What is it about?
This article explores the behavior of low-pressure exhaust gas recirculation (LP-EGR) transport phenomena in the intake manifold during engine transient operation. The research also examines the impact of sound wave propagation in the intake manifold on engine performance. The findings indicate that there is a trade-off between long intake lines that enhance engine volumetric efficiency at low engine speeds and short ones that facilitate quicker EGR transport. The authors also demonstrate the significance of EGR valve synchronization in preventing overshoot when the engine enters the EGR zone. Finally, they conclude that a 1D model can accurately simulate LP-EGR transport and intake manifold acoustics under transient operation by employing the measured valve positions.
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Why is it important?
The key technological aspects of this article are: - Investigation of the trade-off between long and short intake lines in terms of LP-EGR transport and engine performance. The findings demonstrate that long intake lines are beneficial for engine volumetric efficiency at low engine speeds, while short intake lines expedite EGR transport. - Elucidation of the importance of EGR valve synchronization in preventing overshoot when entering the EGR zone. The authors demonstrate that carefully coordinating the timing of the EGR and exhaust throttle valves can effectively mitigate overshoot and ensure smooth engine operation. - Validation of a 1D model for simulating LP-EGR transport and intake manifold acoustics under transient operation. The model's ability to accurately replicate measured CO2 concentrations confirms its suitability for predicting engine behavior in transient conditions. - Development of a methodology for studying LP-EGR in diesel engine transient operations. The methodology combines experimental measurements with a 1D model to provide a comprehensive understanding of the intricate interactions between LP-EGR transport, intake manifold acoustics, and engine performance. The paper has a number of important social implications. These include: - Improving engine performance and fuel efficiency: The research findings can be used to develop more efficient and cleaner diesel engines. This can have a positive impact on air quality and reduce greenhouse gas emissions. - Enhancing engine flexibility: The study shows that the intake manifold design can be optimized to improve engine performance at different engine speeds. This can help to make diesel engines more versatile and suitable for a wider range of applications. - Reducing emissions: The authors demonstrate that careful valve synchronization can help to prevent overshoot when the engine enters the EGR zone. This can help to reduce emissions, particularly harmful NOx emissions. - Increasing safety: By understanding the dynamics of EGR transport in the intake manifold, engineers can design systems that are more reliable and less prone to failures. This can help to improve the safety of diesel engines. - Promoting sustainable transportation: The research findings can be used to develop more sustainable diesel engines. This can help to reduce reliance on fossil fuels and improve air quality.
Perspectives
I am thrilled to share our findings, which have significant implications for the design and development of more efficient, cleaner, and safer diesel engines. We conducted a comprehensive study of the interplay between low-pressure exhaust gas recirculation (LP-EGR) transport and intake manifold acoustics in diesel engine transient operation. The results revealed a delicate balance between the benefits of LP-EGR, such as reduced NOx emissions, and the challenges of managing its transport dynamics during engine load transitions. One of the key insights from our research is the trade-off between the length of the intake manifold and its impact on engine performance. While longer intake lines can enhance engine volumetric efficiency at low engine speeds, they also delay the emptying of LP-EGR from the manifold, which can compromise transient response. Conversely, shorter intake lines facilitate faster EGR transport but may not provide adequate scavenging at lower engine speeds. Another important finding is the critical role of valve synchronization in preventing overshoot when entering the EGR zone. By carefully coordinating the timing of the EGR and exhaust throttle valves, we demonstrated that overshoot can be effectively mitigated, leading to smoother engine operation and improved emissions control. To accurately capture the dynamics of LP-EGR transport and intake manifold acoustics, we developed a 1D model that was validated against experimental data. The model's ability to accurately predict CO2 concentrations in the intake manifold under transient conditions provides a valuable tool for engine designers and engineers. Overall, our research has provided valuable insights into the intricate interactions between LP-EGR transport, intake manifold acoustics, and engine performance in transient operation. The findings can be harnessed to develop more efficient, cleaner, and safer diesel engines that meet the stringent emission and performance standards of modern vehicles. We are excited to see how our work contributes to the advancement of diesel engine technology and its role in sustainable transportation.
Dr. Francisco José Arnau Martínez
Universitat Politecnica de Valencia
Read the Original
This page is a summary of: Analysis of low-pressure exhaust gases recirculation transport and control in transient operation of automotive diesel engines, Applied Thermal Engineering, June 2018, Elsevier,
DOI: 10.1016/j.applthermaleng.2018.03.085.
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