The dynamic behavior of the lower portion of a 4 cylinder in line block can be adequately described by a Spring-Mass model. Small point masses represent the crankshaft bearing caps; these are connected by rigid lines to a large mass representing the body of the cylinder block (in its simplest form).
This model, provided with a means of identification, is presented here. Its results and performances are compared to those of a finite element model and to experimental measurements.
It is used in order to: set the model, perform structural evaluation, optimize the structure through sensitivity analysis, help in establishing specification and give useful information in the initial design stage.
This model constitutes an essential comprehension tool and a functional method for information derived from various sources : tests, calculations, research.
Structural improvements affect acoustical comfort, performance and reliability.