Abstract
Keywords:
Plastic intake manifold, Operating deflection mode shape, Ordinary coherence function
Abstract
Recently, material of the intake manifold has been changed to molded plastic from cast aluminum. This material change is a successful application to achieve a goal of weight reduction, maintaining cast and performance as before. However, in view of noise and vibration, low stiffness of the plastic intake manifold can result in increase of noise and vibration level. This paper is first concerned with identification of noise and vibration characteristics of the plastic intake manifold. To do this, we perform the powertrain anechoic chamber test under firing and motoring condition with different throttle valve opening. From this experiment, it is possible to find out which noise source is dominant among the combustion, mechanical and aerodynamic noise. Then to grasp the noise and vibration characteristics of plastic intake manifold, coherence function analysis and operating deflection mode shape analysis are carried out. This paper is closed with presentation of how the deadener can reduce the noise and vibration level of the plastic intake manifold.