One-Dimensional Simulation Using Port Water Injection for a Spark Ignition Engine

Abstract

Water injection is a promising solution to reduce fuel consumption while improving the performance of a turbocharged gasoline engine. One-dimensional (1D) engine simulation software, AVL BOOST is rarely used to model water injection. Therefore, this study is aimed to demonstrate the detailed port water injection modelling via AVL BOOST. A four-cylinder turbocharged gasoline engine was developed in AVL BOOST based on the specification of the engine test rig and verified to be used as the baseline model. The port water injection modelling was then added to the baseline model. Water to fuel mass ratios of 0.05, 0.10, 0.15, 0.2 and 0.25 were chosen as the variables to investigate the effect of water injection on the engine performance. The results showed that maximum engine torque and IMEP increased by 10.80% and 8.65%, respectively at 3000 rpm. The water injection also reduced the in-cylinder pressure at the end of the compression stroke, reducing the compression work and improving efficiency. The reduction of combustion temperature also indicates potential for NOx reduction. The lower exhaust temperature can reduce the use of fuel enrichment which consequently reduces the fuel consumption. Conclusively, the water injection model can predict the engine performance parameters accurately.