Numerical Investigation of the Effects of Port Water Injection Timing on Performance and Emissions in a Gasoline Direct Injection Engine 2020-01-0287
Port water injection is considered as a promising strategy to further improve the combustion performance of internal combustion engines for its benefit in knock resistance by reducing the cylinder temperature. A thorough investigation of the port water injection technique is required to fully understand its effects on the engine combustion process. This study explores the potential of the port water injection technique in improving the performance of a turbo-charged Gasoline Direct Injection engine. A 3D computational fluid dynamics model was applied to simulate the in-cylinder mixing and combustion for this engine both with and without water injection. Comparison have been given between the original engine and the water injection one and the results show that the water injection can reduce the cylinder temperature both in the compressing and combustion strokes. The pressure oscillation is also suppressed which indicates a better knocking resistance for water injection strategy. Different water injection timings are also investigated and it is found that the injection timing is important to determine the trapped amount of the water steam in the combustion chamber. An optimized injection timings could be found for a particular load condition and also lead to a better combustion performance and emissions.
Peng Yin, Xuesong Li, David Hung, Yadong Fan, Min Xu