The system models valve closing actions and predicts dynamic loading on engine valves, which, says chief technology officer Gian Maria Olivetti, improves accuracy of deformation and stress calculations for valve fatigue life estimation.
“The dynamic loading during valve closing is a decisive factor in designing intake and exhaust valves,” explains Olivetti.
“With the new simulation method, we can quickly calculate the maximum expected valve loads, thus saving time and ensuring targeted development.”
In the design of intake and exhaust valves -- especially those with heavy supercharging or turbocharging – loading conditions during valve closing are particularly important, he explains.
The valve drive system is often still under development as the valves are being designed for new engine projects, restricting valve manufacturers to using simplified simulation models, which limit valve loading evaluation only to the base parameters – such as valve closing speed, valve spring return force and the clearance between valve stem and guide.
The problem here is that during the closing event, one side of the valve usually contacts the valve seat first, which can introduce heavy loading of the valve stem.
The new dynamic simulation model enables precise calculation of these loads, which in turn allows components to be configured optimally from the concept stage and life span to be determined more accurately pfront.
As well as fatigue life calculations, the load values associated with valve closing derived from the transient dynamic FE simulation can also be used to evaluate and rank alternative valve designs, according to Dr Guido Bayard, director technology valves, Federal-Mogul Powertrain.
“Different detail geometry, such as a stem undercut or conical underhead, has a major influence on the stress distribution,” he explains.
“With our simplified FE simulation, we can quickly draw conclusions on maximum valve loading and likely fatigue failure, and make sound decisions on design and material at an early stage of development.”