Abstract:
Eine Ventilhebelbaugruppe mit einem schaltbaren Ventilbetätigungsmechanismus enthält eine erste Abtastfläche (52) zum Abtasten eines ersten Nockens (12), wenigstens eine zweite Abtastfläche (56) zum Abtasten eines zweiten Nockens (14) und einen Ventilhebel (6), der sich an einem maschinenfesten Bauteil (8) und an dem zu betätigenden Ventil (2) abstützt, wobei die zweite Abtastfläche mittels einer an dem Ventilhebel gelagerten, verriegelbaren Exzentereinrichtung (26, 40) relativ zur ersten Abtastfläche verdrehbar ist und die Exzentereinrichtung eine quer durch den Ventilhebel (16) durchführende, relativ zum Ventilhebel (6) drehfeste Exzenteröffnung (30) und eine in der Exzenteröffnung verdrehbar gelagerte Exzenterwelle (40) enthält, die die Lage der zweiten Abtastfläche (56) definiert.
Abstract:
A variable control process and device for an internal combustion engine valve are disclosed, in particular for the throttle-free power circuit control of a spark ignition engine by means of the lifting function of one or several inlet valves (6) per cylinder. The contours of two camshafts (1, 2) which normally turn at the same speed of rotation are scanned by a scanning arrangement (3) of the adder type and the displacement of the scanning arrangement (3) is transmitted to the valve by the actuating arrangement (4) in order to actuate the valve. The contour of one camshaft (1, 2) which acts as an opening camshaft (1) has a base area and a raised area which merge into each other in a closure area. In order to modify the lifting and/or opening time of the valve (6), the phase position between the camshafts (1, 2) is variable. The scanning arrangement (3) is held in contact with the contour of only one camshaft (2) after the valve (6) is closed, so that the actuating arrangement (4) is held in contact with the valve (6). The contour of the other camshaft (2) moves away from the scanning arrangement (3) after the valve (6) is closed and thus comes once again into contact with the scanning arrangement (3) when the valve (6) begins to open.
Abstract:
The invention relates to a device for the variable control of the valves of internal combustion engines, especially for the chokeless load control of four-stroke engines in which the mixture is metered by controlling the travel and opening time of the inlet valves (4a). The device consists of two camshafts (1a, 2a) rotating at the same speed, the cams of which act on suitably shaped detection units (7a, 8a) which are connected to a rocker (3a). The rocker (3a) transmits its movement to a conventional poppet valve (4a) spring-loaded in the closing direction. Characteristic features of the device are the advantageous design of such a valve drive, especially with respect to the selection of the direction of rotation of the two camshafts (1a, 2a) and the kinematic detection conditions with respect to especially favourable travel functions and the linkage of the rocker (3a) and a device for automatic valve clearance balance.