A system includes a rocker arm assembly for operative engagement with a first and second cam. The assembly includes a first arm for operatively engaging the first cam for a first desired lift profile, a second arm for operatively engaging the second cam for a second desired lift profile, where the second arm includes a latch to engage the second arm with the first arm. The latch is responsive to supplied oil pressure and release oil pressure to switch between lift profiles. The system includes the latch coupled to the supplied or released oil pressure to engage the arms before the first and second arms are engaged with the base circle portion of each of the respective first and second cams.

A switching rocker arm for engaging a cam includes a first arm having a first end and a second end, and a first and a second side arm; a second arm disposed between the first and second side arms, having a first end and a second end, where the second arm is an inner arm. The second arm is pivotably secured adjacent its first end to the first arm adjacent the first end of the first arm. The rocker arm includes an over-travel limiter that limits pivoting motion of the first arm relative to the second arm, where the over-travel limiter is pivotally coupled to the outer arm and interacts with the inner arm.

A rocker arm includes an outer arm having a first side and a second side, an inner arm positioned between the first side and the second side of the outer arm, a pivot axle pivotally coupling the inner arm and the outer arm at a first end of each of the inner arm and the outer arm, and a latch having a first position and a second position. The latch in the first position pivotally fixes the inner arm and the outer arm at a second end of each of the inner arm and the outer arm, and in the second position allows the inner arm and the outer arm to pivot independently. The latch is responsive to hydraulic pressure in a hydraulic fluid passage to selectively move to other of the first position and the second position. A lost motion spring is coupled to the inner arm.

A durable system for controlling variable valve actuation of an engine valve corresponding to a cylinder of an automobile engine. The system includes first and second crowned cams having first and second lift profiles and a rocker arm assembly. The rocker assembly includes a first arm having an end connected to said engine valve, having a high impact roller following the first crowned cam operating the engine valves according to a first lift profile. The rocker arm assembly also includes a second arm having durable slider pads riding on the second crowned cam to operate said engine valve according to a second lift profile. A latch secures the second arm relative to the first arm when in a latched position causing the valve to operate according to a second lift profile. The valve operates according to a first lift profile when the latch is not in the latched position.

According to a method of detecting a lift amount of a valve, an area-increasing jig is attached to an upper surface of a retainer attached to the valve. The area-increasing jig has a larger width than a width of the upper surface of the retainer. Then a lift amount of the valve is detected by measuring a distance to the area-increasing jig by using a non-contact sensor disposed above the retainer.

A modified rocker assembly having an offset end is designed for engine heads having an obstruction preventing use of a symmetric switching rocker arm. The modified rocker assembly has an obstructed side and a non-obstructed side and has an outer structure with a first end, and an inner rocker structure fitting within the outer structure, the inner structure also having a first end. The modified rocker assembly has an axle pivotally connecting the first ends of inner structure to the outer structure, such that the inner structure pivots within the outer structure around the axle. At least one torsion spring on one side of the axle rotationally biases the inner structure relative to the outer structure. The outer structure is offset on the obstructed side as it extends from the second end toward the first end, creating the first offset portion to provide additional clearance on the obstructed side.

A system for controlling variable valve actuation in an automobile engine. A first cam has a first lift profile and a second cam has a second lift profile. A rocker arm assembly engages the cams having a first arm for riding on the first cam, and a second arm for riding on the second cam. The second arm has an activatable latch capable of securing the second arm to the first arm when latched. When the first arm is secured to the second arm, the rocker arm assembly achieves a first lift profile and when the first arm is not secured to the second arm, the rocker arm assembly achieves a second lift profile. A non-contact sensor mounted adjacent the rocker arm assembly is adapted to monitor and create data indicative of whether the first arm is secured to the second arm.

A modified rocker assembly having an offset end is designed for engine heads having an obstruction preventing use of a symmetric switching rocker arm. The modified rocker assembly has an obstructed side and a non-obstructed side and has an outer structure with a first end, and an inner rocker structure fitting within the outer structure, the inner structure also having a first end. The modified rocker assembly has an axle pivotally connecting the first ends of inner structure to the outer structure, such that the inner structure pivots within the outer structure around the axle. At least one torsion spring on one side of the axle rotationally biases the inner structure relative to the outer structure. The outer structure is offset on the obstructed side as it extends from the second end toward the first end, creating the first offset portion to provide additional clearance on the obstructed side.

A system for selectively deactivating engine valves of a cylinder of an internal combustion engine. The system employs switching rocker assemblies between the valves of the engine and rotating cam lobes. The disclosed design is able to operate using a single cam lobe per valve. The rocker assembly employs a first arm pivotally attached to a second arm at one end. The first arm engages the valve and the second arm has a roller bearing that engages the cam lobe. A latch causes the first and second arm to move in unison following the cam surface when latched. When unlatched, the second arm follows and moves according to the rotating cam surface, but the first arm does not follow and does not actuate the valve, thereby deactivating the cylinder.

A variety of methods and devices for controlling the operation of the intake and exhaust valves in an internal combustion engine during skip fire operation are described. In various embodiments, an exhaust valve monitor or other suitable mechanism is used to detect exhaust valve actuation faults. When an exhaust valve actuation fault is detected for a particular cylinder, the corresponding intake valve is deactivated (or not activated) in circumstances when it would otherwise be activated in order to prevent the intake valve from opening into a cylinder that contains high pressure combustion gases. The described approach is particularly beneficial when skip fire operation is combined with cylinder deactivation so that air is not pumped through the cylinders during the skipped working cycles.