Investigation of steam utilization mode on performance and emissions characteristics of gasoline engine

In the present study, the steam utilization mode was discussed based on a gasoline engine. The thermodynamic processes of two steam utilization modes were investigated based on the validated model. And, the effects of incylinder direct steam injection (CDSI) and two steam expansion cylinders (TSEC) on engine performance were studied. The results show that the firing cylinder temperature decreases with both CDSI and TSEC engines. However, the in-cylinder pressure increases for the CDSI-engine. The CDSI method can greatly benefit engines from an emissions perspective, as it reduces NOx, HC, and CO by 79.0 %, 2.4 %, and 17.6 % respectively. It is worth noting that the TSEC method cannot improve engine performance through waste heat recovery. The results also demonstrate that the indicated power of the TSEC-engine is higher that the results achieved by using the CDSI method when the steam injection quantity is greater than 0.80 g. All these demonstrate that CDSI approach has great potential for application in gasoline engines. The present results provide strong evidence for the application in gasoline engines.