Abstract: A die apparatus and method for performing a flashless forging operation to manufacture the toothed portion of a steering rack. The die apparatus includes first and second die members and at least one punch member, each having a forming surface shaped substantially as an obverse of a portion of the toothed portion. At least a portion of the forming surface of the first die member is shaped substantially as the obverse of the teeth of the rack. The first and second die members are moveable towards each other to a closed position, thereby partially forging the toothed portion from a blank placed in the die apparatus, and forming a substantially closed cavity defined by the forming surfaces. The punch member is adapted to move into the cavity once the die members are in the closed position, thereby completing the forging operation.

Abstract: A method of manufacturing a steering rack for a vehicle rack and pinion steering system. The rack comprises gear teeth and a shank that has a constant outside diameter and constant wall thickness over the majority of its length. The method comprises performing a forging operation on a tubular member with an elongate member positioned in the bore of a thickened region of the tubular member. The forging operation forms the gear teeth on the thickened region, and the elongate member is retained within the tubular member. The tubular member is made by performing a forming operation on a length of tube stock such that the outside diameter of the thickened region is smaller than the outside diameter of the shank, and the wall thickness of the thickened region is larger than the wall thickness of the shank.

Abstract: A die apparatus and method for performing a flashless forging operation to manufacture the toothed portion of a steering rack. The die apparatus includes first and second die members and at least one punch member, each having a forming surface shaped substantially as the obverse of a portion of the toothed portion. At least a portion of the forming surface of the first die member is shaped substantially as the obverse of the teeth of the rack. The first and second die members are moveable towards each other to a closed position, thereby partially forging the toothed portion from a blank placed in the die apparatus, and forming a substantially closed cavity defined by the forming surfaces. The punch member is adapted to move into the cavity once the die members are in the closed position, thereby completing the forging operation.

Abstract: A cylinder head (3) for an axial flow rotary valve (1). The head comprises a bore (2) having an axis and adapted to house an axial flow rotary valve (1), a window (8) in the bore through which at least one port (12, 13) in the valve periodically communicates with a combustion chamber (9) as the valve rotates, at least two axially extending slots (21) in the bore, adjacent opposite sides of the window, each of the slots being adapted to locate a floating elongate gas sealing element (20), and at least one spark plug hole (7) adjacent to the bore and adapted for mounting a spark plug associated with the valve. The head further comprises at least one elongate axially extending cooling passage (24, 25 26) disposed between the bore and the spark plug hole, adjacent to one of the slots, the passage having a substantially constant cross section and extending axially at least over the length of the slots.

Abstract: A steering rack for a vehicle rack and pinion steering gear and a method of manufacturing a steering rack includes a first member having a toothed region, attached to a tubular second member, the second member includes a bore, the cross section of the bore being circular along the length of the second member. The second member has at least one region of increased wall thickness and reduced bore diameter formed by an upsetting operation.

Abstract: An axial flow rotary valve (1) for an internal combustion engine comprising a cylinder head (10) having a bore in which an axial flow rotary valve (1) rotates. The valve having a cylindrical centre portion (4), and an inlet and an exhaust port (2, 3) terminating as openings (7, 8) in the centre portion, the openings periodically communicating with a combustion chamber (23) through a window (15) in the bore. The clearance between the centre portion and the bore being sealed by an array of floating seals comprising at least two axial seals (16a, 16b) spaced apart on opposite sides of the window. The assembly further comprising at least one floating axially extending masking seal (5) being disposed outside the window and circumferentially remote from the axial seals.

Abstract: An axial flow rotary valve for an engine, that is rotatable about an axis within the bore of a cylinder head. The valve communicating with a respective cylinder in which a piston reciprocates, and an ignition means associated with the cylinder. The valve is provided with inlet and exhaust peripheral openings that periodically communicate with cylinder through a window in the bore. A combustion chamber is formed in the space between the crown of the piston at top dead centre and the cylinder head and the valve. The ignition means comprising first and second spark plugs, each of said spark plugs having a nose located at one end thereof exposed to the combustion chamber, said noses being disposed on opposite sides of said window within the axial extremities of said window.

Abstract: A gas sealing element of an array of floating seals for a rotary valve internal combustion engine. The engine comprising a cylinder head (6) having a bore (8), a rotary valve (1) within the bore with a predetermined clearance, and a window (12) in the bore communicating with a combustion chamber. The sealing element (15) having an elongate form and having a sealing face (23), an underside (24) opposite said sealing face, and first and second side faces (25,26) opposite each other, the sealing element being adapted to be located in a slot (20) in the cylinder head bore. The side face (25) of the sealing element facing the window having at least one channel (17) extending from the sealing face to the underside of the sealing element.

Abstract: A sealing system for an axial flow rotary valve internal combustion engine comprising an array of floating gas seals and an optional oil sealing system. The array of floating seals surrounding a window (15) in the bore (11) of the cylinder head (10) through which the ports (2, 3) of the valve (1) communicate with a combustion chamber (31). The array of floating seals comprising axial seals (16) and circumferential seals (17) housed in slots (18, 19) in the bore of the cylinder head wherein the circumferential seals are disposed axially between the ends of the axial seals.

Abstract: A steering rack for a vehicle rack and pinion steering gear comprising a first member having a toothed region, attached to a tubular second member. The second member having a region of increased wall thickness and reduced bore diameter formed by an upsetting operation. The region of increased wall thickness being located at or near the end of the second member that is attached to the first member.

Abstract: A cylinder head (3) for an axial flow rotary valve (1). The head comprises a bore (2) having an axis and adapted to house an axial flow rotary valve (1), a window (8) in the bore through which at least one port (12, 13) in the valve periodically communicates with a combustion chamber (9) as the valve rotates, at least two axially extending slots (21) in the bore, adjacent opposite sides of the window, each of the slots being adapted to locate a floating elongate gas sealing element (20), and at least one spark plug hole (7) adjacent to the bore and adapted for mounting a spark plug associated with the valve. The head further comprises at least one elongate axially extending cooling passage (24, 25 26) disposed between the bore and the spark plug hole, adjacent to one of the slots, the passage having a substantially constant cross section and extending axially at least over the length of the slots.

Abstract: An axial flow rotary valve (1) for an internal combustion engine comprising a cylinder head (10) having a bore in which an axial flow rotary valve (1) rotates. The valve having a cylindrical centre portion (4), and an inlet and an exhaust port (2, 3) terminating as openings (7, 8) in the centre portion, the openings periodically communicating with a combustion chamber (23) through a window (15) in the bore. The clearance between the centre portion and the bore being sealed by an array of floating seals comprising at least two axial seals (16a, 16b) spaced apart on opposite sides of the window. The assembly further comprising at least one floating axially extending masking seal (5) being disposed outside the window and circumferentially remote from the axial seals.

Abstract: An axial flow rotary valve (1) for an internal combustion engine and method of manufacture thereof. The valve comprising a centre portion (5) having a cylindrical periphery, inlet and exhaust portions (9, 16) both smaller in diameter than the centre portion, and an inlet port (3) and an exhaust port (4) terminating respectively as an inlet opening (6) and an exhaust opening (7) in the periphery of the centre portion. The centre portion having at least one elongate passage (21) communicating between the inlet portion and the exhaust portion, the whole of the passage being disposed circumferentially outside the openings and radially outside at least one of the inlet and exhaust portions.

Abstract: A rack and pinion steering gear for a vehicle comprising a housing (2), a pinion (1) rotatable about a first axis (14) in the housing, a rack (7) laterally displaceable with respect to the housing, and an intermediate gear (8) interposed between, and meshing with, the pinion (1) and with the rack (7), the intermediate gear (8) rotatable about a second axis (9). The second axis (9) is laterally movable with respect to the housing as a function of at least one vehicle parameter, by an actuator mechanism, thereby varying the relationship between the angular displacement of the pinion and the lateral displacement of the rack as a function of the vehicle parameter.

Abstract: A steering system for a vehicle comprising a steering gear (10) having a rack (12) and a pinion (14) in mesh therewith. The rack (12) being laterally displaceable with respect to the vehicle as a function of inputs from a steering wheel (24) through rotation of the pinion (14), and a steering superposition means (32). The steering system further comprising first and second road wheels (20a, 20b) steerable by rotation of first and second steering arms (21a, 21b) respectively by means of first and second tie rods (15a, 15b) arranged to transmit lateral displacement of the rack (12) to the first and second steering arms (21a, 21b) respectively. Lateral displacement of the rack (12) being transmitted to at least one of the steering arms (21a, 21b) through a linear actuator (25). The linear actuator (25) and the steering superposition means (32) being controlled by a control means (30) in response to at least one sensed parameter (31).

Abstract: A method of manufacturing a steering rack bar (6) by forging, the method comprising the steps of pacing a heated cylindrical rack bar (6) in a first forging die (15) and forging a first toothed protion (37) at one end thereof; removing the rack bar; heating the rack bar at or near the other end of said rack; and placing the other end of the rack bar in a second forging die and forging a second toothed portion (39) wherein, prior to forging the second toothed portion, the rack bar is axially and angularly aligned to a predetermined axial location and angularly orientated utilising the first toothed portion or features at or near the one end of the rack bar as a datum, and placed and held in the predetermined axial location and angular orientation prior to forging of the second toothed portion.

Abstract: A throttle valve (1) for an inlet of an internal combustion piston engine comprising an aperture (9) adapted to be variably opened and closed between a first fully opened configuration and a second near closed configuration. The aperture (9) is variably opened and closed by a plurality of coplanar plates (10) mounted about the periphery of the aperture and movable towards the central region of the aperture.

Abstract: A method of producing a bevel gear, particularly a bevel ring gear, the bevel gear comprising mounting surfaces. The method comprising the steps of flashless warm forging a blank, preferably an annular blank, in a forging die to produce the bevel gear with precision forged teeth; performing a hardening operation on the teeth; and then, without machining, finishing the teeth by lapping the teeth with a mating bevel gear. A die apparatus for use in a press for forging the bevel ring gear from the annular blank is also disclosed.

Abstract: A rotary valve internal combustion engine comprising a crankshaft, a throttle (23), a throttle actuator, a cylinder head (7), a combustion chamber (8), and at least one rotary valve (1). The rotary valve (1) having at least two ports (2, 3) terminating as openings (4, 5) in its periphery, the cylinder head (7) having a bore (11) in which the rotary valve (1) rotates, a window (6) in the bore (11) communicating with the combustion chamber (8), the openings (4, 5) successively aligning with the window (6) by virtue of the rotation, a drive mechanism comprising a phase change means (18), the drive mechanism driving the rotary valve (1). The at least two ports (2, 3) comprise an inlet port (2) and an exhaust port (3), and the phase change means (18) applies a phase change in response to changes in the operating conditions of the engine over at least one engine cycle.

Abstract: A position sensor encodes absolute position via n consecutive members of a pseudorandom sequence of bits, where each bit (30a-30k) comprises a region of high transmission or reflectivity adjacent to a region of low transmission or reflectivity. The pseudorandom sequence is chosen such that every series of n consecutive bits (30a-30k) in the sequence is predominantly formed from a predetermined bit value (1 or 0). The light transmitted or reflected from the series is therefore detected as a substantially periodic intensity pattern (42), which can be processed via Fourier analysis to yield an accurate interpolation of relative position. An example is given of a pseudorandom sequence, which can be represented as a cyclic Manchester code, in which at least 8 members of every series of 11 consecutive bits has a bit value of 1.