Vane in the inlet passage of an internal combustion engine

In an internal combustion engine of the type having a cylinder having a central axis;

• an inlet valve;
• a cylinder head closing the top of the cylinder, the cylinder head being formed with an inlet port which is opened and closed by the action of the inlet valve contacting an inlet valve seating surface of the inlet port, and which is of the helical type having a helical surface leading to the inlet valve seating surface;
• an inlet passage, defined by a wall leading to the inlet port;
• and a throttle valve in the inlet passage, the throttle valve being movable between a first position wherein it substantially closes the inlet passage, to a second position wherein it affords a large opening in the inlet passage, and which when it is moved a relatively small amount from the first position affords a small first opening in the inlet passage which is asymmetrically offset towards a particular portion of the wall of the inlet passage;
• the internal combustion engine being CHARACTERIZED IN THAT there is further provided:
• a vane in the inlet passage downstream of the throttle valve, said vane having a concaved leading edge located in proximity to the throttle valve, said leading edge spanning across the inlet passage so as to define a first flow passage having a first flow passage inlet which is aligned with the small first opening defined between the throttle valve and the particular wall portion of the inlet passage, and a second flow passage which is further from the particular wall portion of the inlet passage, said vane having a trailing edge which defines the end of the first flow passage to be disposed substantially at the start of the helical surface.