Study On Dynamic Shift Schedule For Engineering Vehicle Based On New Three-Parameters

Engineering vehicle is a class of non-road vehicles used in construction, whichhas harsh working conditions, and for operating condition is complex and variable,operating load changes frequently, so the driver needs to shift frequently in order tomeet the working requirements. It has great significance for reducing driver’s laborintensity, improving the operating level of engineering vehicle and meeting therequirements of the special circumstances when automatic shift is used on engineeringvehicle.This paper is completed based on the Higher Education Doctoral Fund Project(No.200801830028):Study on Automatic Shift Technology of Engineering Vehiclewith new three-parameters. Choosing ZL50wheel loaders as the study object, aimingat improving vehicle dynamics as the shift strategy, then the analysis for the dynamicshift schedule of engineering vehicles is made in this paper.Considering the operating characteristics of engineering vehicle, then, in order tohave a better description for the diversion of working pump group from the enginepower, also in order to have a better reflection of the operating load’s effect toengineering vehicle shift schedule，a new parameter--the operating load factor isquoted, alculating the working pump group’s consumption of the engine torquethrough the operating load factor.On this basis, a mathematical model of the variousparts of the loader drive system, and vehicle dynamics equation were established.Then,selecting the throttle opening, operating load factor and speed as shift controlparameters, the dynamic shifting strategy is proposed based on the newthree-parameter. this chapter gives the analytical method and graphic method ofsolving dynamic shift schedule, and the optimum shift curve is given by solving thebest shift point speed.In the MATLAB/Simulink simulation environment, this paper establishessimulation model of the vehicle driveline, and makes simulation analysis for thedynamic shift schedule based on new three-parameter.Then, a development of theautomatic transmission’s electronic control system is made. This paper Completes thedesign of the system software program. Finally, a verification test for dynamic shiftschedule is made on the engineering vehicle automatic transmission electrical controltest bench.The results of this experiment show that the shift schedule developed inthis paper is reasonable, in line with the actual work of loaders, dynamic shiftschedule to a certain extent, improves the dynamics of engineering vehicles.