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As modern engine technology has evolved, optimizing engine performance has become a key research focus for the industry in the face of increasingly stringent environmental regulations and growing demand for energy efficiency. The diameter of the exhaust manifold plays a key role in determining engine performance. This study utilized GT-POWER software to develop an engine simulation model aimed at investigating the effects of different exhaust manifold diameters on engine power, torque, and fuel consumption. The results demonstrated that increasing the exhaust manifold diameter within a specified range significantly reduced fuel consumption at lower speeds, with minimal impact on power and torque. However, at moderate to high speeds, enlarging the exhaust manifold diameter led to a significant increase in power output, an increase in peak torque, and a decrease in fuel consumption, resulting in the shift of peak torque and minimum fuel consumption to higher speeds. These findings provide valuable insights for optimizing engine exhaust manifold design.

In the present study, we contrast the change of mechanical and physical properties between VaRTM (Vacuum Assisted Resin Transfer Molding) and hand lay-up process. In the results of mechanical tests, VaRTM specimen is stronger than hand lay-up specimen and hand lay-up specimen became delamination. In the results of physical tests, the resin content of VaRTM specimen is lower than hand lay-up specimen. On micrograph, the strength of specimen by VaRTM between fiber and resin is stronger than that of one by hand lay-up. And the specimen by hand lay-up contains more defects than one by VaRTM. So, VaRTM process can practically apply for automobile engine hood. This paper shows that VaRTM process is one of the most suitable processes for composite parts of automobile.

A number of measurements have been provided to detect formaldehyde in the atmosphere, but there are no clear unified standards in engine exhaust. Nowadays, formaldehyde, an unregulated emission from methanol engine, has been attracting increasing attention by researchers. This paper presents the detection techniques for formaldehyde emitted from the engines applied in recent market, introducing the approaches in terms of unregulated emission tests of formaldehyde, which involved gas chromatography, liquid chromatography, chromatography-mass spectrometry, chromatography-spectrum, Fourier infrared spectroscopy and spectrophotometry. The author also introduces the comparison regarding to the advantages of the existing detection techniques based on the principle, to compare with engine exhaust sampling method, the treatment in advance of detection, obtaining approaches accessing to the qualitative and quantitative analysis of chromatograms or spectra. The accuratest result obtained was chromatography though it cannot be used continuously. It also can be utilized to develop high requirements of emissions and other regulations. Fourier infrared spectroscopy has the advantage of continuous detection for a variety of unregulated emissions and can be applied to the bench in variable condition. However, its accuracy is not as good as chromatography. As the conclusion, a detection technique is chosen based on different requirements.

Even though AI technology is a relatively new discipline, many of its concepts have already found practical applications. Expert systems, in particular, have made significant contributions to technologies in such fields as business, medicine, engineering design, chemistry, and particle physics.

This paper describes an expert system developed to aid mechanical engineering designers in the preliminary design of variable-stroke internal-combustion engines. Variable-stroke engines are more economical in fuel consumption but their design is particularly difficult to accomplish. With the traditional design approach, synthesizing the mechanisms for the design is rather difficult and evaluating the mechanisms is an even more cumbersome and time-consuming effort. Our expert system assists the designer by generating and evaluating a large number of design alternatives represented in the form of graphs. Through the application of structural and design rules obtained from design experts to the graphs, good quality preliminary design configurations of the engines are promptly deduced. This approach can also be used in designing other types of mechanisms.

In this paper, both experimental and analytical flutter analyses are conducted for a typical 5-degree of freedon (5DOF) wing section carrying a flexibly mounted unbalanced engine. The wing flexibility is simulated by two torsional and longitudinal springs at the wing elastic axis. One flap is attached to the wing section by a torsion spring. Also, the engine is connected to the wing by two elastic joints. Each joint is simulated by a spring and damper unit to bring the model close to reality. Both the torsional and longitudinal motions of the engine are considered in the aeroelastic governing equations derived from the Lagrange equations. Also, Peter’s finite state model is used to simulate the aerodynamic loads on the wing. Effects of various engine parameters such as position, connection stiffness, mass, thrust and unbalanced force on the flutter of the wing are investigated. The results show that the aeroelastic stability region is limited by increasing the engine mass, pylon length, engine thrust and unbalanced force. Furthermore, increasing the damping and stiffness coefficients of the engine connection enlarges the stability domain.

Although thermoacoustic devices comprise simple components, the design of these machines is very challenging. In order to predict the behavior and optimize the performance of a thermoacoustic refrigerator driven by a standing-wave thermoacoustic engine, considering the changes in geometrical parameters, two analogies have been presented in this paper. The first analogy is based on CFD analysis where a 2D model is implemented to investigate the influence of stack parameters on the refrigerator performance, to analyze the time variation of the temperature gradient across the stack, and to examine the refrigerator performance in terms of refrigeration temperature. The second analogy is based on the use of an optimization algorithm based on the simplified linear thermoacoustic theory applied for designing thermoacoustic refrigerators with different stack parameters and operating conditions. Simulation results show that the engine produced a high-powered acoustic wave with a pressure amplitude of 23kPa and a frequency of 584Hz and this wave applies a temperature difference across the refrigeration stack with a cooling temperature of 292.8K when the stacks are positioned next to the pressure antinode. The results from the algorithm give the ability to design any thermoacoustic refrigerator with high performance by picking the appropriate parameters.

Computer-aided engineering (CAE) simulation and calculation is a new and effective way to do research on engine performance. A 1D simulation model of an engine fueled by biodiesel was established, and its economic performance was simulated. Then, an engine bench test was carried out to review the simulation results. The simulation and test results showed that the model established by the AVL BOOST software can calculate the biodiesel engine's performance accurately, thereby making it an effective way to study engine performance conveniently.

To explore the maximum of energy saving potential of hybrid loader and analyze the energy-saving ways of hybrid loader, the researcher took use of AMEsim software to build hybrid loader model. The author simulated on the energy saving ways and made the prototype test at the same time. In the end, with the quantitative approaches, the energy saving potential of energy saving ways were shown in the end.

In order to have a depth research for the combustion process and the status of the engine emissions, it is necessary to develop a excellent combustion analysis system. The data collection, data processing, data computing and other display functions were realized by the self-developed combustion analysis system software, and some relative analyses of cylinder dynamic combustion were done. At the same time, it is so important for designers have an optimization of engine if they use the P-Φ indicator diagrams. Pmax indicator diagrams, air-fuel ratio(ξ)and fuel consumption variation data and so on. The test system for an internal engine combustion analysis through continuous testing and use, is feasible. No doubt, Better user interface and lower costs of this combustion system is pretty good for tester analysis the related data. Designers could facilitate the continuous development and utilization, so it has a certain value in engineering.

Even though AI technology is a relatively new discipline, many of its concepts have already found practical applications. Expert systems, in particular, have made significant contributions to technologies in such fields as business, medicine, engineering design, chemistry, and particle physics.

This paper describes an expert system developed to aid mechanical engineering designers in the preliminary design of variable-stroke internal-combustion engines. Variable-stroke engines are more economical in fuel consumption but their design is particularly difficult to accomplish. With the traditional design approach, synthesizing the mechanisms for the design is rather difficult and evaluating the mechanisms is an even more cumbersome and time-consuming effort. Our expert system assists the designer by generating and evaluating a large number of design alternatives represented in the form of graphs. Through the application of structural and design rules obtained from design experts to the graphs, good quality preliminary design configurations of the engines are promptly deduced. This approach can also be used in designing other types of mechanisms.