Hydraulic engine valve actuator
View Patent ↗An integrated hydraulic valve actuator for use in a camless internal combustion engine. The valve actuator includes a separate bolt-on housing defining a through opening receiving a cylindrical liner. The liner internally defines an internal cylinder providing a riding surface, which coaxially surrounds an outer surface of a tubular boost piston. The boost piston defines an inner cylinder, which provides a riding surface for a drive piston fitted within the inner cylinder of the boost piston. The pistons are axially reciprocable within the liner cylinder. A piston position sensor extends radially into the housing and engages a cam on the drive piston to relay the position of the drive piston to a controller. The actuator is preassembled and the housing is attached to an engine cylinder head or cylinder head supply manifold to operate an associated exhaust or intake valve.
1. An integrated hydraulic valve actuator comprising:
a housing internally defining a through opening;
a cylindrical liner received in an upper portion of the housing, the liner internally defining a cylinder and riding surface receiving a reciprocable piston subassembly;
the piston subassembly including a boost piston defining an internal cylinder and a drive piston extending through and reciprocable in the internal cylinder of the boost piston;
the liner cylinder being open to receive pressurized fluid to axially move the piston subassembly within the cylinder; and
a drive piston position sensor extending into the housing and engaging a cam on the drive piston to sense the position of the drive piston within the cylinder.
2. A valve actuator according to claim 1 wherein the housing is formed of metal.
3. A valve actuator according to claim 1 wherein the liner is formed of metal.
4. An integrated hydraulic valve actuator comprising:
a housing internally defining a stepped bore having an upper major diameter, a middle intermediate diameter, and a lower minor diameter;
a cylindrical liner received in the major diameter of the stepped bore, the liner internally defining a cylinder and riding surface;
a piston subassembly received in the cylinder for actuating an engine valve, the subassembly including a tubular boost piston defining an internal cylinder and a drive piston reciprocable in the internal cylinder of the boost piston;
the liner cylinder being open to the major diameter of the stepped bore for receiving pressurized fluid to axially move the piston subassembly within the liner cylinder; and
a drive piston position sensor extending radially into the housing and operable to determine the position of the drive piston within the cylinder.
5. A valve actuator according to claim 4 wherein the boost piston has a flange engaging lower end of liner to limit upward travel of the piston subassembly.
6. A valve actuator according to claim 4 wherein the flange of the boost piston is engagable with an upper end of the stepped bore minor diameter to limit downward travel of the boost piston.
7. A valve actuator according to claim 4 wherein the drive piston has an upper portion received within the boost piston and a tapered lower end extending from the upper portion.
8. A valve actuator according to claim 4 wherein a tapered lower end of the drive piston is engageable with the boost piston to limit upward travel of the drive piston.
9. A valve actuator according to claim 4 wherein a piston position sensor engages the tapered lower end of the drive piston.
10. An integrated hydraulic valve actuator comprising:
a housing internally defining a through opening;
a removable cylindrical liner received in an upper portion of the housing, the liner internally defining a cylinder and riding surface receiving a reciprocable piston subassembly removable with the liner from the housing;
the piston subassembly including a boost piston defining an internal cylinder and a drive piston extending through and reciprocable in the internal cylinder of the boost piston;
the liner cylinder being open to receive pressurized fluid to axially move the piston subassembly within the cylinder; and
a drive piston position sensor extending into the housing and engaging a cam on the drive piston to sense the position of the drive piston within the cylinder.
11. An integrated hydraulic valve actuator comprising:
a housing internally defining a through opening and having an upper portion adapted to be received in a bore of a supply manifold and a flange extending from the housing adapted to attach the housing to the supply manifold;
a cylindrical liner received in an upper portion of the housing, the liner internally defining a cylinder and riding surface receiving a reciprocable piston subassembly;
the piston subassembly including a boost piston defining an internal cylinder and a drive piston extending through and reciprocable in the internal cylinder of the boost piston;
the liner cylinder being open to receive pressurized fluid to axially move the piston subassembly within the cylinder; and
a drive piston position sensor extending into the housing and engaging a cam on the drive piston to sense the position of the drive piston within the cylinder.