Dp 594 en
Exhaust Gas Recirculation and Air Flow virtual sensors for internal combustion turbocharged engines
Author: Jaroslav Tabaček
The emission standards are regularly made more stringent these days which put pressure on automotive industry to create advanced engine control that require the accurate measurements. Also, replacing hardware sensors with virtual sensors without loss of accuracy is highly desirable due to their lower production cost. The exhaust gas recirculation (EGR) mass flow value is very important information for controlling combustion emissions and its physical measuring is difficult, which makes it an ideal candidate for virtual sensing. This thesis describes a process of a creation of EGR mass flow virtual sensor for heavy-duty turbocharged diesel engine with EGR, which could be an alternative for Venturi sensor. The air mass flow is closely related to the EGR mass flow therefore the air mass flow virtual sensor is created as a by-product. A basis of good virtual sensor is reliable model, so few modelling approaches for design of engine's air path model are reviewed. Each of them requires a model creation for each air path component. The particular components are introduced, a polynomial model is created for each one and real steady-state data from a diesel engine are used for their identification. The complete air path model structures which merge the component models are developed and discussed from robustness, accuracy and complexity point of view. Eligible models are simulated and their applicability for further use is also discussed. Based on these findings, the best model is used to create virtual sensor. The virtual sensor design respects all eligible measurements available in a common production engine, which results in simplifying the engine model structure. The final observer design is a combination of a reduced engine model, lambda sensor measurements and a linear Kalman filter with scheduled gain. The possibility of the implementation on Engine Control Unit is discussed.
- Tabaček Jaroslav, mailto:firstname.lastname@example.org