摘要:
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.
摘要翻译:三维凸轮具有沿着凸轮的旋转轴线变化的凸轮轮廓表面形状,并且通过网状烧结来制造。 将网状烧结时的烧结材料的烧结密度设定为7〜7.4g / cm 3,以使凸轮轮廓面的孔率在5〜10%的范围内。 三维凸轮具有改善的耐久性,同时确保高生产率。
摘要:
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. Therefore, it is possible to achieve conformation to the characteristics of the engine and therefore constantly realize a suitable valve characteristic in accordance with the operational condition of the engine. Hence, improvements can be achieved in the output performance of the engine, the fuel consumption, the combustion stability and the like.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.