A valve drive for an internal combustion engine may include a camshaft, at least one cam follower, at least one adjusting device, and at least one control shaft. The camshaft may include at least one cam group. The at least one cam group may include a first cam and a second cam. The at least one cam follower may be drive-connected to the first cam in a first position and to the second cam in a second position. The at least one adjusting device may include a first adjustable engagement element and a second adjustable engagement element. alternately adjustable between a basic position and a switching position. The at least one control shaft may include at least one control element group including a first control element and a second control element adjustable to a switching element position and to a basic element position.

Systems and methods for internal exhaust gas recirculation (iEGR) in internal combustion engines may utilize secondary intake valve lift events during an exhaust valve main event in lost motion valve actuation systems. The secondary intake valve lift event may occur at the beginning or end of the exhaust valve main event. Favorable intake valve lift profiles are obtained with the use of a reset component, which may perform a hydraulic reset on the lost motion component in order to ensure that the intake valve secondary lift event occurs optimally near the beginning of an exhaust valve main event. The reset component may be triggered using motion from an exhaust valvetrain, for example, by a triggering component such as a reset pad, on an exhaust rocker. The reset component may also be triggered on the basis of the intake rocker arm position, in which case a reset pad that is fixed to the engine head or fixed relative to the intake rocker motion may be used.

An engine brake device is provided for attenuating compression. The device is able to brake engine by attenuating a pressure increase in a cylinder by temporarily opening an exhaust valve at the end of a compression stroke of the engine, using an eccentric assembly eccentrically coupled to a pivot center of an exhaust rocker arm and an actuator for pushing up the eccentric assembly.

A method for controlling vehicle speed comprises selecting an engine speed profile for a vehicle. Road grade data is received and processed to determine a road grade for the vehicle. Vehicle speed data is received and processed to determine a vehicle speed for the vehicle. A cylinder deactivation mode for a valvetrain of a multi-cylinder engine of the vehicle is selected. The cylinder deactivation mode comprises deactivating one or more intake valve, exhaust valve, and fuel injection for one or more cylinder of the multi-cylinder engine. The selected cylinder deactivation mode provides a controlled deviation from the selected engine speed profile at the road grade and vehicle speed.

A valve train assembly includes an intake rocker arm, an exhaust rocker arm, a carrier configured to couple to a cylinder block and operably associated with the intake rocker arm and the exhaust rocker arm, the carrier including a first aperture, and a cylinder deactivation (CDA) capsule disposed within the first aperture. The CDA capsule is configured to move between a latched condition that transfers motion from a push rod to one of the intake rocker arm and the exhaust rocker arm, and an unlatched condition that absorbs motion from the push rod and does not transfer the motion to the intake rocker arm or the exhaust rocker arm.

Systems for valve actuation in internal combustion engines provide configurations for hydraulic lash adjusters and valve actuation valvetrain components that are particularly suitable for prevention of HLA jacking in dedicated cam environments including Type II valvetrain architectures. In one implementation, a lash adjuster loading component, which may comprise a stroke-limited spring biased piston associated with the main event valvetrain keeps the lash adjuster under a constant compressive force to prevent jacking.

A variable displacement internal combustion engine control system includes an engine having cylinders, each having an intake valve and an exhaust valve. An engine control module determines when to activate and deactivate the cylinders, and when to purge gas entrained in an oil system. A solenoid-actuated hydraulic control valve communicates with the engine control module to deactivate and activate individual cylinders. An air accumulation estimation program running multiple times per second for each of the cylinders identifies an approximate gas volume accumulating in a control port of the solenoid-actuated hydraulic control valve and if the gas volume has reached a predetermined threshold allows a purge pulse to be issued. The purge pulse initiates at a purge pulse initiation point during one of intake valve lift, exhaust valve lift, and when valve lifters of both the intake and the exhaust valve are on a base circle providing zero lift.

An internal combustion engine includes a cylinder including a piston connected to a rotatable crankshaft, an air guide arranged to guide an air flow to the cylinder an adjustable air flow restriction element arranged to restrict the How through the air guide, an exhaust guide being arranged to guide a gas flow from the cylinder, an adjustable exhaust flow restriction element arranged to restrict the flow through the exhaust guide, an exhaust valve arranged to control a communication between the cylinder and the exhaust guide, and an exhaust valve actuation assembly for actuating the exhaust valve so as to perform in each of a plurality of cycles of the cylinder an exhaust valve actuation sequence, wherein the exhaust valve actuation assembly is adapted to control the commencement of the exhaust valve actuation sequence to occur selectively at any crankshaft angle within a non-zero crankshaft angle interval.

Systems and methods for determining operation of a cylinder deactivating/reactivating device are disclosed. In one example, a direction of engine rotation is selected to maximize air flow through the engine while the engine is rotated without combusting air and fuel. Operation of one or more cylinder valve deactivating mechanisms is assessed while the engine is rotated without combusting air and fuel.

A novel cylinder head arrangement for an in-line four cylinder or eight cylinder engine. A modified arrangement allows additional space for installation of wider rocker arm assemblies used for variable valve lift (VVL), cylinder deactivation (CDA) and other types of variable valve actuation (VVA). In one embodiment, cam towers adjacent the end two cylinders are not used. At least one end support is used, which may be an outboard bearing on a camshaft for each end. The wider rocker assemblies may then be installed. In another embodiment, cam towers adjacent the inner two cylinders are eliminated and a single camshaft support piece with a support bearing is installed between the inner cylinders to provide support for the camshafts. The wider rocker assemblies may then be installed on at least one of the middle cylinders. A novel oil control valve operates latches in switching rocker arm assemblies.