The unreasonable shift point will cause a large shift impact, which will affect the engine fuel economy and the service life of the wet clutch. To decrease shift impact on agricultural tractors with HMCVT (Hydromechanical Continuously Variable Transmission) and find the best working point, the following methods are proposed in this paper: firstly, conducting all-factor method and response surface method (RSM) to design and carry out bench test of shift impact; secondly, using the basic linear fitting, RSM, and stepwise regression analysis to establish comprehensive mathematical models and selecting models with high prediction accuracy; thirdly, putting forward the method of determining the weight of variance to match parameters of three quality evaluation indexes with inconsistent correlation; finally, establishing the total shift quality evaluation index and obtaining the optimal shift working point. It is found that oil filling pressure has a significant effect on speed drop, while the engine speed has a significance on the dynamic load and sliding friction. To make the transmission section of the best quality, the oil pressure at this time is 1 MPa and the engine speed is 1040 r/min. The results show that the proposed method can determine the optimal shift point and provide a reference for developing the control strategy.

中文翻译：

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HMCVT最佳换档点的台架试验和建模分析

不合理的换挡点将引起很大的换挡冲击，这将影响发动机的燃油经济性和湿式离合器的使用寿命。为了减少换档对HMCVT（农用机械无级变速器）对农用拖拉机的影响并找到最佳工作点，本文提出了以下方法：首先，进行全要素法和响应面法（RSM）进行设计和实施。换档冲击的基准测试；其次，利用基本的线性拟合，RSM和逐步回归分析，建立了综合的数学模型，并选择了具有较高预测精度的模型。第三，提出了确定相关性不一致的三个质量评价指标参数的方差权重的方法。最后，建立总的换档质量评估指标，并获得最佳的换档工作点。发现机油填充压力对速度下降有显着影响，而发动机转速对动载荷和滑动摩擦有重要影响。为了使变速箱部分达到最佳质量，此时的油压为1 MPa，发动机转速为1040 r / min。结果表明，该方法可以确定最佳换挡点，为控制策略的开发提供参考。此时的油压为1 MPa，发动机转速为1040 r / min。结果表明，该方法可以确定最佳换挡点，为控制策略的开发提供参考。此时的油压为1 MPa，发动机转速为1040 r / min。结果表明，该方法可以确定最佳换挡点，为控制策略的发展提供参考。