Engine Assembly Research Articles

Anomaly Detection of DC Nut Runner Processes in Engine Assembly

In many manufacturing systems, anomaly detection is critical to identifying process errors and ensuring product quality. This paper proposes three semi-supervised solutions to detect anomalies in Direct Current (DC) Nut Runner engine assembly processes. The nut runner process is a challenging anomaly detection problem due to the manual nature of the process inducing high variability and ambiguity of the anomalous class. These characteristics lead to a scenario where anomalies are not outliers, and the normal operating conditions are difficult to define. To address these challenges, a Gaussian Mixture Model (GMM) was trained using a semi-supervised approach. Three dimensionality reduction methods were compared in pre-processing: PCA, t-SNE, and UMAP. These approaches are demonstrated to outperform the current approaches used by a major automotive company on two real-world datasets. Furthermore, a novel approach to labelling real-world data is proposed, including the concept of an ‘Anomaly No Concern’ class, in addition to the traditional labels of ‘Anomaly’ and ‘Normal’. Introducing this new term helped address knowledge gaps between data scientists and domain experts, as well as providing new insights during model development and testing. This represents a major advancement in identifying anomalies in manual production processes that use handheld tools.

Modeling of Error Transfer in Multistage Rotors Assembly of Aero Engine Considering Rough Surface Contact

Modeling of Error Transfer in Multistage Rotors Assembly of Aero Engine Considering Rough Surface Contact

Analysis of daily work management charts at TVS motor company Ltd

This paper is all about a study that is mainly focused on daily work management (DWM) charts at TVS Motor Company, Mysuru. The objective is to study the process of managing DWM charts and simplification of the process and its impact on the team leader’s decision-making process. The essential information has been gathered from the team leaders of the engine and vehicle assembly through face-to-face interviews, observation, and a deep study of current DWM charts. Secondary information was gathered from books, journals, articles, and websites. Implementation of a dashboard has caused various effects on the DWM of team leaders in different ways one of the major impacts is the reduction (40%) in the time the team leader takes to store the data. It also resulted in a reduction in the shift handover time due to the availability of relevant data in the digitalized format. Not only this, the implementation of digitalized format has also reduced paper consumption in the organization to a greater extent. It has been noticed that the shift handing over time has been reduced to 20 min from 30 min due to a simpler and more precise representation of data from the previous shift through dashboards. Since it has been proved that the digitalization of DWM charts has reduced non-value activities of the team leaders, digitalization of DWM charts can be made in the other units as well

ANALYSIS OF GREASING AND WEAR PROCESSES ON THE SLIDING BEARINGS OF A NAVAL PROPULSION ENGINE

"In recent years maritime and inland waterway transport have developed unprecedentedly in close agreement with the rapid pace of industrialization and the increase in domestic and foreign freight traffic. This led to the development and upgrading of naval equipment. Thus, a series of programs have also been developed in the field of operation and maintenance of naval equipment. This also involved certain upgrades in the field of equipment maintenance and implicitly in terms of lubrication and increasing the service life to their nominal parameters. This development of shipping also included the development of engine oils. an important part of the safe operation of naval propulsion engines. Nothing is more important for the life of an internal combustion engine than proper lubrication and oil filtration for the engine and other moving parts. This paper aims to analyze the lubrication systems and the wear processes at the sliding bearings of the engine assembly for a marine propulsion engine. The last part of the paper presents the thermal calculation of the sliding bearings both due to the fluid friction and the heat release from the engine. The reference engine considered in the calculation of the lubrication system was a naval engine type ROLLS-ROYCE-B32: 40L8P with a rated power of 4000 kW. Starting from the oil flow required for lubrication, the oil flow required to dissipate the heat from the bed bearing was determined. "

The Flow of Lubricant as a Mist in the Piston Assembly and Crankcase of a Fired Gasoline Engine

The tribological performance of the piston assembly of an automotive engine is highly influenced by the complex flow mechanisms that supply lubricant to the upper piston rings. As well as affecting friction and wear, the oil consumption and emissions of the engine are strongly influenced by these mechanisms. There is a significant body of work that seeks to model these flows effectively. However, these models are not able to fully describe the flow of lubricant through the piston assembly. Some experimental studies indicate that droplets of lubricant carried in the gas flows through the piston assembly may account for some of this. This work describes an investigation into the nature of lubricant misting in a fired gasoline engine. Previous work in a laboratory simulator showed that the tendency of a lubricant to form mist is dependent on the viscosity of the lubricant and the type and concentration of viscosity modifier. The higher surface area-to-volume ratio of the lubricant if more droplets are formed or if the droplets are smaller is hypothesised to increase the degradation rate of the lubricant. The key work in the investigation was to measure the size distribution of the droplets in the crankcase of a fired gasoline engine. Droplets were extracted from the crankcase and passed through a laser diffraction particle sizer. Three characteristic droplet size ranges were observed: Spray sized (250–1000 μm); Major mist (30–250 μm); and Minor mist (0.1–30 μm). Higher base oil viscosity tended to reduce the proportion of mist-sized droplets. The viscoelasticity contributed by a polymeric viscosity modifier reduced the proportion of mist droplets, especially at high load.

The Effectiveness of a Vehicle Manufacturing Line Using Probabilistic Process Timing

Abstract: Automotive manufacturing involves several steps, starting with the casting of components and moving on to the machining and assembly processes. The assembly system, particularly for the Single Cylinder S.I. Engine, will be the only emphasis of this project. A considerable number of components must be integrated throughout the engine assembly process. The creation of a decision assistance system based on a discrete event simulation model is discussed in the work provided in this paper. The four closed-loop network arrangement of vehicle assembly and preassembly lines connected by conveyors is targeted at a particular type of manufacturing lines. The design and execution of such industrial processes frequently include simulation. This simulation research aims to select the process throughput for the Single Cylinder S.I. Engine Assembly line. Any possible machine bottlenecks will be identified by the simulation study to avoid blockages and starvation and increase process throughput. Machine cycle times for various processes should be included in the input data for the research. The Arena simulation program will be utilized in this investigation. The goal is to use existing equipment to boost output on the present Head Assembly Line and Sub-Assembly Lines to an anticipated capacity. The outcomes of the simulation will be used to pinpoint the assembly-line procedures that may have an impact on the S.I. Engine's manufacturing schedule. By contrast the study's findings with the actual process throughput, the findings will be illustrated. Additionally, statistical analysis will be done to boost performance.

EFFECTIVENESS ON TRAINING METHOD USING VIRTUAL REALITY AND AUGMENTED REALITY APPLICATIONS IN AUTOMOBILE ENGINE ASSEMBLY

Training and education have become increasingly crucial in obtaining new skills in a variety of fields, especially in assembly and disassembly operations. The main issue in mechanical engineering, particularly in the assembly department, was that automobile engine components assembly was found to be complicated and challenging to assemble using an existing method, where they only rely on a video-based method. The purpose of this paper is to create interactive Virtual Reality (VR) and Augmented Reality (AR) applications that allow users to efficiently assist and complete the assembly tasks. In this work, the authors designed and developed a fully immersive VR application using an HTC Vive headset and two AR applications (marker-less AR application and marker-based AR application) using EPSON MOVERIO BT-300 (AR Smart Glasses). Fourteen engineering students from Universiti Putra Malaysia were selected for the experiment. They were divided into four groups: video-based group, VR-based group, marker-less AR group, and marker-based AR group. They are required to complete all four experiments (video-based experiment, VR-based experiment, marker-less AR experiment, and marker-based AR experiment). The results showed that the marker-less AR application is the best impressive method (37% better), the VR application is the second impressive method (23% better) followed by the marker-based AR application is the third impressive method (3% better) compared to the existing video-based guideline. Therefore, the students favored AR and VR applications rather than the existing method to be used in automobile engine assembly tasks.

Multi-stage hybrid algorithm-enabled optimization of sequence-dependent assembly line configuration for automotive engine

Engines are the most expensive and technology-intensive components in automobiles, so an optimized configuration of the automotive engine assembly line (AEAL) is anticipated to improve efficiency and reduce cost. The traditional methods for assembly line configuration can mainly work out a proper machine number, but they generally ignore process sequences that could also influence the buffer cost derived from the assignment of divergence and confluence buffers. Simultaneously, how to reduce the number of variables in the algorithm iteration process to improve computational efficiency is rarely considered in the existing studies. To bridge the gaps, this study proposes a multi-stage hybrid algorithm based on a backtracking searching algorithm (BSA) to realize an effective configuration that can further improve production efficiency and reduce equipment cost for sequence-dependent AEALs. First, an AEAL configuration model is developed to involve machine number and process sequence as decision variables and aims to satisfy multiple objectives concerned with equipment cost and cycle time. Then, a multi-stage hybrid algorithm is proposed to efficiently acquire the optimal solutions to machine number and process sequence in multiple stages that can improve computational efficiency. Finally, the effectiveness and superiority of the proposed method are validated via a case study. The numerical results show that the proposed method can effectively improve production efficiency and reduce equipment cost for sequence-dependent AEALs with a better convergence and diversity performance.

Structural Optimization Design and Strength Test Research of Connecting Rod Assembly of High-Power Low-Speed Diesel Engine

The connecting rod assembly of a high-power low-speed diesel engine has high quality and high cost. If the connecting rod component is damaged, the whole machine may be paralyzed, resulting in serious economic losses and safety problems, so it is necessary to carry out strength analysis and structure optimization, reduce the failure rate, and increase its life. This paper takes the connecting rod of a low-speed diesel engine as the research object, builds the crank connecting rod mechanism model, and carries on the strength simulation analysis through professional simulation software. During this period, the accurate S-N curve of connecting rod material is obtained through a fatigue test, and the static strength test of the connecting rod assembly is carried out by an electro-hydraulic servo universal testing machine. The numerical modeling is validated based on the test results. Therefore, the influence of the structural parameters of the cross-section and the large end transition fillet on the stress of the connecting rod is analyzed. The results show that optimizing matching between the large end fillet of the connecting rod and the long diameter of the rod section not only reduces the mass but also improves the safety factor. After optimizing the structure of the connecting rod, the mass of the connecting rod is reduced by 5.85%, the maximum stress is reduced by 13.7%, and the safety factor is increased by 16.0%. In addition, due to the low-speed diesel engine connecting rod assembly weight is big, and the simulation computation efficiency is low, this paper by studying the influence of the cross-section parameters of the rod body and the large end transition fillet on the stress of the connecting rod, fitted the empirical formula calculating the maximum stress of connecting rod, for this model and similar type in the conceptual design, technology design provides a new analysis method, improved the efficiency of structural optimization and strength analysis of connecting rod assembly, filled the research gap of strength analysis and structural optimization of low-speed diesel engine connecting rod.

An integer programming mathematical model with line balancing and scheduling for standard work optimization: A realistic application to aircraft engines assembly lines

Aircraft Engine Maintenance Repair and Overhaul (MRO) companies face intense global competition that requires effective management of maintenance costs, TAT (turnaround time), and accurate job standards. These indicators can be improved through methodologies such as line balancing and scheduling of assembly tasks. The main objective of this article is to propose models for standard work definition that can optimize companies’ indicators – TAT, the number of operators, training costs, and load balancing – considering the specificities of the aircraft engine assembly lines. First, a literature review identified features of line balancing and scheduling integrated problems relevant to aircraft engine assembly and highlighted the integer programming mathematical models already proposed. Second, four new MILP models were developed in order to combine some of the features identified during the literature review and include new relevant ones: the multi-skilled operators can work in more than one engine per takt time, and each task may start in one takt time, and finish in the next. Lastly, the models were implemented in the AIMMS system and hierarchically solved by the CPLEX on data of two different assembly lines from a Brazilian MRO company. The results were considerably better than those obtained empirically by the firm. They include a 14.3% reduction in TAT for one assembly line and a 15.4% reduction in the number of operators for another, confirming a suitable decision support tool for the company, which can also help other firms.

Numerical and experimental investigation of heavy-duty EGR cooler thermal performance

Exhaust Gas Recirculation (EGR) cooler is a crucial automotive heat exchanger that decreases the temperature of the recirculated exhaust gas fed to engine cylinders to reduce the NOx emissions. The high temperature gradients in the heat exchanger and its varying hot and cold operation makes it necessary to accurately determine the temperature distribution of the EGR cooler to evaluate vulnerability to various thermal failures. This study demonstrates a thermal assessment of EGR cooler using detailed CFD simulation methods developed and validated with comprehensive experimental design and measurements. The experimental data including detailed boiling detection is collected on a gas burner test bench for eight different working conditions of the EGR cooler with conditioned cooling with an average of 3% repeatability error. The detailed and highly resolved CFD model which includes the heat transfer enhancing features of the heat exchanger is validated at these working conditions and resulted in an average of 1% difference in temperature and maximum 5% difference in pressure drop values. The developed detailed CFD methodology reduces the amount of EGR performance and boiling tests significantly and enables assessment of the EGR cooler at engine assembly conditions which affects the hot gas distribution and resulting temperature gradients. Furthermore, the CFD methodology and its correlation with the experiment proved that a coupled CFD methodology can be used instead of the development tests for analytical sign-off purposes as long as the detailed heat exchanger design is included in the CFD model. • A detailed CFD model with all geometrical features was built as essential alternative to EGR cooler tests. • The detailed CFD model does not require any additional numerical approach for pressure drop or heat transfer. • Acoustic Emission sensor was utilized for the more precise assessment of boiling level. • CFD predictions were validated with experimental data by using acoustic emission sensor measurements. • Predicted temperature and pressure change were validated by experimental results with high accuracy.

Washer Feeder for Engine Assembly Line

Using a feeder-retriever mechanism consisting of a recess, funnel and guiding channels the production line comprised of a series of workstations can be automated. The goal of fixing washers over the cylinder head of various automobile vehicles can be achieved in a cost effective way thereby saving time of production line and increasing rate of production

A study on vibration prediction of diesel engine based on virtual material modeling method of joint surfaces

The vibration prediction model of diesel engine is generally established by finite element method (FEM). In FEM, the components are firstly represented by mesh models, which will be connected to develop a combined model through joint surfaces. The processing method of joint surfaces is key to the accuracy of the combined model, for joint surfaces play an important role in transmitting force and vibration. For this purpose, an equivalent model of transversely isotropic virtual material is proposed to connect the mesh models of the components in this paper. In this model, the different connection characteristics of both normal and tangential are taken into consideration. In addition, the calculation models of the virtual material layer parameters, such as elastic modulus, shear modulus, Poisson’s ratio, thickness, density, and damping coefficient, are established in theory. At the same time, the modal test is introduced to acquire the natural frequency and damping ratio for identifying the unknown parameters of the virtual material layer, by using the BP neural network algorithm. After that, the complete finite element model of a diesel engine assembly can be established, and the vibration prediction is made in time domain, where cylinder gas pressures, piston slap forces, main bearing forces, and valve train forces are taken into consideration comprehensively. Furthermore, the experiment of the engine vibration response is carried out as well. The vibration acceleration level of engine feet and the vibration severity of engine block are adopted to evaluate the structure vibration response of the diesel engine. The results show that there is a good consistency between the prediction results and the experiment results in frequency domain. The consistency of the vibration acceleration level in 1/3 octave is up to 8 kHz, and that of the vibration severity is up to 1 kHz. And the results verify the accuracy of the vibration prediction model of the diesel engine, which is based on transversely isotropic virtual material modeling method of joint surfaces.

Azobenzene-bearing polymer engine powered organic nanomotors for light-driven cargo transport

The construction of artificial organic nanomotors powered by an energy-converting polymer engine for light-driven cargo transport is still a great challenge. Herein, we report on a one-pot preparation of photoactivated sub-200 nm-scaled polymeric nanomotors by a straightforward assembly of light-fueled azobenzene-bearing polymer engine and macromolecular payloads. The versatility of this process allows morphology adjustment and payload replacement in a convenient manner. Upon UV irradiation, the azobenzene-bearing polymer engine enables absorbing the light to trigger the photoisomerization and photothermal conversion, leading to mass migration and thermal generation within the nanomotors, that highly corresponds to light power, particle morphology, and payload rigidity. The photothermal converting polymer engine continuously converts light energy into sufficient kinetic energy for powering the nanomotors to overcome the Brownian motion, and the photoactivated deformation further promotes the self-propulsion. Such light-driven self-propulsion allows the nanomotors carrying bioactive cargoes to traverse various physiological barriers, showing great potential in antitumor therapy.

Simulating the Misting of Lubricant in the Piston Assembly of an Automotive Gasoline Engine: The Effect of Viscosity Modifiers and Other Key Lubricant Components

The presence of lubricant droplets in the gas that flows through the piston assembly and crankcase of an internal combustion engine (generically termed oil misting) has important implications for performance, particularly lubricant supply to the upper piston assembly, oil consumption and lubricant degradation. A significant source of these droplets is thought to be oil shearing and blow-through by blow-by gas flows in the piston assembly. An experimental rig was developed to simulate the high velocity gas and lubricant film interactions at a top piston ring gap where the flow conditions are most severe. Flows of lubricant droplets were produced and characterised in terms of the proportion of the oil flow that formed droplets in the gas flow and the size distribution of the droplets produced. Considering various aspects of a commercial automotive crankcase formulation, the effect of lubricant viscosity was found to be particularly important. Of the lubricant additives evaluated, viscosity modifiers were found to have the greatest effect on the tendency to form droplets: Detailed study on a range of viscosity modifiers identified that the influence of their molecular architectures on viscoelasticity was the key mechanism.

Multimodal Data-Driven Robot Control for Human–Robot Collaborative Assembly

Abstract In human–robot collaborative assembly, leveraging multimodal commands for intuitive robot control remains a challenge from command translation to efficient collaborative operations. This article investigates multimodal data-driven robot control for human–robot collaborative assembly. Leveraging function blocks, a programming-free human–robot interface is designed to fuse multimodal human commands that accurately trigger defined robot control modalities. Deep learning is explored to develop a command classification system for low-latency and high-accuracy robot control, in which a spatial-temporal graph convolutional network is developed for a reliable and accurate translation of brainwave command phrases into robot commands. Then, multimodal data-driven high-level robot control during assembly is facilitated by the use of event-driven function blocks. The high-level commands serve as triggering events to algorithms execution of fine robot manipulation and assembly feature-based collaborative assembly. Finally, a partial car engine assembly deployed to a robot team is chosen as a case study to demonstrate the effectiveness of the developed system.

Development of information technology for improving the production of parts and assembly of serial gas turbine engine within the framework of the "digital twin" concept

Within the framework of the concept of "digital twin" of production, an information technology has been proposed for systematizing data on the parameters of a gas turbine engine and their structural-parametric analysis, which makes it possible to assess the degree of perfection of a newly assembled engine and fi nd the most effective technical solutions in experimental engine refi ning and maintaining serial production.

The Problem of Choice Between Measurement Techniques

The assessment of the current conditions of any technical object is based on measurement. Thus, choosing the qualitative descriptor of the object that is to be assessed represents a relatively complex task. This is related both to the informative value of the qualitative descriptor and to the need for applying one or another measurement technique. There are three different ways to deal with the designated task. One possibility is to fix the required level of informative value and choose the measurement technique based on criteria such as the least money expenses for measuring, the shortest measurement duration and the specialization level of the measurement instruments. The second option is to choose specific measurement techniques and obtain the most complete information possible. The third possibility consists in a compromise between the information content of the descriptor and the overall expenses for measurement techniques. By convention, the first option is applied while facing this task, in which the information on the technical conditions of the object is obtained choosing adequate measurement techniques. Determining the value of the structural parameter of the technical conditions is not always possible. The diagnostic parameter, in its turn, is determined by the structural parameters only at a certain level of probability. The producers of machinery are constantly improving their products, upgrading the design of mating parts, changing the properties of wearing surfaces and introducing new materials. As a result, the aforementioned interrelations between the structural and diagnostic parameters are significantly redetermined, whereas the previously engineered diagnostic devices and the implemented methods lead to the ambiguity of the diagnostics. The areas of such ambiguity are here taken into account using a compression vacuum method in order to determine the technical conditions of the sleeve assembly of an internal combustion engine.

Numerical Analysis of Bird Impact Over the Aircraft Windshield

Bird impact on aircraft is one of the most important foreign object damages, which result in the reduction in airworthiness. Most bird impacts are not fatal but bird impact can be deadly when the impact is at engine assembly, leading-edge and Frontal area of aircraft. This study focuses on bird impact on windshield and its effects on stress concentration and energy absorption. The strength and stiffness of the windshield play a vital role during foreign object damage. Laminated glass is used as a windshield, the reason to use interlayer is to avoid separation of other layers after impact which ultimately reduces risk to pilot. Laminate configurations glass/PMMA/glass and PMMA/Polycarbonate/PMMA are used for the windshield. Impact analysis has been carried out at velocities of 50m/s, 100m/s and 150m/s. Modeling and solving are done in LS-Pre post and LS-Dyna using a FE-SPH approach. Simulations are carried out impact against bird, stress and energy absorption as the output. Based on results, PMMA/Polycarbonate/PMMA laminate is most likely to sustain the bird strike impact without failure.

Verifying Valve Lash in Engine Assembly Using Tolerance Interval Method for Monitoring Process Performance

The process capability refers to the ability of a process to produce parts or provide services that are able to meet the given specification requirement. The process capability is commonly measured by process capability indices (PCIs) such as Cp and Cpk to evaluate process yield, process consistency, and statistical variation compared to the specification. Most of the component or hardware manufacturing industries require exhibiting a process capability index (Cpk) of 1.33 or above. This paper presents an alternate approach for monitoring a process to verify valve lash in engine assembly. Valve lash is the gap between the rocker arm and the valve spring in an engine and this gap must be tightly controlled due to the critical role valves play in engine performance. Achieving and maintaining process capability of valve lash of 1.33 is difficult and unrealistic due to the nature of the assembly process and multiple factors being involved. Using historical data collected from 1200 valves in 100 engines assembly, this paper illustrates the tolerance interval method for monitoring the process performance of valve lash in engine assembly is more practical and economical as compared to the conventional process capability.