Abstract: With reference to FIG. 1, the present invention provides valve operating system for operating a pair of poppet valves (10, 32) of an internal combustion engine. The system comprises a source of pressurised hydraulic fluid (22), a fluid return (23), a first hydraulic actuator (13) which the first poppet valve (10) and a second hydraulic actuator (13) acts on the second poppet valve (32). A first valve (21) is connected to both the source of pressurised fluid and the fluid return (23). A second valve (20) is connected between the first valve (21) and the first hydraulic actuator (13). A third valve (30) is connected between the first valve (21) and the second hydraulic actuator (31). An electronic controller (40) controls operation of the valves (20, 21, 30) to open and close the pair of poppet valves (10, 32).

Abstract: With reference to FIG. (1), the present invention relates to a sound synthesizer system for use in a vehicle having an internal combustion engine. The system comprises a sound synthesizer unit (12) operable to produce sound signals by generating and combining signals of different frequencies, a speed sensor (10) for providing a speed of revolution signal indicative of speed of revolution of the internal combustion engine of the vehicle, and an inclinometer (11) attachable to a throttle control of the internal combustion engine which provides an inclination signal indicative of inclination of the throttle control. The sound synthesizer unit (12) receives the speed of revolution signal from the speed sensor (10) and the inclination signal from the inclinometer (11) and uses both signals to determine what sound signals are produced thereby, the sound synthesizer) unit (12) varies the sound signals with changes in the speed of revolution signal and changes in the inclination signal.

Abstract: The present invention relates to a control valve for controlling flow of hydraulic fluid. The control valve comprises: a valve housing (10); a sleeve (11) slidable in a valve chamber in the valve housing (10); a first fluid conduit (12) for connecting the valve chamber to a source of pressurised hydraulic fluid; a second fluid conduit (14) for connecting the valve chamber to a fluid return for returning hydraulic fluid to a reservoir; and a third fluid conduit (16) for connecting the valve chamber to deliver hydraulic fluid to and receive hydraulic fluid from apparatus which uses the hydraulic fluid flow controlled by the control valve. The sleeve (11) is a tubular sleeve having, a tubular passage therethrough. The valve housing has a pair of spaced apart valve seat surfaces (22, 23), a first valve seat surface (22) which is engageable by a first end of the tubular sleeve (11) and a second valve seat surface (23) which is engageable by a second end of the tubular sleeve (11).

Abstract: The present invention relates to an electrically operated valve (10), which has a valve housing (11); a spool (12); a first fluid conduit (14) connecting the valve (10) with a source of pressurized fluid; a second fluid conduit (15) connecting the valve (10) with a reservoir of fluid; and a third fluid conduit (16) in communication with valve (10) which delivers fluid to or receives fluid from apparatus which uses the hydraulic fluid flow controlled by the valve (10). The spool (12) is biased to a rest position by a pair of opposed springs (17,18) and in the rest position closes off the first (14) and second (15) fluid conduits. A first electric coil (19) associated with a first end of the spool (12) when activated displaces the spool (12) to open the first fluid conduit (14). A second electric coil (20) associated with a second end of the spool (12) when activated displaces the spool (12) to open the second fluid conduit (15).

Abstract: The present invention (with reference to FIG.

Abstract: The present invention (with reference to FIG.

Abstract: The present invention relates to an electrically operated valve (10), which has a valve housing (11); a spool (12); a first fluid conduit (14) connecting the valve (10) with a source of pressurised fluid; a second fluid conduit (15) connecting the valve (10) with a reservoir of fluid; and a third fluid conduit (16) in communication with valve (10) which delivers fluid to or receives fluid from apparatus which uses the hydraulic fluid flow controlled by the valve (10). The spool (12) is biassed to a rest position by a pair of opposed springs (17,18) and in the rest position closes off the first (14) and second (15) fluid conduits. A first electric coil (19) associated with a first end of the spool (12) when activated displaces the spool (12) to open the first fluid conduit (14). A second electric coil (20) associated with a second end of the spool (12) when activated displaces the spool (12) to open the second fluid conduit (15).

Abstract: The present invention relates to a control valve for controlling flow of hydraulic fluid. The control valve comprises: a valve housing (10); a sleeve (11) slidable in a valve chamber in the valve housing (10); a first fluid conduit (12) for connecting the valve chamber to a source of pressurised hydraulic fluid; a second fluid conduit (14) for connecting the valve chamber to a fluid return for returning hydraulic fluid to a reservoir; and a third fluid conduit (16) for connecting the valve chamber to deliver hydraulic fluid to and receive hydraulic fluid from apparatus which uses the hydraulic fluid flow controlled by the control valve. The sleeve (11) is a tubular sleeve having, a tubular passage therethrough. The valve housing has a pair of spaced apart valve seat surfaces (22, 23), a first valve seat surface (22) which is engageable by a first end of the tubular sleeve (11) and a second valve seat surface (23) which is engageable by a second end of the tubular sleeve (11).

Abstract: A displacement machine (10) comprises a housing (11), a reciprocating member (12) reciprocable linearly along an axis of reciprocation (13) in the housing (11) and defining with the housing (11) first (14) and second (15) variable volume chambers. A fluid inlet (17) is connected to the first variable volume chamber (14). A fluid outlet (78) is connected to the second variable volume chamber. An inlet value (16) allows flow of fluid through the fluid inlet (17) into the first variable volume chamber (14) and prevents flow of fluid from the first variable volume chamber (14) out of the fluid inlet (17).