Torsional vibration analysis of a powertrain with a power reflux hydraulic transmission system

Abstract

World-wide constraints on the supply of fossil fuel resources exist in conjunction with stringent environmental constraints. Therefore, it is very important to develop advanced technologies to reduce fuel consumption. The transmission efficiency of an automatic vehicle is low because of the torque converter. Hence, in this study, a power reflux hydraulic transmission system (PRHTS) was proposed. It is important to avoid the phenomenon of resonance in a powertrain with a PRHTS, and thus it is necessary that the resonance point of a powertrain with a PRHTS does not exist in the resonance region of the engine. A dynamic and mathematical model of a powertrain with a PRHTS was developed to study the resonance characteristic of the powertrain. The amplitude-frequency characteristic curve of a powertrain for different speed ratios was obtained. The effect of torsional stiffness of the coupling and engine shock absorber on the amplitude-frequency characteristics of a powertrain with a PRHTS were examined. The simulation result indicated that it was necessary to exclude the resonance frequencies of the powertrain with a PRHTS from the operation range of the engine.