Research On Graph Modeling And Configuration Synthesis And Design Of EVT Hybrid Electric Powertrains

As the growing of resources and environment problems and the fourth stage of fuel economy regulations "2020", domestic auto-enterprises urgently need a sustainable development of new energy solution to deal with these problems and strict emission regulations. The global new energy market changes and researches of domestic and foreign show that, hybrid electric vehicle is the only way for the development of automobile technology. Concerning the characteristic of HEV, powertrain system is the key component of HEV, and its effect on HEV performance is critical. Because of the characteristic of Planetary gear trains: multiple degree of freedom, compact structure and higher efficiency, EVT(Electronic Variable Transmission) is widely used in HEV.In this paper, taking EVT Planetary gear trains as the object of study, the main contents of this paper are as follows:(1) Taking topology theory as an analysis tool and through the study on existing power coupling method, input/output layer can be added to the graph model based on the canonical graph theory. This method can improve the model accuracy and information capacity, and establishes a more accurate topology model of EVT-HEV powertrain.(2) Based on the hierarchical graph model, and taking the adjacent matrix as the study object, the number of feasible links can be calculated based on the “complete graph” theory. Binary sequence comprised of matrix elements can produce all possible EVT configurations without omission after transforming between decimal and binary. After that, these configurations must be screened according to its feasibility. Based on the configuration atlas, EVT architectures with single clutch and double clutch can be created through configurations' combination.(3) To solve the dynamic and kinematic modeling problem of configurations, graph theory and fundamental circuit theory is the basis of planetary gear analysis of dynamic and kinematic. Parameters' matrix and state matrix can be firstly constructed in consideration of the planet inertia. Based on the matrix operation theory and the software of MATLAB, a set of auto-modeling theory are approved to solve the modeling problem and improve the model accuracy and reduce the human error.(4) Through the global optimal algorithm “Dynamic Programming”, simulation of double clutch EVT architecture is finished under the driving cycle NEDC and UDDS.