Experimental and numerical analysis of the seat track vibrations caused by engine starts in a power-split hybrid electric vehicle

Abstract

An important method for saving energy and reducing the emissions from hybrid electric vehicles is to shorten the working time of the engine, which results in frequent engine starts and stops. The accompanying vibration and noise problems cause the driveability and the ride comfort to deteriorate significantly. In this study, experiments on the vibrations of the driver’s seat track are performed and analysed to evaluate quantitatively the vibrations during the engine start. The measurement results show that vibrations in the longitudinal direction are the most severe, whereas vibrations in the lateral direction are the weakest. Based on the test results, a full-vehicle multi-body dynamics model, including the driveline, the powertrain mounts and the suspensions, is developed and verified. Some countermeasures are researched using numerical simulations to reduce the uncomfortable longitudinal vibrations. Optimization analysis demonstrates that the effects of the reduction in the vibrations are limited even by the optimal initial crank angle, the start-up time and the stiffnesses of the torsional damper and the half-shafts. Hence, parameter optimizations cannot completely eliminate the uncomfortable vibrations. Fortunately, as compensation control benefits from the fast response of electric motors in hybrid vehicles, it can play an active role in reducing the longitudinal seat track vibrations and in improving the ride comfort. However, the effect of the compensation controller greatly depends on the accuracy of the torque estimator.

Research on the energy control of a dual-motor hybrid vehicle during engine start-stop process

“…Liu et al [17] tested the vibrations of the driver's seat and evaluated them during the engine start. A full-vehicle dynamic model was built to research the countermeasures to reduce the unwanted longitudinal vibration.…”

Investigating the effect of engine noise on power management strategy of a hybrid electric vehicle

“…Using Figure 2, in this revolution the maximum achievable value of the engine power (P E ) for which the engine noise is less than the road noise is determined. The minimum value between this power value and the upper power variation range limit (shown in equations (3) and (4)) is introduced as the new upper limit. The flowchart of this process is presented in Figure 7.…”

“…In addition, the noise emission of vehicles is also a crucial problem, especially in urban transportation, as the number of people exposed to traffic noise is way more than the other noise sources. [1][2][3] Continuous exposure to high levels of noise results in some diseases such as sleep disturbance, tinnitus, and cardiovascular problems. 4 Hence, reducing the vehicle noise level is also necessary.…”

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.…”