Search Results

It is well known that backpressure is one of the important parameters to be minimised during the exhaust system development. Unfortunately, during the first phases of an engineering process of a new engine, engine prototypes are not available yet. Due to this the exhaust system backpressure is generally evaluated using simulation software, and/or measuring the backpressure by a flow rig test at room temperature. Goal of this paper is to compare exhaust backpressure results obtained respectively: i) at the room temperature flow rig; ii) at the engine dyno bench; iii) by simulation with one of the most common 1D fluidodynamics simulation tool (Gt-Power). A correlation of the three different techniques is presented.

Through a case history, we report a procedure to age exhaust flexibles on a Road Simulation Bench, in order to reproduce the acoustic failures occurred during vehicle ageing. The bench ageing has been the key instrument to solve an acoustic problem (a ring) observed on the vehicle after ageing. It is shown that it was mainly due to the partial loosening of the external outer braid (which caused the flapping of the outer braid against the bellows).