Design and Control of an Automated Cooled Exhaust Gas Recirculation System for a Teaching and Research Engine Test Cell

Given the need of the automotive industry to improve fuel efficiency, many companies are moving towards lean burn and low temperature combustion regimes. Critical control of these methods requires an accurate Exhaust Gas Recirculation (EGR) system that can maintain its desired rate and temperature. In this area, the literature illustrates different methodologies to control and monitor this EGR system; however, it lacks a discussion of how the non-linear nature of wave dynamics and time responses of an engine must be taken into account. In order to perform research into the use of EGR for these combustion regimes, an automated, closed-loop EGR system that uses a microprocessor to compute the slope change of the EGR rate and temperature as part of its feedback algorithm was constructed for use in a teaching and research laboratory. The findings illustrate that the system works as intended by replicating known combustion trends with EGR. Moreover, the use of banded control involving slope change calculations allows the system to maintain the EGR rate and temperature to within 1% and 1K of user-defined setpoints, respectively. The continued enhancement of this laboratory through an updated design methodology involving linkage to the fuel injection system (i.e., rail pressure) and subsequent application of the EGR system serve as a teaching opportunity while allowing for future research into more advanced combustion regimes.