# US 5,345,904 A · Valve control means > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,345,904 A - Document ID: US5345904A - Status: Granted - Kind: A - Application number: 08/128,527 - Filed: 1993-09-29 - Granted: 1994-09-13 - Earliest claimed: 1990-02-16 - Assignees: Group Lotus PLC - Inventors: Clive Dopson; Jeffrey Allen - Web page: https://patentgrep.com/patent/US5345904A ## CPC - F01L 1/245: Hydraulic tappets - F01L 1/143: {for use with overhead camshafts} - F01L 1/25: between cam and valve stem - F01L 1/267: {with means for varying the timing or the lift of the valves} - F01L 13/0005: {Deactivating valves} - F01L 13/0031: {by modification of tappet or pushrod length} - F01L 13/0036: {the valves being driven by two or more cams with different shape, size or timing or a single cam profiled in axial and radial direction} - F01L 13/0063: {by modification of cam contact point by displacing an intermediate lever or wedge-shaped intermediate element, e.g. Tourtelot} - F01L 2305/00: Valve arrangements comprising rollers - F02F 7/006: {Camshaft or pushrod housings} - F01L: CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES - F02F: CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES ## Abstract The invention relates to valve control for an internal combustion engine. The valve control includes a valve, a first camshaft having a first cam member and a second cam member having a different profile from the first cam member and a cam follower assembly for transmitting reciprocating movement to the valve from the cam. The cam follower assembly includes a first cam follower member in engagement with the valve and a second cam follower member movably relative to the first cam follower member, and locking means to enable the follower members to be linked to move together. When the follower members are not linked the valve means is controlled by the first cam follower member in engagement with and following the profile of the first cam member and when the follower members are linked the valve is controlled by the second cam follower member in engagement with and following the profile of the second cam member. One of the cam members having a circular axial cross-section to enable valve deactivation. ## Claims ### Claim 1 Valve control means for controlling valve means of an internal combustion engine comprising: cam means comprising a rotatable camshaft having a first cam member and a lobe of circular axial cross-section, transmitting means for transmitting reciprocating movement to the valve means from said cam means, said transmitting means comprising a first follower member in engagement with said valve means and a second follower member movable relative to said first follower, and locking means to enable said follower members to be linked so as to move together, wherein when the follower members are not linked by the locking means the valve means is controlled by the first follower member in engagement with and following the profile of the lobe of circular cross-section and when the follower members are linked by the locking means the valve means is controlled by the second follower member in engagement with and following the profile of the first cam member and wherein the second follower member has a bore therethrough and the first follower member is in the form of an inner member located within the bore, said first follower member being movable in the bore relative to the second follower member when the follower members are not linked to move together. ### Claim 2 (depends on 1) Valve control means as claimed in claim 1 wherein the second follower member is generally cylindrical and has a generally cylindrical bore therethrough and the first follower member is a cylindrical member located within the cylindrical bore of the second follower member. ### Claim 3 (depends on 2) Valve control means as claimed in claim 2 wherein the locking means comprises a locking element movable within the second follower member between a first position in which the follower members are not linked and a second position in which the locking element engages a stopped diameter of the first follower member to link the two follower members. ### Claim 4 (depends on 1) Valve control means as claimed in claim 1 wherein the lower edge of only the first follower member directly abuts the top of the controlled valve whereby when the follower members are disconnected the second follower member makes no contact with the valve and transmits no motion thereto. ### Claim 5 (depends on 1) Valve control means as claimed in claim 1 further comprising hydraulic lash adjustment means located between the valve and said first follower member. ### Claim 6 (depends on 1) Valve control means as claimed in claim 1 wherein the first follower member directly abuts the lobe of circular cross-section and the second follower member directly abuts the first cam member. ### Claim 7 (depends on 1) Valve control means as claimed in claim 1 further comprising a third follower member located between said first follower member and said lobe of circular cross-section to provide indirect engagement therebetween. ### Claim 8 (depends on 7) Valve control means as claimed in claim 7 in which said third follower member is held in engagement with said lobe of circular cross-section by spring means. ### Claim 9 (depends on 1) Valve control means as claimed in claim 1 comprising a second cam member on the rotatable camshaft having the same profile as the first cam member and provided on the side of the lobe of circular cross section opposite to the first cam member, wherein the second follower member engages with and follows the profiles of both the first and second cam members. ### Claim 10 (depends on 1) Valve control means as claimed in claim 1 in which actuating means is provided to actuate and de-actuate the locking means for different speeds and loads of the engine. ### Claim 11 (depends on 10) Valve control means as claimed in claim 10 in which the actuating means is manually or automatically operable. ### Claim 12 (depends on 1) Valve control means as claimed in claim 1 in which the first and second follower members are linked at higher engine speeds to improve efficiency of the engine. ### Claim 13 (depends on 1) Valve control means as claimed in claim 1 in which the locking means comprises a locking element movable within said second follower member and held restrained in an unlocked position by spring means. ### Claim 14 (depends on 1) Valve control means as claimed in claim 1 in which the locking means comprises a locking element movable within said second follower member and held restrained in an unlocked position by fluid pressure. ### Claim 15 (depends on 13) Valve control means as claimed in claim 13 in which the locking element has a shaped surface adapted to cooperate with a complementary surface of said first follower member in a locked position. ### Claim 16 (depends on 14) Valve control means as claimed in claim 14 in which the locking element has a shaped surface adapted to cooperate with a complementary surface of said first follower member in a locked position. ### Claim 17 (depends on 14) Valve control means as claimed in claim 14 in which the locking element is moved from a unlocked position to a locked position by means of fluid pressure. ### Claim 18 (depends on 15) Valve control means as claimed in claim 15 in which the locking element is moved from an unlocked position to a locked position by means of fluid pressure. ### Claim 19 (depends on 14) Valve control means as claimed in claim 14 wherein the first follower member has a stepped portion and the locking element engages the stepped portion to link the first and second follower members. ### Claim 20 (depends on 15) Valve control means as claimed in claim 15 wherein the first follower member has a stepped portion and the locking element engages the stepped portion to link the first and second follower members. ### Claim 21 (depends on 1) Valve control means as claimed in claim 1 in which the second follower member is held in engagement with the first cam member by spring means. ### Claim 22 (depends on 1) Valve control means as claimed in claim 1 in which the second follower member is biased toward said first cam member by spring means. ### Claim 23 (depends on 22) Valve control means as claimed in claim 22 in which the spring means holds the second follower member in engagement with the first cam member when the follower members are not linked to move together. ### Claim 24 (depends on 1) Valve control means as claimed in claim 1 in which when the second follower member is linked in engagement with said first follower member there is a gap between said first follower member and the lobe of circular cross-section during the period in which the second follower member engages the lift portion of the first cam member. ### Claim 25 (depends on 1) An internal combustion engine having valve control means as claimed in claim 1. ### Claim 26 (depends on 1) An internal combustion engine having valve control means as claimed in claim 1 wherein the cylinder head of the engine has a bore in which the first and second follower members are located, the second follower member being slidable in the bore relative to the cylinder head.