NVH characteristics of thermoplastic composite engine covers

Thermoplastic composites have been increasingly used for automotive under-the-hood applications, like engine covers. To compete with other lightweight materials, such as aluminium and magnesium, the thermoplastic composite has to demonstrate sound structural performance, such as long-term durability and noise, vibration and harshness (NVH) performance. In the current study, the NVH characteristics of the thermoplastic composite engine cylinder head covers were studied. Tests were carried out on a vehicle chassis dynamometer in an anechoic chamber under loaded wheels and operating drive conditions. NVH performance of the thermoplastic composite covers was processed for spatial transmissibility, sound pressures and psychoacoustic parameters. Results demonstrate that a well-designed thermoplastic composite cover can achieve the same structural requirements (NVH) as other lightweight metal covers (magnesium and aluminium), in addition to provide substantial cost saving and weight reduction.