Experimental and numerical analysis for the transmission gear rattle in a power-split hybrid electric vehicle

Experimental and numerical analyses are carried out for the investigation of the gear rattle issue appearing in a novel power-split hybrid transmission. The gear rattle in the transmission takes place mainly owing to engine excitations, unloaded gear pairs and gear backlashes. For the analysis of gear rattle phenomena, a non-linear dynamics model is established for the power-split hybrid driveline, and also acoustic measurements for the gear rattle in the hybrid vehicle are performed in a semi-anechoic chamber equipped with a single-axle dynamometer. It is clearly demonstrated by test results that the gear rattle occurs when electric machines are idly operated. Numerical analyses are further undertaken according to the non-linear dynamics model, and noise sources of the gear rattle of this hybrid transmission are identified with simulation results. By optimisation of the hybrid vehicle control strategies, the rattle noise is obviously reduced and the vehicle comfort is improved as well.