Abstract: An apparatus for improving the performance of a radial compressor 36 forming part of an inlet system of an engine 10 is disclosed in which the configuration and positioning of a flow management device 137 used to generate pre-whirl is optimized so as to produce a pressure drop below a maximum acceptable level. An inlet duct ‘I’ connected to the radial compressor 36 has a tapered end portion so that a flow management device 137 of a larger diameter d2 can be accommodated than the diameter d1 of an inlet port ‘IP’ to the radial compressor 36.

Abstract: An apparatus for improving the performance of a radial compressor 36 forming part of an inlet system of an engine 10 is disclosed in which the configuration and positioning of a flow management device 137 used to generate pre-whirl is optimized so as to produce a pressure drop below a maximum acceptable level. An inlet duct ‘I’ connected to the radial compressor 36 has a tapered end portion so that a flow management device 137 of a larger diameter d2 can be accommodated than the diameter d1 of an inlet port ‘IP’ to the radial compressor 36.

Abstract: A cylinder head for an internal combustion engine of the reciprocating piston type includes a helical inlet port with a flat wall portion in a section of the port upstream of a bowl-shaped recess about a valve stem guide. The flat walled section meets a generally cylindrical portion of the recess adjacent a cusp-shaped swirl edge. The orientation of the flat portion with respect to a reference feature, such as the axis of the valve stem guide, may then be used as a measure of the accuracy of casting of the inlet port, and may also be altered if so desired to vary the swirl characteristics of the inlet port.