Abstract: First and second connecting portions 61a and 62a are arranged in parallel and relatively turnably connected to a rocker arm 36 and a movable support portion 62b of a second link arm 62 is placed nearer to an engine valve 19 than a fixed support portion 61b of a first link arm 61. This makes it possible to decrease the size of a valve operating system and ensure the follow-up ability of the opening/closing operation as well as to vary a lift amount of the engine valve continuously while maintaining the reliability and durability of drive means.

Abstract: A hydraulic tappet including: a bottomed cylindrical body; a plunger slidably fitted in the body; a check valve mounted at one end of the plunger so that the check valve is interposed between a high-pressure chamber and an oil chamber, the high-pressure chamber being formed between a closed end of the body and one end of the plunger, the oil chamber being formed within the plunger; and a return spring mounted between the body and the plunger to bias the plunger in a direction to increase the volume of the high-pressure chamber. The return spring is disposed outwardly of the body. Thus, it is possible to decrease the volume of the high-pressure chamber to provide a reduction in size of the hydraulic tappet.

Abstract: An engine valve operating system is provided in which a rocker arm (63) linked and connected to an engine valve (19) and has a cam-abutting portion (65) to abut a valve operating cam (69) is turnably connected, via first and second connecting shafts (64, 66), to one end of a first link arm (61) turnably supported on an engine body (10) and one end of a second link arm (62) turnably supported by a displaceable movable shaft (68a). Also, oil supply means (58) which supply oil to the upper connecting shaft (64) of first and second connecting shafts (64, 66) are fixed to the engine body (10). This makes it possible to implement an engine valve operating system which is compact in size, ensures follow-up ability of the valve opening/closing operation, has a simple lubricating structure with a reduced number of parts, and ensures smooth valve operation while allowing the lift amount of the engine valve to be varied continuously.

Abstract: In an engine having a cylinder head which forms a portion of an engine body and is provided with an intake valve operated for opening and closing operations by an intake valve operating device having an intake camshaft and an exhaust valve driven for opening and closing operations by an exhaust valve operating device having an exhaust camshaft, the intake camshaft (30) is placed higher in position than the exhaust camshaft (35) by increasing the distance between the intake camshaft (30) and a combustion chamber (17) along a cylinder axis (C) of the engine body (11) relative to that between the exhaust camshaft (35) and the combustion chamber (17). Lubricating oil is thereby enabled to be easily used for exhaust valve operating device after being used for lubrication and cooling of the intake valve operating device, thus achieving efficient lubrication and cooling of the exhaust valve operating device.

Abstract: An engine valve operating system is provided in which a rocker arm that swings by following a valve operating cam abuts against an engine valve via a hydraulic tappet, a receiving member (41) receiving the hydraulic tappet (12) being slidably fitted into the rocker arm (13), the hydraulic tappet (12) being fitted into the rocker arm (13), a restricting part (29) being provided so as to face the receiving member (41) from the side opposite to the hydraulic tappet (12), and an adjustment screw (44) for adjusting a clearance between the restricting part (29) and the receiving member (41) when the engine valve is in a valve-closed state being screwed into an engine main body (5) so that its position can be adjusted back-and-forth so as to abut against the receiving member (41) when the engine valve is closed.

Abstract: First and second connecting portions 61a and 62a are arranged in parallel and relatively turnably connected to a rocker arm 36 and a movable support portion 62b of a second link arm 62 is placed nearer to an engine valve 19 than a fixed support portion 61b of a first link arm 61. This makes it possible to decrease the size of a valve operating system and ensure the follow-up ability of the opening/closing operation as well as to vary a lift amount of the engine valve continuously while maintaining the reliability and durability of drive means.

Abstract: There is provided an intake air amount control system for an internal combustion engine, which controls the amount of intake air by executing both cam phase control and valve lift control, and is capable of enhancing response and accuracy of the intake air amount control, while avoiding interaction between the cam phase control and the valve lift control. In the intake air amount control system 1, an ECU 2 controls the amount of intake air according to a target valve lift Liftin_cmd and a target cam phase Cain_cmd. The Liftin_cmd and Cain_cmd are respectively calculated as the sums of master values Liftin_cmd_ms and Cain_cmd_ms for causing an actual intake air amount Gcyl to converge to a target intake air amount Gcyl_cmd, and slave values Liftin_cmd_sl and Cain_cmd_sl set according to the master values Liftin_cmd_ms and Cain_cmd_ms (steps 56 and 64).

Abstract: An engine valve operating system is provided that includes a variable valve lift mechanism in which, when there is a possibility that the rotational speed of the engine might increase beyond an allowed rotational speed due to a downshift error in a manual transmission, etc., the amount of valve lift is decreased without changing the opening angle of the valve (19). By so doing, the curvature at the top of the curve of lift of the valve (19) is reduced, the inertial force applied to the valve (19) is reduced, and improper movement of the valve (19) can be prevented. Moreover, it is possible to prevent any increase in the intake air volume due to a decrease in the amount of lift of the valve (19), and prevent the effectiveness of engine braking from being degraded, thus enabling the rotational speed of the engine to be decreased and thereby preventing improper movement of the valve (19) from being promoted.

Abstract: In an engine in which a lift amount of a valve can be changed continuously, an engine valve operating system including a valve lift-changing mechanism is capable of increasing and decreasing the lift amount of the valve without changing an opening angle for the valve and capable of decreasing a tappet clearance in accordance with a decrease in lift amount of the valve. Thus, it is possible to prevent the ratio of the tappet clearance to the lift amount at a low valve lift from being increased to minimize the influence of the dispersion of the tappet clearance and to reduce the seating speed of the valve at the low valve lift to prevent the generation of a noise. It is also possible to prevent a reduction in performance of the engine at a high valve lift due to the dispersion of the tappet clearance and to decrease the seating noise of the valve at the low valve lift.

Abstract: A valve-operating system for an internal combustion engine includes cam followers which have cam abutment portions abutting against valve-operating cams provided on a camshaft and which are swingably carried in an engine body and operatively connected to engine valves biased in a closing direction by a valve spring. The cam followers are biased in a direction of abutment of the cam abutment portions against the valve-operating cams by a resilient biasing means different from the valve spring. A resilient biasing means includes a pull rod connected at one end thereof to the cam follower, and a compression coil spring interposed between the other end of the pull rod and the engine body to pull the pull rod to bias the cam follower in a direction of abutment of the cam abutment portion against the valve-operating cam. Thus, the resilient biasing means is constructed to be compact, leading to an increase in degree of freedom of the design of the structure of the valve-operating system.

Abstract: A hydraulic tappet including: a bottomed cylindrical body; a plunger slidably fitted in the body; a check valve mounted at one end of the plunger so that the check valve is interposed between a high-pressure chamber and an oil chamber, the high-pressure chamber being formed between a closed end of the body and one end of the plunger, the oil chamber being formed within the plunger; and a return spring mounted between the body and the plunger to bias the plunger in a direction to increase the volume of the high-pressure chamber. The return spring is disposed outwardly of the body. Thus, it is possible to decrease the volume of the high-pressure chamber to provide a reduction in size of the hydraulic tappet.

Abstract: A drive of a variable valve lift mechanism for driving a control shaft controlling a variable valve lift mechanism provided between an engine valve and an engine valve operating cam in order to change lift amount of the engine valve, comprises: a rotational force generating actuator; power conversion means for converting a rotational force of the rotational force generating actuator into a pivoting force of the control shaft; and a casing containing the power conversion means with the rotational force generating actuator coupled to an outer face of the casing. One end of the control shaft protrudes outward from one side of an engine body. The casing into which one end of the control shaft is inserted is attached to the one side of the engine body through fixing means which can be repeatedly attached and detached. Thus, it is possible to avoid the engine body from being complex and improve maintainability.

Abstract: In an internal combustion engine including a valve actuating mechanism, a vibration control member made of vibration control alloy is interposed in a path of vibration transmission between a camshaft and a cylinder head. The vibration control alloy has a vibration isolation capability comparable to that of rubber, but provides a durability and a resistance to degradation comparable to those of metal and alloy that are typically used in internal combustion engines. Therefore, a desired vibration control can be achieved while ensuring a required reliability, durability and resistance to degradation. The present invention is particularly useful when the valve actuating mechanism is provided with a variable lift, variable timing or variable compression mechanism because such a variable mechanism increases the stress to the engine, and tends to cause more vibrations than a more conventional non-variable valve actuating mechanism.

Abstract: To allow both the valve lift and valve timing for an engine valve to be varied in a continuous manner, the variable valve actuating device (1) comprises a camshaft (8) rotatably supported by a fixed part of the engine and provided with a cam (7), a first rocker arm (9) pivotally supported by a fixed part of the engine, the first rocker arm being provided with a first point (12) engaging a stem of an engine valve (6), a drum (11) rotatably supported by a fixed part of the engine and at least partly surrounding the cam, a second rocker arm (10) having a first point (20) pivotally supported by the drum, a second point (21) adapted to engage the cam and a surface engaged by a second point (22) of the first rocker arm, and a control member (25, 26) for selectively turning the drum over a prescribed angular range.

Abstract: In an internal combustion engine including a valve actuating mechanism, a vibration control member made of vibration control alloy is interposed in a path of vibration transmission between a camshaft and a cylinder head. The vibration control alloy has a vibration isolation capability comparable to that of rubber, but provides a durability and a resistance to degradation comparable to those of metal and alloy that are typically used in internal combustion engines. Therefore, a desired vibration control can be achieved while ensuring a required reliability, durability and resistance to degradation. The present invention is particularly useful when the valve actuating mechanism is provided with a variable lift, variable timing or variable compression mechanism because such a variable mechanism increases the stress to the engine, and tends to cause more vibrations than a more conventional non-variable valve actuating mechanism.

Abstract: A drive of a variable valve lift mechanism for driving a control shaft controlling a variable valve lift mechanism provided between an engine valve and an engine valve operating cam in order to change lift amount of the engine valve, comprises: a rotational force generating actuator; power conversion means for converting a rotational force of the rotational force generating actuator into a pivoting force of the control shaft; and a casing containing the power conversion means with the rotational force generating actuator coupled to an outer face of the casing. One end of the control shaft protrudes outward from one side of an engine body. The casing into which one end of the control shaft is inserted is attached to the one side of the engine body through fixing means which can be repeatedly attached and detached. Thus, it is possible to avoid the engine body from being complex and improve maintainability.

Abstract: To allow both the valve lift and valve timing for an engine valve to be varied in a continuous manner, the variable valve actuating device (1) comprises a camshaft (8) rotatably supported by a fixed part of the engine and provided with a cam (7), a first rocker arm (9) pivotally supported by a fixed part of the engine, the first rocker arm being provided with a first point (12) engaging a stem of an engine valve (6), a drum (11) rotatably supported by a fixed part of the engine and at least partly surrounding the cam, a second rocker arm (10) having a first point (20) pivotally supported by the drum, a second point (21) adapted to engage the cam and a surface engaged by a second point (22) of the first rocker arm, and a control member (25, 26) for selectively turning the drum over a prescribed angular range.

Abstract: An optical pick-up apparatus-includes a light source, an inclined multi-division phase shift diffraction grating, an objective lens that collects light emitted from the light source onto an optical recording medium, a light diverging element that-diverges reflection light reflected on the optical recording medium, and a light receiving element that receives diverged reflection light. The diffraction grating is formed on a light-transmitting rectangular substrate, and is manufactured by being cut out in such a manner that a virtual line as a symmetric axial line that forms the diffraction grating line-symmetrically, becomes parallel to at least one side of the substrate. This makes it possible to adjust the assembling position by placing the visually observable one side of the substrate, used as a guiding index, to become perpendicular to the radius direction of the optical recording medium. Hence, the assembling position adjustment of the diffraction grating can be extremely easy.

Abstract: In order to increase in concentration of HC in an exhaust gas due to an axial gap between a ring groove and a piston ring, when an internal combustion engine is at a lower temperature, particularly, during the starting or the low-speed operation of the internal combustion engine in which the moving speed of a piston is lower, a restricting ring having a radially outward tension is inserted in a wedge shape into between axially opposed surfaces of a ring groove and a piston ring so that in a lower-speed operational range of a piston, the axial movement of the piston ring within the ring groove is restricted by the wedging action of the restricting ring, and in a higher-speed operational range of the piston, the wedging action of the restricting ring is removed by a floating force of the piston ring generated with the descending movement of the piston.

Abstract: In order to increase in concentration of HC in an exhaust gas due to an axial gap between a ring groove and a piston ring, when an internal combustion engine is at a lower temperature, particularly, during the starting or the low-speed operation of the internal combustion engine in which the moving speed of a piston is lower, a restricting ring having a radially outward tension is inserted in a wedge shape into between axially opposed surfaces of a ring groove and a piston ring so that in a lower-speed operational range of a piston, the axial movement of the piston ring within the ring groove is restricted by the wedging action of the restricting ring, and in a higher-speed operational range of the piston, the wedging action of the restricting ring is removed by a floating force of the piston ring generated with the descending movement of the piston.