Valve gear of internal combustion engine

• US 6,854,432 B2
• Filed: 04/09/2001
• Issued: 02/15/2005
• Est. Priority Date: 04/10/2000
• Status: Expired due to Term

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Hirano, Makoto
• Primary Examiner(s): Denion, Thomas
• Assistant Examiner(s): Eshete, Zelalem
• Application Number:
  US10/257,319
• Publication Number:
  US 20030154942A1
• Time in Patent Office: 1,408 Days
• Field of Search: 123/90.16, 123/90.44, 123/90.39, 123/90.41, 123/90.48
• US Class Current: 123/90.16
• CPC Class Codes: F01L 1/143 for use with overhead camshafts
• CPC Class Codes: F01L 13/0015 for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
• CPC Class Codes: 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
• CPC Class Codes: F01L 2001/0537 Double overhead camshafts [DOHC]
• CPC Class Codes: F01L 2305/00 Valve arrangements comprising rollers
• CPC Class Codes: F01L 2307/00 Preventing the rotation of tappets
• CPC Class Codes: F02B 2275/18 DOHC [Double overhead camshaft]

Abstract

A valve operating system for an internal combustion engine including a main valve lifter, a subsidiary valve lifter, a low-speed cam operating the main valve lifter, a high-speed cam operating the subsidiary valve lifter, a connecting device switched over between a non-connecting state in which the valve lifters are disconnected from each other, and a connecting state in which the valve lifters are connected to each other, a valve spring for biasing the valve in a closing direction, a lifter spring for biasing the subsidiary valve lifter toward the cam; thus, in a low-speed mode, that is non-connected states, an influence of a load of the lifter spring on the valve can be prevented, and in a high-speed mode, that is connected states, a sum total of loads of the valve spring and the lifter spring cap be applied to both of the valve lifters to improve the closing responsiveness of the valve.

Claims

1. A valve-operating system for an internal combustion engine, comprising:

a main valve lifter moved in unison with valve mounted in an engine body;

first and second subsidiary valve lifters adjoining said main valve lifter and slidable relative to said main valve lifter;

a main cam for providing a first operational mode to the valve through said main valve lifter;

a subsidiary cam capable of operating said subsidiary valve lifter with a lift amount larger than said main cam in a direction to open the valve;

main and subsidiary guide bores provided in said main and subsidiary valve lifters to extend in a direction perpendicular to a direction of operation of said main and subsidiary valve lifters; and

connecting means having a connecting member for moving between a non-connecting position where said connecting member is received in only one of said main and subsidiary guide bores and a connecting position where said connecting member is received in both of said guide bores, so that when said main and subsidiary valve lifters are connected to each other by the connecting state of said connecting means, said subsidiary cam provides a second operational mode to the valve, in which said valve is opened more largely than in said first operational mode,

wherein said main and subsidiary valve lifters have flat faces relatively slidably superposed on each other, and are formed so as to be slidably received in a common lifter guide bore in the engine body, said flat faces being formed to extend in parallel to an axis of said lifter guide bore, and said main and subsidiary guide bores are provided in said main and subsidiary valve lifters so as top open into said corresponding flat faces, respectively, and

wherein the first and second subsidiary valve lifters are disposed on opposite sides of said main valve lifter, and the first and second subsidiary cams moved at different lift amounts are disposed in correspondence to said first and second subsidiary valve lifters, so that said main valve lifter can be connected individually to said first and second subsidiary valve lifters through the first and second connecting members.

2. A valve-operating system for an internal combustion engine, comprising:

a main valve lifter moved in unison with a valve mounted in an engine body;

a subsidiary valve lifter adjoining said main valve lifter and slidable relative to said main valve lifter, wherein the main and subsidiary valve lifters are slidably received in a lifter guide bore of a substantially circular cross section, said main valve lifter being positioned near a center of the lifter guide bore and associated with the valve;

a main cam for providing a first operational mode to the valve through said main valve lifter;

a subsidiary cam capable of operating said subsidiary valve lifter with a lift amount larger than said main cam in a direction to open the valve;

main and subsidiary guide bores provided in said main and subsidiary valve lifters to extend in a direction perpendicular to a direction of operation of said main and subsidiary valve lifters; and

connecting means having a connecting member for moving between a non-connecting position where said connecting member is received in only one of said main and subsidiary guide bores and a connecting position where said connecting member is received in both of said guide bores, so that when said main and subsidiary valve lifters are connected to each other by the connecting state of said connecting means, said subsidiary cam provides a second operational mode to the valve, in which said valve is opened more largely than in said first operational mode,

wherein said main and subsidiary valve lifters have flat faces relatively slidably superposed on each other, said flat faces being formed to extend in parallel to an axis of said lifter guide bore, and said main and subsidiary guide bores are provided in said main and subsidiary valve lifters so as to open into said corresponding flat faces, respectively,

wherein a hydraulic pressure chamber is connected to an outer end of the subsidiary guide bore in the subsidiary valve lifter through an annular step, and

wherein the outer end of the subsidiary guide bore in the subsidiary valve lifter is closed by a closing plug fitted in the main valve lifter.

3. A valve-operating system for an internal combustion engine, comprising:

a main valve lifter moved in unison with a valve mounted in an engine body;

a subsidiary valve lifter adjoining said main valve lifter and slidable relative to said main valve lifter, wherein the main and subsidiary valve lifters are slidably received in a lifter guide bore of a substantially circular cross section, said main valve lifter being positioned near a center of the lifter guide bore and associated with the valve;

a main cam for providing a first operational mode to the valve through said main valve lifter;

a subsidiary cam capable of operating said subsidiary valve lifter with a lift amount larger than said main cam in a direction to open the valve;

main and subsidiary guide bores provided in said main and subsidiary valve lifters to extend in a direction perpendicular to a direction of operation of said main and subsidiary valve lifters; and

connecting means having a connecting a member for moving between a non-connecting position where said connecting member is received in only one of said main and subsidiary guide bores and a connecting position where said connecting member is received in both of said guide bores, so that when said main and subsidiary valve lifters are connected to each other by the connecting state of the connecting means, said subsidiary cam provides a second operational mode to the valve, in which the valve is opened more largely than in the first operational mode,

wherein a roller is carried on at least one of said main and subsidiary valve lifters to come into contact with the corresponding cam,

wherein a hydraulic pressure chamber is connected to an outer end of the subsidiary guide bore in the subsidiary valve lifter through an annular step, and

wherein the outer end of the subsidiary guide bore in the subsidiary valve lifter is closed by a closing plug fitted in the main valve lifter.