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Residual stress is most likely to cause deformation in a diesel engine block (DBs). The traditional independent analysis method is no longer suitable for obtaining the residual stress of multi-process diesel engine blocks (DBs), because the stress is constantly produced and changed during the casting, heat treatment, and cutting processes. Therefore, an evolution analysis method (EAM) is proposed. First, an evolution analysis model of a diesel engine block (DBs) was established. Subsequently, the residual stress of the diesel engine block (DBs) in the casting and heat treatment processes was analyzed using ProCAST and ABAQUS. Finally, the material removal of the diesel engine block (DBs) during the machining process was simulated by using ABAQUS. The residual stresses for every process were calculated by coupling inherited and process-induced stresses. Thus, the final stress distribution of the diesel engine block (DBs) was deduced by considering the entire machining process. The evolution analysis of the residual stress is significant for controlling the deformation of the diesel engine block (DBs).

Significant residual stresses are often generated during the manufacturing of cast Al-Si alloy engine blocks due to differential cooling rates, the mismatch in the thermo-physical properties of adjacent materials in direct contact and volumetric changes caused by solid-state phase transformations during cooling. These may be modified during heat treatment and operation. These residual stresses may lead to distortion (affecting performance and economy) or premature failure of the engine block. For this reason, it is of fundamental importance to have reliable numerical and experimental methods for characterizing the residual stresses in the engine blocks at several steps during the manufacturing process. Sectioning and neutron diffraction techniques have been widely used to determine the residual stresses in the engine blocks. Numerical techniques have been developed to predict these residual stress but require experimental validation. The authors reviewed several numerical and experimental studies of residual stress evolution in engine blocks and showed how the residual stresses, microstructures, and mechanical properties are correlated.

The new designs or new materials used in foundries for sand casting products in Vietnam now often rely on experience and adopt the try-to-fix method to gradually find the best implementation. This method is very time-consuming, and the product is often unsatisfactory in the first many castings. This study developed a casting simulation model to compare experimental and simulated results using the Fenotec molding technology for the RV95 engine body. The 3D simulation model that was used to simulate the casting process with the same boundary conditions as the experiment also gave similar results. The results show that when making new castings for the first time from experience, there are many casting defects such as cracking, metal deficiency, porosity, etc. In order to improve the casting results, the pouring gate, the arrangement of additional risers and the size of the runner were studied on the simulation to improve the defect results on the casting. After that, the parameters in the simulation model used in the experiment reveal that the molded product meets the required quality and no longer has defects. This molded product, after checking the mechanical and geometric parameters, can be put into mass production

When the hydraulic cylinder moves at high speed to the end of the stroke, it usually produces severe pressure, shock, and vibration, and makes the system very unstable, so the buffer device is often used to buffer the deceleration process of the hydraulic cylinder. In this paper, the cushioning process of a high-pressure hydraulic cylinder buffer device is modeled mathematically, the motion parameters in the cushioning process are calculated based on Simulink, and different structural parameters of the cylinder block are optimized and compared, to study the influence of structural parameters of the cushioning device on the cushioning process.

This paper presents how the manufacturing technologies are designed for the assembly of a single-cylinder engine block, four strokes, air-cooled. It is presented, from the constructive and technological point of view, the design stages of the main element of the core of an engine, respectively, the engine block. This engine is currently used on light vehicle categories such as ATVs, quads, and motorcycles. In the researches, activities are developed such as the following: designing of various digital technologies to achieve virtual prototype, obtaining a prototype using additive manufacturing technologies, and manufacturing the engine block using CNC technologies, under a range of unique products or small series. Many of the designing activities are materialized in an original software system, named GENgine, developed by authors using Open DCL and Visual LISP programming environments.

Stiffener ribs are widely used to increase the stiffness of engine blocks, shifting the vibration modes to higher frequencies where excitation is weaker so that radiated noise can be reduced. The effect of different rib design parameters on the radiated noise emission of a diesel engine has been investigated considering its impact on block weight. A heavy-duty engine block was modeled using finite element method, multi-body dynamics approach was used to determine the excitation forces acting due to combustion pressure and inertias, and boundary element method was used to find the acoustic transfer vectors which give the relationship between engine surface velocities and sound pressure levels at predetermined microphone locations. Initially, the baseline analytical sound pressure level and surface velocity results for the engine without ribs were obtained. Two prototype engines, with and without stiffened ribs, were tested in an acoustic dynamometer in complete speed range. Then, the problem was narrowed down to a specific surface patch on the block at a critical engine speed. The effects of various ribbing design parameters have been identified iteratively. A noticeable decrease in engine noise can be achieved by increasing the number of ribs, using thicker or higher ribs particularly in the frequency range corresponding to the engine skirt breathing modes. Increasing the rib height was found to be the most efficient way to reduce noise emissions with least impact on the block weight.

Purpose – The purpose of this paper is to develop a good calculation model to accurately predict the lubrication characteristic of main bearings of diesel engine and improve the service life. Design/methodology/approach – Based on the coupling of the whole flexible engine block and the flexible crankshaft reduced by the Component Mode Synthesis (CMS) method, considering mass-conserving boundary conditions, the average flow model equation and Greenwood/Tripp asperity contact theory, an elastohydrodynamic (EHD)-mixed lubrication model of the main bearings for the diesel engine is developed and researched with the finite volume method and the finite element method. Findings – Obviously, the mixed lubrication of bearings is normal, while full hydrodynamic lubrication is transient. The results show that under the whole flexible block model, maximum oil film pressure, maximum asperity contact pressure and radial shell deformation decrease, while minimum oil film thickness increases. Oil flow over edge decreases, and so does friction loss. Therefore, coordination deformation ability of whole engine block is favorable to mean load. In the whole block model, friction contact happens on both upper shell and lower shell positions. In addition, average oil film fill ratio at the key position becomes smaller in the whole engine block model, and consequently increases the chances of cavitations erosion more. So, wearing resistance of both upper and lower shells and anti-cavitations erosion ability must be enhanced simultaneously. Originality/value – Based on the coupling of the whole flexible engine block and the flexible crankshaft reduced by the CMS method, considering mass-conserving boundary conditions, the average flow model equation and Greenwood/Tripp asperity contact theory, an EHD-mixed lubrication model of the main bearings for the diesel engine is built, which can predict the lubrication of journal bearings more accurately.

Magnesium alloys have been widely applied in the automotive world cars or motorcycles and aircraft engines. This is because the weight of the magnesium itself is very lightweight and have high strength. And magnesium alloys have good thermal conductivity, high elastic modulus and good mechanical properties. Magnesium in engineering applications is usually in the mix with elements such as Al, Ag, Mn, Zn, Si, Zr and RE (rare element). Magnesium alloys with zinc are mostly found and used. This research has been carried out precipitation hardening treatment-Mg alloy-0.5Y 6Zn using variable temperature 150oC, 175oC and 200oC with a holding time of 12 hours, 24 hours and 36 hours. The results show microstructure formed is αMg, MgZn, and Mg3Zn6Y (i-Phase). The formation of precipitates during the process of aging raise hardness values up to 75.8 BHN. Aging treatment reduces the thermal resistance of the alloy Mg-6Zn-0.5%Y.

Engine blocks of modern passenger car engines are generally made of light metal alloys, mostly hypoeutectic AlSi-alloys. Due to their low hardness, these alloys do not meet the tribological requirements of the system cylinder running surface—piston rings—lubricating oil. In order to provide a suitable cylinder running surface, nowadays cylinder liners made of gray cast iron are pressed in or cast into the engine block. A newer approach is to apply thermal spray coatings onto the cylinder bore walls. Due to the geometric conditions, the coatings are applied with specifically designed internal diameter thermal spray systems. With these processes a broad variety of feedstock can be applied, whereas mostly low-alloyed carbon steel feedstock is being used for this application. In the context of this work, an iron-based wire feedstock has been developed, which leads to a nanocrystalline coating. The application of this material was carried out with the Plasma Transferred Wire Arc system. AlMgSi0.5 liners were used as substrates. The coating microstructure and the properties of the coatings were analyzed.

Recommender systems have been widely adopted by electronic commerce and entertainment industries for individualized prediction and recommendation, which benefit consumers and improve business intelligence. In this article, we propose an innovative method, namely the recommendation engine of multilayers (REM), for tensor recommender systems. The proposed method utilizes the structure of a tensor response to integrate information from multiple modes, and creates an additional layer of nested latent factors to accommodate between-subjects dependency. One major advantage is that the proposed method is able to address the “cold-start” issue in the absence of information from new customers, new products or new contexts. Specifically, it provides more effective recommendations through sub-group information. To achieve scalable computation, we develop a new algorithm for the proposed method, which incorporates a maximum block improvement strategy into the cyclic blockwise-coordinate-descent algorithm. In theory, we investigate algorithmic properties for convergence from an arbitrary initial point and local convergence, along with the asymptotic consistency of estimated parameters. Finally, the proposed method is applied in simulations and IRI marketing data with 116 million observations of product sales. Numerical studies demonstrate that the proposed method outperforms existing competitors in the literature.