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Exhaust pressures (P3) are hard parameters to measure and can be readily estimated, the cost of the sensors and the temperature in the exhaust system makes the implementation of an exhaust pressure sensor in a vehicle control system a costly endeavor. The contention with measured P3 is the accuracy required for proper engine and vehicle control can sometimes exceed the accuracy specification of market available sensors and existing models. A turbine inlet exhaust pressure observer model based on isentropic expansion and heat transfer across a turbocharger turbine was developed and investigated in this paper. The model uses 4 main components; an open loop P3 orifice flow model, a model of isentropic expansion across the turbine, a turbine and pipe heat transfer models and an integrator with the deviation in the downstream turbine outlet parameter.

Exhaust temperatures are some of the hardest parameters to measure and estimate based on the range of the signal and the environment that an engine exhaust system creates. Accurate exhaust temperature inputs in vehicle and engine control systems are important for performance, fuel economy, emissions and aftertreatment control. A turbine inlet exhaust temperature observer model based on isentropic expansion and heat transfer across a turbocharger turbine was developed and investigated in this paper. There are 4 main components used to model the exhaust temperature; an open loop exhaust manifold gas temperature mass/energy model, an isentropic expansion across the turbine, a turbine heat transfer model and an observer using the downstream turbine outlet temperature. Another method using only a reverse isentropic expansion model and heat transfer parts of the observer model was analyzed and compared to the observer model.