The disclosure relates to a preassembled module of a variable-lift valve train for an internal combustion engine. The module includes an electric linear actuator that lies on a top side of a base plate of the module. A slide plate, movable by the electric linear actuator by means of a linear guide, also lies on the top side of the base plate. A retaining wall extends under a bottom side of the base plate and has two actuation fingers. A free end of each actuation finger includes a contract surface for moving a coupling slide of a switchable rocker arm. In a region of an outer transverse side of the slide plate, a contact wall arranged in front of the electric linear actuator extends upward. The contact wall contacts an actuation pin of the electric linear actuator to move the slide plate in a longitudinal direction.

Systems and methods are provided for operating an internal combustion engine in a two-stroke mode or a four-stroke mode to achieve greater fuel efficiency and minimize emissions. The system comprises a mode-adaptable valve; a valve rocker arm to actuate opening and closing of the mode adaptable valve; a cam follower of a first cam for carrying out a two-stroke mode; a cam follower of a second cam for carrying out a four-stroke mode; and a pin to mechanically couple the valve rocker arm to the cam follower of the first cam or the cam follower of the second cam. Coupling the valve rocker arm to the cam follower of the first cam enables a two-stroke mode and coupling the valve rocker arm to the cam follower of the second cam enables a four-stroke mode.

Disclosed is a control and monitoring method via H bridge of an electromagnet including a solenoid through which a current can be passed in one direction and in the opposite direction. The solenoid delivers a signal corresponding to a mechanical locking movement. Once a current flows in the solenoid, the bridge switches automatically into high impedance with all transistors thereof blocked. A measurement is then taken at the terminals of the solenoid to verify the locked state of the electromechanical system.

An engine that can implement cylinder deactivation (CDA) includes: a plurality of cylinders; a variable valve duration apparatus that is mounted in at least one of the plurality of cylinders and that performs a long duration mode and a short duration mode of an intake valve of a corresponding cylinder; a CDA apparatus that is mounted in at least another one of the plurality of cylinders and that performs a general operation mode and a CDA mode of an intake valve and an exhaust valve of a corresponding cylinder; and a controller that controls operation of the variable valve duration apparatus and the CDA apparatus according to an operation state of an engine, wherein the controller controls the variable valve duration apparatus to operate in a short duration mode, when the CDA apparatus operates in the CDA mode.

A valve drive device for actuating valves of an internal combustion engine a rocker arm device and a switchover device that includes at least two actuators for the at least one rocker arm device. The two actuators respectively include a switching element adjustable between a first position and a second position; a resetting device for resetting the switching element with a resetting force into the second position; a holding coil for offsetting the resetting force of the resetting device; a switching coil that counteracts the resetting force during operation. The switching coil and the holding coil adjust the switching element into the first position.

A method for operating an electromagnetic actuator (10) with an actuating pin (9) is proposed which comprises the following steps: —determining a pin actuation actual dead time (t11), during which the magnetic armature (15) is substantially immobile while a magnetic coil (12) is supplied with current, wherein the actual dead time ends with the current break-in at the magnetic coil, as a result of counter induction of the magnetic armature overcoming the magnetic force threshold; —determining, before a subsequent pin actuation, the starting time of the magnetic coil current supply, wherein the starting point of the current is advanced compared with that of the target movement start of the pin out of the actuator housing (13) and the determined actual dead time.

A variable valve lift apparatus includes a lever body having a set length for a lever motion. One end of the lever body is connected with a hydraulic pressure supply portion and another end thereof is connected with the valve. A rotation shaft is disposed such that a width direction of the lever body is a length direction of the rotation shaft. A roller rotates around the rotation shaft. A high cam is disposed at the camshaft to rotate together with the camshaft and has a lobe shape for rolling-contact the roller to realize a high lift. A low cam is disposed at the camshaft to rotate together with the camshaft and has a lobe shape for rolling-contacting the roller to realize a low lift. The roller is disposed to slide along the length direction of the rotation shaft and selectively rolling-contact with the high cam or the low cam by sliding.

A multiple variable valve lift apparatus may include a camshaft rotating by driving of an engine, a cam portion formed in a cylindrical shape having a hollow that the camshaft is inserted into, rotating together with the camshaft, configured to move along an axial direction of the camshaft, and forming a zero cam and a normal cam, a valve opening/closing device configured to be operated by at least one of the zero cam or the normal cam which are formed at the cam portion, an operating device disposed on an exterior circumference of the camshaft so as to move together with the cam portion, and a solenoid configured to selectively move the operating device along an axial direction of the camshaft, in which a journal, which has a radius being equal to a radius of the zero cam, is formed at the cam portion.

A camshaft for a multiple-cylinder internal combustion engine may include a sliding element comprising at least two cam elements, as well as a splined shaft that extends in an axial direction and on which the sliding element is received. The sliding element may comprise an internal spline system that interacts with an external spline system of the splined shaft such that the sliding element is seated fixedly on the splined shaft so as to rotate with the splined shaft. The sliding element may be received on the splined shaft such that the sliding element can, at least initially, be displaced axially. For axially-fixing the sliding element to the splined shaft, the sliding element may include a positively locking connection that is configured in the axial direction and is produced by way of at least one calked connection between the sliding element and the splined shaft. It should be understood that many camshafts include more than one sliding element.

A camshaft may include a shaft as well as a sliding element that is disposed on the shaft such that the sliding element is axially displaceable along a shaft axis. The shaft may comprise an external tooth for transmitting torque between the shaft and the sliding element. The external tooth may engage a mating tooth geometry formed in a passage of the sliding element. The sliding element on its axial end faces may comprise bearing collars that with the shaft form radial supporting bearings of the sliding element on the shaft. Further, the shaft may comprise cylindrical bearing portions for forming the radial supporting bearings, wherein the bearing portions can be configured with a diameter that is smaller than a diameter circumscribed by tips of the mating tooth geometry that protrude into the passage of the sliding element.