Abstract

Exhaust gas recirculation (EGR) has emerged as a pivotal strategy to reduce nitrogen oxide (NOx) emissions from diesel engines, which significantly contribute to air pollution and environmental degradation. NOx emissions pose serious concerns due to their role in forming smog, acid rain, and adverse health impacts.By recirculating a portion of the exhaust back into the intake manifold, EGR reduces these emissions by restricting the manufacturing of NOx and effectively lowers combustion heat.This process has become an essential focus of research and development in modern diesel engine technology. While EGR effectively reduces NOx emissions, it presents trade-offs, including increased particulate matter (PM) emissions, reduced fuel efficiency, and potential engine wear due to deposit formation. These challenges have spurred the development of advanced EGR technologies, such as variable-rate systems and EGR cooling mechanisms, to optimize its benefits.The efficiency of EGR is further enhanced by combining it with in addition pollution control strategies like diesel particulate filters (DPFs) and selective catalytic removal (SCR). This review also explores EGR’s potential in future applications, particularly in hybrid powertrains and engines running on alternative fuels, such as biodiesel and hydrogen. Adaptive EGR systems, utilizing real-time sensors and machine learning algorithms, hold promise for improving performance and efficiency while addressing operational challenges. These innovations highlight the need for a balanced approach to implementing EGR, ensuring emissions reduction aligns with maintaining engine durability and operational efficiency.EGR remains a cornerstone technology for meeting increasingly stringent environmental regulations. Its evolution underscores its role in advancing sustainable diesel engine designs and reducing the environmental footprint of internal combustion engines. By continuing to innovate and integrate EGR with emerging technologies, the automotive industry can meet the dual goals of minimizing emissions and achieving optimal engine performance.

Keywords:Exhaust gas recirculation (EGR), NOx emissions, diesel engines, engine efficiency, emissions control, combustion optimization

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1. Heywood JB. Internal Combustion Engine Fundamentals. 2nd ed. New York: McGraw-Hill Education; 2018.
2. Johnson TV. Diesel engine emissions and their control. SAE Int. 2008;52(1):23–37.
3. Zhao H. Advanced Direct Injection Combustion Engine Technologies and Development. Cambridge: Woodhead Publishing; 2010.
4. Dec JE. A conceptual model of diesel combustion based on laser-sheet imaging. J Engines. 1997;106(3):1319–1348.
5. Reitz RD. Directions in internal combustion engine research. Combust Flame. 2013;160(1):1–8.
6. Hountalas DT, Mavropoulos GC, Binder KB. Effect of exhaust gas recirculation (EGR) temperature for various EGR rates on heavy duty DI diesel engine performance and emissions. Energy. 2008;33(2):272–283.
7. Rajan K, Senthilkumar KR. Effect of exhaust gas recirculation (EGR) on the performance and emission characteristics of diesel engine with sunflower oil methyl ester. Jordan J Mech Ind Eng. 2009;3(4):306–311.
8. Shahid EM, Jamal Y. A review of biodiesel as vehicular fuel. Renew Sustain Energy Rev. 2008;12(9):2484–2494.
9. Atadashi IM, Aroua MK, Aziz AA. High quality biodiesel and its diesel engine application: a review. Renew Sustain Energy Rev. 2010;14(7):1999–2008.
10. Kusaka J, Okamoto T, Daisho Y, Kihara R, Saito T. Combustion and exhaust gas emission characteristics of a diesel engine dual-fueled with natural gas. JSAE Rev. 2000;21(4):489–496.
11. Ghosh S, Dutta D. Performance and emission parameters analysis of gasoline engine with EGR. Int J Eng Res Dev. 2012;4(10):8–12.

Abstract

Exhaust gas recirculation (EGR) has emerged as a pivotal strategy to reduce nitrogen oxide (NOx) emissions from diesel engines, which significantly contribute to air pollution and environmental degradation. NOx emissions pose serious concerns due to their role in forming smog, acid rain, and adverse health impacts.By recirculating a portion of the exhaust back into the intake manifold, EGR reduces these emissions by restricting the manufacturing of NOx and effectively lowers combustion heat.This process has become an essential focus of research and development in modern diesel engine technology. While EGR effectively reduces NOx emissions, it presents trade-offs, including increased particulate matter (PM) emissions, reduced fuel efficiency, and potential engine wear due to deposit formation. These challenges have spurred the development of advanced EGR technologies, such as variable-rate systems and EGR cooling mechanisms, to optimize its benefits.The efficiency of EGR is further enhanced by combining it with in addition pollution control strategies like diesel particulate filters (DPFs) and selective catalytic removal (SCR). This review also explores EGR’s potential in future applications, particularly in hybrid powertrains and engines running on alternative fuels, such as biodiesel and hydrogen. Adaptive EGR systems, utilizing real-time sensors and machine learning algorithms, hold promise for improving performance and efficiency while addressing operational challenges. These innovations highlight the need for a balanced approach to implementing EGR, ensuring emissions reduction aligns with maintaining engine durability and operational efficiency.EGR remains a cornerstone technology for meeting increasingly stringent environmental regulations. Its evolution underscores its role in advancing sustainable diesel engine designs and reducing the environmental footprint of internal combustion engines. By continuing to innovate and integrate EGR with emerging technologies, the automotive industry can meet the dual goals of minimizing emissions and achieving optimal engine performance.

Keywords:Exhaust gas recirculation (EGR), NOx emissions, diesel engines, engine efficiency, emissions control, combustion optimization

🔒 This is a subscription article

Full text is available to subscribers and institutional members. Please choose an option below to access it.

1. Heywood JB. Internal Combustion Engine Fundamentals. 2nd ed. New York: McGraw-Hill Education; 2018.
2. Johnson TV. Diesel engine emissions and their control. SAE Int. 2008;52(1):23–37.
3. Zhao H. Advanced Direct Injection Combustion Engine Technologies and Development. Cambridge: Woodhead Publishing; 2010.
4. Dec JE. A conceptual model of diesel combustion based on laser-sheet imaging. J Engines. 1997;106(3):1319–1348.
5. Reitz RD. Directions in internal combustion engine research. Combust Flame. 2013;160(1):1–8.
6. Hountalas DT, Mavropoulos GC, Binder KB. Effect of exhaust gas recirculation (EGR) temperature for various EGR rates on heavy duty DI diesel engine performance and emissions. Energy. 2008;33(2):272–283.
7. Rajan K, Senthilkumar KR. Effect of exhaust gas recirculation (EGR) on the performance and emission characteristics of diesel engine with sunflower oil methyl ester. Jordan J Mech Ind Eng. 2009;3(4):306–311.
8. Shahid EM, Jamal Y. A review of biodiesel as vehicular fuel. Renew Sustain Energy Rev. 2008;12(9):2484–2494.
9. Atadashi IM, Aroua MK, Aziz AA. High quality biodiesel and its diesel engine application: a review. Renew Sustain Energy Rev. 2010;14(7):1999–2008.
10. Kusaka J, Okamoto T, Daisho Y, Kihara R, Saito T. Combustion and exhaust gas emission characteristics of a diesel engine dual-fueled with natural gas. JSAE Rev. 2000;21(4):489–496.
11. Ghosh S, Dutta D. Performance and emission parameters analysis of gasoline engine with EGR. Int J Eng Res Dev. 2012;4(10):8–12.