Research On Shift Decision Technology For Pure Electric Bus Based On The Operating Routes

Due to the atmospheric pollution and fossil energy crisis, the energy saving andemission reduction of automobile is more and more important. Electric vehicles are the mosteffective way to solve this problem, so the development of electric vehicles has become thesubject and direction of development of the world’s automotive industry. In the city bussystem to develop electric vehicle is one of the effective ways to achieve energy saving, andthe best breakthrough of electric vehicle fast and reasonable development.At present, most of electric buses are assembled with fixed ratio deceleration devices,so motor often works in inefficient area. That leads to larger energy consumption and shorterdriving range, it restricts the use and development of electric buses. So multi-speed is thetrend of electric vehicle development. For multi-speed automatic transmission system therational use of gear makes a direct impact on pure electric vehicle’s economy and power.Combined with the special project of international cooperation "dedicated automaticmechanical transmission of electric bus cooperative research and development", this papertakes the three gears pneumatic AMT transmission as study objection, combined with theoperating characteristics of pure electric bus, conducted a study on gears decision technologybased on pure electric bus operating routes, presents a new intelligent shift decisions.Experiments showed that this shift decision well suited to a variety of actual conditions ofpure electric bus，and improved the pure electric bus driving range. The main contents of thispaper are:1) Pure electric vehicle automatic transmission ratio optimization. Introduced thedrivetrain of pure electric buses, especially introduced the structural features of pure electricvehicle’s automatic transmission gearbox compared with conventional vehicle with aninternal combustion engine. Determined the ratio coverage by vehicle dynamic performanceindicators. Optimized gear ratios and verified vehicle performance. 2) Research on basic shift schedule of electric bus. Solved the optimum power scheduleof pure electric bus by using analytical method based on the analysis of the shift scheduleaffect the performance of pure electric vehicle. With energy efficiency as a starting point,obtained the best economy shift schedule based on the motor efficiency.3) Research on integrated shift decision technology for pure electric bus based on theoperating route, established shift decision system. Divided the operating route of pureelectric bus to two different segments by component analysis and cluster analysis. Determinethe current vehicle travel segment by using GPS. With vehicle location assistance, combinedwith road features and recognition algorithm to Judge the special conditions of the vehicleduring operation, such as curves and ramps encountered. Develop an appropriate shiftschedule for different travel segments. Make shift remediation strategies or differentconditions. Developed integrated shift decision system for pure electric bus based on theoperating route.4) Experimental study. Established pure electric vehicle test method. Verified shiftdecision of smooth road, congested roads and ramps and corners conditions. The resultsshowed that shift schedule of the smooth sections can significantly improve electric bus’driving range, shift schedule of congested road can guarantee vehicle dynamics and comfortin complex traffic situations, gear modification strategy of corners and ramps can solveunexpected shift and shift circulation phenomenon of vehicles and will help improve drivingsafety and ride comfort of pure electric bus.