| 摘要 |
<p>A method of constructing a piecewise linear engine performance model, comprises the steps of:
(a) providing a non-linear engine performance model which iteratively calculates engine performance variables y from a plurality of sub-models, each sub-model representing the performance of a component of the engine;
(b) defining a plurality of engine power conditions, each engine power condition being defined by one or more engine state variables x;
(c) for each of the engine power conditions, using the non-linear engine performance model to determine partial derivatives ´y of the engine performance variables y with respect to engine control variables u and with respect to the engine state variables x, the values of the partial derivatives ´y being determined so that, on integrating the partial derivatives ´y, the error between steady state values for the engine performance variables y calculated by the non-linear engine performance model and steady state values for the engine performance variables y calculated from the integrated partial derivatives ´y is reduced or eliminated; and
(d) constructing a piecewise linearised engine performance model in which calculation of the engine performance variables y involves combining each of the engine control variables u and the engine state variables x with the respective partial derivative ´y.</p> |
