Abstract
For the improvement of the calibration process in CI engine, it is required to optimize both fuel injection timing and its rate by using the model based control (MBC) on ECU (on-board) during cycle-by-cycle calculation. The on-board MBC is consisted of 6 calculation models, such as a gas flow, a splay, a formation of mixture, combustion, an ignition delay, and a heat loss. The present study developed the on-board heat loss model, which needs to calculate the on-board gas flow model developed in our successive study. This model enables to predict the following five parameters, such as a wall heat flux, a wall heat loss, a polytropic index, an in-cylinder gas temperature, and auto-ignition timing. For the calculation of the on-board heat loss, we improved the new model to discretize the calculation points and to reduce the calculation load, referred to as the discretized heat loss model. Furthermore, the polytropic index and the auto-ignition timing were estimated by using the discretized heat loss model, whose RMS error was 0.1% and the estimation error was less than 1 deg., respectively, compared with the results from the 1-D engine simulation. In addition, the calculation time for the model was less than 40 μs, which corresponded to the time within 1 cycle.
