| The quality of the braking performance is the most reliable guarantee for the high-speed operation safety of EMUs.With the continuous improvement of EMU running speed,the probability of sliding failure under braking conditions is increasing.The wheel set failures caused by slip,e.g.,scotching,will not only reduce the comfort of passengers,but bring additional impact and vibration to on-board components,severely increasing the failure rate of on-board equipment,reducing their service life,and posing significant safety risks for the safe and stable operation of the EMU;thus the corresponding potential hazards should not be ignored.For this reason,how to improve the antiskid function of the brake and efficiently prevent the wheel sets from skidding and scotching has become the main research content of this paper.Firstly,the in-depth analysis on the composition and principle of EMU braking and antiskid system is made.Based on the deep understanding of the composition and principle of EMU braking and antiskid system,the mechanics principle of wheel set sliding is analyzed,the basic elements of sliding are mastered,and the antiskid principle and sliding detection method are explained.Secondly,in order to analyze the role of the braking system in emergencies,a statistical analysis of typical operating EMUs(CRH1A,CRH2 A,CRH3A,CRH380 A and CRH380D)applying emergency braking from 2010 to 2018 is conducted.The basic antiskid principles of these EMUs are analyzed by combining with the cases,and the advantages and disadvantages of the protection control mode are described respectively.Finally,this paper,on the basis of the antiskid modes of the above-mentioned three models of EMUs,elaborates on the suggestions for improving the antiskid performance from the aspects of failure disposal management and hardware/software transformation.In terms of failure disposal management,the emphasis is placed on the organization and management model of EMUs,eight common operation conditions are simulated respectively,such as rain,snow,ice,frost and other bad weather before leaving the depot,parking at stations,antifreeze oil stains on the rail surface,and failure information alarm when the driver finds that the full train brake is not applied or the braking force is obviously insufficient,the braking force is insufficient,and the antiskid device fails,and then the antiskid measures are proposed accordingly.In terms of software and hardware transformation,CRH1 A and CRH2 A are taken as examples to discuss the idea of installing sanding devices on such two models,and then,with the sanding device on CRH2 A as an example,the proposed ideas and suggestions are demonstrated.Furthermore,this paper also puts forward emergency disposal suggestions and complete solutions for failure of antiskid device caused by the defect of the braking software of EMUs.At the end of this paper,the author analyzes the amount of turning repair for the treads of the wheel sets to eliminate the hidden danger of wheel set failures after sliding;estimates the economic loss of the EMU overhaul caused by one wheel set slip by combining purchase price of the wheel set,production organization,cost consumption and energy consumption;and calculates the daily direct economic losses in the premise of assuming that the failure occurs in a busy high-speed passenger transportation project in China. |
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