Engine Assembly Research Articles

Simulation based knowledge elicitation: Effect of visual representation and model parameters

Since much knowledge is tacit, eliciting knowledge is a common bottleneck during the development of knowledge-based systems. Visual interactive simulation (VIS) has been proposed as a means for eliciting experts’ decision-making by getting them to interact with a visual simulation of the real system in which they work. In order to explore the effectiveness and efficiency of VIS based knowledge elicitation, an experiment has been carried out with decision-makers in a Ford Motor Company engine assembly plant. The model properties under investigation were the level of visual representation (2-dimensional, 2½-dimensional and 3-dimensional) and the model parameter settings (unadjusted and adjusted to represent more uncommon and extreme situations). The conclusion from the experiment is that using a 2-dimensional representation with adjusted parameter settings provides the better simulation-based means for eliciting knowledge, at least for the case modelled.

Study on Carrying out Kanban Production System in a Engine Assembly Workshop

Combined with the field survey data, this paper firstly analyzed the production status of an engine assembly plant, identified the problems reduced production efficiency; and then proposed re-introduction of Kanban production system to help enterprises overcome the present impasse. This paper focused on describing the import plan, the overall design and executing conditions of Kanban production system，which to be a reference example for other enterprises who want to adopt Kanban production system

Study on the Assembly and Adjustment Technology of the Low-Speed Marine Diesel Engine

This paper takes the high-power low-speed marine diesel engine as an object to carry out a series of technical researches. These technologies include the assembly and the precision adjustment on the components of the piston, the crosshead and the connecting rod, and the assembly and the timing adjustment on the fuel and exhaust system, the assembly and the precision adjustment on the crankshaft and the engine base. The test technology and system of the high-power marine diesel engine are studied. The new method to determine the assembly quality of the piston and crosshead based on the strain measurement for the small end of the connecting rod and the oil film thickness measurement for the crosshead and the supporting plate is proposed. The stress measuring system for the engine body is built. The engine body’s deformation before and after the crankshaft assembly and the bearing block’s deformation during the crankshaft movement are analyzed to evaluate the stress situation of the crankshaft after the installation. Therefore the assembly technology for the low-speed high-power diesel engine is improved to ensure the reliability of the diesel engine work.

Avaliação do processo de desenvolvimento de um novo produto utilizando earned value management system

Retrata-se uma situação de integração do processo de desenvolvimento de produtos - PDP ao longo da cadeia de suprimentos por meio do fluxo de valor. Avalia-se um caso de aplicação de um modelo de PDP numa empresa de autopeças líder em seu segmento. A partir da aplicação do pensamento enxuto na cadeia de suprimentos, e da metodologia EMVS na análise de desempenho do PDP, é criado um Check List para evitar desperdícios no gerenciamento de projetos. Os resultados demonstram que a metodologia tem aspectos positivos, mas sua aplicação leva tempo e tem reflexos em toda cadeia de suprimentos.

Parameter Optimization of Kanban Production System for an Engine Assembly Workshop Based on Witness

To kanban production system of a engine assembly shop as the empirical study, the simulation model of the Kanban production system about designing, running and optimizing are elaborated, which is on the basis of understanding basic theory of Kanban production system. More importantly, using optimization, researched further the effects of different value of safety factor and coefficient of variation of Kanban production system on the impact of the results, and determined the optimal combined scheme.

Pervading Cold Testing of Engines in the Automobile Zone

Although the quality of a completed engine ready for shipping is traditionally assured by adopting the firing run at the final process of the engine assembly line, we have still not readily accepted the testing of engines in cold state i.e. without actual combustion & continue to neglect all its long term benefits in view of the immediate shortcomings which not only enhances the inspection speed, fault detection but also poses zilch threat to the environment around us. It increases the effectiveness of the “In-Process Quality Control” of an Engine production line.

Case Study on Failure of Ball Bearing of an Aeroengine

Heavy damage was reported on the outer race and rolling elements of a ball bearing belonging to jet engine of a military aircraft. Flaking type of damage was noticed only at one particular location on the outer race of the bearing and on almost all the balls of the bearing. The inner race and the cage of the bearing were free from any damage. The chemistry, hardness, and microstructure of the bearing components met the specification requirements. In the actual engine assembly, the bearing was mounted on shaft of bevel gear. Careful examination of the inner diameter (ID) of the inner ring of the bearing revealed nonuniform contact marks. The contact marks were observed in the form of discoloration of the ID surface. The nonuniform contact was attributed to eccentricity caused by improper mounting of the bearing onto the shaft of the bevel gear. This resulted in preferential loading, causing flaking at one particular location on the raceway of the outer ring and damage to the balls of the bearing. Hence, it was concluded that the ball bearing had failed because of assembly error after the last repair of the engine.

Dynamic Characteristics Analysis of Abnormal Vibration for Power Assembly of Diesel Engine of SUV

With regard to the problem of abnormal vibration for power assembly of diesel engine of the Sport Utility Vehicle in working rotation speed conditions, the method of test mode combined finite element simulation analysis was adopted, the dynamic characteristics of the power assembly were studied in all conditions. First vibration modal testing of the power assembly was carried out in whole vehicle condition and in test bed, the cause of abnormal vibration of the power assembly was found out, the bending stiffness was low, then a kind of actual finite element simulation model of the power assembly was set up, the constraint mode was calculated. The rationality of finite element simulation model of the power assembly was validated. Integrated modal testing and simulation analysis showed that the low stiffness of flywheel shell led to the low first modal frequency of power assembly which was easily in the excitation frequency range of diesel engine working rotational speed, and resulted in system resonance of the power assembly

Information Modeling and Knowledge Management Approach to Reconfiguring Manufacturing Enterprises

This research aims to gain a detailed understanding of data producers, data consumers and format/flow of the data within automotive industry for defining and using Bill of Process (BoP) for engine assembly lines. The focus remained on the real industrial challenge of rapid constraint evaluation for designing and/or reconfiguration of Powertrain assembly lines to cater for a new/changed product. A methodology is developed to facilitate Ford Company to quickly model and re-configure new/changed assembly line for building new/changed engine. This is made possible with the help of modular approach and developing relationships among products, processes and resources. The data and information of the PPR is made available to all the stake holders of the organisation independent of the platform or specific application being used at the department/facility.

Evaluation of tribological properties of bearing materials for marine diesel engines utilizing acoustic emission technique

Acoustic Emission (AE) technique, which has detection capability for minute failures, has been tried to monitor the condition of a plain bearing under the laboratory conditions. In this paper, the bearing materials for marine diesel engines – tin alloy as known as “white metal”, aluminum alloy of 40% tin mass and aluminum alloy 40% tin mass with resin overlay – were tested using a sleeve-to-plate tribo-tester. The frictional force and back temperature were measured as well as the AE signals. The possibility of AE technique to monitor the bearing condition was also assessed by evaluating tribological properties under different operating conditions such as start–stop simulating the crankshaft turning during engine assembly and seizure tests. These results indicate that AE is useful for monitoring the lubricated condition of the sliding surfaces and evaluating tribological properties of the bearing.

Distribution of piston compression ring pressure against the deformed cylinder wall

The following study presents typical cylinder deformations that come up during engine assembly and operation and provides results of analysis of how these changes affect the operation of the compression ring. Special attention has been paid to the effect of cylinder diameter increase on the distribution of the circumferential wall pressure and the cause of light gaps formation has been explained. The analyses presented in the following paper have been carried out using a computer program that has been formulated based on a compression ring mathematical model. Exemplary results of simulation have been obtained for a medium speed generator engine of a cylinder diameter of 0.48 m.

Classification analysis for simulation of the duration of machine breakdowns

Machine failure can have a significant impact on the throughput of manufacturing systems, therefore accurate modelling of breakdowns in manufacturing simulation models is essential. Finite mixture distributions have been successfully used by Ford Motor Company to model machine breakdown durations in simulation models of engine assembly lines. These models can be very complex, with a large number of machines. To simplify the modelling we propose a method of grouping machines with similar distributions of breakdown durations, which we call the Arrows Classification Method, where the Two-Sample Cramér-von-Mises statistic is used to measure the similarity of two sets of the data. We evaluate the classification procedure by comparing the throughput of a simulation model when run with mixture models fitted to individual machine breakdown durations; mixture models fitted to group breakdown durations; and raw data. Details of the methods and results of the classification will be presented, and demonstrated using an example.

Análise das estratégias de produção de seis montadoras de motores para automóveis

São identificadas e analisadas neste artigo as Estratégias de Produção (EP) adotadas, durante o período 2005-2006, por 6 empresas montadoras de motores para automóveis instaladas no Brasil. Três delas instalaram-se há várias décadas no País e são aqui denominadas "estabelecidas"; as outras três, apenas há alguns anos, são denominadas "entrantes". Para o levantamento de informações sobre as EPs adotadas, entrevistas semiestruturadas foram feitas com pelo menos um dos principais responsáveis - gerentes - pela unidade produtora de motores em cada empresa. Observou-se que as EPs adotadas pelas empresas são distintas entre os grupos e em cada grupo (intragrupos), marcadas por diferenças nas áreas de decisão estruturais, apesar de haver semelhanças entre as estratégias competitivas das empresas em cada grupo (estabelecidas e entrantes). Alguns dos resultados encontrados nesta pesquisa confirmam proposições da literatura, outros indicam que há temas que precisam ainda ser cuidadosamente investigados.

Information Modeling and Knowledge Management Approach to Reconfiguring Manufacturing Enterprises

This research aims to gain a detailed understanding of data producers, data consumers and format/flow of the data within automotive industry for defining and using Bill of Process (BoP) for engine assembly lines. The focus remained on the real industrial challenge of rapid constraint evaluation for designing and/or reconfiguration of Powertrain assembly lines to cater for a new/changed product. A methodology is developed to facilitate Ford Company to quickly model and re-configure new/changed assembly line for building new/changed engine. This is made possible with the help of modular approach and developing relationships among products, processes and resources. The data and information of the PPR is made available to all the stake holders of the organisation independent of the platform or specific application being used at the department/facility.

Simulation analysis and performance improvement of engine assembly line

Simulation is used frequently for performance measurement and improvement. The purpose of this paper is to investigate an existing engine assembly line at Detroit Diesel with a known bottleneck station, and determine the best solution to improve the output of this process and accommodate a future decrease in cycle times. The assembly line uses automated guided vehicles (AGVs) to transport the engines and at this station there is a second path available to add an additional process. A simulation of the existing system is completed, and improvement ideas are simulated and analysed to determine which solution best suits the assembly line’s need for throughput improvement. The study shows significant performance improvement in two automatic system of the valve lash operation. The confidence interval shows lower variability if two-automatic system is used compared to hybrid system. The concern was raised for the manual operation due to ergonomical problems. Flexible simulation shows how to improve the system without disrupting production and operational systems.

A Study of Selective Assembly for Product with Multi Mating Features

In order to firstly assure the mating features of high importance during the selective assembly process, a selective assembly method considering the feature weightings is proposed. All of the features are evaluated by fuzzy entropy weight method. Their weight coefficients which present the importance are defined. Based on the dissymmetrical quality loss function and the weight coefficients, the multi-objective model for selective assembly is established. A specific generic algorithm considering target weightings is used to solve the optimization model. It can search the preference region using the Pareto dominant order to derive satisfactory solutions with high quality. Finally, the method is used for the selective assembly of a certain aero engine’s subassembly to invalidate the feasibility.

Operations and Technology Strategy Trajectories followed by automotive engine manufacturers set up in Brazil

This paper aims to identify and analyze recent trajectories followed by two engine assembly plants set up in Brazil (one mature company and one newcomer), regarding operations and technology strategies undertaken by them. In short, the mature company has made efforts to increase quality and flexibility, while the newcomer has prioritized cost reduction and quality enhancements, besides taken action to increase its product nationalization. The main findings indicate that (1) competitive priorities seem to "pull" the trajectories, translating market needs into specific tasks that must be fulfilled by each strategy, while the advances made in each step may "push" the trajectories, setting the basis for new strategies and making them capable of moving further; (2) although advances along trajectories are intended and planned, they cannot be foreseen and alternate decisions may be necessary and (3) secondary factors like the degree of autonomy assigned to firms and accumulated knowledge also influence trajectories.

A Study of Cycle-to-Cycle Variations and the Influence of Charge Motion Control on In-Cylinder Flow in an IC Engine

An experimental study is performed to investigate the cycle-to-cycle variations and the influence of charge motion control on in-cylinder flow measurement inside an internal combustion engine assembly. Molecular tagging velocimetry (MTV) is used to obtain the multiple point measurement of the instantaneous velocity field. MTV is a molecular counterpart of particle-based techniques, and it eliminates the use of seed particles. A two-component velocity field is obtained at various crank angle degrees for tumble and swirl measurement planes inside an optical engine assembly (1500 rpm and 2500 rpm engine speeds). Effects of charge motion control are studied considering different cases of: (i) charge motion control valve (CMCV) deactivated and (ii) CMCV activated. Both the measurement planes are used in each case to study the cycle-to-cycle variability inside an engine cylinder. Probability density functions of the normalized circulation are calculated from the instantaneous planar velocity to quantify the cycle-to-cycle variations of in-cylinder flows. In addition, the turbulent kinetic energy of flow is calculated and compared with the results of the probability density function. Different geometries of CMCV produce different effects on the in-cylinder flow field. It is found that the charge motion control used in this study has a profound effect on cycle-to-cycle variations during the intake and early compression; however, its influence reduces during the late compression. Therefore, it can be assumed that CMCV enhances the fuel-air mixing more than the flame speed.

Interactive assembly tool planning based on assembly semantics in virtual environment

Assembly tool planning in virtual environment remains to be a challenge because of the complexity and variety in tools configuration and manipulation. In order to solve the problem, an interactive assembly tool planning based on assembly semantic model is proposed. After detailed analysis on assembly tool planning in virtual environment, an improved assembly semantic model is represented, and a new assembly tool model is developed based on assembly semantic model. With the help of assembly semantic processing method, such as recognition, solving, navigation and so on, a series methods including assembly tool selection, orientation, manipulation are proposed for interactive assembly tool planning in virtual environment. Finally, tightening tool planning for connecting rod caps of auto engine assembly line demonstrates the feasibility and validity of presented methods.

Risk Factors for Plantar Fasciitis Among Assembly Plant Workers

The objective of this study was to determine the relative contributions of work activity (time spent standing, walking, or sitting), floor surface characteristics, weight, body mass index, age, foot biomechanics, and other demographic and medical history factors to the prevalence of plantar fasciitis. A cross-sectional observational study design was used. The study site was an automobile engine assembly plant. Full-time employees of the assembly plant who had been working at least 6 months. The independent variables included baseline demographics, medical history, ergonomic exposures, psychosocial factors, discomfort ratings, shoe characteristics, and foot biomechanics. The dependent variable was the finding of plantar fasciitis on physical examination. The study demonstrated that forefoot pronation on physical examination, high metatarsal pressure on the gait assessment, increasing time spent standing on hard surfaces, increased time spent walking, medium tenure at the plant, and an increased number of times getting in and out of the vehicle (for the truck/forklift drivers) increased the risk of presenting with plantar fasciitis. Rotation of shoes during the work week was found to reduce the risk of presenting with plantar fasciitis. Increased supervisor support showed a trend toward reducing the prevalence of plantar fasciitis. Plantar fasciitis is relatively common in the manufacturing setting. These findings suggest several options for primary and secondary prevention strategies. Shoe rotation may be an effective strategy that may be used as either a primary or secondary strategy. The use of shoe orthoses with a medial longitudinal arch and metatarsal pad may be used as a preventive or treatment strategy. Work stations that decrease the percentage of time walking or standing on hard surfaces (eg, allowing workers to alternate between sitting and standing postures or providing cushioning mats for concrete surfaces) may lower the risk for plantar fasciitis.