Quantitative analysis of the energy saving mechanism of a hybrid electric tracked vehicle by an analytical method

As an effective energy-saving technology, hybrid powertrains have recently been applied from the on-road to the non-road vehicle fields. In different application scenarios, the main energy saving means of hybrid powertrains are different and need to be studied separately rather than generalized. The analysis of energy saving mechanisms, such as the energy saving means, contribution rate, influence factor and potential, is of great significance for choosing the direction of hybrid powertrain energy saving optimization. To reveal the energy saving mechanism of a hybrid electric bulldozer, an innovative analytical analysis method is proposed. An analytical equation is derived to indicate the quantitative functional relationship between the equivalent fuel saving ratio of the hybrid electric bulldozer and all the influencing factors. By combining the output data of the simulation model with the equation, the energy saving mechanism of the hybrid electric bulldozer is analysed quantitatively. The research results show that the energy saving contribution of hybrid electric bulldozers originate mainly from the increased efficiencies of components on the diesel-electric drive path and the removed hydraulic torque converter. In addition, there is almost no energy that can be recovered by braking and no cancellable idle fuel consumption for energy savings because of the low speed and cycle operation features. The improvement of engine efficiency has the most positive effect on energy savings among pivotal component efficiencies. With increasing bulldozing resistance or speed, the energy saving effect decreases. The energy saving limit values can be calculated under different conditions. The equivalent fuel saving ratio can be maximally increased by 13.8% by optimizing present control, which is approximate to the optimization result by the dynamic programming algorithm with fewer calculations. The analysis results provide underlying insights to guide the design and optimization of hybrid electric bulldozers.

Automated summary

Hybrid powertrains, as an effective energy-saving technology, are being applied in various vehicle fields. Different application scenarios require separate study and optimization of energy-saving mechanisms. Analysis of energy-saving mechanisms provides insights for optimizing hybrid powertrains.