Research On Optimization Of Hybrid Model Framework Based Automotive Powertrain And Transmission Systems

Recent years,there is a wide usage of cars in domestic market,which causes two main problems:one is the energy source,and the other is the environmental pollution. For using fuel effectively and to the most extent decreasing harmful gas resulting from burning fossil fuel,currently,besides partly or completely substituting new energy source for fossil fuel,a more practical method is adopting new control strategies to enhance the burning efficiency of fuel and decrease the disposal of waste gas.To apply well performed control strategies to the cars to save energy and lower cost,first,we need an accurate description for the car model.Powertrain and Transmiss-ion system is the kernel of the car,and is also the main part of energy cost and disposing waste gas.If we can construct the model description of this part and implement efficient control on it,then,we will hit the target to save energy and lower disposal of waste gas.So,this paper focuses on how to establish the model of Automo-tive Powertrain and Transmission system and applying optimal theories to the model to save energy and decrease the disposal of waste gas.Some valuable results in this paper are gained:(1) Automotive Powertrain and Transmission system is a complicated nonlinear system containing both continuity of power part and discreteness of transmission part. The whole system is hybrid.So,describing it under hybrid framework is more appropr-iate.First,this paper constructs powertrain,transmission and steering system submodels according to corresponding referenecs,and then relates powertrain to steering with transmission and forms DAE to describe the above systems'relationship,finally,acco-rding to concrete driving conditions,the paper defines gears switching sequences and presents subsystem switching diagrams,which constitute the powertrain and transmis-sion hybrid model.(2) Changing gears and throttle control strategies are different based on driving conditions.After describing hybrid model,the paper designs two problems related to optimization:the one is car accelerating problem considering the optimal switching times and throttle control strategies when the car accelerates from a start velocity to an objective one on a flat road,and the other is car tracing problem considering the optimal switching times and throttle control strategies when the car runs for the head car from an initial distance until it reaches the safe distance from the head car and equates the velocity of the head car.(3) Solve the above problems with simultaneous methods to rapid the solving ra-te and make reasonable analysis and comparison.