Research On Matching Of Powertrain System Using The Urban Bus Driving Cycle Method

Vehicles have met all kinds of our requirements but also brought trenmendious damage to the limited energy and fragile environment which put the vehicle enterprise and engine manufacture under the pressure to increase fuel economy and reduce emissions.The driving cycle which can represent the real work driving condition of the vehicle is the essential input to evaluate the fuel economy and emission.For urban buses,the four mode driving cycle quoted in GB/T12545.2-2001<> deviates from the real word driving cycle.The ESC duty cycle quoted in GB17691-2005<>is also not consistent with the real world duty cycle of the engine.So how to resolve this issue and to meet the requirements of vehicle enterprise and engine manufacutre is the main topic in this paper.Focusing on the characteristics of the urban traffic and urban bus driving condition,taking Wu han urban bus as research target.The related theory and statistic software was adopted to develop the urban bus driving cycle which was validated by field test and simulation.Then,based on the real distribution of the engine duty cycle,the steady engine duty cycle was developed.According to the developed driving cycle,several methods were proposed to optimize the vehicle performance and the thought of evaluating the vehicle performance by engine bench test was raised.The main contents of this paper are as below:(1)Research on the real traffic condition and urban bus driving conditionFocusing on the real traffic condition and urban bus driving condition,the field test plan for collecting the urban bus drive cycle was created and an integrated data acquisition system was developed.(2)Research on the methods of developing the vehicle driving cycleDifferent theories of developing the vehicle driving cycle are analyzed. Referring to the current stuty status of this topic,the urban bus driving cycles were developed by adopting methods of fixed-step,short trip and acceleration-velocity. Then these three driving cycles were validated by field test and simulation.At last, the analysis software for vehicle driving cycle was established.(3)Research on the methods of developing the engine steady duty cycle Theory analysis and testing validation were conducted on the transforming method,interzone method and functional response method that are used to establish the engine steady duty cycle.In the end,according to the characteristis of the objective,the best method to develop the engine steady duty cycle of urban bus was raised and the 15 mode duty cycle was developed by this method which was taken as the basis for engine performance simulation.(4)The application of driving cycle and duty cycle for the vehicle performance optimizationAccording to the developed urban bus driving cycle,the impact of urban bus power train system,engine performance and auxiliary on the vehicle performance was analyzed using co-simulation techniques.Then the theory of DOE was used to analyze the impact on vehicle performance of transmission,rear axle ratio and GVW and the best optimization method was identified.At last,the thought of optimizing the vhicle driveability and fuel economy by utilizing the engine bench test was raised.