort, the balance criterion, the maximum shear force at spine joint and the maximum pressure force at spine joint. The simulation results show that various human performance measures predict different lifting strategies: the balance and shear force performance measures predict back-lifting motion and the dynamic effort and pressure force performance measures generate squat-lifting motion. In addition, the effects of box locations on the lifting strategies are also studied. All kinematics and kinetic data are successfully predicted for the lifting motion by using the predictive dynamics algorithm and the optimal solution was obtained in about one minute.

Kinematics of the Roller Motion and CAM Size Optimization of Disc CAM-Follower Mechanisms With Translating Roller Followers

2009 ◽  
Author(s):  
Paulo Flores ◽  
Gaspar J. B. Q. A. Machado ◽  
Rui M. S. Pereira ◽  
J. C. Pimenta Claro
Keyword(s):  
Objective Function ◽  
Working Conditions ◽  
Kinematic Analysis ◽  
Geometric Constraints ◽  
Size Optimization ◽  
Radius Of Curvature ◽  
Maximum Pressure ◽  
Analysis And Design ◽  
Cam Follower ◽  
Base Circle

This paper deals with the kinematic analysis and design optimization of disc cam mechanisms with eccentric translating roller followers. The objective function considered in the present work takes into account the three major parameters that influence the final cam size, namely the base circle radius of the cam, the radius of the roller and the offset of the follower. Furthermore, geometric constraints related to the maximum pressure angle and minimum radius of curvature are included to ensure good working conditions of the system. Finally, an application example is offered.

Bearing Characteristic Parameters to Estimate the Optimum Counterweight Mass of a 6-Cylinder In-Line Engine

2001 ◽  
Author(s):  
Richard E. Stanley ◽  
Dinu Taraza
Keyword(s):  
Critical Speed ◽  
Engine Speed ◽  
Inertia Force ◽  
Maximum Pressure ◽  
Operating Parameters ◽  
Cylinder Pressure ◽  
Characteristic Parameters ◽  
Pressure Force ◽  
Bearing Load ◽  
Bearing Characteristic

Abstract Two dimensionless relationships that estimate the maximum and average bearing load of a 6-cylinder 4-stroke in-line engine have been found. These relationships may assist the design engineer in choosing a desired counterweight mass. It has been demonstrated that: 1) the average bearing load increases with engine speed and 2) the maximum bearing load initially decreases with engine speed, reaches a minimum, then increases quickly with engine speed. This minimum refers to a critical speed at which the contribution of the inertia force overcomes the contribution of the maximum pressure force to the maximum bearing load. The critical speed increases with an increase of counterweight mass and is a function of maximum cylinder pressure and the operating parameters of the engine.

scholarly journals ANALYSIS OF THE METHODS TO RESTORE CAMSHAFTS OF INTERNAL COMBUSTION ENGINES

2014 ◽  
Author(s):  
Yaroslav Leniv
Keyword(s):  
Working Conditions ◽  
High Performance ◽  
Internal Combustion Engines ◽  
Recovery Process ◽  
High Wear Resistance ◽  
Combustion Engines ◽  
Advantages And Disadvantages ◽  
High Durability ◽  
The Cost ◽  
Engine Power

The article analyzed the methods and technologies of restoration the camshaft of internal combustionengine, their advantages and disadvantages , as well as working conditions couple camshaft cam − lifter.Found, that there is currently no rational way of recovery, which combined have a high performance, costeffectiveness, as well as high wear resistance of the camshaft cam and lifter.Requirement to ensure high wear couples camshaft cam - lifter is of particular relevance due to thefact that the currently increasing engine power, by increasing the speed of the crankshaft.In this regard, it is urgent search for new universal recovery technologies camshafts internalcombustion engines, that can increase the service life of the reduced camshaft, to ensure environmentalcleanliness recovery process, reduce the cost and complexity of repairs, ensure high durability couplescamshafts cam − lifter.

Analysis on Plane and Ball Compression Behaviour of Spacer Fabric

2011 ◽  
Vol 332-334 ◽  
pp. 1049-1052
Author(s):  
Guang Kai Ji ◽  
Xiao Liu ◽  
Zhao Qun Du
Keyword(s):  
Strain Curve ◽  
Maximum Pressure ◽  
Stress And Strain ◽  
Compression Stress ◽  
Compression Force ◽  
Pressure Force ◽  
Compression Behaviour ◽  
Spacer Fabric ◽  
Plane Plate ◽  
Spherical Ball

In present paper, the compression force and strain curve for both plane plate and spherical ball compressions are conducted, where the compression stress and strain curve in plane plate compression is calculated and divided into three linear sections. Each linear region has corresponding compression modulus. In addition, three compression characters of both plate plane and spherical ball compressions are featured as compression work, maximum pressure/force and linear degree. Correlations between the three characters of compression property show that there exist high correlations between compression work and maximum pressure/force for plane plated and spherical ball compression. Moreover, effects of sample size and shape on compression properties are also conducted, and we find that there are no significant effects and the three compression characters are stable in both plane plate and spherical ball compression. Finally, the explicit formula derived in the Part I of this series for the spherical ball compression is used, and the ball compression force and strain curves are simulated based on the compression stress and strain curves based on plane plate compression tests. The comparing results between measured and theoretical results indicate that the theoretical model is effective to simulate ball compression behaviour of general knitted spacer fabrics. It is highly helpful in designing and predicting compression force of knitted spacer fabric for virtual processing of textile materials.

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