Modeling and Simulation of Power Coupling System in Hydraulic Hybrid City Bus

Abstract

In order to solve the coupling problem of power in Hydraulic Hybrid City Bus (HHB), a hydraulic hybrid power coupling system based on planetary gear transmission principle is proposed in this paper. The system consists of diesel engine, power coupler, hydraulic pump/motor, etc. The realizable operating modes of power coupling system are analyzed in this paper. Under coordination of clutches, the engine driven mode, hydraulic driven mode, hybrid driven mode, hydraulic enginestart mode and braking energy recovery mode are realizable. Based on Lagrange equation, kinetic analysis and kinematics analyses are presented. In addition, the simulation model of the power coupling system is proposed, which includes diesel engine model, power coupler model, hydraulic pump/motor model, etc. The example simulation analysis is proposed under the hybrid driven mode; the results show that the power coupling system proposed in this paper can realize power coupling of hydraulic hybrid city bus. Compared with traditional city bus, the hydraulic hybrid city bus can choose small-displacement engine so as to improve fuel economy and dynamic property.

Conceptual design of hydraulic hybrid test rig for engine performance enhancement

“…To represent the relation between the output torque of the power coupler, hydraulic motor torque and the engine torque, the equation is defined by [4] as:…”

“…Numerous research on the hydraulic hybrid technology have focused on heavy nd trucks, as the heavy mass of these vehicles produces a generous amount of energy which can potentially be reused [2][3][4].…”

“…Power management and component sizing such as hydraulic motor/pump need to be optimized and match with the vehicle characteristic, so that it can achieve optimal fuel consumption [2][3][4] has adopted planetary gear transmission principle as a power combining devices. Based on simulation results through MATLAB/Simulink, in [4] found that by combining the torque from engine and hydraulic motor, the coupled torque can increase the total torque and provided the vehicle a short burst of power for a limited time as shown in Fig. 3.…”