Analysis Of Configuration Of EVT For Power-split Hybrid Electric Vehicle

The key factor that influences the performance of Power-Split HybridElectric Vehicle is the configuration of Electrical Variable Transmission(EVT). Chapter1summarizes the configurations that have been applied forproduction, categorizing them into two groups: Toyota group and GM group. Itis the major goal and emphasis of this thesis to discover the separatedevelopment of the two groups and the reasons why certain configurations areadvantageous.Before analyzing the configuration of EVT, the author summarizessystematically the most fundamental and crucial method to do theanalyzing-Lever Analogy. Chapter2establishes10basic principles forapplying Lever Analogy. Not only being the prerequisite for applying the method,the principles are also instrumental to extend the application of Lever Analogy.Thus, in addition to presenting the dynamic relationship between EVT and eachassembly and that between each planetary clearly, Lever Analogy can also beused to discuss compound planetary, dynamic process of EVT, and configurationswith fixed gears, etc.Based on Lever Analogy and the idea of analysis of necessity on appliedconfigurations, this thesis focuses on the two groups mentioned above. WithLever Analogy, the development of each group can be discovered; and analysisof necessity on applied configurations makes it possible to find out thedesigning theory on which details (like the amount of planetaries or the momentof mode-switching) are based, and to find out the advantages of applied configurations and the reasons why they seem to be irreplaceable.In Chapter3-the chapter talking about Toyota group, the necessity of THSas one-planetary one-mode EVT is shown in the first place:6different possibleInput-Split configurations are compared in some ways-the scope of MechanicalPoint, that of the torque and speed of each MG and the percentage of electricalpower to total engine power, and the conclusion that THS is the best choicefor one-mode EVT is reached. Moreover, the torque-augmenting EVTs in Toyotagroup are discussed. After listing all possible torque-augmenting ones,parameter i (the evaluating index of effect of torque-augmenting) comes up,showing the pros and cons of these configurations. Following the discussionof structural parameter in each configuration, the analysis and evaluation oftheir main focus is done. The development of Toyota group appears.Chapter4talks about GM group, concentrating on the features and necessityof two-mode EVT, and the fuction of fixed gears.The chapter expresses dynamicprocess of EVT twice in Lever Analogy, and draws conclusions that the two-modeEVT with3Mechanical Points is more efficient and that this EVT necessarilycontains3planetaries. What is more, the EVTs with fixed gears have certainfunctions that the two-mode EVT with3Mechanical Points does not have,but theyalso have his own drawbacks. To sum up, the EVTs with fixed gears are moresuitable to Full-size SUVs. The development of GM group goes from the two-modeEVT with3Mechanical Points to the EVTs with fixed gears.In addition, the author evaluates some configurations that have not beenapplied yet, such as the“serial+Power-Split” configuration from CATARC, FHSfrom Ford, and the two-planetary two-mode EVT from Timken.Futhermore, newdesigning ideas are proposed. For example, compound planetary and simpleplanetary seem to be interreplaceable.