A cam phaser is described for selectively engaging in a torque transmitting mode or an angle control mode. In the torque transmitting mode, torque from a camshaft is transmitted to an e-motor, which functions as a generator and provides electrical energy.

Systems and methods for managing excessive intake flow path pressure and counter flow are implemented to support enhanced engine braking applications, such as 2-stroke or 1.5-stroke engine braking implementations where the intake flow path may be exposed to excessive transient pressures in the combustion chamber during activation or deactivation of an engine brake. Intake throttle, exhaust gas recirculation (EGR) valve, intake manifold blow-off valve, compressor bypass valve, exhaust throttle, turbocharger geometry or turbocharger waste gate may be controlled to effectuate counter flow management separately or in combination. Excessive transient conditions may also be prevented or managed by sequential valve motion in which brake motion activation occurs first and then exhaust valve main event deactivation occurs second. Delay between brake activation and main event deactivation may be facilitated using mechanical and/or hydraulic implements as well as electronically.

A variable camshaft timing (VCT) system includes an independent camshaft phaser, receiving input from a crankshaft of an internal combustion engine, having an output coupled to one of an inner concentric camshaft or an outer concentric camshaft; and a dependent camshaft phaser, coupled to the other of the inner concentric camshaft or the outer concentric camshaft, comprising a half-Oldham link configured to permit radial movement of the inner concentric camshaft relative to the outer concentric camshaft in one radial direction and at least one pivotable arm configured to permit radial movement of the inner concentric camshaft relative to the outer concentric camshaft in another, different radial direction.

A hydraulically-actuated variable camshaft timing (VCT) system comprises a spool valve including a sleeve and a spool, having a plurality of radially-outwardly extending lands, received within a sleeve; a sleeve fluid pathway, extending axially along the sleeve and formed within the sleeve, configured to receive fluid from a fluid supply; an advancing port in the sleeve in fluid communication with an advancing chamber of a hydraulically-actuated camshaft phaser; a retarding port in the sleeve in fluid communication with a retarding chamber of the hydraulically-actuated camshaft phaser; a first fluid supply port formed in the sleeve; a second fluid supply port formed in the sleeve; and an exhaust port axially positioned in the sleeve in between the first fluid supply port and the second fluid supply port or in between the advancing port and the retarding port, wherein the exhaust port is configured to selectively receive fluid from either the advancing chamber or the retarding chamber depending on an axial position of the spool relative to the sleeve.

A valve gear for an engine includes cam shafts, first and second support walls, and rocker arms supported on the first and second support walls by supports. The supports switch among a plurality of support modes. The supports include first and second shaft holes, rocker shafts, tracks in the support walls, and return springs. The rocker shafts, move to positions where the support walls and the rocker arms are connected via the rocker shafts in a first support mode. In a second support mode, the rocker shafts move to positions where the connection between the support walls and the rocker arms is canceled. This makes it possible to provide a valve gear for an engine capable of smoothly switching a normal operation state support mode and cylinder resting state support mode, thus increasing the reliability of the operation.

An internal combustion engine is provided. Facing pistons eliminate a cylinder head, thereby reducing heat losses through a cylinder head. Facing pistons also halve the stroke that would be required for one piston to provide the same compression ratio, and the engine can thus be run at higher revolutions per minute and produce more power. An internal sleeve valve is provided for space and other considerations. A combustion chamber size-varying mechanism allows for adjustment of the minimum size of an internal volume to increase efficiency at partial-power operation. Variable intake valve operation is used to control engine power.

The aim of the invention is to ensure that a hydraulic drive (10) for accelerating and braking a gas exchange valve (20) of internal combustion engines or other reciprocating engines operates in a simple, reliable and recuperative manner. To this end, a first pressure tank (41) for providing a first pressure p.sub.1, a restoring energy accumulator preferably embodied as a spring (25), and at least one hydraulic basic pressure tank (40) having a lower pressure p.sub.0 than the first pressure tank (41) are provided. A controllable opening (49) of a first valve (46) is arranged with at least one non-return valve (47) located upstream or downstream of the opening in the flow path, in a connection line (48) between the first hydraulic pressure tank (41) and the working cylinder (22), said non-return valve allowing the pressure medium (30) to flow towards the working cylinder (22) but preventing it from flowing back towards the pressure tank (41). In order to also initiate the closing movement or the braking of the gas exchange valve in a hydraulically simple and reliable manner, a controllable opening (59) of a second valve (56) is arranged in a second connection line (58) between the first pressure tank (41) and the working cylinder (22), with a non-return valve (57) that prevents flow towards the working cylinder (22) but allows backflow towards the pressure tank (41).

A variable camshaft timing system including a first camshaft phaser having an input that is configured to receive rotational force from a crankshaft and an output that is configured to link with a first camshaft of a concentric camshaft assembly to change the angular position of the first camshaft relative to a crankshaft; and a second camshaft phaser having an output that is configured to link with a second camshaft of the concentric camshaft assembly to change the angular position of the second camshaft relative to the crankshaft, wherein the first camshaft is concentrically positioned to the first camshaft and the first camshaft phaser is mechanically linked to the second camshaft phaser to communicate rotational force from the crankshaft to the second camshaft phaser through the first camshaft phaser and the mechanical link.

An actuation arrangement for actuating a plurality of latching arrangements of a respective plurality of dual body rocker arms of a valve train assembly of an internal combustion engine includes: a first shaft comprising one or more first selector cam for controlling the latching arrangements of a first group of one or more of the dual body rocker arms; and a second shaft comprising one or more second selector cams for controlling the latching arrangements of a second group of one or more of the dual body rocker arms. At least a portion of the first shaft is received in the second shaft, and the first shaft and the second shaft are controllable to rotate independently of one another, thereby to allow control of the latching arrangements of the dual body rocker arms on a per group basis.

The present disclosure provides systems and methods to compensate for backlash within a cam phasing system. For example, compensating for backlash by commanding a predetermined amount of additional actuator movement to account for backlash within a cam phaser. According to some aspects, a spring is provided within a cam phaser to unidirectionally take up the backlash within the cam phasing system.