Study On Product-Development Key Technology Of Mechatronic Coupling Transmission

Plug-in hybrid electric vehicle(PHEV)is one of the focal points of New Energy Vehicles development in China.As the core component of PHEVs/HEVs,the productdevelopment key technology for dedicated mechatronic coupling transmissions(MCTs)is also one of the focuses for auto industry.The following research works on product-development key technology for mass-production MCTs,entrusted by a domestic automaker according to its strategic plan,have been carried out in this dissertation.A comprehensive evolutional analysis of mainstream MCT's architectural configurations/ layouts is made,resulting in 3 basic layouts from which various MCTs are derived,namely single electric machine parallel hybrid(P2),dual e-machine serial/parallel combined hybrid(CH)and power-split(Electric Continuous Variable Transmission,ECVT)types.Through the implementation of multi-scenario concurrent engineering,a sub-/objectively combined MCT configuration assessment methodology is set up,by an in-depth multidimensional overall evaluation study of performance,processability,cost and IPR barrier overcoming/avoiding probability etc.,with consideration of market information and knowledge/competence accumulated by the enterprise.Using it,the main direction of configuration/layout for MCT design is well defined,and on this premise,a series of MCT products,from simple to complex,will be successively developed.A method for large-scale objective evaluation of MCT configurations called PVS(Powertrain variation Study)is designed.A multi-stage modelling technique based on the target of minimum instantaneous equivalent fuel consumption is proposed,along with the application of Radau pseudo-spectral splicing method,to implement the large-scale objective MCT layout evaluation process.It is validated by examples that the Radau pseudo-spectral splicing method has the global optimization ability comparable to the dynamic programming algorithm,and the solution speed is significantly improved.Based on the PVS objective evaluation of the 3 basic configurations considering their dynamic performance,fuel-economy,cost and so on,quantitative objective comparisons under given boundary conditions between the three are made.Then with the additional considerations of enterprise,market and IPR aspects etc.,objective/subjective combined evaluation scores of the 3 configurations are obtained,resulting to that the main configurational direction is CH(combined hybrid)for the enterprise.Thanks to this,not only some advantagous configurational schemes with own IPRs but also the solid foundation for subsequent R&D and production works,are formed consequently.For specific PHEVs that will use the MCT onboard,selection and parameter design of the powertrain's major components are preliminarily carried out.Then a somewhat rule-based energy management strategy for realistic vehicle application is proposed.Based on AMESim and Simulink combined PHEV model of forward-simulation type,parameter matching optimization of the PHEV powertrain is conducted,and the optimal system sizing/matching is achieved.Design works of the key subsystems are then carried on.By means of analyses using integrated model coupling multi-physic-fields,the cooling and lubrication functionalities of clutches,e-machines and gearings are optimized.In order to validate the performance of the MCT's control strategy,structural reliability,cooling,lubrication etc.,relevant bench and onvehicle-board tests are conducted.Through the vehicle fuel-economy tests in NEDC and WLTC cycles,advanced nature of the system design and energy management strategy are verified;while the vehicle driving durability and thermal balance tests reveal that the structural reliability,system's cooling and lubrication performance meet the set requirements.To sum up this dissertation,based on the “forward engineering” process,the productdevelopment key technology of mechatronic coupling transmission for PHEVs/HEVs is studied systematically,a reusable MCT product-development methodology with originality,integrality and related knowledge frame is thus formed,which has strongly supported a family of MCTs to be developed into a mass-produced products with market competitiveness(also awarded as one of the World Top 10 Transmissions 2019' by China Automobile Evaluation Academy).