Methods and systems for adjusting exhaust valve timing of an engine are described. In one example, exhaust valve timing of a compression ignition engine is adjusted responsive to a difference between a commanded exhaust valve opening timing and an actual exhaust valve opening timing, the actual exhaust valve opening timing determined from cylinder pressure.

A method of transitioning between two intake valve lift states while providing constant engine torque output comprehends the steps of receiving a lift change request from an engine control device, determining the current phase angles of the camshafts, and determining whether the intake and exhaust camshafts are at transition positions. The transition positions are experimentally or empirically determined combinations of operating conditions that result in constant engine torque output before and after the intake valve lift transition. If they are, an appropriate, i.e., low to high or high to low cam lift state transition of the intake valves occurs. If they are not, the cam phasers move the intake and exhaust camshafts to transition positions. When the cam phasers have moved the intake and exhaust camshafts to the transition positions, i.e., positions of constant engine torque output, the intake valve lift transitions from high to low or low to high.

A combined oil filter and restrictor assembly is disclosed having an oil flow restrictor interposed between first and second filters so that, irrespective of the direction of oil flow through the restrictor, debris cannot enter a small diameter bore 32 in a body of the restrictor thereby reducing the likelihood of restrictor blockage. The combined oil filter and restrictor assembly includes a metal threaded member that enables the combined oil filter and restrictor assembly to be easily and quickly assembled to or removed from a component such as a cylinder head of a variable displacement engine. The combined oil filter and restrictor assembly can be used to provide a restricted flow of oil from oil supply passages to signal oil passages used for controlling the operation of deactivatable hydraulic lash adjusters so as to purge the signal oil passages when the deactivatable hydraulic lash adjusters are not deactivated.

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.

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.

Methods and systems are provided for a phase control apparatus in a variable cam timing (VCT) system of an engine, the phase control apparatus having a locked configuration where a locking pin coupled to a first vane of the vane rotor is engaged with a locking pin recess in a cover plate of the phase control apparatus. In one example, the phase control apparatus includes a rubber or plastic isolator pad positioned in a recess in a wall adjacent to the first vane such that when the vane rotor is rotated to the locked configuration, the first vane contacts the isolator pad before it can strike the housing. The isolator pad serves to maintain the gap between the first vane and the housing, and also reduces the likelihood of other vanes of the vane rotor from striking the housing.

An apparatus and method of controlling an electronic continuously variable valve timing (CVVT) is provided. The apparatus includes a sensor disposed in a motor facing a reducer and an intelligent motor controller. The sensor determines a rotation speed of a first and second projection of a first and second rotation member and generates a sensing signal that corresponds to an output waveform of each rotation speed and inputs the signal to an intelligent motor controller coupled to the motor. The intelligent motor controller receives the signal and separates a crank shaft and cam shaft position signal. The signals are compared to detect an actual phase angle of the suction or exhaust valve. A phase deviation between the detected, actual and predetermined target phase angle is calculated.

A cam-switching device switches between first and second cams provided so as to correspond to intake exhaust valves of an engine. In a case of switching from the first cam to the second cam, a cylinder resting unit stops the opening and closing operations of the intake and exhaust valves in the same combustion cycle, and a cam shaft moving unit starts sliding the cam shaft in a first cam angle range. In a case of switching from the second cam to the first cam, the cylinder resting unit stops the opening and closing operations of the intake and exhaust valves in the same combustion cycle, and the cam shaft moving unit starts sliding the cam shaft in a second cam angle range.

A method for operating a reciprocating internal combustion engine in an engine braking mode includes, in a working cycle of the engine braking mode, a first outlet valve of a first cylinder is closed for a first time, then opened for a first time, and subsequently closed for a second time, and then opened for a second time, in order to thereby discharge gas that has been compressed in the first cylinder from the first cylinder by a cylinder piston. The outlet valve is held open after the first opening and prior to the second dosing long enough for the cylinder to be filled with gas that flows out of a second cylinder via at least one outlet channel, where when the engine braking mode is activated, at least one camshaft for activating at least one gas exchange valve of the reciprocating internal combustion engine is adjusted.

A method of phasing the opening and closing of internal combustion engine intake and exhaust valves relative to the rotation of the crankshaft is based upon changes in engine speed, engine load and ambient relative humidity. During certain conditions of higher humidity, in order to maintain good combustion stability and thus overall engine operation, it is necessary to reduce intake and exhaust valve overlap by adjusting the phase of the intake and exhaust camshafts. This is achieved by utilizing a set of cam position reference values and constraints based upon engine speed, engine load and humidity that are contained in lookup tables that adjust and limit cam position and valve overlap. Generally speaking, in order to maintain optimum engine performance, intake and exhaust valve overlap is reduced with higher ambient humidity and vice versa.