Valve and In-Cylinder Flow Generated by a Helical Port in a Production Diesel Engine

Abstract

The flow generated by the helical port of a production Diesel engine has been investigated by laser Doppler anemometry under steady flow and operating conditions at ∼ 900 rpm and compression ratio of 8. The flow around the valve periphery was found to be non-uniform with the axial velocity distribution being more sensitive to valve lift. The in-cylinder swirl distribution at inlet valve closure exhibited an axial stratification in the disc-chamber while turbulence intensity remained constant in the clearance volume during the rest of the compression stroke with levels of 0.5 vp and a minimum of about 0.4 vp at top-dead-center following a rapid decay at θ=340°.