scholarly journals Computational and Experimental Method for Assessing the Thermal Strength of High-Loaded Diesel Engines

2021 ◽  
Vol 2096 (1) ◽  
pp. 012204
Author(s):  
V P Belov ◽  
D V Apelinskiy
Keyword(s):  
Diesel Engines ◽  
Thermal Loading ◽  
Thermal Strength ◽  
Piston Head ◽  
Correct Calculation ◽  
Deformation Kinetic ◽  
Kinetic Criterion ◽  
Experimental Values ◽  
Specific Implementation ◽  
Isothermal Stamping

Abstract The article discusses the reasons of fatigue failure of pistons of high-loaded diesel engines. A deformation-kinetic criterion is proposed, generalized to non-isothermal loading, which allows more correct calculation of the number of thermal loading cycles before the appearance of fatigue damage. For a specific implementation of the proposed criterion, a calculated assessment of the piston stress-strain rate was carried out using the FEM. The boundary conditions for the calculation were obtained by thermometry of the piston head on a non-motorized thermal stand (TS). Comparison of the calculated and experimental values of the number of thermal cycles before the appearance of cracks on the edge of the combustion chamber (CC) of pistons made by casting and isothermal stamping is given.

INCREASING THE RESOURCE OF DIESEL CYLINDER HEADS BY IMPROVING THE TECHNOLOGY OF THEIR RESTORATION

2020 ◽  
Vol 15 (7) ◽  
pp. 950-957
Author(s):  
G.D. Mezhetskiy ◽  
◽  
V.A. Strelnikov ◽  
Keyword(s):  
Diesel Engines ◽  
Thermal Loading ◽  
Theoretical Calculations ◽  
Operating Conditions ◽  
Advanced Technology ◽  
Temperature Fields ◽  
Cylinder Block ◽  
Diesel Cylinder ◽  
Thermal Intensity

The article presents the results of studies of the thermal fatigue strength of diesel cylinder heads and their resource under operating conditions, by using the most advanced technology for their restoration. Based on the results of theoretical calculations of durability and operational studies, a restoration technology has been proposed, which makes it possible to increase the resource of cylinder heads by 2 ÷ 2.5 times. For this purpose, the non-uniformity of the temperature field on the firing bottom of the cylinder heads of YaMZ-238NB diesel engines was theoretically determined and experimentally confirmed. On the basis of theoretical calculations, the most heatstressed sections of the plane of the cylinder heads of diesel engines bonded to the cylinder block were determined, and the appearance of cracks in them. When developing a method for calculating the temperature fields of the fire bottom, the universal finite element method (FEM) was used. This method makes it possible to take into account the geometry and conditions of thermal loading of the cylinder heads quite accurately. For the determination of temperature fields, a well-founded assignment of the boundary conditions is crucial. With this in mind, a number of surfaces were determined that characterize the durability of the entire part during operation. As a result of calculations carried out on a computer, temperature fields have been obtained that make it possible to analyze the distribution of temperatures and temperature gradients at any point of the fire bottom. The highest temperatures (620...635K) are localized in the central part of the fire bottom, which is two times higher in thermal intensity than the peripheral one and confirms the appearance of cracks in these places during the operation of diesel cylinder heads.

scholarly journals Micro-grinding temperature prediction considering the effects of crystallographic orientation

2019 ◽  
Vol 6 ◽  
pp. 22
Author(s):  
Man Zhao ◽  
Xia Ji ◽  
Steven Y. Liang
Keyword(s):  
Crystallographic Orientation ◽  
Thermal Loading ◽  
Factor Model ◽  
Orientation Distribution ◽  
Taylor Factor ◽  
Energy Partition ◽  
Grinding Forces ◽  
Material Microstructure ◽  
Temperature Prediction ◽  
Experimental Values

Tensile stress and thermal damage resulting from thermal loading will reduce the anti-fraying and anti-fatigue of workpieces, which is undesirable for micro-grinding, so it is imperative to control the rise of temperature. This investigation aims to propose a physical-based model to predict the temperature with the process parameters, wheel properties and material microstructure taken into account. In the calculation of heat generated in the micro-grinding zone, the triangular heat-flux distribution is adopted. The reported energy partition model is also utilized to calculate the heat converted into the workpiece. In addition, the Taylor factor model is used to estimate the effects of crystallographic orientation (CO) and its orientation distribution function (ODF) on the workpiece temperature by affecting the flow stress and grinding forces in micro-grinding. Finally, the physical model is verified by performing micro-grinding experiments using the orthogonal method. The result proves that the prediction matches well with the experimental values. Besides, the single-factorial experiments are conducted with the result showing that the model with the consideration of the variation of Taylor factor improves the accuracy of the temperature prediction.

Paper 5: Design Aspects of Large Marine Engines

1966 ◽  
Vol 181 (8) ◽  
pp. 10-19
Author(s):  
J. F. Butler ◽  
F. Ørbeck
Keyword(s):  
Thermal Loading ◽  
Bending Moments ◽  
Bending Stress ◽  
Slow Speed ◽  
Piston Head ◽  
Marine Engines ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Frame Stiffness

The paper deals with large slow-speed marine engines with a section on crankshaft stresses, including dynamic torque calculation; static bending moments owing to firing pressure, inertia, and misalignment; combined torque and bending stress; and experimental determination of stress concentration factors in the fillet radii. Other sections deal with top end bearing loading including cyclic variation, piston head stresses, deflection of bearing housings, prestressing of main bolts, frame stiffness, and stress in combustion chamber studs as a result of pressure and thermal loading.

Paper 2: Some Aspects of the Development of the LVA24 Traction Engine

1968 ◽  
Vol 183 (2) ◽  
pp. 24-34
Author(s):  
A. Dolenc ◽  
R. Lees
Keyword(s):  
Diesel Engines ◽  
High Speed ◽  
Thermal Loading ◽  
Lightweight Design ◽  
Practical Experience ◽  
Specific Output

Lightweight design, high speed and high mean pressures permit high specific output of diesel engines but these are normally associated with high mechanical and thermal loading of critical parts. The paper outlines the approach to the development of the Sulzer LVA24 traction engine and explains the practical experience gained with the components.

scholarly journals Suspension Plasma-Sprayed Thermal Barrier Coatings for Light-Duty Diesel Engines

2019 ◽  
Vol 28 (7) ◽  
pp. 1674-1687 ◽  
Author(s):  
Wellington Uczak de Goes ◽  
Joop Somhorst ◽  
Nicolaie Markocsan ◽  
Mohit Gupta ◽  
Kseniya Illkova
Keyword(s):  
Combustion Chamber ◽  
Functional Properties ◽  
Diesel Engines ◽  
Fuel Efficiency ◽  
Thermal Spraying ◽  
Ceramic Coatings ◽  
Thermal Spray Process ◽  
Spray Process ◽  
Piston Head ◽  
Light Duty

Abstract Demands for improved fuel efficiency and reduced CO2 emissions of diesel engines have been the driving force for car industry in the past decades. One way to achieve this would be by using thermal spraying to apply a thermal insulation layer on parts of the engine’s combustion chamber. A candidate thermal spray process to give coatings with appropriate properties is suspension plasma spray (SPS). SPS, which uses a liquid feedstock for the deposition of finely structured columnar ceramic coatings, was investigated in this work for application in light-duty diesel engines. In this work, different spray processes and materials were explored to achieve coatings with optimized microstructure on the head of aluminum pistons used in diesel engine cars. The functional properties of the coatings were evaluated in single-cylinder engine experiments. The influence of thermo-physical properties of the coatings on their functional properties has been discussed. The influence of different spray processes on coating formation on the complex piston head profiles has been also discussed. The results show that SPS can be a promising technique for producing coatings on parts of the combustion chamber, which can possibly lead to higher engine efficiency in light-duty diesel engines.

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