Scheme Design and Optimal Selection for HEV Planetary Gear Coupling Mechanism

Esmail

Modelling and Simulation in Engineering

2020

The basic relationships among gear ratios, velocity succession, torque directions, power ratios, energy losses, and efficiency are derived from first principles. The techniques presented here can be applied to ordinary, planetary, or mixed gear trains. Also, these techniques provide more insight into how power is flowing through the different parts of the mechanism. Power flow relationships are a helpful tool to study power amplification and power circulation in multipath transmissions. They also provide more insight into how the gear pair entities (GPEs) or gear train entities (GTEs) affect total power losses and allow immediate derivation of the overall efficiency. A representative two-input mechanism is analyzed to demonstrate the effectiveness of improved techniques. The theoretical results are compared with experimental data of previous work. The theoretical and experimental curves exhibit identical trends with a distinct jump in friction loss. The jump is explained by a change in the way of the power flow through the mechanism. The conditions under which power circulation occurs are determined. The results have important implications for understanding how to improve the efficiency of multipath power flow systems.

Section: Introductionmentioning

confidence: 99%

Power Flow Simulation for Two-Degree-of-Freedom Planetary Gear Transmissions with Experimental Validation

Esmail

Modelling and Simulation in Engineering

2020

Int.J Automot. Technol.

“…And appropriate evaluation criteria (Zhu et al, 2010) can be established to reach the required optimums. Given the size of gearbox, gears' layout, location of motor and assembling convenience, the last scheme in Figure 6 is chosen as the structure of EMT.…”

Section: Prototyping Of Emt For Phev Applicationmentioning

confidence: 99%

Systematic synthesis method and prototyping of fixed-axle vehicular electrified mechanical transmission

Zhang

Zhong

Chen

2015

In the process of mechanism creative design, structure synthesis is the primary and the most important issue. This paper proposes a systematic and automatic synthesizing method of fixed-axle gear sets by means of morphological analysis. And the process is implemented to synthesize Electrified Mechanical Transmission (EMT) schemes which are parallel hybrid electric transmission composed of fixed-axle gear sets. First, independent design parameters as well as feasibility constraints and consistency conditions are defined by analyzing the structure and functions of EMT. According to these boundary conditions, structure variables such as the quantity of components and their connection relationship are solved. Then, the scheme quantity of each structure type is synthesized. Secondly, based on the abstraction of practical mechanisms with topology models, the corresponding adjacency matrixes are derived, and they are used to filtering unqualified schemes and retrieve all potential transmission paths of the remaining schemes. These potential transmission paths are further used to find out the layout and operating mode of each scheme. Finally, all schemes satisfying the structural and functional requirements are synthesized. For example, one EMT prototype is built based on one of the final schemes found and an ICE car is modified to adapt to such transmission. Vehicle test results verify the effectiveness and feasibility of the chosen transmission scheme.

“…In all types of the power coupling mechanism used in HEV, the double planetary gear power coupling mechanism is widely used because of its properties of small size, light weight, strong bearing capacity, and high transmission efficiency [3]. Planetary gear is widely used in the coupling of hybrid electric vehicles, and its dynamic characteristics directly affect the transmission performance of the coupling mechanism.…”

Section: Introductionmentioning

confidence: 99%

Analysis and Optimization of the Vibration and Noise of a Double Planetary Gear Power Coupling Mechanism

Zhou

Zuo

Zheng

2018

Shock and Vibration

As the key component of a hybrid electric vehicle (HEV), the dynamic performance of the power coupling mechanism is found to have a significant effect upon the vibration and noise of the whole vehicle. In this paper, a dynamic model with rigid and flexible bodies of a double planetary gear power coupling mechanism is established. Then, the characteristics of the bearing constraining forces in time domain and frequency domain are simulated and analysed. At the same time, the finite element model of the housing of the power coupling mechanism is established. Then, the vibration response of the housing is analysed under the excitation of the bearing constraining forces, and the vibration displacement of the housing surface is obtained. Furthermore, based on the vibration displacement of the housing surface, a prediction model of housing radiating noise is established. Then, the radiating noise characteristics of the housing and the acoustic contribution of each panel are analysed. Finally, the free damping structure and new stiffener structure are adopted to optimize the rear end cover of the housing. The optimization model based on the vibration acceleration of the rear end cover surface is established by applying K-S function and response surface method. Then, the optimization model is solved by applying the sequential quadratic programming to obtain the optimal structure of the housing. The optimization results demonstrate that the acoustic power level after optimization is decreased by 3.94 dB, 3.92 dB, 5.59 dB, and 2.84 dB at frequencies of 770 Hz, 870 Hz, 1650 Hz, and 2480 Hz, respectively. Therefore, the optimization effect of the housing structure is obvious, and this can be the theoretical basis and reference for reducing the vibration and noise of the power coupling mechanism.