Although new materials and production techniques are being developed to reduce valve and seat wear, these advances have been outpaced by demands for increased engine performance. At present no rules exist to arrive at a satisfactory valve life. Each wear problem, therefore, has to be investigated, the cause isolated and remedial action taken. The objective of this work was to develop design and failure analysis tools for use in industry to assess the potential for valve recession and solve problems that occur more quickly.
A semi-empirical wear model for predicting valve recession has been developed based on data gathered from laboratory simulation experiments. A software program, RECESS, was developed to run the model. Model predictions are compared with engine dynamometer tests and bench tests. The model can be used to give a quantitative prediction of the valve recession to be expected with a particular material pair or a qualitative assessment of how parameters need to be altered in order to reduce recession.
Flow charts have been developed, based on a review of literature, failure analysis and modelling carried out, to assist in diagnosing and rectifying valve/seat failures and to help in reducing valve recession by design.
The valve recession model and design tools can be integrated into an industrial environment in order to help reduce costs and timescales involved in solving valve/seat wear problems.