# US 7,610,881 B2 · Apparatus for an internal combustion engine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,610,881 B2 - Document ID: US7610881B2 - Status: Granted - Kind: B2 - Application number: 11/721,182 - Filed: 2005-01-12 - Published: 2009-10-08 - Granted: 2009-11-03 - Earliest claimed: 2005-01-12 - Assignees: Volvo Lastvagnar AB - Inventors: Sergi Yudanov - Web page: https://patentgrep.com/patent/US7610881B2 ## CPC - F01L 1/053: overhead type - F01L 1/181: {Centre pivot rocking arms} - F01L 1/26: characterised by the provision of two or more valves operated simultaneously by same transmitting-gear; peculiar to machines or engines with more than two lift-valves per cylinder (with coaxial valves F01L1/28) - F01L 13/08: for decompression, e.g. during starting; for changing compression ratio - F02M 26/01: Internal exhaust gas recirculation, i.e. wherein the residual exhaust gases are trapped in the cylinder or pushed back from the intake or the exhaust manifold into the combustion chamber without the use of additional passages - F02D 13/0261: {Controlling the valve overlap} - F02D 13/0269: {Controlling the valves to perform a Miller-Atkinson cycle} - Y02T 10/12: Improving ICE efficiencies - F01L: CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES - F02M: SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A valve actuation system for providing added motion in the valve mechanism of an internal combustion engine with at least one inlet valve and at least one exhaust valve is provided. The valve mechanism includes a rotatable camshaft including rising and falling ramps designed to interact with a valve control plunger inside a cylinder for actuation of the inlet or exhaust valve under the action of a valve spring. The cylinder communicates with a hydraulic fluid feed line via a check valve and with a hydraulic control circuit allowing a return movement of a valve to be delayed in relation to the timing of the corresponding falling ramp. The hydraulic control circuit includes a first and a second hydraulic fluid flow restrictor connected to the control plunger cylinder at different levels along its longitudinal axis. A selector valve enables a connection between the cylinder and hydraulic fluid return line to be opened via either one only or both flow restrictors. ## Claims ### Claim 1 A valve actuation system for providing added motion in a valve mechanism of an internal combustion engine, the valve actuation system comprising the valve mechanism, the valve mechanism comprising at least one inlet valve and at least one exhaust valve, the valve mechanism comprising a rotatable camshaft with a cam curve including rising and falling ramps designed to interact with a valve control plunger that is movable inside a cylinder for actuation of the inlet or exhaust valve under action of a valve spring, the plunger cylinder communicating with a hydraulic fluid feed line via a check valve and with a hydraulic control circuit allowing a return movement of an engine valve to be delayed in relation to the timing of the corresponding falling ramp, wherein the hydraulic control circuit comprises a first and a second hydraulic fluid flow restrictor connected to the plunger cylinder at different levels along a longitudinal axis of the plunger cylinder, and a selector valve enables a connection between the cylinder and hydraulic control circuit to be opened via at least one of the first and second flow restrictors. ### Claim 2 (depends on 1) The valve actuation system as claimed in claim 1, wherein the selector valve is connected in series with an ON/OFF valve for opening and closing the connection to the return line. ### Claim 3 (depends on 2) The valve actuation system as claimed in claim 2, wherein the plunger cylinder is provided with an outlet port to the hydraulic fluid return line at a distance from an end of the plunger stroke that corresponds to closed engine valve. ### Claim 4 (depends on 3) The valve actuation system as claimed in claim 3, characterized in that the plunger cylinder is provided with a second outlet port to the return line, the second outlet port being disposed at a distance from the first outlet and at a further distance from the end of the plunger stroke. ### Claim 5 (depends on 4) The valve actuation system as claimed in claim 4, wherein the plunger cylinder is provided with a third outlet port to the outlet line at the end of the plunger stroke which corresponds to closed engine valve. ### Claim 6 (depends on 1) The valve actuation system as claimed in claim 1, wherein the control member comprises a hydraulic piston cylinder which is mechanically connected to the valve and can be actuated by the hydraulic control circuit. ### Claim 7 (depends on 1) The valve actuation system as claimed in claim 1, wherein the control member is applied to the engine exhaust valves for internal exhaust gas recirculation. ### Claim 8 (depends on 1) The valve actuation system as claimed in claim 1, wherein the control member is applied to the engine inlet valves for varying the closing sequence. ### Claim 9 (depends on 1) The valve actuation system as claimed in claim 1, wherein the plunger cylinder is provided with an outlet port to the hydraulic fluid return line at a distance from an end of the plunger stroke that corresponds to closed engine valve. ### Claim 10 (depends on 9) The valve actuation system as claimed in claim 9, characterized in that the plunger cylinder is provided with a second outlet port to the return line, the second outlet port being disposed at a distance from the first outlet and at a further distance from the end of the plunger stroke. ### Claim 11 (depends on 10) The valve actuation system as claimed in claim 10, wherein the plunger cylinder is provided with a third outlet port to the outlet line at the end of the plunger stroke which corresponds to closed engine valve. ### Claim 12 (depends on 9) The valve actuation system as claimed in claim 9, wherein the control member comprises a hydraulic piston cylinder which is mechanically connected to the valve and can be actuated by the hydraulic control circuit. ### Claim 13 (depends on 9) The valve actuation system as claimed in claim 9, wherein the control member is applied to the engine exhaust valves for internal exhaust gas recirculation. ### Claim 14 (depends on 9) The valve actuation system as claimed in claim 9, wherein the control member is applied to the engine inlet valves for varying the closing sequence.