An engine valve actuating apparatus includes a housing that contains an activation piston bore and an actuation piston bore. The activation piston is disposed in the activation piston bore and configured to actuate an engine valve. The actuation piston includes at least one side surface that is in sliding contact with the inner surface of the actuation piston bore so that the actuation piston can slide within the actuation piston bore. The actuation piston also has a guide mechanism, which guides the first and second links to move in a plane between the first position and the second position. At least a part of the guide mechanism is below at least a part of the at least one side surface of the actuation piston.

Systems and methods for preparing an engine for a cold start are described. In one example, the air is injected into one or more pre-chambers of engine cylinders in response to an engine start request so that one or more cylinders may be heated before the engine is started. The engine may or may not be rotated while air is being injected to pre-chambers of engine cylinders.

Methods and systems are provided for providing secondary air to an exhaust system during catalyst warm-up. In one example, a method may include, during a cold start condition, operating an engine with a first number of cylinders unfired and a remaining number of cylinders fired during an engine cycle, opening an intake valve of an unfired cylinder of the first number of cylinders during an expansion stroke of the unfired cylinder, and opening an exhaust valve of the unfired cylinder during a compression stroke of the unfired cylinder. In this way, the unfired cylinders may provide the secondary air to the exhaust system during a stroke that increases mixing of the secondary air with burned exhaust gas from fired cylinders, thus increasing exotherm production in the exhaust system to increase a temperature of the catalyst.

Several devices are disclosed that can be usable together or used in other valvetrains. Disclosed herein are a rocker arm assembly, compliance capsules for a switchable capsule of the rocker arm, actuators, and support structures for the actuators. The alternative compliance capsules can be electromechanically actuated by the alternative actuators, which are hung over the rocker shaft by the support structure. A cam actuator can be in addition to an overhead cam rail and in addition to the rocker shaft. The cam actuator can be configured with a compliance capsule so that the switching of the switchable capsule is mechanically linked and less reliant on precise electrical signal timing.

A rocker arm assembly can comprise a rocker tube configured to be positioned around a rocker shaft, the rocker tube comprising a retention mechanism. A first rocker arm can be press-fit to the rocker tube. A second rocker arm can be pivotably mounted around the rocker tube and retained on the rocker tube by the retention mechanism. An alternative rocker arm assembly, that can be combined with the first rocker arm assembly, can comprise a first and second rocker am and a plate fixed to the first rocker arm. The plate can comprise an extension extending over the second rocker arm. A lost motion spring can be installed between the second rocker arm and the extension.

A valve actuation system comprising a valve actuation motion source configured to provide a main event valve actuation motion to at least one engine valve via a main motion load path that comprises at least one valve train component. The valve actuation system further includes a lost motion component arranged within a first valve train component in the main motion load path, the lost motion component being controllable to operate in a motion conveying state or a motion absorbing state. The valve actuation system also comprises a high lift transfer component arranged in the main motion load path, with the high lift transfer component being configured to permit the main motion load path to convey at least a high lift portion of the main event valve actuation motion when the lost motion component is in the motion absorbing state.

A method of determining a condition of a component (e.g., valves) of an engine having a manifold air pressure sensor during a cold test includes providing pressurized air to an intake of the engine. The method includes rotating a crankshaft of the engine. The method includes measuring pressures with the manifold air pressure sensor as a function of crankshaft rotational position. The method includes comparing the pressures with a predetermined baseline. The method includes indicating a condition of the component based on the comparison of the pressures with the baseline.

An asymmetry cylinder de-activation (CDA) engine provided with a first, a second, a third and a fourth cylinder of which CDA apparatuses are mounted thereto respectively may include a crankshaft connected with pistons of each cylinder through a first, a second, a third and a fourth cranking journal respectively, and a controller configured to control operations of the CDA apparatuses, in which phase differences between cranking journals according to firing order may include 90±10 degrees and 270±10 degrees.

A rocker assembly for a type III center pivot valvetrain comprises a rocker arm comprising a cam end, a center pivot bore, and a valve end. The valve end comprises a first actuator bore and a second actuator bore. A cylinder deactivation actuator is in the first actuator bore. An engine brake actuator is in the second actuator bore. The rocker assembly can be part of a valve assembly and can impart an engine braking function, a cylinder deactivation function, and a main lift function to first and second valves. It is also possible to impart an early exhaust valve opening, a main lift function, and a late exhaust valve closing to the engine braking valve.

An internal combustion engine may include at least one cylinder, a first outlet valve and a second outlet valve for directing exhaust gas out from a combustion chamber of the at least one cylinder. The first outlet valve may include a first valve opening and a first valve body where the first valve opening is adjustable between a closed position and an open position. The second outlet valve may include a second valve opening and a second valve body where the second valve body is adjustable between a closed position and an open position. An adjusting lever may adjust one or both of the first valve body and the second valve body between the open position and the closed position.