Valve gear of internal combustion engine

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.

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.