Advanced Materials Research Vols. 860-863

Abstract: Crankshaft is one of the most important parts in diesel engine. The fatigue failure and fracture of crankshaft may lead to damage to the other parts, even some accidents. Recently with the increasing requirement of engine power and engine reliability, the investigation of the crankshaft strength becomes more important. Since during the engine work process, the extremely complicated force are loaded on the crankshaft and different vibration caused by torque, bending, etc., the crankshaft may create the resonance and appended dynamic stress in the working frequency range, which will be easy to bring about the bending and torsion damage after short work period. In this paper, the traditional algorithm on the basis of MATLAB/SIMULINK software is used to carry out the dynamic calculation and analysis for a certain type of diesel engine crankshaft. The crankshaft stress state and its variation are analyzed, and the results of the bending moment, torsion versus crank angle are obtained. Finally, the fatigue strength of crankshaft is checked and the safety factor is calculated to verify the crankshaft reliability.

Abstract: A calculation model of turbocharged diesel engine was developed based on one-dimension simulation software GT-power,which can provide a steady boundary condition for the flow field analysis of EGR system.The three-dimension simulation software Fluent was applied in establishing the flow field model of the air-intake system under different air inlet position to analize the distribution of the exhaust gas,and then obtained the impact of the EGRs air-inlet position to uniformity of EGR system, thereby we could acquire the parameters which achieves the best maching between the EGR system and the diesel engine, it also provided a reference for engine performance optimization.

Abstract: According to performance characteristics and functional requirements of EGR system, a set of EGR system was designed for supercharged diesel engine on light duty. This system employed continuous current dynamo EGR valve, and hardware circuit of control unit was designed and control software was authored implementing on Freescale MC9S12XS128. The universal characteristics of EGR ratio was tested after this system calibration and matching. Compared to traditional system, new EGR system has better actual control accuracy, improves the motorcycle economical efficiency under common duty and decreases NOx emission simultaneously.

Abstract: In order to assess the rationality of the combustion chamber structure of 2.0L diesel engine equipped with high pressure common rail system, evaluation methods of the interior flow dynamic characteristics was put forward .And numerical simulation was carried out on the effect of different combustion chamber structure matching different fuel injection system parameters on the transient distribution of velocity field, concentration field, temperature field. The results show that: the suggested evaluation method in the combustion chamber structure design is reasonable; and for certain injection system, reasonable design and optimized combustion chamber structure parameters are used to organize air flow characteristic effectively. These are important measures to realize energy conservation and emission reduction on diesel engines.

Abstract: The nonlinear Hammerstein model was designed. The model was used to compensate the dynamic behavior of an electronic throttle body at different operating conditions. It consisted of a static nonlinear function and a dynamic linear function. The static nonlinear function was used to representing the coulomb friction and limp-home return springs and the dynamic linear function was used to representing dynamic piecewise-linear characteristic. An observer model, known as kalman was used for the on-line throttle position and angular velocity estimation. The control strategy was designed which combined the feed-forward control based on Hammerstein model and feedback control based on proportional-integral-derivative (PID) controller. The control structure has the quick response characteristic of the feed-forward control and disturb compensation characteristic of the feedback control. The experimental results revealed that the dynamic position control delay less than 100ms, the static position error less than 0.5o and the controller satisfied requirement of GDI for precise in-charge control.

Abstract: This document focus on the car's dynamic performance characteristics.Because MATLAB has many advantages such as intuitive, clear physical meaning, a small amount of programming, data visualization and high degree of merit. This paper Computes and analysis with the introduction of an instance practice vehicle models.In light of the specific model parameters, this paper has analyzed car driver and driving resistance balance, power balance and power factor based on the application of Mat Lab's data analysis and graphics, and drawn the relevant graph, according to the mapping feature maps.The paper analysis of the car comprehensive power the car's dynamic graphing features calculation and research method are provided. The paper has provided new ideas of vehicle parameter selection and design.It has some practical value.

Abstract: Based on the entity model of the type 4B26 diesel engine, calculated by CFD FIRE and combined with the software BOOST for the initial boundary conditions, the influence of combustion chamber structural parameters, such as boss height, surface-volume ratio and diameter-depth ratio of combustion chamber, on in-cylinder flow field of diesel engine was investigated. The results show that the influence of the boss height on flow field in the cylinder and the transient swirl ratio is obvious, and increasing the boss height is beneficial to urge the formation of mixture rapidly. Reducing the surface-volume ratio is beneficial for improving the maximum transient swirl ratio, and the air strength maintains well also, but has little influence to the retentivity of the swirl intensity. Meanwhile, reducing the diameter-depth ratio does not only improves the air flow movement strengthen in the combustion chamber, but also enhances the maximum transient swirl ratio, and the retentivity of swirl flow movement is satisfying.

Abstract: To solve the problem about prototype development of electrical-excited power conversion system of large-scale direct-driven wind turbine and the test challenges during mass-production, advance technology solutions by full power back-to-back testing, focusing on the electrical topology including the key technologies and the working modes. Finally, introduce the relevant standards and the test methods in pilot project, listing part of test results and their analysis.

Abstract: In order to investigate the match between the nozzle tip penetration and the double-layers diffluent combustion chamber geometry, a simulation model was developed which was based on the 135 diesel engine to simulate the equivalence ratio distribution of air-fuel mixture and the temperature distribution during combustion process. At the same time, an experiment was executed by a 135 diesel engine equipped with the high-pressure common rail fuel injection system. The research results show that the air-fuel mixture becomes more uniformed and the combustion process is improved when the nozzle tip penetration is reasonable selected which lead to higher in-cylinder pressure and better brake specific fuel consumption while NO_X emission is increased and soot emission is decreased for the double-layers diffluent combustion system.

Abstract: Propose cylindrical cam lateral transmission mechanism for the first time, define the agency's three specific types. Design gearless reducer type A, B and C for construction elevator by the application of the agency to reducer industry. Conduct physical prototype processing manufacture based on cylindrical cam lateral transmission theory and virtual prototype design of gearless reducer. By contrast processing and experimental tests to determine that the theory of cylindrical cam lateral transmission mechanism is feasible. Gearless reducer have the advantage of high efficiency and energy saving, low cost, small volume, light weight, saving raw materials resources.