An efficient analytical approach to assess root cause of nonlinear electric vehicle gear whine

Abstract

Noise, vibration, and harshness (NVH) issues pose considerable challenges for electric vehicle powertrain engineers. Gear vibrations generate an intrusive gear whine noise, with significant impact on the sound quality of electric powertrains. Dynamic transmission error (DTE) is the most quantitative indicator for gear NVH. Backlash, time variable meshing stiffness and damping contribute to DTE. Hence, a better understanding of these excitation sources is essential. A gear tribodynamics model is developed using potential energy method to estimate time variable meshing stiffness (TVMS). A fully analytical time-efficient model is proposed for lubricated contact stiffness based on transitions in the regimes of lubrication. The model accounts for the combined effects of surface elasticity and lubricant stiffness. Film thickness and damping coefficients are transiently updated at each instant during meshing cycle. The predictions from this model are compared with measured results from the literature and predicted results from Hertz contact model. The lubricated contact model successfully shows the contribution of the lubricant stiffness to TVMS and its variations with elasticity and viscosity parameters during meshing cycle. Gear harmonic and super-harmonic resonances are accurately estimated in terms of amplitude, frequencies and stiffness softening nonlinearities. Time history responses and phase-displacement diagrams show good agreement with the gear dynamics response at the main harmonic and second super-harmonic frequencies. The proposed model has a reasonable accuracy, significantly better than those from Hertzian contact models, and is considerably time efficient in comparison to numerical EHL solvers.

The Impact of Pedestrian Distraction on Safety Behaviours at Controlled and Uncontrolled Crossings

“…This may have implications for interactions between pedestrians and electric vehicles. Electric vehicle noise output is much lower than that of internal combustion engines, with research being conducted to predict the intrusive noise of electric vehicles [35] in order to further reduce it. However, although previous research has found that distracted pedestrians are poorer at detecting approaching vehicle noise, their gap acceptance is unaffected [36].…”

System Modeling and Simulation for Investigating Dynamic Characteristics of Geared Symmetric System Based on Linear Analysis

“…To determine the key parameters related to the specific noise and vibration issues, linear analysis can be performed as a fundamental step to reveal the critical system parameters relevant to the NVH problems in question [1][2][3][4][5][6][7]. When it comes to examining system responses, the analytical approach is commonly more efficient for diagnosing and improving vehicle driveline problems under symmetric conditions than the experimental method, as experiments generally require more significant costs and time than simulations [16][17][18][19].…”

“…To verify this measurement, the authors exploited it to compare the theoretical and experimental methods. Mughal et al introduced a gear tribodynamics model using the potential energy method to estimate time variable meshing stiffness (TVMS) [17]. In this research, the authors suggested a fully analytical and time-efficient model for lubricated contact stiffness based on transitions in the regimes of lubrication.…”

Sound Quality Performance of Orthogonal Antisymmetric Composite Laminates Embedded with SMA Wires

“…Although the engine is no longer the primary source of noise for new energy vehicles, the sound pressure level in such vehicles is significantly lower than that of conventional vehicles. However, the acoustical comfort of new energy vehicles has not been significantly improved, and the acoustical quality problem is more outstanding [5][6][7]. The main cause is the alteration of sound quality parameters such as loudness, sharpness, and roughness brought on by structural resonance and abnormal noise.…”