System for controlling engine exhaust temperature

The present invention relates generally to fuel limiting strategies for internal combustion engines, and more specifically to such systems for controlling engine exhaust temperatures during engine operation. A system is provided for limiting engine exhaust temperature to a maximum temperature limit. The system is operable to limit either a first or a second fueling parameter in accordance with an engine exhaust temperature estimation model. An engine exhaust temperature-limited fueling command is computed from the respective fueling parameter, and fuel supplied to the engine is limited thereby in order to maintain the actual engine exhaust temperature below the maximum temperature limit. In one embodiment, the engine exhaust temperature model is based on current values of engine speed, intake manifold temperature, mass charge flow, default fuel command parameters, and a first set of model constants. In an alternative embodiment, the engine exhaust temperature model is based on current values of engine speed, intake manifold temperature, intake manifold pressure, mass charge flow, default fueling parameters, and a second set of model constants including a lower heating value of fuel constant.