Cylinder sleeve of the internal combustion engine. Mathematical model of the deformation process

During the operation of internal combustion engines, deformation of the cylinder sleeve is possible, which causes its premature wear during the operation of the “piston ring – sleeve” pair. Imagine the sleeve as a two-stage hollow cylinder with forces applied to it, which cause deflection in the section. It can be assumed that if the greatest deformation of the cylinder is in the section of the application of forces, then with distance from this place it will decrease. At some distance from the point of application of forces, the deflection of the sleeve will be equal to zero. It is required to simulate a mathematical formula that would make it possible to evaluate the possibility of estimating the value depending on the basic geometric dimensions of the cylinder sleeve. A mathematical model of the deformation process of a hollow two-stage sleeve of an internal combustion engine has been developed, an analytical dependence has been obtained for the value of the “neutral” section depending on the main geometrical dimensions of the cylinder sleeve of the engine, a rather extensive analysis of the influence of various parameters on the value of the “neutral” section has been carried out.

Research on the Influence of Train Speed Change on the EMI of Pantograph-Catenary Arc to Main Navigation Stations

The electromagnetic interference (EMI) of the pantograph-catenary arc (PCA) to the main navigation stations will be affected when the speed of the high-speed train is changed. In order to study the influence of the speed change, we measured and analyzed the electric field intensity of the PCA generated at common and neutral section of power supply line at different train speeds. The frequency range in this study is the frequency of the main navigation stations (108 ~ 336 MHz). Both theoretical and experimental results show that PCA radiation increases with the increase of train speed. Besides, we calculated the maximum train speed without interfering the navigation signal. This work is useful for estimating EMI of the PCA at different train speeds and mitigating the interference to the navigation station near the highspeed railway by proposing corresponding speed limits.

Use of Dynamic Analysis to Investigate the Behaviour of Short Neutral Sections in the Overhead Line Electrification

The ‘short’ neutral section is a feature of alternating current (AC) railway overhead line electrification that is often unreliable and a source of train delays. However hardly any dynamic analysis of its behaviour has been undertaken. This paper briefly describes the work undertaken investigating the possibility of modelling the behaviour using a novel approach. The potential for thus improving the performance of short neutral sections is evaluated, with particular reference to the UK situation. The analysis fundamentally used dynamic simulation of the pantograph and overhead contact line (OCL) interface, implemented using a proprietary finite element analysis tool. The neutral section model was constructed using physical characteristics and laboratory tests data, and was included in a validated pantograph/OCL simulation model. Simulation output of the neutral section behaviour has been validated satisfactorily against real line test data. Using this method the sensitivity of the neutral section performance in relation to particular parameters of its construction was examined. A limited number of parameter adjustments were studied, seeking potential improvements. One such improvement identified involved the additional inclusion of a lever arm at the trailing end of the neutral section. A novel application of pantograph/OCL dynamic simulation to modelling neutral section behaviour has been shown to be useful in assessing the modification of neutral section parameters.

A Novel Co-Phase Power Supply System for Electrified Railway Based on V Type Connection Traction Transformer

Power quality and neutral section are two technical problems that hinder the development of electrified railway to high-speed and heavy railway. The co-phase power supply technology is one of the best ways to solve these two technical problems. At present, a V type connection traction transformer is widely used in a power frequency single-phase AC traction power supply system, especially in high-speed railway. In this paper, a new type of co-phase power supply system for electrified railway based on V type connection traction transformer is proposed. One single-phase winding in the V type connection traction transformer is used as main power supply channel, and three ports are used as compensation ports. Neutral section is no longer set with traction substation, and the train is continuously powered through. The independent single-phase Static Var Generators (SVGs) are used to compensate the three-phase imbalance caused by single-phase traction load. When necessary, the power factor can be improved at the same time. The principle, structure, control strategy, and capacity configuration of the technical scheme are analyzed in this paper, and the effectiveness of the scheme is verified by using the measured data of electrified railway. The advantage of this scheme lies in the universal applicability of the V type connection traction transformer, and the flexibility of the SVG device.