Inlet air swirl control means for I.C. engines

Claim 2

1 . An I.C. engine of the reciprocating-piston type, the or each cylinder of which has one or more inlet ports of either "helical" or."directed" type as hereinbefore defined, the or each inlet port being provided with an inlet valve of poppet type, there being a movably-mounted insert provided in the inlet passage of the or each inlet port, the insert having a deflector vane or tongue portion at its inner end which, in use, protrudes into the bowl of the port, characterised in that the insert (35, 36) is in sliding contact with the interior wall of the inlet passage (13) for longitudinal and/or circumferential sliding movement relative thereto, and that the engine has means (49, 44, 43; 49, 60, 61; 63, 62) for moving the insert (35, 36) during the running of the engine so as to adjust the dispostion of its protruding vane or tongue (37) in the bowl (14) of the port (12) and hence to control the degree of swirl produced by that port (12) in the associated cylinder.

Claim 3

An I.C. engine of the reciprocating-piston type, the or each cylinder of which has one or more inlet ports of either "helical" or "directed" type as hereinbefore defined, the or each inlet port being provided with an inlet valve of poppet type, there being a movable insert in the form of a liner sleeve mounted in the inlet passage of the or each inlet port which has at its inner end a tongue portion which is adapted to project inwardly into the bowl of the port, characterised in that the sleeve (35, 36) is in slidable engagement with the internal wall of the passage (13) for sliding movement either .linearly along the length of the passage (13) or angularly around the internal circumference of the passage (13) or with a combination of said linear and angular sliding movements, and that the engine also has means (49, 44, 43; 49, 60, 61; 63, 62) operable during the running of the engine to move the sleeve (35, 36) of the or each inlet port (12) linearly and/or angularly in the inlet passage (13) so as to vary the disposition of its projecting tongue (37) in the bowl (14) and hence to alter the directional pattern of the inlet air as it enters the associated cylinder past the inlet valve (15, 16), and the degree of swirl produced in the engine.

Claim 4

An I.C. engine of the reciprocating-piston type, the or each cylinder of which has one or more inlet ports of either "helical" or "directed" type as hereinbefore defined, the or each inlet port being provided with an inlet valve of poppet type, there being a movable insert in the form of a liner sleeve mounted in the inlet passage of the or each inlet port which has at its inner end a tongue portion which is adapted to project inwardly into the bowl of the port, characterised in that the sleeve (35, 36) is in slidable engagement with the internal wall of the passage (13) for sliding movement either .linearly along the length of the passage (13) or angularly around the internal circumference of the passage (13) or with a combination of said linear and angular sliding movements, and that the engine also has means (49, 44, 43; 49, 60, 61; 63, 62) operable during the running of the engine to move the sleeve (35, 36) of the or each inlet port (12) linearly and/or angularly in the inlet passage (13) so as to vary the disposition of its projecting tongue (37) in the bowl (14) and hence to alter the directional pattern of the inlet air as it enters the associated cylinder past the inlet valve (15, 16), and the degree of swirl produced in the engine.

Claim 5

An engine as claimed in Claim 1 or Claim 2 which has a multiplicity of inlet ports each with an insert sleeve, characterised in that a part (49) of the means for moving the inserts (35, 36) is common to all the movable inserts (35, 36) and operates automatically to move all the inserts (35, 36) in unison in response to a change in an engine operating condition.

Claim 6

An engine as claimed in Claim 1 or Claim 2 or .Claim 3, characterised in that the means (49, 44, 43; 49, 60, 61; 63, 62).for moving the or each insert includes a rotatable shaft (49) coupled to the or each insert (35, 36) by a transmission mechanism (44, 43; 62, 63) which transforms rotation of the shaft (49) into linear movement of the insert (35, 36) along the inlet passage (13).

Claim 7

An engine as claimed in Claim 4, characterised in that the transmission mechanism is a rack-and-pinion . mechanism (44, 43).

Claim 8

An engine as claimed in Claim 1 or Claim 2 or Claim 3, characterised in that the means for moving the or each insert (35, 36) includes a rotatable shaft (49) coupled to the or each insert (35, 36) by a transmission mechanism (60, 61) which transforms rotation of the shaft (49) into rotation of the insert (35, 36) around the longitudinal axis of the inlet passage (13).

Claim 9

An engine as claimed in Claim 6,. characterised by a cam (63) and follower (62) coupling between the or each insert (35, 36) and the fixed structure of the cylinder head (10) whereby the rotation of the insert (35, 36) in the inlet passage (13) automatically causes corresponding linear movement of the insert (35, 36) along the passage (13).

Claim 10

An engine as claimed in any one of the preceding claims, characterised by means for automatically effecting the adjustment of the disposition of the or each insert (35, 36) in its associated inlet passage during the running of the engine in response to variations in one or more engine operating parameters, e.g. engine speed and/or load.