Research On The Prediction Method Of Power Performance And Fuel Economy Of Loader Based On V-type Loading Cycle

Research on the Prediction Method of Power Performance and FuelEconomy of Wheel Loader Based on V-type Loading CycleWheel loader is playing a more and more important role in the country’s modernization construction as one of the most common earth moving machinery in engineering project. As a typical earth moving machinery, the wheel loader can not only work in running condition but also in shoveling material. The power from engine is partly used for transmission system to drive vehicle, partly used for hydraulic system to drive working device and steering system, and the other remaining about 10% of the power for driving the attachment. The power from engine transported into hydraulic system is depended on the extra load suffered by hydraulic actuator. There are numerous impact factors which make the load changes with so great unpredictability that make the engine power distribution complex. The wheel loader’s working condition is extremely bad and the suffered load is complex and changing. The wheel loader can adapt to complicated road conditions because of the self-adaptability of torque converter that makes the whole transmission system flexible. In a word, the complex extra loads, the flexible transmission system and time variable engine power distribution make it difficult to predict the theoretical working fuel consumption, and the traditional static calculation can not meet the current requirement. In this paper, based on the V-type loading cycle of wheel loader, the prediction method of the power performance and economy characteristics of wheel loader was studied, mainly to solve the problem that the vehicle performance of wheel loader can not be accurately predicted in design phase, and the research also provided a theoretical basis for the design and optimization of wheel loader. The mainly research contents and conclusions are as follows.(1) According to the test standard of wheel loader, a 7 ton wheel loader ’s vehicle performance and load spectrum of hydraulic system were tested. The traction characteristics, power performance and fuel economy were tested, mainly including the maximum traction force, the maximum speed at each gear, the maximum climbing capacity, fuel consumption of 100-kilometers and the fuel consumption in V-type loading cycle. Especially, the hydraulic system data and fuel consumption were tested when a wheel loader loaded three different materials in a typical V-type loading cycle such as freestone, sand and stone, and the fuel consumption in one V-type loading cycle were respectively 385 mL per time, 360 mL per time and 395 mL per time. In the aspects of load spectrum of hydraulic system, the import and export pressure and flow data of working pump and steering pump that changed with time were tested when the loader worked in V-type loading cycle, and the test data would be used for establishing the dimensionless power deduction equation of engine.(2) The test data were processed and analyzed, the import and export pressure and flow data of working pump and steering pump were extracted, the power consumption curve of hydraulic system when the loader worked in the V-type loading cycle was gotten by theory calculation, and the dimensionless power deduction equations of hydraulic power system for loading three different materials such as freestone, sand and stone were obtained by data processing which could be used as the experience formula to calculate the fuel consumption in V-type loading cycle. The calculation method of power performance and fuel economy characteristic were found. The dynamic matching calculation method of wheel loader was presented that made the prediction of V-type loading cycle more accurately and made dynamic traction characteristic of wheel loader calculated. The dynamic matching method could provide a reference to assess the working performance of wheel loader.(3) The model of wheel loader’s power transmission system was established and the mathematic model of wheel loader was complied, the static calculation program and the dynamic simulation model which was based on Simulink were established, and the Graphical User Interface(GUI) made them together that the power performance and fuel economy characteristic simulation platform of wheel loader in V-type loading cycle was built. Many characteristics of wheel loader were simulated and analyzed based on the platform, compared with the test results, the results showed that the performance indicators of wheel loader could be calculated by the method referred in the paper, including traction characteristic, dynamic characteristics and economy performance, especially the fuel consumption in the V-type loading cycle could be predicted accurately, and the factors which could influence the working economy of wheel loader were analyzed. The dynamic matching calculation method in V-type loading cycle of wheel loader made it possible to predict the working economy characteristic of wheel loader which was impossible for traditional static matching method. And the power performance and fuel economy simulation platform for wheel loader based on V-type loading cycle provided a reference for the design and optimization of wheel loader.