Optimal design of an engine mount using an enhanced genetic algorithm with simplex method

This study provides an analysis of the applications of optimization routines for designing fluid mounts. After summarizing the concept of fluid mounts and their dynamic characteristics, we review the importance of the notch and resonance peak that occur in dynamic stiffness of fluid mounts. Fluid mounts are tuned for specific application so that their notch frequency coincides with the disturbance frequency, by selecting the proper parameters for the mount. Additionally, the mount parameters are selected such that the notch remains as deep (close to zero) as possible and the resonance peak is kept as short as possible. The notch depth and resonance peak present opposing requirements for the selection of mount parameters in the sense that lowering one will result in increasing the other. Using a bond graph model, this study will evaluate the effect of various parameters on the mount notch depth and resonance peak height characteristics. The results show that different parameters can have a varying effect on the notch frequency and depth, as well as the resonance frequency and peak height. The results of the study are extended by examining the effectiveness of two different optimization methods—namely, the Enhanced Genetic Algorithm (EGA) and Sequential Quadratic Programming (SQP)—for selecting the combination of parameters that can yield the deepest notch and shortest resonance peak. Using two different design cases, the study shows that SQP exhibits much more sensitivity to the initial conditions that are selected for the mount parameters than EGA. Both methods, however, are able to converge to an optimal solution within the constraints that are selected for the parameters. For both cases, EGA is able to converge to the set of parameters that provide a deep notch and a short resonance peak.     

CANDY statement of methods

This paper presents a detailed overview of CANDY, a catenary–pantograph dynamic interaction software. Authors describe the main key points of the formulation, focusing on its time-integration scheme, the pantograph and contact models as well as the solution of the initial equilibrium problem. Nonetheless one of the most important features of CANDY is its moving finite element mesh, which enables accurate results without excessive computational cost. The validation of the model against the European Standard EN 50318 and some conclusions and comments about the results of the benchmark are also included.     

Simulation of a powertrain system for the diesel hybrid electric bus

The plug-in hybrid electric bus (HEB) is designed to overcome the vulnerable driving range and performance limitations of a purely electric vehicle (EV) and have an improved fuel economy and lower exhaust emissions than those of a conventional bus and convention HEBs. The control strategy of the plug-in parallel HEB??s complicated connected propulsion system is one of the most significant factors for achieving a higher fuel economy and lower exhaust emissions than those of the HEV. The proposed powertrain control strategy has flexibility in adapting to the battery??s state of charge (SOC), exhaust emissions, classified driving patterns, driving conditions, and engine temperature. Simulation is required to model hybrid powertrain systems and test and develop powertrain control strategies for the plug-in parallel HEB. This paper describes the simulation analysis tools, powertrain components?? models and modifications, simulation procedure, and simulation results.     

Relationship between lean six sigma, environmental management systems, and organizational performance in the Malaysian automotive industry

In the globalization era, lean initiatives and environmental management systems are increasingly implemented in the automotive industry. The aim of this report is to investigate and perform structural analysis of Lean Six Sigma (LSS) and Organizational Performance (OP). Data were obtained from 252 top management leaders in the Malaysian automotive industry. This report presents the results of the Exploratory Factor Analyses (EFA), Confirmatory Factor Analysis (CFA), and reliability analysis, which are empirically verified and validated. A set of assessment measurements of LSS and OP is expected to be suitable for their characteristics and improve their competitiveness. Thus, the main objective of the analysis was to provide additional insight into the relationship between LSS and OP by examining the effects of ISO 14001 certification as a moderator. The results indicate that ISO 14001 certification does not significantly moderate the relationship between LSS and OP in the Malaysian automotive industry. However, the OP values for ISO 14001 certified companies are higher than those without ISO 14001 certification.     

Technology analysis and low-cost design of automotive radar for adaptive cruise control system

Recently, the advanced driver assistance system (ADAS), which helps mitigate car accidents, has been developed using environmental detection sensors, such as long and short range radar, lidar, wide dynamic range cameras, ultrasonic sensors and laser scanners. Among these detection sensors, radars can quickly provide drivers with reliable information about the velocity, distance and direction of a target obstacle, as well as information about the vehicle in changing weather conditions. In the adaptive cruise control system (ACCS), three radar sensors are usually needed because two short range radars are used to detect objects in the adjacent lane and one long range radar is used to detect objects in-path. In this paper, low-cost radar based on a single sensor, which can detect objects in both the adjacent lane and in-path, is proposed for use in the ACCS. Before designing the proposed radar, we analyzed the world-wide radar technology and market trends for ACCS. Based on this analysis, we designed a novel radar sensor for the ACCS using radar components, such as an antenna, transceiver module, transceiver control module and signal processing algorithm. Finally, target detection experiments were conducted. In the experimental results, the proposed single radar can successfully complete the detection required for the ACCS. In the conclusion, the perspective and issues in the future development of the ACCS radar are described.     

Development of control logic for hydraulic active roll control system

Developed in this research is a control logic for the ARC (Active Roll Control) system that uses rotary-type hydraulic stabilizer actuators at the front and rear axles. The hydraulic components of the system were modeled in detail using AMESim, and a driving logic for the hydraulic circuit was constructed based upon the model. The performance of the driving logic was evaluated on a test bench, and it demonstrated good pressure tracking capability. The control logic was then designed with the target of reducing the roll motion of the vehicle during cornering. The control logic consists of two parts: a feedforward controller that generates anti-roll moments in response to the centrifugal force, and a feedback controller that generates anti-roll moments in order to make the roll angle to follow its target value. The developed ARC logic was evaluated on a test vehicle under various driving conditions including a slowly accelerated circular motion and a sinusoidal steering. Through the test, the ARC system demonstrated successful reduction of the roll motion under all conditions, and any discomfort due to the control delay was not observed even at a fast steering maneuver.     

Numerical modeling of journal bearing considering both elastohydrodynamic lubrication and multi-flexible-body dynamics

This study uses an elastohydrodynamic lubrication model coupled with multi-flexible-body dynamics (MFBD) to analyze dynamic bearing lubrication characteristics, such as pressure distribution and oil film thickness. To solve the coupled fluid-structure interaction system, this study uses an MFBD solver and an elastohydrodynamics module. The elastohydrodynamics module passes its force and torque data to the MFBD solver, which can solve general dynamic systems that include rigid and flexible bodies, joints, forces, and contact elements. The MFBD solver analyzes the positions, velocities, and accelerations of the multi-flexible-body system while incorporating the pressure distribution results of the elastohydrodynamics module. The MFBD solver then passes the position and velocity information back to the elastohydrodynamics solver, which reanalyzes the force, torque, and pressure distribution. This iteration is continued throughout the analysis time period. Other functions, such as mesh grid control and oil hole and groove effects, are also implemented. Numerical examples for bearing lubrication systems are demonstrated.     

Experimental study on the characteristics of nano-particle emissions from a heavy-duty diesel engine using a urea-SCR system

Particulate matter in diesel engine exhaust, particularly nano-particles, can cause serious human health problems including diseases such as lung cancer. Because diesel nano-particle issues are of global concern, regulations on particulate matter emissions specify that not only the weight of particulate matter emitted but also the concentration of nanoparticles must be controlled. This study aimed to determine the effects on nano-particle and PM emissions from a diesel engine when applying a urea-SCR system for NO_x reduction. We found that PM weight increases by approximately 90% when urea is injected in ND-13 mode over the emission without urea injection. Additionally, PM weight increases as the NH₃/NO_x mole ratio is increased at 250 °C. In SEM scans of the collected PM, spherical particles were observed during urea injection, with sizes of approximately 200 nm to 1 μm. This study was designed to determine the conditions under which nano-particles and PM are formed in a urea-SCR system and to relate these conditions to particle size and shape via a quantitative analysis in ND-13 mode.     

Application of a thermodynamic model with a complex chemistry to a cycle resolved knock prediction on a spark ignition optical engine

A combination of experimental and numerical methodologies is proposed for the investigation of knocking in spark ignition engines to aid in better understanding the physical and chemical processes that occur and to exploit the capabilities of a developed computational tool. The latter consists of a thermo-fluid dynamics model, which is part of an advanced 1-D fluid dynamics code for the simulation of the entire engine, and a complex chemistry model, which can be embedded into the thermo-fluid dynamics model using the same integration algorithm for the conservation equations and the reacting species. Their mutual interaction in the energy balance will be considered. The experimental activity was carried out in the combustion chamber of an optically accessible, single-cylinder P.F.I. engine equipped with a commercial head. The experimental data consisted of optical measurements correlated to the combustion and auto-ignition processes within the cylinder. The optical measurements were based on 2-D digital imaging, UV visible natural emission spectroscopy and the chemiluminescence of radical species (OH and HCO). The engine parameters, the pressure signals of the related data and optical acquisition are compared on an individual cycle basis in the simulation by running the engine at a constant speed and varying the spark advance from normal combustion to heavy knock conditions.     

Effect of residual stress on impact damage in a dissimilar laminated plate at a biaxial bending mode

Systematic investigations have been performed on the mechanisms that lead to impact damage in a dissimilar laminated plate with a thermal residual stress at a biaxial bending mode. Glass/polymer laminated plates are often used as blast-proof safety screens, and bullet-proof windows, and in windshields in the automotive and the aerospace and aeronautical fields. Their many advantages, the development of new materials, and the need for high-performance, low-weight structures ensure that laminated plate construction will continue to be in demand. In this work, the impact damage in glass/Al alloy laminated circular plates cured at RT and 80°C was investigated using an instrumented long bar impact tester at a biaxial bending mode. A circular plate was cured at different curing temperatures to form a thermally induced residual stress at the bonding interface. To improve the damage tolerance of laminated circular plates, various geometric (thickness ratio of the inner to outer layer) and material parameters are considered by determining their effects of maximizing impact absorbed energy. The measured impact force profiles and the impulse of the force explained the impact damage behaviors induced in the laminated circular plates. We show that a compressive residual stress could reduce the initiation of radial cracks and the impact damaged area of the laminated plate in the outer layer. Greater an inner layer thickness results in smaller a damaged area. A design guideline for effective dissimilar laminated plate construction is proposed.