# Bench Test and Analysis of Cleaning Parameter Optimization of 4 L-2.5 Wheat Combine Harvester
## 1 Introduction
[17] took the cleaning and loss rates as evaluation indices, and the feeding speed, suction pressure, cylinder height, and angle of the lower cone as test factors in an orthogonal simulation of the cleaning process. In this way, the optimal cleaning parameter combination was identified. Furthermore, a field test validated the simulation optimization results in order to improve the cleaning performance of a wheat combine harvester in intercropping mode. Using the test-bed of a cyclone separation and cleaning system with double threshers and taking wheat as the test object, the rotation speed of the first-stage thresher, second-stage thresher, and suction fan as test factors, and cleaning rate as the test index, [PERSON] et al. [18,19,20] performed orthogonal and regression tests to optimize the parameters, providing a basis for the design of a portable grain chopper cleaning system. Using the cyclone separation system of the double thresher within a micro grain combine harvester as the research object, the rotation speed of the two-stage thresher and the suction fan as test factors, and the grain cleaning rate, cleaning loss rate, and grain crushing rate as test indexes, a cleaning performance regression test was performed and the motion parameters for the cleaning system were optimized; this research serves as an experimental foundation for the parameter design of cleaning systems for micro-grain combine harvesters. As a result of that research, a composite device was developed for conveying, separating, and cleaning grain effluent; the optimal parameters of this device were obtained through indoor tests, and its cleaning capacity was improved. Using orthogonal tests, general rotation combination tests, and a novel design, [PERSON] et al. [21] reported the optimum combination of structural parameters and motion parameters of each part of the cyclone separation and cleaning system without a guide vane in the separation cylinder. The results revealed improved cleaning performance of the micro wheat combine harvester. [PERSON] et al. [22] selected the main parameters that affect the cleaning performance index using a self-made cleaning system test-bed with the upper cone angle of the separation cylinder, the height of the cylinder,the number of guide vanes, the speed of the suction fan, and the speed of the thresher as design variables. The optimal combination of parameters and performance were obtained through orthogonal tests, a second general rotation combination test, and a novel design, which serves as a further foundation for the design of cleaning systems for micro wheat combine harvesters. In spite of the aforementioned studies, research on the top optimization of wheat harvester cleaning parameters and their impact on cleaning quality is still insufficient. The cleaning parameters studied are few and incomplete, resulting in inaccurate and untimely cleaning parameter adjustments during wheat combine harvester field operation. Wheat machine cleaning is often inefficient; it restricts the cleaning operation level of the combine harvester and limits the annual wheat crop output. In light of these issues, this paper takes all five adjustable parameters (operation speed, chaffer opening, throttle opening, fan speed, and shale shaker crank speed) that affect the cleaning quality of wheat combine harvesters as cleaning parameters, takes cleaning loss rate and impurity rate as cleaning quality evaluation indicators, and uses Design Expert software to complete the response surface experiment design. A bench test of the optimized wheat harvester cleaning parameters was completed using a self-made 4 L-2.5 threshing and cleaning test bed. The contribution rate and response effect of the five cleaning parameters relative to the two cleaning quality evaluation indexes were analyzed using the contribution rate and response surface methods, and the hierarchy of wheat mechanical cleaning parameters was obtained.