Abstract: A variable valve mechanism of an internal combustion engine includes a plurality of swing members and a variable device that displaces a control shaft to displace a plurality of slider gears of the swing members at a time, thereby changing valve lifts of the plurality of swing members at a time by meshing of helical splines. The swing members include a first swing member for a predetermined cylinder of a plurality of cylinders and a second swing member for a cylinder other than the predetermined cylinder, and a helix angle of the helical splines varies between the first and the second swing members. The variable device displaces the control shaft to a predetermined normal position to perform a normal operation, and displaces the control shaft to a predetermined cylinder cutoff position to perform a cylinder cutoff operation in which the second swing member does not drive a valve.

Abstract: A variable valve mechanism of an internal combustion engine includes a plurality of swing members and a variable device that displaces a control shaft to displace a plurality of slider gears of the swing members at a time, thereby changing valve lifts of the plurality of swing members at a time by meshing of helical splines. The swing members include a first swing member for a predetermined cylinder of a plurality of cylinders and a second swing member for a cylinder other than the predetermined cylinder, and a helix angle of the helical splines varies between the first and the second swing members. The variable device displaces the control shaft to a predetermined normal position to perform a normal operation, and displaces the control shaft to a predetermined cylinder cutoff position to perform a cylinder cutoff operation in which the second swing member does not drive a valve.

Abstract: A profile of a cam (33) of a camshaft (32) is set based on a relationship of a stop position of a vane rotor (36) at a most retarded phase relative to a housing rotor (37). In other words, the profile of the cam (33) arranged in the camshaft (32) is set so that a second opening (110B) of a communication passage (100), which opens in a second retardment chamber (52B), is located upward in a vertical direction from the axis C of the camshaft (32) when the camshaft (32) is at a neutral position, that is, when torque applied from the cam (33) to the camshaft (32) is the smallest.

Abstract: A profile of a cam (33) of a camshaft (32) is set based on a relationship of a stop position of a vane rotor (36) at a most retarded phase relative to a housing rotor (37). In other words, the profile of the cam (33) arranged in the camshaft (32) is set so that a second opening (110B) of a communication passage (100), which opens in a second retardment chamber (52B), is located upward in a vertical direction from the axis C of the camshaft (32) when the camshaft (32) is at a neutral position, that is, when torque applied from the cam (33) to the camshaft (32) is the smallest.

Abstract: The cam face of an intake cam has a main lift portion, which causes an intake valve to execute a basic lift operation, and a sub lift portion, which assists the action of the main lift portion. The main lift portion and the sub lift portion continuously change in an axial direction of the intake cam. An axial movement mechanism moves the intake cam in the axial direction to adjust the axial position of the cam face that drives the intake valve. The axial movement of the intake cam results in the valve being given a variety of valve lift characteristics in the form of a combination of a cam lift pattern realized by the main lift portion and a cam lift pattern realized by the sub lift portion. Therefore, various engine performances required according to the running conditions of the engine can be fully satisfied by the valve characteristics.

Abstract: A three-dimensional cam has a cam profile surface shape that changes along a rotating axis of the cam, and is produced by net-shape-sintering. The sintered density of a sintering material at the time of net-shape-sintering is set to 7 to 7.4 g/cm3 to achieve a hole rate of the cam profile surface within the range of 5 to 10%. The three-dimensional cam has an improved durability, while securing high productivity.

Abstract: A valve train for an internal combustion engine has a variable valve performance mechanism for changing the valve open angle of at least one set of intake valves and exhaust valves. The valve train further includes an electronic control unit (ECU) for controlling the variable valve performance mechanism and a sensor for detecting the running state of the engine. The ECU judges whether there is a malfunction in the engine based on detection signals from the sensor. If there is a malfunction in the engine, the ECU actuates the variable valve performance mechanism to decrease the valve overlap thereby performing a failsafe. The ECU also advances the closing timing of the intake valves. Alternatively, the ECU retards the opening timing of the exhaust valves.

Abstract: A variable valve apparatus of an internal combustion engine is capable of realizing more precise valve characteristic control by reducing the error in-detection of the amount of movement of a camshaft caused by a difference in the rate of thermal expansion. The variable valve apparatus has a camshaft that is supported so as to be rotatable and slidable in a direction of an axis thereof and that has three-dimensional cams whose cam profile continuously changes in the direction of the axis. The apparatus also has an actuator for moving the camshaft in the direction of its axis. The apparatus further has a camshaft position sensor provided in a cylinder head, a detected portion provided in the camshaft, and a camshaft movement amount detection portion for detecting the amount of movement of the camshaft in the direction of the axis. The camshaft movement amount detection portion is provided near a camshaft reference position.

Abstract: Variable valve characteristic control apparatuses realize a change in a valve characteristic in accordance with a requirement of an internal combustion engine and a three-dimensional cam for use in the variable valve characteristic control apparatus. In the case of an intake valve, two lift patterns and continuously varying lift patterns between the two lift patterns are realized by the three-dimensional cam through the driving of the variable valve characteristic control apparatus. The two lift patterns provide different amounts of lift in the delay side of a peak within a valve operation angle, but provide equal amounts of lift in the delay side of the peak. Since the intake cam has the two lift patterns, it is possible to select a phase where the two lift patterns provide equal amounts of lift and provide different amounts of lift in phases other than the equal-lift phase so as to accord to the characteristics of the internal combustion engine.

Abstract: Variable valve characteristic control apparatuses realize a change in a valve characteristic in accordance with a requirement of an internal combustion engine and a three-dimensional cam for use in the variable valve characteristic control apparatus. In the case of an intake valve, two lift patterns and continuously varying lift patterns between the two lift patterns are realized by the three-dimensional cam through the driving of the variable valve characteristic control apparatus. The two lift patterns provide different amounts of lift in the delay side of a peak within a valve operation angle, but provide equal amounts of lift in the delay side of the peak. Since the intake cam has the two lift patterns, it is possible to select a phase where the two lift patterns provide equal amounts of lift and provide different amounts of lift in phases other than the equal-lift phase so as to accord to the characteristics of the internal combustion engine.

Abstract: A valve train for an internal combustion engine has a variable valve performance mechanism for changing the valve open angle of at least one set of intake valves and exhaust valves. The valve train further includes an electronic control unit (ECU) for controlling the variable valve performance mechanism and a sensor for detecting the running state of the engine. The ECU judges whether there is a malfunction in the engine based on detection signals from the sensor. if there is a malfunction in the engine, the ECU actuates the variable valve performance mechanism to decrease the valve overlap thereby performing a failsafe. The ECU also advances the closing timing of the intake valves. Alternatively, the ECU retards the opening timing of the exhaust valves.

Abstract: Variable valve characteristic control apparatuses realize a change in a valve characteristic in accordance with a requirement of an internal combustion engine and a three-dimensional cam for use in the variable valve characteristic control apparatus. In the case of an intake valve, two lift patterns and continuously varying lift patterns between the two lift patterns are realized by the three-dimensional cam through the driving of the variable valve characteristic control apparatus. The two lift patterns provide different amounts of lift in the delay side of a peak within a valve operation angle, but provide equal amounts of lift in the delay side of the peak. Since the intake cam has the two lift patterns, it is possible to select a phase where the two lift patterns provide equal amounts of lift and provide different amounts of lift in phases other than the equal-lift phase so as to accord to the characteristics of the internal combustion engine.

Abstract: A valve train for an internal combustion engine has a variable valve performance mechanism for changing the valve open angle of at least one set of intake valves and exhaust valves. The valve train further includes an electronic control unit (ECU) for controlling the variable valve performance mechanism and a sensor for detecting the running state of the engine. The ECU judges whether there is a malfunction in the engine based on detection signals from the sensor. If there is a malfunction in the engine, the ECU actuates the variable valve performance mechanism to decrease the valve overlap thereby performing a failsafe. The ECU also advances the closing timing of the intake valves. Alternatively, the ECU retards the opening timing of the exhaust valve.

Abstract: A valve lifter for a three-dimensional cam and a variable valve operating apparatus have enhanced flexibility in the design of a detent mechanism of the valve lifter for the three-dimensional cam, as well as enhanced durability. It is possible to form a thick wall portion which is sufficiently thick without increasing the weight by providing an offset between an outer peripheral surface and an inner peripheral surface of the valve lifter. Therefore, a sufficiently large projection can be mounted without deforming the valve lifter. This structure makes it possible to increase an area contacting a detent groove, reduce the surface pressure, and enhance the durability. The thick wall portion exists longer in an axial direction of the valve lifter, so the detent mechanism can be formed on the outer peripheral surface instead of a top surface. Therefore, the flexibility of design of the detent mechanism can be enhanced.

Abstract: A rocking follower mechanism for a three-dimensional cam is provided. The rocking follower mechanism prevents a hit sound without generating excessive abrasion on a cam follower or a cam surface of the three-dimensional cam, while providing a wide portion for the cam follower. The cam follower is restricted from moving in the axial direction. The wide portion of the cam follower is formed at a position so as not to be brought into contact with the cam surface of the intake cam. As a result, collision of the cam surface against an angular portion defined by a thrust surface and an end surface of the wide portion, i.e., direct abutment against the end surface, can be avoided. Therefore, it is possible to prevent the hit sound without generating excessive abrasion on the cam surface of the intake cam or the cam follower itself. Accordingly, excellent riding comfort of the vehicle can be maintained.

Abstract: In a variable valve control device, the minimum operating hydraulic pressure necessary for controlling the vane rotor is arranged to be higher than that for axially moving the piston member. Thus, whenever the angular phase is actually changed, the hydraulic pressure sufficient enough to move the piston member may be always ready to be applied to the axial movement control member. Therefore, when the intake camshaft is at the lowest lift stroke position, the intake camshaft may be easily shifted from the lowest lift stroke position to the higher lift stroke position without time delay so that a highly accurate angular phase control of the intake camshaft relative to the timing pulley may be secured.

Abstract: A cam follower mechanism for transmitting the movement of a three-dimensional cam to an intake valve. The cam operates a valve through a cam follower mechanism. A valve lifter includes a guide groove having an arcuate cross section. A cam follower is received in the guide groove and engages the cam. The cam follower can pivot about a pivoting axis. The cam follower has an arcuate cross section. The follower includes tapered surfaces, which are inclined less than ninety degrees with respect to the pivoting axis. Contact between the tapered surfaces and the guide groove prevents the cam follower from moving in the direction of the pivoting axis.

Abstract: A revolution speed control apparatus is provided. In particular, a variable valve drive apparatus for an internal combustion engine is provided, capable of continuously and variably setting a valve lift in conjunction with use of a three-dimensional cam. The apparatus provides a proper fail-safe system by setting an appropriate allowable engine revolution speed. An actual amount of adjustment in the position of a cam shaft, that is performed by a valve lift varying actuator, is detected by a shaft position sensor. Based on the actual amount of adjustment, the apparatus determines a cam profile of each intake cam contacting the corresponding cam follower. That is, the apparatus determines what portion of the oblique cam surface of each intake cam is providing a present valve lift. A valve lift is thus specified in addition to other parameters needed to determine an allowable revolution speed. These parameters include the valve spring load and the valve mass, for example.