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Abstract Due to the increasing requirements for efficiency, the wide range of characteristics and the improved possibilities of modern development and production processes, compressors in turbochargers have become more individualized in order to adapt to the requirements of internal combustion engines. An understanding of the working mechanisms as well as an understanding of the way that losses occur in the flow allows a reduced development effort during the optimization process. This article presents three-dimensional (3D) Computational Fluid Dynamics (CFD) investigations of the loss mechanisms and quantitative calculations of individual losses. The 3D-CFD method used in this article will reduce the drawbacks of one-dimensional calculation as far as possible. For example, the twist of the blades is taken into account and the “discrete” method is used for loss calculation instead of the “average” method.

Abstract This article discusses a multi-item planning and scheduling problem in a job-shop system with consideration of energy consumption. Planning is considered by a set of periods, each one is characterized by a demand, energy, and length. Scheduling is determined by the sequences of jobs on available resources. A Mixed-Integer Linear Programming (MILP) problem is formulated to integrate planning and scheduling, it is considered as an NP-difficult problem. A Genetic Algorithm (GA) is then developed to solve the MILP, and then a hybridized approach of simulated annealing with genetic algorithm (HGASA) is presented to optimize the results. Finally, numerical results are presented and analyzed to evaluate the effectiveness of the proposed algorithms.

Abstract Turbocharging can provide a low cost means for increasing the power output and fuel economy of an internal combustion engine. Currently, turbocharging is common in multi-cylinder engines, but due to the inconsistent nature of intake air flow, it is not commonly used in single-cylinder engines. In this article, we propose a novel method for turbocharging single-cylinder, four-stroke engines. Our method adds an air capacitor-an additional volume in series with the intake manifold, between the turbocharger compressor and the engine intake-to buffer the output from the turbocharger compressor and deliver pressurized air during the intake stroke. We analyzed the theoretical feasibility of air capacitor-based turbocharging for a single-cylinder engine, focusing on fill time, optimal volume, density gain, and thermal effects due to adiabatic compression of the intake air.

Abstract Optimization is essential in real-life mechanical engineering problems that mostly are nonlinear, depend on mixed decision variables, and are usually subject to constraints. However, most of the studied problems are modelled assuming continuous variables. A limited number of studies have been devoted to cases with mixed variables. Moreover, there is a lack of algorithm treating mixed variable problems properly. This article introduces a hybrid algorithm that can handle constrained problems depending on continuous or mixed variables. The proposed algorithm combines two meta-heuristics, Jaya and particle swarm optimization (PSO). PSO is one of the most popular methods to solve nonlinear problems, and Jaya is a novel parameter-free optimization algorithm. This new hybrid optimization algorithm is proposed in order to improve the convergence speed and to investigate what improvements it will bring to optimization problem solutions.

Abstract Lightweight and high-strength high-pressure die casting (HPDC) aluminum has been widely used in automotive components such as the cylinder block, lower crankcase extension, transmission case, and drive unit. Die cast parts have good surface finishes with relatively higher material strength in the casting skin than the center core material, maintain consistent features and tolerance, and maximize metal yield, therefore making it the most cost-effective casting process for mass production of aluminum parts. However, due to the rapid filling rates, the HPDC process tends to form large porosity and oxides because of the entrapped gas and solidification shrinkage, thereby deteriorating the mechanical properties of the casting parts.

Abstract The Noise, Vibration, and Harshness (NVH) performance of automotive powertrain (PT) mounts involves the PT source vibration, PT mount stiffness, road input, and overall transfer path design. Like safety, performance, and durability driving dynamics, vehicle-level NVH also plays a major contributing factor for electric vehicle (EV) refinement. This article highlights the recent research on PT mounting-related NVH controls on electric cars. This work’s main contribution lies in the comparative study of the internal combustion engine (ICE)-based PT mounting and EV-based PT mounting system (PMS) with specific EV challenges. Various literature on PT mounts from the passive, semi-active, and active mounting systems are studied. The parameter optimization technique for mount stiffness and location by various research papers is summarized to understand the existing methodologies and research gap in EV application.

Abstract In view of the combustion efficiency and emission performance, various new clean combustion modes put forward higher requirements for the performance of the fuel injection system, and the cavitating two-phase flow characteristics in the injector nozzle have a significant impact on the spray atomization and combustion performance. This article comprehensively discusses and summarizes the factors that affect cavitation and the effectiveness of cavitation, and presents the research status and existent problems under each factor. Among them, viscosity factors are a hot research topic that researchers are passionate about, and physical properties factors still have the value of further in-depth research. However, the importance of material surface factors ranks last since the nozzle material was determined. Establishing a more comprehensive cavitation–atomization model considering various factors is the focus of research on cavitation phenomena.

Abstract Electromagnetic forming (EMF) is a high-speed impulse forming process developed during the 1950s and 1960s to acquire shapes from sheet metal that could not be obtained using conventional forming techniques. In order to attain required deformation, EMF process applies high Lorentz force for a very short duration of time. Due to the ability to form aluminum and other low-formability materials, the use of EMF of sheet metal for automobile parts has been rising in recent years. This review gives an inclusive survey of historical progress in EMF of continuum sheet metals. Also, the EMF is reviewed based on analytical approach, finite element method (FEM) simulation-based approach and experimental approach, on formability of the metals.

Abstract Active suspension was a topic of great research interest near the end of last century. Ultimately broad bandwidth active systems were found to be too expensive in terms of both energy and financial cost. This past work, developing the ultimate vehicle suspension, has relevance for today’s vehicle designers working on more efficient and effective suspension systems for practical vehicles. From a control theorist’s perspective, it provides an interesting case study in the use of “practical” knowledge to allow “better” performance than predicted by theoretically optimal linear controllers. A brief history of active suspension will be introduced. Peter Wright, David Williams, and others at Lotus developed their Lotus modal control concept. In a parallel effort, Dean Karnopp presented the notion of inertial (Skyhook) damping. These concepts will be compared, the combination of these two distinctly different efforts will be discussed, and eventual vehicle results presented.

Abstract The fuel injection pressures used in gasoline direct injection (GDI) engines have increased in recent years to improve fuel efficiency and reduce emissions. Current GDI engines use injection pressures of up to 350 bar, and there is evidence that even higher fuel injection pressures could yield further improvements in atomization. Higher injection pressures could also improve mixture formation by increasing the spray velocity; however, the research with higher injection pressures over 1000 bar is limited due to a limit of mechanical components. This manuscript summarizes experimental investigations into the effect of injection pressure, injection mass, and nozzle shape on spray-induced air motion with ultrahigh injection pressure over 1000 bar.

Abstract The inspection process of non-rigid parts during manufacturing and assembly is inherently challenging. This is exacerbated by the need for accurate real-time part data in the digital age. Although many ad hoc techniques exist, there are no rigorous methods to evaluate the quality of a fixture layout before final parts and gauges are available. This typically happens so late in the manufacturing process that errors found can scarcely be remedied. Additionally, the modifications to the gauge are usually costly and can result in significant delays, when performed this late in the process. This article proposes an optimization-driven mathematical approach tailored toward non-rigid parts to identify the best locator layout, early in the part design phase. A metric is proposed using robotic grasping theory to quantify the quality of the locating scheme and serves as the objective of optimization.

Abstract To improve the lubrication and friction of the crankpin bearing (CB) in the engine, the design of surface textures on the bearing surface is proposed and researched based on the CB hydrodynamic dynamic model. To enhance the reliability of the research results and its closeness to reality, the optimal CB parameters, the experimental data of the external dynamic load W0 acting on the crankpin, and the CB surface roughness in the well-known existing researches are referred to as input data for the simulation process. The effect of the distribution density {n, m}, diameter D, and depth of the microcircular textures hd on improving the lubrication and friction are then analyzed based on the indexes of the increase in the oil film pressure, decrease in the solid asperity contacts in the mixed lubrication region (MLR), friction force, and coefficient of friction (COF) between the crankpin and bearing surfaces, respectively.

Abstract Jet engine hot parts (e.g., jet nozzle) are a crucial source of aircraft’s infrared (IR) signature from the rearview, in 1.9-2.9 μm and 3-5 μm bands. The exhaust nozzle design used in a jet aircraft affects its performance and IR signature (which is also affected just by performance) from the engine layout. For supersonic aircraft (typically for M ∞ > 1.5), a converging-diverging (C-D) nozzle is preferred over a convergent nozzle for optimum performance. The diverging section of the C-D nozzle has a full range of visibility from the rearview; hence, it was not considered a prudent choice for low IR observability. This theoretical study compares the IR signature of the C-D nozzle with that of the convergent nozzle from the rearview in 1.9-2.9 μm and 3-5 μm bands for the same thrust.

Abstract New analytical structural stress solutions for a rigid inclusion in a finite square thin plate with clamping edges under opening loading conditions are developed. The new solutions are used to derive new analytical structural stress and stress intensity factor solutions for similar and dissimilar spot welds in cross-tension specimens. Three-dimensional finite element analyses are conducted to obtain the stress intensity factor solutions for similar spot welds and dissimilar magnesium/steel spot welds in cross-tension specimens of equal thickness with different ratios of half-specimen width-to-weld radius. A comparison of the analytical and computational solutions indicates that the analytical stress intensity factor solutions for similar spot welds in cross-tension specimens of equal thickness are accurate for large ratios of half-specimen width-to-weld radius.

Abstract The article contains the results of operational investigations of deposit formation on external and internal surfaces of injector nozzles of the marine self-ignition engines during their operational use. The aim of this article is to introduce an image analysis method for global assessment of the quantity and quality of injector nozzle deposits in piston internal combustion engines. The components of medium-speed marine engines fueled with distillation and residual fuels were investigated. Digital images of new and used injector nozzles without deposits and with random deposits formed after natural operation on marine ships, respectively, were taken. Macro and microscopy images of external surfaces were taken in a shadowless tent and were illuminated with low-temperature lamps. The characteristic surfaces of the injector nozzles were virtually separated from the white background.

Abstract In this article, we propose a method of combining neural networks (NN) with nonlinear state-space models (SSM). Such model parts that are well understood can be integrated into the state space, while the NN can estimate such parts that are uncertain or hard to model. We apply the method to vehicle state estimation on a race track. Therefore, we derive a nonlinear two-track model with a scaled magic formula and adaptively estimate the tire parameters—stiffnesses and maximum friction potential—with the NN. The results show that the NN is able to reach an excellent estimation performance and generalizes over different model parameters, such as tire type, tread depth, surfaces conditions, and maneuvers. The trained model is furthermore integrated into an Extended Kalman Filter (EKF) to estimate the longitudinal speed, lateral speed, and yaw rate of the vehicle.

Abstract The objective of this work is to analyze the signal of a piezoelectric washer installed under the spark plug and to compare the combustion metrics evaluated with such signal to the indexes from a standard piezoelectric sensor for the in-cylinder pressure measurement, considered as the reference. In the first part of the article, the spectrum analysis of the piezoelectric washer pressure trace is proposed. It is demonstrated how such a signal can be used to measure the main combustion and knock indexes. Nevertheless, due to the intrinsic characteristics of the system, the knock index evaluated from the raw pressure trace cannot be directly used to estimate the instantaneous knock intensity. For this reason, a model-based algorithm for Real-Time (RT) application is developed to calculate a corrective factor of the high-frequency content of the signal.

Abstract The manufacturing of diesel injector nozzles requires precision processing to produce multiple micro-holes. An abrasive fluid containing a mixture of mineral oil and hard particles is used for rounding them, ensuring the hydrodynamics of the injection. As verified in a previous investigation, the viscosity of the fluid undergoes uncontrolled changes during hydro-erosive (HE) grinding. Such undesired viscosity changes are detrimental to the process and difficult to assess. The current investigation aims to study the possibility of using the refractive index of the oils used in the HE grinding for assessing their viscosities. A calibration curve correlating the refractive index and viscosity was obtained from the analysis of samples produced by mixing two distinct mineral oils in different proportions. The determined calibration curve was tested with 45 samples of filtered oil, collected directly from the tanks during the HE grinding.

Abstract Accelerated durability testing of automotive components has become a major interest for the ground vehicle Industries. This approach can predict the life characteristics of the vehicle by testing fatigue failure at higher stress level within a shorter period of time. Current tradition of laboratory testing includes a rigid fixture to mount the component with the shaker table. This approach is not accurate for the durability testing of most vehicle components especially for those parts connected directly with the tire and suspension system. In this work, the effects of the elastic support on modal parameters of the tested structure, such as natural frequencies, damping ratios and mode shapes, as well as the estimated structural fatigue life in the durability testing were studied through experimental testing and numerical simulations.

Abstract The paper presents a complete description of the design and manufacturing of a Carbon Fiber/epoxy mold with an embedded Carbon Fiber resistor heater, and the mold performances in terms of its surface temperature distribution and thermal deformations resulting from the heating. The mold was designed for manufacturing aileron skins from Vacuum Bag Only prepreg cured at 135°C. The glass transition temperature of the used resin-hardener system was about 175°C. To ensure homogenous temperature of the mold working surface in the course of curing, the Carbon Fiber heater was embedded in a layer of a highly heat-conductive cristobalite/epoxy composite, forming the core of the mold shell. Because the cristobalite/epoxy composite displayed much higher thermal expansion than CF/epoxy did, thermal stresses could arise due to this discrepancy in the course of heating.