NVH-INTEGRATION OF ALL-WHEEL-DRIVEN DRIVETRAINS IN RESPECT OF DOWNSIZING AND VIBRATIONAL TRADE-OFFS

摘要

The customers and legislators demand of lower CO_2 emissions from passenger cars is accomplished by downsizing combustion engines. Modern combustion engines can be characterized by a reduction of displacement with a high low-end-torque due to supercharging. The size reduction is often combined with a reduction of cylinders. That leads to a torque fluctuation with higher rotational irregularities (RI), which excite the drivetrain and may cause NVH-issues (NVH: Noise, Vibration and Harshness). In this paper an all-wheel-driven drivetrain with a downsized four-cylinder-diesel-engine is investigated with regards to the acoustic behaviour of the whole passenger car. Due to the different excitation mechanisms (impulsive excitation due to tip-in and periodical excitations due to the combustion) a trade-off in the driveline can be detected. For reducing this conflict a control strategy of existing all-wheel-drive components is suggested.