Simplified Automatic Transmission Model for a Powertrain Simulator.

A powertrain simulator with a simplified automatic transmission model was developed to aid the development and verification of control schemes for automatic transmission systems. To simplify the model, characteristics of engagement, slippage and release of clutches and one-way clutches were described approximately as a single model of clutches and one-way clutches respectively. And a conventional mathematical model for geartrains which was described by 79 equations was replaced by a model which was described by 9 equations. Algebraic loops was removed in the new model, and as a result, the run-time of the simulator was reduced by about one-sixth. This simulator was used to simulate acolal simple clutch pressure control during shifting and it was confirmed that this simulator was capable to examine the effect of shift shock reduction control.