Dual loop EGR mass flow rate estimation

Abstract

The key step of Diesel engine development is to keep low the emission and fuel consumption altogether, while the formation of some harmful emissions is counterproductive. Due to its complexity, turbocharged Diesel engines with low and high pressure exhaust gas recirculation systems give us a controlling challenge, where determining the recirculated exhaust gas mass flow rate is always an issue. This paper presents an experiment-based method for estimating the recirculated exhaust gas mass flow rate both in the high and the low pressure system. The estimated exhaust gas mass flow rates are function of the mean piston speed, the brake mean effective pressure, the exhaust gas recirculation valves and the exhaust brakes. In this case, the task of the exhaust brakes is to increase the recirculated exhaust gas mass flow rate. The paper presents the measurement-based characteristics of the mass flow rates in function of the inputs. Then the applied formulas are shown for steady state estimation. Finally, the comparison between the measurement-based estimation and the new method proves its suitability. The paper also gives the parameter values for testing the method in other engines. In further research the outcome will be used in a two-state composition-based mean-value engine model.