摘要:
The invention relates to a device for the variable actuation of gas exchange valves for internal combustion engines, wherein at least one cam (2) pertaining to a camshaft (1) mounted in a housing rotates according to the engine speed. The cam (2) first drives an intermediate member (4) which performs a clear oscillating, rotary movement and has a rotatioral axis (7) that can be displaced in the housing parallel to itself along a curve of displacement (8), said intermediate member comprising a control cam (5) having a lifting region (5b) and actuating an output member (11) that, in turn, actuates at least one valve (13). The aim of the invention is to enable one such device to be reliably controlled To this end, the control cam (5) has a catch region (5a), and the intermediate member (4) is mounted on a bearing having an axis which corresponds to the rotational axis (7), said bearing being arranged in such a way that it is guided in a forced manner and can be displaced parallel to the curve of displacement (8, 28, 35), by means of an articulation (16, 24, 26) connected to the cylinder head or the housing or by a slide (34) that is guided in the housing in a positively locking manner. The invention also relates to a method for operating an internal combustion engine comprising a plurality of cylinders using at least one of the inventive devices.
摘要:
A device for actuating a valve in an internal combustion engine consists of a casing and a cam mechanism including a cam which is rotatably joined to the casing. The cam engages a tappet at a cam/tappet interface and the tappet engages a output link at a tappet/drive link interface. During cam rotation, the cam causes an acceleration to occur in the output link. The drive link moves alternately in either of two directions and is operably disposed within the casing so that the drive link transmits its motion to the valve. The cam is shaped such that in the interval between valve closure and reopening, the acceleration transmitted by the cam, at the cam/tappet interface in normal direction, is substantially constant and is directed away from the cam. During portions of the cycle of operation, the various mechanical links are kept in contact solely by the effect of inertial force thereby reducing the need for additional springs, such as commonly used to maintain contact between the intermediate link or tappet and the cam. A support element or stop engages the output link during valve closure such that the drive link does not engage the tappet at the tappet/drive link interface. This provides more linear acceleration and enhanced lubrication at the tappet/drive link interface during engine operation.
摘要:
The aim of the invention is to fulfill, in a way that is superior to that of the previous state of the art, the demands placed by the engine on a variable valve control with regard to the shaping and accuracy of the valve lifting curves, to the simplicity of the structural design of the valve drive and of the associated adjusting mechanism, and to mechanical losses due to friction. These demands are met without any additional structural complexity, and, more particularly, without any changes to the overall height. This feat is achieved by means of the provision of a rotatable drive consisting of a housing (G), a shaft (W), an intermediate element (Z), and of an output element (A).
摘要:
The invention is characterized in that the gas exchange valves of a cylinder are displaced in a displacement unit (15, 34) jointly and independently of the displacement of the displacement devices of the other cylinders. Every displacement unit (15, 34) is associated with separate actuators for actuating the same. Angle of rotation sensors (42, 43) are provided to detect the angle or rotation signals of the crankshaft and the camshaft or any other shaft rotating at half the crankshaft speed. These angle of rotation signals are used to derive the common idle phase of all valves of a cylinder to be jointly adjusted, a control unit (44) effecting the displacement of every displacement unit (15, 34) during said common idle phase.
摘要:
The invention relates to a revolving gear consisting of a housing (G), a shaft (W), an intermediate member (Z) and an output member (A). The shaft is revolvably guided in the housing in a rotating joint (wb) and actuates the intermediate member by means of a curved joint (zw). The intermediate member is supported by a curved joint (zg) in the housing and is actively connected to the output member by another curved joint (za). The curved joint between the intermediate member and the housing has a controlling section enabling movement to be transmitted to the output member and a locking section preventing movement from being transmitted to the output member. The output member is unequivocally guided in the housing and transmits movement to at least one valve (V).
摘要:
The invention relates to a device for the variable actuation of the gas exchange valves of internal combustion engines, whereby a continuously revolving cam drives an intermediate member which carries out an oscillating, pure rotational movement and moves a drive member in accordance with the respective valve lift curve via a control cam. In order to modify the valve lift curve, the position of the rotational axis of the intermediate member can be modified along an advance curve. The rotational axis of the intermediate member is represented by a pin which is freely rotatable at its guide end and which carries cam plates that are linked therewith in a rotationally fixed manner. Said cam plates define either directly or indirectly the respective required position on the advance curve. The pin is rotated via a suitable joining element.
摘要:
A device is described for actuating the charge-cycling valves (V) in reciprocating internal combustion engines, consisting of a housing (G); a cam (N) mounted in the housing (G) in a revolute joint (ng) so as to be able to rotate, the rotational movement of which cam is derived from a crankshaft; an intermediate member (Z) activated by this cam (N) by way of a first cam joint (zn); and a power take-off member (A) that transfers the movement to the valve (V), and is connected to act with the intermediate member (Z), directly or via other transfer elements, and at least one other cam joint (za) is provided within the active connection from the first cam joint (zn) to the power take-off member (A), whereby this other cam joint (za) is formed by a cam (Kz or Ka, respectively) on one of the two gear mechanism members (Z, A) that form the cam joint (za), in and of themselves, the shape of which cam has at least one point of inflection (W) in the contact region in which a valve lift is produced, whereby the point of inflection (W) is disposed in the region of the cam (Kz or Ka, respectively) that describes the greatest possible valve lift. In order to minimize the forces, i.e. moments between the gear mechanism members, and thus to keep the reactive forces in the system as low as possible, it is proposed that the point of inflection (W) be disposed in such a manner that the surface normal in the contact point, at which the greatest valve lift is achieved, is approximately equal to the surface normal in the contact point, at which the highest valve acceleration occurs.
摘要:
A process for gravimetric production of test gas by re-weighing includes a series of sequential process steps, the first of which is weighing an evacuated gas container on a scale and then connecting a gas feed line to a control valve that is connected to the gas container by a controllable adjustment element connected to the scale. The controllable valve is automatically opened to fill a first test gas component, with the amount placed in the first test gas component being automatically monitored by weighing the gas container. After a selected quantity of test gas is provided, the controllable valve is closed. The connection between the gas feed line and controllable valve is accomplished by an adjustable fluid cylinder which automatically disconnects the gas feed line from the scale. The gas container is then reweighed and the process repeated for each subsequent test gas component placed in the gas container.
摘要:
An apparatus for operating the valves on internal combustion engines with a variable valve lift curve has a multimember, rotary gear, which comprises the valve-guiding case, a rotary cam connected to the case via a pivot joint and whose drive is derived from the crankshaft, an intermediate member operated by the cam by a curve joint and a driven member, which is supported by a joint on the case and operatively connected to the intermediate member via a joint and which transfers the movement to the valve. The intermediate member is supported by a curve joint on the case, with the curve of the curve joint, located on the intermediate member, having a portion forming a locking device and also a control portion. The position of the curve supported on the case and associated with this curve joint or the position of the pivot joint of the cam is adjustable during operation.
摘要:
The present invention provides a disassemblable camshaft for internal combustion engines features a cylindrical shaft which in a single operation can be inserted in the bearing bores and cams arranged in between, so that undivided bearings of relatively small diameter can be used. The cams are joined in rotationally fixed fashion to the shaft by pinch-fitting them on the shaft. Transverse screw joints utilizing tensionally stressed clamping screws improve the fixed joint between the cam and both the conic sleeve and shaft. The screw joints are fashioned in a manner such that no additional construction space is needed as compared to conventional camshafts and assembly can be performed with only standard tools.