Velocity Characteristics of Steady Flows through Engine Inlet Ports and Cylinders

Laser-Doppler anemometry was used to investigate steady flows both in an axisymmetric port and in a helical port from a production engine. To enable optical access to all parts of the port and cylinder the working fluid was a mixture of liquids with a refractive index identical to that of the acrylic material used for the test section. In the case of the axisymmetric port measurements were made of the three mean velocity components and the corresponding levels of the kinetic energy of turbulence for four valve lifts. In the case of the helical port one velocity component was measured for a single valve lift.

The results from the axisymmetric port illustrate the existence of four different modes of flow over the range of valve lift. Peak values of the kinetic energy of turbulence were about ten times as high in the cylinder as they were in the port. The effects of valve lift and port shape on the development of the flow downstream of the valve are discussed. The measurements are in suitable form for use in the development and assessment of numerical calculations of the flows.