Quantification of dynamic forces applied by engine fuel injector by inverse methods

The Transfer Path Analysis relies on the estimation of the dynamic forces at the connecting points between the vibratonal source and its receiving structure. Inverse methods are widely used, in which a matrix of measured accelerances is inverted at each frequency and used with the operational acceleration data to find the forces. However, the results can be unreliable due to the poor conditioning of this matrix. In this article, some recently proposed techniques to deal with the problem of ill conditioning are applied on an industrial case : the estimation of the dynamic forces applied by a fuel injector on a receiving structure, in the frequency range 0- 15 kHz. In a first step, the experimental procedure has been defined and validated using artificial excitation. In a second step, it has been applied with different type of fuel injector. This article details the selection of optimised sensor location to reduce the condition number of the accelerance matrix and the use of improved singular value rejection methods.