Powertrain radiated noise is an important design factor that must be evaluated during the concept phase of the design process. Unfortunately, the tools currently available to evaluate radiated noise, empirically derived relationships, detailed CAE models, or experimental data, are not useful during this critical phase of the design when many of the fundamental design aspects are determined. Empirical models are too general to capture the impact of many typical design decisions, and detailed CAE models or hardware tests are not practical due to the level of design detail necessary, the cost involved, and the timing.
This paper lays out a simplified approach for the prediction of powertrain radiated noise that is useful for both quantitative and qualitative evaluation of design alternatives. The methodology used first details the kinematic engine excitation due to valvetrain and cranktrain inertia loads and combustion forces, and then applies this excitation to a rigid powertrain mass representation in order to predict radiated noise. This simplified model can then be used to predict the noise radiation due to changes in the cranktrain and valvetrain inertial loads, engine torque or cylinder pressure, or the overall powertrain mass and inertia properties.