| At present, the world car ownership is rapidly expanding, and 99.9% of which are traditional energy vehicles. The energy consumption and environmental pollution pressure it brings has become a global challenge. In this background, improving the fuel economy of the traditional energy vehicles has become an effective way to ease the pressure of energy and environment In the condition of vehicle braking and downhill, a considerable part of the vehicle energy is lost in the braking process, if part of the kinetic energy of the automobile is recovered during braking and downhill condition,on the one hand the fuel economy of the vehicle can be improved,on the other hand the brakes thermal load can be reduced and the service life of the brake parts and components can be prolonged.At present, the most mature technology is the electrochemical energy storage brake energy recovery system in the braking energy recovery area,but this system can only be applied to the new energy vehicles. In this paper, a simple system named the Flywheel Automotive-brake Energy Recovery and Retarder System(FAERRS) is proposed, which can be applied to the traditional energy vehicle.The system on the one hand will play the role of recycling part of the car kinetic energy during braking and downhill condition, on the other hand it will paly the role of the retarder during long downhill condition.The device is particularly suitable for truck and bus.This paper mainly completes the following work:Firstly, according to the FAERRS function requirements, the paper analyzed the basic components of the system. The transmission device, flywheel energy and energy conversion device are defined before they are fully compared.Secondly, on the basis of the mechanical structure,its stress situation under braking and downhill conditions were analyzed. According to kinetic theory, deduced the formulas of effective braking energy recovery was obtained. This paper also elaborates the electromagnetic clutch’s work situation at each stage of the brake deceleration and downhill conditions.Again, according to the working principle and working process of the FAERRS, to maximize the recovery braking energy and make the system has a certain anti-interference ability, developed the system’s control flow during braking and downhill condition. In the environment of Matlab/simulink, the simulation models of the system during braking and downhill condition are built, and the simulation is carried out with the NEDC cycling condition as the input condition.. The simulation results show that the FAERRS can effectively recover about 10%-14% braking energy.Besides, the main structural parameters — the maximum torque of the electromagnetic clutch,the transmission ratio of the energy storage flywheel and the rotational inertia of the energy storage flywheel that affect the systems efficiency are simulated. It is found that the braking energy recovery efficiency increases with the increase of the three factors.At last, The paper researched the mechanical structure, working principle, control flow and energy flow of the system that achieve retarder. On this basis, simulation model of the system in the condition of long downhill was established, and its working process was simulated. The FAERRS has three work modes when it regenerating energy. The characteristics of the three work modes were analyzed, and the system in urban conditions, suburban conditions and the long downhill conditions under the condition of selecting the best mode were analyzed. The influence of the weight of the system on the fuel economy in the NEDC cycle is analyzed.The simulation results show that the braking energy recovery index(the ratio of the effective braking energy and the energy consumption of the recovered energy) canreach 17.7~24.7. |
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