Yin Han Gao

Experimental Research of HCCI Combustion Based on Late Exhaust Duct EGR Strategy

Late exhaust duct EGR strategy is one of internal EGR strategies to realize HCCI combustion. Based on a single-cylinder test engine system equipped with an electronic controlled hydraulic variable valve train system, the effects of valve phases in this strategy were studied. The results show that at engine speed 1000r/min, equivalent air-fuel ratio λ= 1, when the IVO phase is put off, EGR ratio increases gradually, CA10 and CA50 are postponed and combustion duration becomes longer. At the same time, peak pressure and maximum pressure rise rate have a tendency to descend. When the SEVO phase is postponed, the parameters of the test engine will also be affected. However, when the phase is postponed above the critical point, the parameters have a backward trend. The property of HCCI combustion is not sensitive to SEVO phase.

The Analysis and Simulation of Contact Loss between Pantograph and Catenary on Electric Railway

Based on the classical Mayer-arc model, this paper establishes the equivalent circuit of traction network for AC25kV electric railway from the essence of contact loss discharge. The voltage waves of contact loss arc at different moments are obtained by MATLAB/simulink. Through the analysis, it can be confirmed that the EMI (electromagnetic interference) with broad band and high amplitude will appear at the moment the contact loss between pantograph and catenary happens. Finally, relevant measures are given to avoid the probability event of contact loss.

Simulation Research on Resistive Coupling of High-Speed Railway

With the rapid development of high-speed railway, the problem caused by railway has become the focus of public attention. Whether the railway will damage the electromagnetic environment become an unavoidable topic. Choosing the AC 25KV high-speed railway to study, the impact of its resistive coupling on the human body or different devices is explored. Using the existing analytical formula, the ground potential rise caused by the resistive coupling has been simulated, which intuitively show the different ground potential rise in different situations. Finally, the impact of resistive coupling has been analyzed.

The Analysis of a Transmission Line Crosstalk in the Time Domain Based on First-Order Upwind

This article will combine the difference scheme of first-order upwind with the multi-conductor transmission lines equation to analysis the multi-conductor transmission lines crosstalk in the time domain. First-order upwind is a finite difference algorithm in the time domain; it has a first order accuracy, in the discontinuous solution there is no non-physics-oscillation, when simulate the signal. The flux splitting method which is applied to the first-order upwind solved the problem that the characteristic line direction of the wind type make plus or minus transformation along with the coefficient, make the programming simple. In this paper, simulation results of transmission line crosstalk in this algorithm will be compared with the traditional leapfrog scheme, to verify its effectiveness.

Noise Transfer Function Refinement of Commercial Vehicle Cab Based on the Vibro-Acoustic Model

The TPA method has gradually developed into a mature approach to solve the internal noise problem of vehicles in recent years. Among the excitation transfer path from excitation to the noise at the target point, the noise transfer function is an important path. The noise transfer function is an inherent property of the commercial vehicle cab like the modes. When noise transfer function is low; the noise caused by the vibration transformed from the suspension is relatively low, which will be great help for the comfort of the cab. A vibro-acoustic model of some commercial vehicle cab has been built in this research, and the low frequency region noise transfer function from the mount points to the drivers ears has been simulated. From the comparison of the numerical result and the relevant test result, the accuracy of the simulation model has been proved. For the sensitive frequencies, the vibro-acoustic modes have larger vibration on some thin plates, which has been proved to be the reason for the peak for the noise transfer function. In order to reduce the noise transfer function, damping materials were applied to the sensitive thin plates, the modification effect proved to be content in the real working condition.

The Analysis of Automotive Wiring Harness Dynamic Crosstalk

Since the installation and strapping of the harness, and the vehicle motion state of the automotive is different. The crosstalk automotive wire harness is not a fixed value, but a certain dynamic range in the actual situation. Through the analysis of the factors of influence cable crosstalk can draw a conclusion that the cable relative position and disturbed line termination impedance is a major factor in the production of dynamic change. We analyze the dynamic range of crosstalk of 14 core wire harness model by using a statistical method, as a result of the change of the relative position of cable far-end crosstalk (FEXT) range within 1 dB, but when the disturbed line termination impedance changes from 50Ω to 1000Ω, the cable far-end crosstalk range reached 15 dB. It provides reference basis for the automotive wiring harness electromagnetic compatibility design.

Transient Analysis of Multi-Conductor Transmission Line Based on the Second-Order Upwind Scheme

On the basis of the second-order upwind scheme, combined with the flux splitting method, we derive a uniform multi-conductor transmission line time-domain calculations. This method is a direct time-domain discrete numerical method with second order accuracy. It does not have any special requirements for circuit and the application process and complex transformations which lead to facilitate the preparation of the program. Numerical experiments show that this method of preparation of general purpose computing program has roughly the same computational efficiency with the traditional leapfrog scheme and at the discontinuous solutions, there are no non-physical oscillations. It can easily be used to calculate a uniform multi-conductor transmission line coupling.

The Research of the Electric Vehicle Wiring Harness Dynamic Crosstalk Based on Statistical Simulation Method

In the actual situation, because of the shock of automobile in the movement process and the wire harness in undulating tube placement is random, leading to the relative position of the wire harness is not fixed, Thus lead to crosstalk value has certain dynamic range. In this paper, obtained the unit mutual inductance and mutual capacitance of wire with insulation layer using mirror image method, simulation and prediction of crosstalk dynamic interval by statistical simulation method, obtain harness near end crosstalk changes range within 3dB at a confidence level of 80%. This provides a reference for EMC design of automotive wiring harness.

Extracting Parameter Matrix of Automotive Cable Harness

Convert Inhomogeneous media space into infinite homogeneous medium space with method of image charges, obtain the relations between Inhomogeneous media wire bound charge and free charge rely on electromagnetic theory and deduced analytical the model of parasitic capacitance per unit length of Inhomogeneous dielectric wire in insulation in automotive cable harness. Taking a car harness for example, analytical formulas and Ansys Q3D Extractor software were used to calculation and analysis harness unit length parameter matrix. Among them, the algorithm of Ansys Q3D Extractor software to calculate the parasitic of automotive cable harness is two-dimensional static finite element method, numerical methods belong.

The Model of Estimating MTL Crosstalk in Inhomogeneous Medium

Based on the transmission line theory, this paper applies the mode theory to predict the MTL(multi-conductor transmission line) crosstalk by selecting voltage as the research object, thus establish the model of estimating MTL crosstalk in inhomogeneous medium. Then make numerical calculation in MATLAB for the estimate model established in this paper, and also compare the calculated values with the simulated values in EMC studio. The compared results show that the calculated results of this model is highly consistent with the practical simulated values, verifying the correctness and feasibility of mode theory in MTL crosstalk prediction.