Research And Application Of Dozer Thermal Management Systems

Bulldozer,as one of the most important machines in the field of earth-moving machinery,is a typical machine with cycling operations.The engine of bulldozer is working in a high rotating speed with unstable thermal load,and the traditional engine cooling system can't be adjusted by the heat budget.At the same time,it brings higher energy consumption and the particulate matter pollution.Based on the problems above,the paper presents a design scheme for hard& software on the heat management system that is fixed on a type of bulldozer,and takes electronic fans as a core.The performance of the thermal system has been approved by actual engineering sample.The main contents are as follows:Firstly,it analyzes the disadvantages of the current bulldozer cooling system which uses the traditional mechanical or hydraulic cooling fan,in order to determine the advantages of applying thermal management system with the electronic control-cooling fan.Based on the current model of bulldozer,the paper designs the overall thermal management system.According to the analysis and calculation of bulldozer heat source,it determines how many fans to be used,and the principle of grouping cooling and grading control.In addition,the entire system is simplified to multiple DC motor speed control system with temperature control.It gives the principle and method of control speed for PWM DC based on this characteristic.Secondly,the hardware has been designed carefully,including the temperature sampling circuit,motor control circuit,current sampling circuit,voltage-sampling circuit,CAN bus communication and so on.Considering of the bulldozer's complicated word conditions,and changeable thermal system,the paper adopts fuzzy control as its control method.This control method can achieve good effect.Finally,the experimental prototype has carried out the approval tests in typical work conditions.The result shows the fuel saving rates reach to 13%,and the de-noising reduces 3d B(A).Thermal management with multiple electronic fans system achieves good effect,and accumulates a large amount of data for later applications in construction machinery.