Quantitative analysis of water condensation in LP-EGR systems for internal combustion engines

Low-pressure exhaust gas recirculation (LP-EGR) is promising strategy for reducing NOx emissions in internal combustion engines, but it presents challenges due to water vapor condensation that can lead to compressor impeller erosion. This study presents a comprehensive thermodynamic analysis to quantify condensate formation and determine dew point temperatures across varying fuels and engine operating conditions. Novel mathematical models are developed to estimate specific humidity and condensation using only standard engine parameters, making them applicable without additional sensors. Results show that both fuel composition - particularly the hydrogen-to-carbon ratio - and LP-EGR rates strongly influence condensation. The study also highlights the impact of alternative fuels and ambient conditions on condensation risk. The developed methodology supports real-time evaluation of condensation potential and offers critical input for erosion risk assessment, component design, and emission control strategy optimization in modern powertrain.