A Review of the State-of-the-Art Emission Control Strategies in Modern Diesel Engines

Accurate prediction and control of diesel engine-out emissions are vital areas of interest for automotive manufacturers and researchers. This article presents an investigative review of performance and emission control improvements in diesel engines over the past few decades. A brief background of environmental organizations like the Environmental Protection Agency has been included because they initiated stringent emission norms. These requirements caused diesel engine development to be a more tedious task and also triggered various technologies employed by engine manufacturers to meet the new norms. This review focuses on various diesel engine modeling methods that have evolved during the last few decades and have contributed to the technological advancement in modern diesel engines. Three types of modeling methods and their applications are discussed in detail along with a few controlling methods using different control theories. A detailed emphasis on recent engine control strategies reviews controlling gridlocks and viable solutions in diesel engines. Significant challenges such as model fitness, accuracy, robustness, and precise predictions that provide extensive scope for researchers working in diesel engine out emission control are addressed. Various advancements in optimized engine model development for further performance enhancement are also reported.