Effect of High and Low-Pressure Exhaust Gas Recirculation System on NOx Emissions in a Bus Diesel Engine

Dinh Xuan Thanh

Abstract: This study aims to design the exhaust gas recirculation (EGR) system for a bus diesel engine in order to reduce exhaust emissions. This includes the experiment and simulation of the test engine based on the Emission Test Cycles ECE-R49. The comparison of high and low-pressure exhaust gas recirculation systems fitted on a bus engine was conducted to analyze the effects of their control on fuel consumption, pollutant emissions. The research results showed that the test engine retrofitted high-pressure exhaust gas recirculation systems (H-EGR) results in a lower ratio of EGR in comparison with that of low-pressure exhaust gas recirculation systems (L-EGR). In addition, due to the higher intake gas velocity and pressure, the local loss in case of H-EGR is also higher than the one of the L-EGR at the venturi assembly position. The H-EGR was only effective at the engine load less than 75 %, consequently, the role in reducing NOx emissions was less effective than that of the L-EGR. The maximum reduction of NOx emissions in case of H-EGR was 41.27 % at a load of 75 % and a velocity of 1400 rpm. Meanwhile, the NOx emission can be reduced to 62.43 % in case of L-EGR.

Keywords: Exhaust gas recirculation, Fuel consumption enhancement, Diesel engine, Engine characteristic, Nitrogen emissions

How to Cite?: Dinh Xuan Thanh, "Effect of High and Low-Pressure Exhaust Gas Recirculation System on NOx Emissions in a Bus Diesel Engine", Volume 6 Issue 9, September 2017, International Journal of Science and Research (IJSR), Pages: 756-760, https://www.ijsr.net/getabstract.php?paperid=ART20176659, DOI: https://dx.doi.org/10.21275/ART20176659