The enhancement of emission regulations and the enforcement of mileage regulations are a global phenomenon. To make engines satisfactorily meet such regulations in the short term, innovations in engine development technology are essential.
In this paper, an innovative technique for the optimization of the transient performance of engines, ‘STATE’, was developed. Recently, the Design of Experiments (DoE) has gradually been used to optimize the static performance of engines, however it takes a long time to create a response surface model including all operating conditions of an engine. The newly developed technique ‘STATE’ shown in this paper was able to create the response surface model in a very short time by means of multivariate analysis of the transient performance data of time series.
A new transient engine test cycle, named ‘universal mode’, was developed for the efficient creation of response surface models. The experimental data of the ‘universal mode’ was analyzed by the newly developed technique ‘STATE’, and a response surface model was created. The model could be used for the prediction of NOx, smoke and so on under each regulation test cycle, for example, JE05*1, FTP*2 and ETC*3. Moreover it could be also used for the optimization of the engine control system, hence the engine performance and emissions are improved.
It was found that the NOx and smoke predicted by this model showed good agreement with the measured data. The better control value for the engine control system was derived by optimal value analysis using the response surface model. The newly developed technique ‘STATE’ improved the efficiency of the development of the response surface model by more than 90% in terms of time, in comparison with that of the DoE technique.
An example of the optimization of the transient engine performance under the JE05 engine cycle, Japanese regulation mode, by means of the newly developed technique is demonstrated.