Abstract: An internal combustion engine includes: intake and exhaust ports; an intake valve including an intake valve shaft and an intake valve head; and an exhaust valve including an exhaust valve shaft and an exhaust valve head. The surface of the intake valve includes an intake-valve-head front surface exposed in a combustion chamber when the intake valve is closed and an intake-valve-head back surface exposed in the intake port when the intake valve is closed. The surface of the exhaust valve includes an exhaust-valve-head front surface exposed in the combustion chamber when the exhaust valve is closed and an exhaust-valve-head back surface exposed in the exhaust port when the exhaust valve is closed. The arithmetic mean roughness of the whole exhaust-valve-head back surface is greater than the arithmetic mean roughness of each of the whole intake-valve-head front surface, the whole intake-valve-head back surface and the whole exhaust-valve-head front surface.

Abstract: A cam follower roller device, in particular for a fuel injection pump of an internal combustion engine, includes a tappet with a sleeve having an opening for partially accommodating a roller, a roller mounted rotatably in the sleeve and having a portion which protrudes axially from the opening of the sleeve provided to cooperate with a cam, and a roller support body housed in the sleeve. The roller includes a cylindrical spindle and a cylindrical body, the ends of the spindle projecting from the lateral faces of the body. The support body includes supports open towards the opening of the sleeve and supporting the ends of the spindle.

Abstract: A roller lifter for internal combustion engines is provided, which has higher rigidity of the lifter body, prevents cocking in the cylinder, and can achieve a size reduction. The roller lifter includes a cylindrical lifter body having a sliding surface on an outer circumferential surface thereof and a roller rotatably attached to the lifter body via an axial support pin and making contact with a rotating cam lobe. The lifter body includes a pair of support portions supporting the axial support pin. The axial support pin is mechanically fastened to the pair of support portions, with both ends thereof inserted in support holes formed in the support portions. The lifter body includes an anti-rotation retainer extending radially outward from the sliding surface. The sliding surface is formed on both front and rear sides in the sliding direction of the anti-rotation retainer.

Abstract: Disclosed is a coating material for intake/exhaust valves and a method for manufacturing the same. The coating material comprises: a Cr or Ti bonding layer formed on a mother material which makes up the intake/exhaust valve; a WC, CrN, TiN or TiCN support layer that is disposed on a surface of the boding layer; and a Si-DLC or SiO-DLC functional layer that is disposed on a surface of the support layer. According to the present invention, wear resistance and heat resistance of the valve are improved.

Abstract: During engine operation, valve retainers and valve springs are constantly rubbing and impacting each other resulting in heat and wear. The purpose of this invention is to provide a surface coating onto the valve retainer to reduce the friction with the valve spring and thus improve durability. Specifically, this invention teaches a method to thermally apply coatings to the surface of the valve retainer. Although typically fabricated from steel, the usage of lighter weight titanium valve retainers is increasing for high performance, or racing engines. The reduced mass allows valves to move more readily and requires less spring pressure to operate, producing more power and a faster revving engine, however titanium is typically not as wear resistant as the steel it replaces. In one embodiment, a porous molybdenum or other oleophilic metal is applied to the surface of the valve retainer. In another embodiment, hard coatings of cermets, carbides, and super alloys are applied as coatings to valve retainers.

Abstract: A valve system for controlling the charge exchange in an internal combustion engine may include a valve seat ring and a valve having a valve seat configured to form a sealing system with the valve seat ring, wherein the valve seat may be nitrocarburised.

Abstract: An engine valve comprising a chromiferous steel and a protective surface layer (5) which consists of iron chrome oxide. A method for manufacture of an engine valve with a protective layer includes an engine component of a chromiferous steel which is heated (200) at a predetermined temperature for a predetermined time so that a layer (5) of iron chrome oxide is formed on the engine component's surface, and the engine component is then cooled (300) to room temperature.

Abstract: An internal combustion engine component is composed of an aluminum alloy containing silicon, and includes a plurality of silicon crystal grains located on a slide surface. The slide surface has a ten point-average roughness RzJIS of about 0.54 ?m or more, and a load length ratio Rmr(30) at a cut level of about 30% of the slide surface is about 20% or more.

Abstract: A cylinder head assembly for an internal combustion engine including a cylinder head at least partially defining a flow path through the engine, including an intake port, an exhaust port, and a combustion chamber disposed between the intake port and the exhaust port. A valve is coupled to the cylinder head and movable relative to the cylinder head to selectively open the combustion chamber to one of the intake port and the exhaust port. A valve spring is positioned between the valve and the cylinder head and biases the valve to a closed position. A thermally insulating washer is positioned between the cylinder head and the valve spring.

Abstract: An engine component is composed of an aluminum alloy containing silicon, and includes a plurality of primary-crystal silicon grains located on a slide surface. The plurality of primary-crystal silicon grains have an average crystal grain size of no less than about 12 ?m and no more than about 50 ?m.

Abstract: A low friction sliding element for reciprocating engine parts, including a sliding contact surface that is in sliding contact with a counterpart during relative sliding motion of the sliding element and the counterpart. The sliding contact surface has microscopic recesses and plateaus interrupted by the recesses. The recesses have depths regularly varying in a sliding direction of the sliding element.

Abstract: The invention relates to a valve rotator having an annular body in which are circumferentially provided several ball pockets having inclined ball races and in which a ball and a tangential spring are located in each case. In a rest position, the tangential springs press the balls at an upper point of the inclined ball races. An annular cover is also provided, which is rotatable and axially displaceable relative to the body. There is also an axial spring device between the body and the cover, the axial spring device pressing them apart axially in the rest position and if a valve spring tension is applied the body and the cover are pressed axially against one another and the balls roll along the ball races to a lower point. There is a clearly defined rotation between the body and the cover. A drastic reduction of wear is brought about in that the axial spring device is spaced from the balls and on one axial side of the axial spring device is provided a pivot bearing. The balls are in contact with the cover.

Abstract: The external surface configuration of a portion of a mounted member that is joined to a mounting member includes, at a distal end position which first comes into contact with the mounting member when the mounted member is pressed against the mounting member, a curved surface bulged toward the mounting member. Other curved surfaces are bulged toward the mounting member with radii of curvatures larger than that of the curved surface and linking up with the curved surface.

Abstract: An exhaust valve for an internal combustion engine including a movable spindle with a valve disc of a nickel-based alloy which also constitutes an annular seat area at the upper surface of the valve disc. The seat area abuts a corresponding seat area on a stationary valve member in the closed position of the valve. At manufacturing, the seat area of the valve disc is subjected to a thermo-mechanical deformation process at a temperature lower than or around the recrystallization temperature of the alloy. The seat area on the upper surface of the valve disc has been given dent mark preventing properties in the form of a yield strength of at least 1000 MPa at a temperature of approximately 20° C. by means of the thermo-mechanical deformation process and possibly a yield strength increasing heat treatment.