Multibody dynamics analysis for the coupled vibrations of a power split hybrid electric vehicle during the engine start transition

Abstract

Minimizing working time of the internal combustion engine is an important method for hybrid electric vehicles to save energy and reduce emissions. However, vibrations caused by frequent engine starts and stops deteriorate driveability and ride comfort. Especially in power split hybrid vehicles, there is no kinematically decoupled device between the engine and transmission, so that vibrations transfer from the powertrain to the car body through not only engine mounts but also the driveline system. Hardware test results show that the longitudinal vibration of seat track is the most severe with a maximum peak-to-peak acceleration of 1.8 m/s 2. In this study, dynamic models of the driveline system and the powertrain mounting system are respectively established in detail. The natural characteristic analyses of the two dynamic models reveal that engine order vibrations can stimulate a series of low-frequency resonances during the engine starts, which is finally embodied in the car body vibrations. Then, two dynamic models are coupled together to analyze the transient dynamic characteristics associated with engine starts. It is evident by simulations that the longitudinal vibration of car body is mainly transferred by the driveline, whereas the vertical vibration of car body is mainly transferred by the powertrain mounting system. Besides, the initial crankshaft position of the gasoline engine has an obvious effect on the engine order vibration, and further results in different transient responses of the full vehicle system.

Powertrain modelling for engine stop–start dynamics and control of micro/mild hybrid construction machines

“…By replacing equations (2) to (5) into equation (1), the belt transmission is represented by Pinion-ring gear transmission sub-model. Through the gear transmission, the dynamic relations between the starter and engine can be expressed as…”

“…There has been much research effort on the hybridisation technologies in terms of fuel economy and environmental impacts for various applications ranging from transportation to construction equipment. In the construction site, although full hybrid electric systems 1 could offer many advantages over traditional configurations, they suffer from a comparatively high cost for the implementations, reliability and consumer acceptability. Recently, micro/mild hybridisation (MMH) has been widely used for modern vehicles due to its advantages, including high fuel efficiency, low emission and especially, low cost and easy installation regardless of the drivetrain configuration.…”

“…There are a number of studies on ESS control for both conventional vehicles 5 and hybrid vehicles. 1,6 Although the engine performance could be improved using the suggested methodologies, the control optimisation is complex and carried out offline. These ESS control approaches lack adaptability in the real-time applications and normally consist of non-linearities and uncertainties.…”

Modeling and Dynamic Response Analysis of a Compound Power-Split Hybrid Electric Vehicle During the Engine Starting Process

“…Zeng [29][30] established a power-split HEV model including an engine model based on a BP neural network, and found that the torque change rate of the power source is the main reason for large vehicle jerk during the mode switching process. Using experimental data from a powersplit HEV, Liu [31][32] found that the longitudinal vibration of the seat track was most affected by the engine initial angle during the engine starting process. Wang [33] tested vehicle jerks in the mode transition process with engine starting, and found that the main reason for the obvious jerk was the engine ripple torque.…”

An experimental investigation of resonance sources and vibration transmission for a pure electric bus

“…Yi et al 13 utilized an integrated method comprising Campbell diagram, modal energy, and speed sweep analysis to identify the resonance of the electromechanical system. Liu et al 14 found that the natural-frequency-overlapped vibration increased the intensity of the resonance and the vertical and longitudinal vibrations were mostly transferred by powertrain mounts and driveline, respectively. Chen et al 15,16 proposed a non-model-based expansion technique to expand the vibration characteristics at a sparse set of points to a much larger set of points without the use of a finite element model.…”