Investigation of Scavenging Process for Steady-State Operation of a Linear Internal Combustion Engine-Linear Generator Integrated System 2017-01-1087

The Linear Internal Combustion Engine-Linear Generator Integrated System (LICELGIS) is different from conventional crank-based engine for reducing frictional losses by eliminating the crankshaft. Thus, the LICELGIS piston stroke is not constrained geometrically and the system compression ratio is variable. During steady-state operation, the LICELGIS converts the fuel chemical energy into electric power with piston assembly reciprocating motion, which can be used as a range-extender in hybrid electric vehicles.

The LICELGIS scavenging process is prerequisite and key for the system steady-state operation, which has remarkable influence on mixture gas and, eventually, on engine combustion performance. In order to achieve high scavenging performance, a LICELGIS is investigated in this paper. The LICELGIS motion characteristics and scavenging process were analyzed. For the deeper investigation of scavenging process, a numerical simulation architecture was concentrated on by coupling of zero-dimensional (0D) dynamics and three-dimensional (3D) computational fluid dynamics (CFD). The numerical simulation architecture was set up and validated with a LICELGIS prototype tested data. Based on port height and port angle, influence rules of scavenging system structure on scavenging performance were obtained, qualitatively. For improving scavenging efficiency, large height of scavenging and exhaust ports, tangential inclination of chief scavenging port (CSP) at 65°and axial inclination of sub scavenging port (SSP) at 50° should be taken into account. For enhancing turbulent kinetic energy of in-cylinder gas, which is in favor of combustion rate, small height of scavenging and exhaust ports, small tangential inclination of CSP and large axial inclination of SSP should be taken into account.