| Electrified vehicle is an efficient method for energy saving and environmentprotection. Meanwhile, regenerative brake is an important technology to improveelectrified vehicle’s energy economy. The simulation and real vehicle tests are carriedout for electric buses in this thesis. The typical driving conditions and friction brakingforce participation features during vehicle braking are analyzed for research of theactuator characteristics in regenerative braking system. The evaluation criteria methodsof the energy economy contribution of the regenerative braking system are searchedbased on analysis of the energy flow model of the electrified buses and real vehicle testin this thesis.First, the characteristics of pneumatic braking system based on high speed on-offsolenoid are analysed in typical braking processes and China typical city bus operatingcondition. The operating life of the valves has been studied. Then, the pressure controlby proportional valve is researched. It is indicated that by using the PID control methodit could achieve a rapid and accurate control of the braking pressure.Then, the evaluation method of the energy economy contribution is researchedbased on the analysis of the energy flow model of the electrified buses. Thecharge-discharge efficiency of the energy storage device and the energy consumption ofthe accessory system are taken into account in this method. Then, the test andcalculation methods of the energy economy contribution are simplified reasonably forengineering application based on real vehicle tests.Finally, the regenerative braking system is integrated in three different types ofelectrified buses. Real vehicle tests are conducted to analyse the strategy, which indicatethat the series regenerative braking strategy gains satisfactory driving comfort andsuperior fuel economy. The sliding brake regeneration strategy can effectively reducethe vehicle fuel consumption in the operating condition which has more glide phases. |
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