Search

Development of a model that allows performance and combustion characteristics for a supercharged diesel engine was the main objective sought by the present work. Thus, the developed model is used, to examine the impact of start combustion, combustion duration, compression ratio, and heat flux, as well as intake conditions such as pressure and temperature, on the combustion characteristics of the supercharged diesel. For this purpose, a one zone thermodynamic prediction model was adopted with Wiebe function for combustion sub-model. The heat transfer was correlated using Woschni correlation. A numerical simulation is developed considering the crankshaft angle as the independent variable. Validation of the computational code has been favorably evaluated using our experimental data. To give a more general aspect to the developed model, experimental data found in the literature, are also used for this purpose. The results show that the addition of a turbocharger increases low-speed airflow and hence fuel consumption. In addition, an increase in intake pressure contributes to the rise of the heat flux released during combustion, while an increase in intake temperature leads to a strong increase in combustion temperature. Moreover, an increase in the compression ratio leads in a remarkable increase in all parameters simultaneously. However, maximum combustion pressure limits must not be exceeded. This is because the pressure has an effect with the engine mechanical strength. [ABSTRACT FROM AUTHOR]

The Miller cycle is a program that effectively reduces NOx emissions from marine diesel engines by lowering the maximum combustion temperature in the cylinder, thereby reducing NOx emissions. To effectively investigate the impact of Miller cycle optimum combustion performance and emission capability under high load conditions, this study will perform a one-dimensional simulation of the performance of a marine diesel engine, as well as a three-dimensional simulation of the combustion in the cylinder. A 6-cylinder four-stroke single-stage supercharged diesel engine is taken as the research object. The chassis dynamometer and other related equipment are used to build the test system, carry out the diesel engine bench test, and collect experimental data. The simulation results are compared with the test results, and the error is less than 5%. In this study, the authors will use simulation software to simulate several Miller cycle scenarios designed for early inlet valve closure and analyze the impact of the Miller cycle on combustion and emissions at 100% load conditions. By comparing the flow field distribution of the engine at 1500 r/min condition, it was found that proper EIVC can prolong the ignition latency period and homogeneous fuel-air mixture combustion acceleration, but it can reduce pressure and temperature within the piston chamber and NOx emission. However, the Miller cycle reduces end-of-compression temperatures, which increases combustion duration and exhaust temperatures, making it difficult to improve fuel economy at the optimum fuel consumption point, and closing the intake valves prematurely leads to excessive fuel expenditure. Furthermore, temperature and heat release rate within the piston chamber, NOx, and SOOT generation were significantly enhanced. [ABSTRACT FROM AUTHOR]

Due to the cold water temperatures, the East China Sea (ECS) is usually unfavorable for typhoon development. Recently, in a rare event, Typhoon Bavi (2020) reached major typhoon status and became the strongest typhoon in the ECS in the past decade. Based on in situ observations and model simulations, we discover that this typhoon is fueled by a marine heatwave, which creates a very warm ocean condition with sea surface temperature (SST) exceeding 30 °C. Also, because of suppressed typhoon-induced SST cooling caused by the shallow water depth (41 m) and strong salinity stratification (river runoff) within the ECS, the SST beneath the typhoon remains relatively high and enhances the total heat flux for the typhoon. More interestingly, due to the fair weather ahead of the typhoon, we find that the rapid development of this marine heatwave is likely, in part, attributed to the typhoon itself. As the risks from typhoons and marine heatwaves are heightening under climate change, this study provides important insights into the interaction between typhoons and marine heatwaves. [ABSTRACT FROM AUTHOR]

The performance of the centrifugal compressor, which is the main component of the electric supercharger, significantly impacts the engine's dynamics, economy, emissions, and responsiveness. The purpose of this paper is to enhance the aerodynamic performance of the centrifugal compressor of the electric supercharger for the two-stroke engine by optimizing the design of its impeller and diffuser parameters. The paper employs the numerical simulation method and applies the Spalart–Allmaras turbulence model to solve the RANS equations to analyze the impact of impeller-related parameters on the centrifugal compressor's performance. Subsequently, the paper optimizes the initial model parameters based on the simulation results and confirms its performance through an experiment. The findings indicate that enhancing the isentropic efficiency and pressure ratio of the compressor can be achieved by increasing the number of blades on the impeller, selecting an appropriate blade backward angle, and increasing the relative outlet width. After optimization, the compressor's efficiency can achieve 0.842, the pressure ratio can reach 1.49 with a working margin of 22%, and the efficiency is enhanced by 1.4%, while the pressure ratio is increased by 1.8% compared to the pre-optimization state. Moreover, the optimized model is experimentally validated to meet the design requirements. [ABSTRACT FROM AUTHOR]

The electric superchargers driven by a high-speed motor instead of exhaust gas to operate the compressor have excellent transient characteristics and can effectively reduce the turbo lag of diesel engines. To develop an optimal control strategy for the electric superchargers, it is necessary to explore the combined effects of the electric supercharger and turbocharger under transient processes. Therefore, this study investigated the influence of different intervention speed and time of the electric supercharger on the transient performances of a turbocharged diesel engine. The combined effects of the electric supercharger and turbocharger were analyzed to optimize control strategy through simulations. Effects of the optimization in control strategies were tested through engine experiments. According to the results, the optimized control strategy (slope control strategy) was able to effectively balance transient responsiveness and stability since the rise time of intake pressure were reduced by 52.5 % compared to the base engine and the fluctuations in intake pressure and engine torque were significantly eliminated. Besides, the slope control strategy achieved the lowest PM and NOx emissions during the transient loading process. • The transient characteristics are greatly improved by the electric supercharger. • The combined effects of the electric supercharger and turbocharger are investigated. • An advanced control strategy of the electric supercharger is developed. • Emissions during the transient process are reduced by the electric supercharger. [ABSTRACT FROM AUTHOR]

Rapid widespread vehicle electrification has incentivized fast chargers to improve their performances. In this article, an integrated-magnetic-based differential-mode Ĉuk rectifier (IM-DMCR) as a universal battery supercharger is introduced. The design challenges associated with the high-power operation of IM-DMCR are outlined, and optimized solutions are presented. A SiC-based full-scale 60-kW experimental prototype for the IM-DMCR is built and tested to verify the design. [ABSTRACT FROM AUTHOR]

In this paper, an electric supercharger was installed on a GDI gasoline engine with LP EGR system. The engine performance and emission changes were experimentally investigated with electric supercharger and EGR. The experimental result shows that EGR has effects on energy saving and emission reduction. But it also decreases some power performance of engine, which electric supercharger could compensate. Electric supercharger even could enhance the engine dynamic property at low speed. Meanwhile, higher EGR rate could suppress the NOx emission to extremely low levels. But it is noticeable that high EGR rate will cause THC increase. [ABSTRACT FROM AUTHOR]

This paper reports the improved model of a tempering machine for heating the formulation mixture of marshmallow, characterized by heat supply to the working tank through the replacement of a steam jacket with heating by a film resistive electric heater of radiative type (FREhRT). The surface of the heat exchange of the device was increased by heating the stirrer with FREhRT; secondary energy (30....85 °C) was used by converting it by Peltier elements for the autonomous operation of superchargers for cooling the engine compartment. The proposed solution will lead to an increase in the efficiency of the device, which is explained by a decrease in its specific metal consumption through the use of FREhRT. A reduction in the duration of heating (75 °C) a marshmallow formulation mixture was experimentally established: in the examined model, 530 s, compared with the analog, 645 s. That confirmed the reduction in heating time to the set temperature by 21.7 % compared to the MT-250 basic design. The calculations have established a decrease, by 13 %, in the specific energy consumption for heating the volume of a unit of product when using the improved structure, 205.7 kJ/kg, when using the basic one – 232.1 kJ/kg. The increase in the efficiency of the proposed structure is explained by a decrease in the specific metal consumption of the device from 474 kg/m2 in the base apparatus to 273 kg/m² in the improved one. The study results confirm the increase in the resource efficiency of the improved tempering machine, which is achieved by eliminating the steam jacket; increasing the heat exchange surface by heating the stirrer. The heat transfer by FREhRT simplifies the operational performance of the temperature stabilization system in a working tank. The reported results could prove useful when designing thermal devices with electric heat supply under the conditions of using secondary energy, which is relevant for ensuring resource efficiency. [ABSTRACT FROM AUTHOR]

Improving the performance of internal combustion engines (ICE), together with lowering emissions, are the main targets for specialists in the automotive field. One option for increasing engine efficiency is creating a considerable amount of boost for the inlet combustion air by means of supercharging. In addition to common turbochargers, an alternative solution that has interested researchers for almost a century is the pressure wave supercharger (PWS). This paper is, at first, a complimentary tribute to most of the researchers that studied, experimented with and improved PW supercharging technology from the 50′s to the present. Second, this review emphasizes the performance achieved by ICEs when using PW supercharging, highlighting the limits of these main parameters in different operating conditions, based on the main reported results in the literature. It also provides an overview of PW supercharging technology, with its main advantages and disadvantages and suggests some technical solutions or geometric adjustments to improve its operation. Even though in recent years this technology has registered a decrease of interest, there are still preoccupations, especially in the aeronautical industry, justified by the profitability and simplicity of PW devices. The results of this theoretical work can be exploited practically in PWS design and applications. [ABSTRACT FROM AUTHOR]

The current study focuses on the influence of various boosting technologies as well as a comparative examination of singlecylinder four-stroke diesel engines. The experiment was conducted out on a single-cylinder 4-S VCR diesel engine with a crank-driven supercharger, turbocharger, and Tri-charged, which combines the turbocharger, crank-driven supercharger, and electric-driven supercharger system. Because the crank-driven supercharger uses engine power and the turbocharger has turbo-lag, the tri-charged system is used. The trials were carried out at a constant speed of 1500 rpm and a varied loading capacity of 0kg to 12kg at 2 kg intervals. The results increased the volumetric efficiency (VE) of the tri-charger from 81.17 to 122.35 percent. It is also raised in super and turbo running modes. Tri-charging lowered the BSFC from 0.36 Kg/Kwh to 0.31 Kg/Kwh, while thermal brake efficiency rose from 31.34 percent to 32.97 percent when compared to a traditional engine. The tri-charged method also helps to reduce pollution. The CO level dropped from 0.12 percent to 0.07 percent. NOX IS rises from 1015 ppm to 1210 ppm due to super, 1268 ppm due to turbocharger, and further lowered to 1128 ppm owing to super and turbocharger, although higher than conventional. This rise in NOx is caused by the increase in combustion temperature caused by the boost charger. Thus, the findings show that a tri-charged system is optimum for single-cylinder diesel engines in terms of performance enhancement and fulfilling rigorous emissions standards with emission reduction. [ABSTRACT FROM AUTHOR]

The degree of engine strengthening is growing as CO2 emission rules become more rigorous. The airway throat sections of the intake and exhaust systems have a significant impact on the flow loss of the diesel engine under high-pressure circumstances. The proper distribution of the throat area of the intake and exhaust ports in the limited cylinder headspace is critical for increasing supercharged engine performance. The research object in this project was a largebore, high-pressure ratio diesel engine. To begin, the three-dimensional (3D) flow simulation approach was used to disclose the effect law of different throat areas on engine intake and exhaust flow under steady-state circumstances, and a steady-flow test bench was developed to validate the simulation model and law. Second, using the 3D steady-state computation and test findings, a more accurate one-dimensional simulation model was built, and a joint optimization simulation platform based on the dynamic data link library was produced. Based on this, a mathematical expression of the multi-objective enhancement of airway throat size was formed using machine learning methods such as a genetic algorithm, the design domain and boundary conditions of variable parameters were clarified, and the collaborative optimization objective of integrated flow coefficient and flow loss is proposed to achieve fast and accurate optimization of intake and exhaust throat diameters. [ABSTRACT FROM AUTHOR]

The twin-spool turbofan engine is an important component of almost every modern aircraft. Fault detection at an early stage can improve engine performance and health. The current research is based on the construction of an inference system for fault diagnosis in a generalized fuzzy environment. For such an inference system, finite-state deterministic intuitionistic fuzzy automata (FDIFA) are established. A semigroup of FDIFA and its algebraic properties including substructures and structure-preserving maps are studied. The FDIFA semigroups are used as variables for the inference system, and FDIFA semigroup homomorphisms are used to indicate the relation between variables. The newly established model is then applied to diagnose the possible fault and their nature in aircraft twin-spool turbofan engines by modelling the performance of the supercharger and air cooler. [ABSTRACT FROM AUTHOR]

In the rapidly developing automotive technology, the efforts to achieve high performance with less fuel consumption is one of the most important issues today. The purpose of the supercharged systems developed for this reason is to send more air into the cylinder. For high engine performance and low exhaust emission values, the intake air temperature, which is heated in the turbo-compressor and has the oxygen concentration (the amount of oxygen in the unit air) decreased, must be kept at certain levels. Therefore, the heated air between the compressor outlet and the cylinder inlet must be cooled. In this study, different types of intercoolers were designed and analyzed with the help of ANSYS Fluent (CFD) program, and optimum conditions were tried to be obtained by comparing them with each other. [ABSTRACT FROM AUTHOR]

Energy management plays a decisive role in the design of efficient 48V mild hybrid drives owing to the limited amounts of energy and power. In particular, strong nonlinearities of an electrified engine air path and the high interaction between the 48V mild hybrid powertrain and the electrical system pose a major challenge. Current research results show the fundamental potential of optimization-based energy management strategies. However there is a lack of optimization-based solutions that allow online direct control of the electrified air path and the electric motor. In this context, this study presents a nonlinear model predictive control (NMPC) approach for a 48V mild hybrid powertrain with an electric supercharger, which is able to simultaneously improve the response behavior and energy consumption. The control concept is developed on the basis of a detailed system description. The special features of optimization-based control for the degrees of freedom of the powertrain, i.e., the belt starter generator (BSG) and the electrified air path through a throttle, waste gate, and electric supercharger (eC), are addressed. After an analysis and verification of the control properties, the NMPC is evaluated in dynamic driving cycle simulations through a comparison with a state-of-the-art rule-based control strategy. The investigations show that the NMPC is able to control the system well even under transient situations with a high influence of disturbance variables. In addition, the NMPC allows a specific and fuel saving use of the 48V system while improving the driving dynamics at the same time. [ABSTRACT FROM AUTHOR]