Systems and methods for opening and closing exhaust poppet valves of an engine are disclosed. In one example, the exhaust poppet valves may be opened and closed twice during a cycle of an engine via two serially arranged cam lobes that are coupled to a crankshaft so that hydrocarbons may be retained in a cylinder.

A sensor assembly for a sliding camshaft of a motor vehicle is provided. The sliding camshaft includes a base shaft that extends along a longitudinal axis and rotates about the longitudinal axis. The sliding camshaft further includes lobe banks rotationally fixed to the base shaft. Each lobe bank is axially movable between first and second positions relative to the base shaft. The sensor assembly includes a detection element rotationally fixed relative to the base shaft and axially movable between first and second positions relative to the base shaft. The sensor assembly further includes a sensor operably coupled to the detection element and configured to generate a signal indicative of an axial position of the detection element relative to the base shaft and at least one of an angular speed of the base shaft and an angular position of the base shaft about the longitudinal axis.

A cam having at least two part cams are arranged axially behind one another along a longitudinal axis includes an undercut between the cam parts. The part cams have running faces which lie radially on the outside of the part cams and have different variable running face contours. The undercut has a profile with a variable contour which is dependent in each case on that adjacent running face contour which is at a smaller radial spacing from the longitudinal axis than the other running face contour.

The disclosure concerns a variable valve train for an internal combustion engine, comprising a camshaft, a gas exchange valve and a cam carrier. The cam carrier is arranged rotationally fixedly and axially displaceably on the camshaft and has a first cam and a second cam. The variable valve train has a force transmission device with a force transmission element, in particular a finger follower or rocker arm, which, depending on an axial position of the cam carrier, creates an active connection either between the first cam and the gas exchange valve or between the second cam and the gas exchange valve. The variable valve train has a first actuator for axial displacement of the cam carrier, wherein the first actuator is received at least partially in the force transmission device.

The application relates to an electromagnetic control device, in particular for adjusting camshafts or a camshaft section of an internal combustion engine, comprising: an energizable coil unit via which, in the energized state, an armature mounted for movement along a longitudinal axis of the control device can be moved relative to a pole core between a retracted position and an extended position; a tappet which interacts with the armature and is mounted for movement along the longitudinal axis, having a free end, via which the tappet interacts with the camshaft in the extended position in order to adjust the camshaft; and an adapter, via which the control device can be fastened to a component, in particular to cylinder head cover, wherein the armature and the tappet are connected to each other for conjoint rotation, and the control device has a first bearing section inside the adapter for rotatable mounting of the tappet and a second bearing section outside of the adapter for rotatable mounting of the tappet and/or the armature.

The application relates to an electromagnetic control device, in particular for adjusting camshafts or a camshaft section of an internal combustion engine, comprising: an energizable coil unit, via which, in an energized state, an armature mounted for movement along a longitudinal axis of the control device can be moved relative to a pole core between a retracted position and an extended position; at least one tappet, which is mounted for movement along the longitudinal axis and, in an extended position, interacts with the camshaft via a free end in order to adjust the camshaft and is connected at an inner end to the armature, wherein the tappet has a first diameter in the region of the free end and has a second diameter in the region of the inner end, and the first diameter is greater than the second diameter.

A valve drive for a cylinder head of an internal combustion engine has a camshaft which is rotatably mounted in a first and a second camshaft bearing and which includes at least one cam with a first cam curve and a second cam curve that differs from the first cam curve. A gas exchange valve can be actuated by the first or the second cam curve via a cam follower. A camshaft section is provided, by which the cam can be moved by an actuator such that the gas exchange valve can be actuated either via the first or the second cam curve via the cam follower. The camshaft and the cam have a fixed position relative to each other. The camshaft can be axially moved in the first and the second camshaft bearing. The camshaft bearings consist of a camshaft bearing block and a common bearing frame. A lubricant supply bore is provided which opens into a fourth lubricant groove in the bearing frame in order to supply the bearing points with lubricant. A first lubricant groove is provided in the first camshaft bearing block, and a second lubricant groove is provided in the second camshaft bearing block. These lubricant grooves correspond to the fourth lubricant groove and are open in the direction of the cam follower.

An engine camshaft has a lubricating oil passage formed along the longitudinal axis of the same, a cam communicating oil hole is radially formed from the lubricating oil passage to an outer peripheral surface of the camshaft at the same axial position as an engine valve. Cam lubrication holes are radially formed from the inside to cam surfaces of cam lobes formed around a cam carrier fitted around the camshaft. One of the cam lubrication holes of the cam lobes shifted to a position for operating the valve communicates with the cam communicating oil hole of the camshaft to supply lubricant oil.

An engine variable valve train is provided with a cylindrical cam carrier fitted on a camshaft in a manner axially slidable to and co-rotatable with the camshaft. The cam carrier has therearound mutually adjoining low-speed and high-speed cam lobes selectively acting on the engine valve and being different in cam profile. The cam carrier has therearound lead grooves to be engaged with or disengaged from changeover pins for axial shift of the cam carrier. The lead grooves include a speed-increasing lead groove for changeover from the low-speed to the high-speed cam lobe and a speed-decreasing lead grooves for changeover from the high-speed to the low-speed cam lobe. The speed-increasing and speed-decreasing lead grooves are different in groove contour. This enables the cam carrier to axially shift smoothly and to improve the durability of the lead grooves.

Systems and methods for determining the presence or absence of cylinder misfire of an internal combustion engine are presented. In one example, a threshold for establishing or denying the presence of cylinder misfire is determined via engine acceleration amounts of active and non-active cylinders. Engine acceleration values are then compared to the threshold to determine the presence or absence of cylinder misfire.