Engine Assembly Research Articles

A discrete whale swarm algorithm for hybrid flow-shop scheduling problem with limited buffers

• The HFSP with limited buffer and two process routes is studied for the first time. • A new discrete WSA (DWSA) is proposed to solve the LBHFSP efficiently. • A real case from a diesel engine plant is studied to prove DWSA is helpful. This paper studies a hybrid flow-shop scheduling problem with limited buffers and two process routes that comes from an engine hot-test production line in a diesel engine assembly plant. It extends the classical hybrid flow-shop scheduling problem by considering practical constraints on buffer area resources and alternative process routes. Because of its NP-hardness and large scale, traditional optimization methods and heuristic rules cannot obtain satisfactory solutions. A discrete whale swarm algorithm (DWSA) is proposed to identify near-optimal solutions efficiently. The proposed algorithm adopts an encoding method based on the problem characteristic and a greedy delayed decoding strategy to avoid infeasible solutions. A hybrid initialization is used to ensure the quality of the initial population and diversity. A new way of computing distances and a movement rule between individuals are designed. Five mutation operators and a deduplication strategy are proposed to improve the population diversity. The effectiveness of the proposed DWSA is validated on three groups of instances and a real-world industrial case.

Research on the Influence of Euro VI Diesel Engine Assembly Consistency on NOx Emissions

The assembly consistency of a diesel engine will affect its nitrogen oxides (NOx) emission variation. In order to improve the NOx emissions of diesel engines, a study was carried out based on the assembly tolerance variation of the diesel engine’s combustion system. Firstly, a diesel engine which meets the Euro VI standards together with the experimental data is obtained. The mesh model and combustion model of the engine combustion system are built in the Converge software (version 2.4, Tecplot, Bellevue, DC, USA), and the experimental data is used to calibrate the combustion model obtained in the Converge software. Then, the four-factor and three-level orthogonal simulation experiments are carried out on the dimension parameters that include nozzle extension height, throat diameter, shrinkage diameter and combustion chamber depth. Through mathematical analysis on the experimental data, the results show that the variation of nozzle extension height and combustion chamber depth have a strong influence on NOx emission results, and the variation of combustion chamber diameter also has a weak influence on NOx production. According to the regression model obtained from the analysis, there is a quadratic function relating the nozzle extension height and NOx emissions and the amount of NOx increases with increasing nozzle extension height. The relationship between emission performance and size parameters is complex. In the selected size range, the influence of the variation of the chamber diameter on NOx is linear. The variation of the chamber depth also has an effect on NOx production, and the simulation results vary with the change of assembly tolerance variation. Thus, in the engine assembly process, it is necessary to strictly control the nozzle extension height and combustion chamber depth. The research results are useful to improve the NOx emission of diesel engine and provide a basis for the control strategy of selective catalytic reduction (SCR) devices.

Analysis of Stirling Engine Structure and Assembly Technology by Virtual Reality Technology

Virtual reality technology is a simulation technology that makes the display world more realistic with the help of computer technology. It is one of the hotspots of research and application in recent years, and its application field is very wide. Under this background, this paper introduces the concept and characteristics of virtual reality technology, and analyzes the structure and assembly process of Stirling engine by using three-dimensional parametric modeling software Unigraphics and virtual reality editor software VRP Bulider.

Design Methodology of Centrifugal Automatic Decompression System in Small Gasoline Engine

<div class="section abstract"><div class="htmlview paragraph">This paper deals with designing methodology of centrifugal type automatic decompression system (CADS) for small gasoline engine. CADS reduce the operator’s fatigue to start the engine. When engine cranked, CADS releases combustion pressure of the engine via opening of exhaust valve momentarily during compression stroke, which drastically reduces the hand pulling force required to start the engine with recoil starter unit. A 172 cc gasoline engine, which has applications in agricultural purposes, has been used for designing and development of CADS, which has to be installed at camshaft cam gear assembly of engine. With the new developed concept operator’s hand pulling force for starting the engine has been reduced to 41 % and henceforth durability of engine starting system increased significantly. In this paper detailed design approach has been discussed of working model of CADS. Based on predicted failure modes and generated RPN values, design calculations were carried out for various geometrical parameters of sub parts of CADS like mass of centrifugal flyweight, number of coils, wire diameter, spring rate of torsion spring. PTC CREO 3.0 has been used to make rough 3 D model of assembly and further it is optimized based on calculated design values and ease of manufacturability. A testing approach also has been discussed for checking desired spring rate of torsion spring and on engine overall working mechanism of CADS.</div></div>

Zero Defect Assurance of Three-Wheeler Product Using IoT Systems

By considering quality improvement in three-wheeler vehicle, IOT based Zero Defect Assurance framework is created which can keep up basic discharge related processes and product parameters and parts alongside the vehicles. This includes various forms like IOT products and procedure parameters catching and child part capturing against the vehicle number and quality creation. The system will be created utilizing different IOT gadgets, sensors, PLC’s, programming’s and databases. This application will be conveyed in Engine Assembly, Vehicle Assembly and Sub Assembly lines. These frameworks will be utilized for maintaining a strategic distance from abandons going to the next stage and additionally to recover the information for dissecting field grumblings and emanation related grievances. It is likewise used to enhance the procedure and product characteristics in the system. The hard-wares utilized in this work are useful to peruse the information from the parts and to show the on-time capacity of the parts and guide against the Unique Vehicle Number (UVN).

Thermo-mechanical analysis and estimation of turbine blade tip clearance of a small gas turbine engine under transient operating conditions

Turbine blade tip clearance is one of the significant factors that influence turbine efficiency, Specific Fuel Consumption (SFC), Exhaust Gas Temperature (EGT), and emissions. Controlling these parameters in a small gas turbine engine (SGT) is a challenging task due to small blade height and viscous working environment. SGT are subjected to high-temperature gradients at the combustor outlet, which affects the turbine blade tip clearance. This paper presents the thermo-mechanical analysis of a typical SGT engine to study the blade tip clearance influenced by the deformation of turbine stage components (turbine rotor, nozzle guide vane (NGV) with integral blade shroud) during transient phases. ANSYS Workbench is used to perform transient thermal and structural analyses. The structural analysis is performed taking the material properties to be temperature-dependent. The SGT engine under consideration operates at a design speed of 45,000 rpm. Initially, steady-state thermal analysis and static structural analysis were carried out to understand the structural behaviour of the system under a thermal and centrifugal loading environment. Since different components of the engine assembly operate at different temperatures, the effects of convection and conduction at the interfaces influence the radial clearances between the static and rotating parts of the engine. A one-way coupled transient thermal-structural analysis was performed on a three-dimensional model to capture the actual behaviour of the tip clearance during transient operating conditions. Significant growth of blade and rotor was observed relative to the casing resulting in minimal clearances during these transient operations. Hence, it is important to estimate desired cold clearance, considering transient phenomena, to avoid mechanical blade rub with the shroud. It is observed that high-temperature gradients contribute primarily to the stresses and radial displacement of the rotor compared to centrifugal effects. The turbine rotor takes more time (t = 600 s) to reach steady-state temperatures compared to NGV (t = 120 s) due to the solid mass of the disc. The location and magnitude of maximum and minimum equivalent stress changes with time in NGV and rotor, and they experience maximum stress at the initial time steps compared to steady-state.

Development of Damping Support for a Turbine Pump Assembly of a Cryogenic Fuel Aviation Gas Turbine Engine

Theoretical studies and design studies have been conducted to demonstrate the possibility of using a long hydrodynamic damper in the supports of a hydrogen pump rotor was shown. The complex problem of rotor dynamics and design synthesis of a hydrodynamic damper for a turbopump assembly (TPA) was solved. The geometric parameters of the hydrodynamic damper are determined that ensure the necessary damping level, d = 3 × 103 N s/m. It is shown that at such a damping level, the amplitude of rotor oscillations does not exceed the value of clearances in supports and on blade shoulders.

블렌디드 러닝을 위한 자동차 엔진 조립 증강현실 시뮬레이션 개발

본 연구는 블렌디드 러닝을 위한 자동차 엔진 부품 조립에 대한 증강현실 콘텐츠 개발을 하고 설문을 통 해 교육 효과의 유용성을 확인하였다. 자동차 엔진 조립에 대한 커리큘럼을 설계하고, 각 커리큘럼에 따라 조립 해야 할 부품의 모양, 위치, 조립 순서 등을 증강현실 콘텐츠로 개발하였다. 개발된 증강현실 시뮬레이션 콘텐츠 는 학습자 중심의 협력 활동과 결합하여 학생들이 능동적으로 학습할 수 있도록 하였고, 교사는 촉진자 역할을 수행하도록 설계하였다. 본 콘텐츠와 전통적인 학습을 한 학생들과 비교 실험하여 약 2배의 학습 시간이 절감되 는 것으로 나타났다. 본 연구를 통해 학생들의 문제해결, 프로세스 기술, 시스템 기술 및 인지 능력 등이 강화되 는 것을 확인할 수 있었다.

Shortest-Path Optimization of Ship Diesel Engine Disassembly and Assembly Based on AND/OR Network

Ship diesel engine disassembly and assembly (SDEDA) is essential for ship inspection and maintenance and navigation safety. The SDEDA consists of various machinery parts and operations. It is crucial to develop a system of SDEDA operations to improve the efficiency of disassembly and assembly (D&A). Considering the “AND” and “OR” relations (modeled as links) among the D&A operations (modeled as nodes), an “AND/OR” network is developed to extend a specialized graph model for the D&A sequencing problem in the context of education and training. Then, we devised a mixed-integer linear program (MILP) to optimize the SDEDA sequence based on the AND/OR network. Considering the flow balance in the AND/OR network, we developed exact algorithms and random search algorithms using breadth-first, branch cut and depth-first strategies to minimize the cost of the shortest path that represents an optimal sequence of D&A operations. To the best of our knowledge, it is the first try to formulate the D&A operations by an extended network model. Numerical experiments show that the proposed algorithms are practical for solving large-scale instances with more than 2000 D&A operations. The breadth-first shortest-path algorithm outperforms the MILP solver from the perspective of solution quality and computing time, and all developed algorithms are competitive in terms of computing time.

Productivity enhancement in engine assembly using lean tools and techniques

Lean assembling is bound together with a framework that is involved with a lot of ways of thinking, rules, instruments and strategies, which whenever forced, take out critical burn through and loss of time in all business formats for constant enhancement. But very scarce explorations about lean manufacturing implementation have been done in automobile industry. This paper represents the productivity enhancement using basic lean manufacturing tools in engine assembly at Renault Nissan Automotive India Private Limited Coimbatore. This paper highlights a methodology developed for standardization and improvement in the process of engine assembly activities using lean manufacturing tools and techniques line by using DMAIC approach. Productivity enhancement is the primary goal which is to be achieved for any profitable manufacturing system. All this initiated by performing study on the manual operator’s activities. For an engine assembly processes the tools description, process description and existing sheets were studied which provided detailed information about all the movements of assembly activities.

Selection of optimal assembly strategy at an engine assembly plant using fuzzy multi-criteria decision-making tools

This paper is presenting a methodology to select an optimal assembly strategy using two fuzzy multi-criteria decision making (MCDM) tools as illustrated in a case study of an engine assembly plant. Based on an automotive engine assembly system, the existing challenges and related criteria are identified. Four potential assembly strategies compatible with existing system are developed to address the challenges. Two different fuzzy MCDM tools (VIKOR and TOPSIS) are applied for the multi-criteria problem to select the optimal assembly strategy. Four decision makers (DMs) from middle-level management are involved during the process. A comparison of results from the two MCDM tools is performed to consolidate the decision. For the present case, reconfigurable assembly system (RAS) is found to be the most preferred assembly strategy by both the MCDM tools. The ranking for rest of the alternatives are also found.

엔진 어셈블리 구조해석

엔진 어셈블리 구조해석

Recurrent neural network for motion trajectory prediction in human-robot collaborative assembly

Effective and safe human-robot collaboration in assembly requires accurate prediction of human motion trajectory, given a sequence of past observations such that a robot can proactively provide assistance to improve operation efficiency while avoiding collision. This paper presents a deep learning-based method to parse visual observations of human actions in an assembly setting, and forecast the human operator's future motion trajectory for online robot action planning and execution. The method is built upon a recurrent neural network (RNN) that can learn the time-dependent mechanisms underlying the human motions. The effectiveness of the developed method is demonstrated for an engine assembly.

A hybrid decision making framework based on fuzzy PIPRECIA-fuzzy EDAS for failure mode and effects analysis

The main purpose of the current work is to propose a hybrid multi-criteria decision making (MCDM)-based methodology for the prioritisation of failure modes based on their associated risk levels. In the current work, a novel hybrid MCDM approach, i.e., fuzzy pivot pairwise relative criteria importance assessment (PIPRECIA) integrated with fuzzy evaluation based on distance from average solution (EDAS) has been used to prioritise the different failure modes based on their risk levels. A case study of engine assembly process of tractor is presented to illustrate the demonstration of proposed hybrid MCDM based fuzzy PIPRECIA-fuzzy EDAS methodology. The results obtained by fuzzy PIPRECIA-fuzzy EDAS methodology are validated by the two different hybrid MCDM approaches, i.e., fuzzy PIPRECIA-fuzzy ERVD method and fuzzy PIPRECIA-fuzzy ARAS method. The results obtained by fuzzy PIPRECIA-fuzzy EDAS are quite similar to that obtained by fuzzy PIPRECIA-fuzzy ERVD and fuzzy PIPRECIA-fuzzy ARAS method.

KRANK KASNAKLARINDA KULLANILAN KAUÇUK RİNGİN FARKLI ÜRETİM TEKNİKLERİ İLE YAPIŞM

The crank pulley is a tuned mass damper that is used to reduce torsional vibrations in the crankshaft in internal combustion engines and to dampen the damage of torsional movement to the engine assembly. The damping ability of the crank pulleys is realized with the help of the rubber on the pulley. In addition to the mechanical properties of rubbers, their rigidity during the manufacturing and assembly stages is important. According to the literature researches, it is known that the damping capabilities of rubbers change depending on the manufacturing method. In this study, two different tight fit methods for rubber rings used in crank pulleys were examined. The mechanization method was applied to the investigated processes. Before and after mechanization tests of the crank pulleys produced by two different methods were carried out and the results were discussed.

Reduction of Cycle Time in Vehicle Engine Assembly LineUsing Karakuri Kaizen

Just In Time (JIT) based automotive manufacturing companies use the takt time and cycle time as indicators of their manufacturing performance. This study explores the vehicle engine assembly line for Station 2 Cylinder Block Products, which has a cycle time of 184 seconds, while the company targets a 180 second for takt time. Though ideally, the cycle time should not exceed the takt time. This research aims to identify the Non-Value Added (NVA) activities in Station 2 and minimize them with Karakuri Kaizen. The results of the Process Activity Mapping (PAM) show that Station 2 Cylinder Block has 16 Value Added (VA) activities, 19 Necessary Non-Value Added (NNVA) activities, and 7 Non-Value Added (NVA) activities with a manufacturing cycle effectiveness (MCE) 78%. Based on the activity mapping, the researchers find the primary causes and designed a proposed improvement using the Karakuri Kaizen method to reduce two NVA activities. The company can speed up the cycle time at Station 2 Cylinder Block to 180 seconds and the MCE to 80% by implementing Karakuri Kaizen.

Fracturing Behavior of Metalware Made of 30KhGSA Steel

The reasons for fracture of fasteners made of 30KhGSA steel were analyzed. It was found that, in the case of fracture of bolts in the package connecting the frame elements, the damage of the bolts is the result of the fretting corrosion due to the mutual friction between bolts and elements of skin, belt, and tape. Fretting corrosion develops in the locations of the cadmium coating damage of bolts in the process of friction. The break-in scuffing of the openings and corrosive damage (fretting corrosion) triggering intergranular fracture, which is the most severe in the skin and tape, contribute to the fractures in the belt, skin, and tape. The reason for fracture is structural and technological factors: high stresses in the investigated package, micro-displacement of the mating parts, violation of the cadmium coating, insufficient protection against corrosion and environmental impact. Fracture of the self-locking nuts made of 30KhGSA steel with the anticorrosion cadmium coating used during assembly of an auxiliary gas turbine engine is induced by their severe overheating—the impact of the melted coating on the surface of the loaded nuts and penetration of the liquid metal into the base material along the grain boundaries. Application of the cadmium coating for the operation of the steel parts at a temperature exceeding (even for a short time) the melting temperature of Cd (Tmelt = 320.9°C) under the condition of contact with the stressed metal owing to the Rebinder effect leads to a dramatic loss of strength and premature failure of the part. Fracture of the galvanized bolts made of 30KhGSA steel was studied in the process of the repeated static testing. It was found that several factors contributed to the onset of the multiple fractures: rough scratch marks, sandblasting performed before galvanizing with the use of large sand fractions, dents which contribute to the premature origin of cracks, areas with deposits formed during coating with loose adhesion of the layer. The presence of a large number of pits along with the fatigue grooves indicates the operation of the material under high load. The investigation was carried out by the method of optical and scanning electron microscopy applying the X-ray microanalysis.

AR-based interaction for human-robot collaborative manufacturing

Abstract Industrial standards define safety requirements for Human-Robot Collaboration (HRC) in industrial manufacturing. The standards particularly require real-time monitoring and securing of the minimum protective distance between a robot and an operator. This paper proposes a depth-sensor based model for workspace monitoring and an interactive Augmented Reality (AR) User Interface (UI) for safe HRC. The AR UI is implemented on two different hardware: a projector-mirror setup and a wearable AR gear (HoloLens). The workspace model and UIs are evaluated in a realistic diesel engine assembly task. The AR-based interactive UIs provide 21–24% and 57–64% reduction in the task completion and robot idle time, respectively, as compared to a baseline without interaction and workspace sharing. However, user experience assessment reveal that HoloLens based AR is not yet suitable for industrial manufacturing while the projector-mirror setup shows clear improvements in safety and work ergonomics.

Research on Scheduling Problem of Discrete Manufacturing Workshop for Major Equipment in Complicated Environment

This paper studies the scheduling problem of discrete equipment manufacturing workshops for major equipments in the context of commercial aircraft engine assembly workshops. At present, the manufacturing process of aircraft engines is still based on manual assembly, involving a large number of tooling parts, the workshop has large flow and long assembly period but limited labor. In this paper, the production scheduling process is optimized under the condition of multi-skilled human resources constraints. The mathematical programming model is established by abstracting the problem, and a heuristic algorithm based on multi-priority rules suitable for this problem is selected to solve the problem. Then, using Plant Simulation to establish a simulation model for the actual discrete assembly system, input different scheduling schemes and combine the logistics process for collaborative verification, and analyze the best scheduling results as a guide. The research shows that this method can effectively guide the workshop operation process, adapt to the constantly adjusted workshop layout, improve the resource utilization rate and assembly efficiency, and has a strong reference for practical application.

Selection of optimal assembly strategy at an engine assembly plant using fuzzy multi-criteria decision-making tools

This paper is presenting a methodology to select an optimal assembly strategy using two fuzzy multi-criteria decision making (MCDM) tools as illustrated in a case study of an engine assembly plant. Based on an automotive engine assembly system, the existing challenges and related criteria are identified. Four potential assembly strategies compatible with existing system are developed to address the challenges. Two different fuzzy MCDM tools (VIKOR and TOPSIS) are applied for the multi-criteria problem to select the optimal assembly strategy. Four decision makers (DMs) from middle-level management are involved during the process. A comparison of results from the two MCDM tools is performed to consolidate the decision. For the present case, reconfigurable assembly system (RAS) is found to be the most preferred assembly strategy by both the MCDM tools. The ranking for rest of the alternatives are also found.