## 3 Experimental Results and Analysis
### Comprehensive Analysis of Factors Influencing Climbing Characteristics
Factors such as the load weight and the power-to-weight ratio, as inherent vehicle characteristics, exert influence throughout the entire climbing process on the experimental route, affecting the vehicle's speed. As shown in Figure 10a, within the range of slope values \(i\in[3,5]\) and load weight \(M\in[15,50]\), \(DV\) generally exhibits an increasing trend with increasing gradient and load weight, with minor fluctuations observed on the three-dimensional surface. When projecting the three-dimensional image onto the Y-Z plane, as depicted in Figure 10b, \(DV\) approximately demonstrates a linear positive correlation with load weight, with the level of dispersion remaining relatively constant as load weight increases. From Equation (5), it can be observed that the larger the maximum vehicle speed and the smaller the minimum vehicle speed, the greater the \(DV\) value, making it more likely to cause disturbance to trailing vehicles. Figures 10-12 illustrate the variation of \(DV\) for pure electric heavy-duty vehicles under the combined influence of the slope with load weight, power-to-weight ratio, and initial climbing speed, respectively, the power-to-weight ratio ranges from [0.00431, 0.00775], and the initial climbing speed ranges from [60; 80]. Analyzing the color transition lines in the three-dimensional images reveals the extent of their combined impact on \(DV\) within common value ranges. When the slope is jointly influenced by the load weight or power-to-weight ratio, the color transition lines in the three-dimensional images are approximately at a \(45^{\circ}\) angle to the axis corresponding to the slope, indicating that the influence of slope is comparable to that of the load weight or power-to-weight ratio on \(DV\). Furthermore, when the slope is jointly influenced by the power-to-weight ratio, the increase in \(DV\) is more pronounced. This is because the power-to-weight ratio represents the ratio of motor-rated power to the total vehicle mass, making it a crucial indicator for assessing vehicle power performance and exerting a greater influence on the climbing performance of pure electric heavy-duty vehicles. On the other hand, when the slope is jointly influenced by initial climbing speed, the three-dimensional images exhibit a wavy pattern, with the color transition lines approximately perpendicular to the axis corresponding to the slope. This indicates that the influence of slope on the climbing performance of pure electric heavy-duty vehicles is significantly greater than that of initial climbing speed. Figures 13 and 14 depict the variation of \(DV\) values for pure electric heavy-duty vehicles under the dual influence of the initial climbing speed and load weight, as well as the initial climbing speed and power-to-weight ratio. When the initial climbing speed interacts with the load weight or power-to-weight ratio, the angle formed by the color transition lines in the three-dimensional images with the axis corresponding to the initial climbing speed is relatively small, indicating a weaker impact of initial climbing speed on the \(DV\) value for heavy-duty vehicles. By comprehensively considering the combined influence of various factors and identifying the key factors affecting \(DV\), this analysis can provide a reference for setting control standards for road designers and frei  
Figure 10: Relationship between slope, load weight, and \(DV\). (**a**) Three-dimensional plot; (**b**) Y-Z plane. Figure 11: Relationship between slope, power-to-weight ratio, and \(DV\). Figure 12: Relationship between slope, initial climbing speed, and \(DV\). Figure 13: Relationship between initial climbing speed, load weight, and \(DV\).