Controllers coordination for diesel engines NOx emissions management

Abstract

Tightened diesel pollutants emissions regulations rendered the performance of steady-state map controls, which are commonly used in Internal Combustion Engine (ICE) management, unsatisfactory. To overcome these performance constraints, control systems must deal with engine transient operation, subsystem coupling and the trade-off between different requirements to efficiently manage the engine. The research demonstrates the utility of a reference generator for coordinating the air path and combustion control systems of a turbocharged diesel engine for heavy-duty applications. The control system coordinator is based on neural networks and allows following different engine-out Nitrogen Oxides (NOx) targets while satisfying the load request. The main idea is to generate air path targets, intake O2 concentration and Intake MAnifold Pressure (IMAP), in accordance with the ones of the combustion control system, engine load, in the form of Brake Mean Effective Pressure (BMEP), and NOx. As a result, the air path control system provides the global conditions for the engine proper operation, while the combustion control responds to rapid changes in the engine operating state and compensates for any remaining deviations from load and NOx targets. The reference generator, as well as the two controllers, are suitable for real-time implementation on rapid-prototyping hardware. The performance was overall good, achieving average deviations of 0.1 bar for the BMEP and 150 ppm for the NOx.