Internal combustion engine having cam actuated valves that can be controlled to facilitate the use of different air charge levels in different cylinders or sets of cylinders are described. In one aspect a first set of cylinders is operated in a skip fire manner in which the corresponding cylinders are deactivated during skipped working cycles. Cam actuated intake valves associated with a second set of cylinders are operated differently so that the air charge in the cylinders in the second set is different than the air charge in fired cylinders subject to the skip fire control. According to another aspect, an engine having cam actuated intake valves is operated in a dynamic firing level modulation mode. During the dynamic firing level modulation operation, the cam actuated intake valves are controlled in at least two different manners to such that different cylinder working cycles have different air charges.

Techniques for controlling a forced-induction engine having a low pressure cooled exhaust gas recirculation (LPCEGR) system comprise determining a target boost device inlet pressure for each of one or more systems that could require a boost device inlet pressure change as part of their operation and boost device inlet pressure hardware limits for a set of components in the induction system, determining a final target boost device inlet pressure based on the determined sets of target boost device inlet pressures and boost device inlet pressure hardware limits, and controlling a differential pressure (dP) valve based on the final target boost device inlet pressure to balance (i) competing boost device inlet pressure targets of the one or more systems and (ii) the set of boost device inlet pressure hardware limits in order to optimize engine performance and prevent component damage.

An internal combustion engine may include a first piston reciprocatingly disposed in a first cylinder, and a second piston reciprocatingly disposed in a second cylinder. A crankshaft may be coupled with the first piston and the second piston for rotational motion associated with reciprocating movement of at least one of the first piston and the second piston. A combustion chamber may be fluidly coupled with the first cylinder and the second cylinder. An intake valve may provide selective fluid communication between an intake system and the combustion chamber. The intake valve may be generally centrally disposed relative to the first cylinder and the second cylinder. An exhaust valve may provide selective fluid communication between an exhaust system and the combustion chamber. An ignition source may be at least partially disposed within the combustion chamber.

An internal combustion engine may include a first piston reciprocatingly disposed in a first cylinder, and a second piston reciprocatingly disposed in a second cylinder. A crankshaft may be coupled with the first piston and the second piston for rotational motion associated with reciprocating movement of at least one of the first piston and the second piston. A combustion chamber may be fluidly coupled with the first cylinder and the second cylinder. An intake valve may provide selective fluid communication between an intake system and the combustion chamber. The intake valve may be generally centrally disposed relative to the first cylinder and the second cylinder. An exhaust valve may provide selective fluid communication between an exhaust system and the combustion chamber. An ignition source may be at least partially disposed within the combustion chamber.

Methods and systems are provided for a valve system for actuating two cylinder valves in an engine. In one example, the valve system may include a single pump and a solenoid valve capable of non-concurrently actuating the two cylinder valves coupled to separate cylinders.

Methods and systems are provided for a valve system for actuating two cylinder valves in an engine. In one example, the valve system may include a single pump and a solenoid valve capable of non-concurrently actuating the two cylinder valves coupled to separate cylinders.

A multi-cylinder engine includes first and second subsets of cylinders. A dedicated-cylinder exhaust gas recirculation (EGR) system is associated with the second subset of cylinders. A plasma ignition system is disposed in the second subset of cylinders. A controller operates the plasma ignition system to control the plasma igniters to execute plasma discharges in the second subset of cylinders to generate residual exhaust gas, which is recirculated through the dedicated-cylinder EGR system to the intake air system for introduction into intake air.

A multi-cylinder engine includes first and second subsets of cylinders. A dedicated-cylinder exhaust gas recirculation (EGR) system is associated with the second subset of cylinders. A plasma ignition system is disposed in the second subset of cylinders. A controller operates the plasma ignition system to control the plasma igniters to execute plasma discharges in the second subset of cylinders to generate residual exhaust gas, which is recirculated through the dedicated-cylinder EGR system to the intake air system for introduction into intake air.

A counterweight forms a crankshaft of an engine, and includes: an arm connecting a crank journal and crank pin of the crankshaft; a neck extending from a first connection face of the arm in a direction opposite to the crank pin; and a substantially fan-shaped weight continuous with a portion of the neck opposite to the crank journal. The weight has left and right shoulders continuous with the neck, and each of the shoulders is tilted to be away from the neck at an angle with respect to a horizontal line orthogonal to a crankshaft center when viewed along the crankshaft center, the angle being 15 or more and 22.5 or less.

In some aspects, reciprocating engines can include a drive mechanism for generating a rotational motion output from reciprocating piston assembly, where the drive mechanism includes an axially translating y-axis component to reciprocate along a y-axis with the piston assembly; an x-axis component: i) configured to reciprocate substantially perpendicularly to the y-axis, ii) having an internal ring gear, and iii) having an orbital engagement component substantially concentric with the internal ring gear; an output shaft assembly having an output pinion gear engaging tangentially with the internal ring gear; and a stationary engagement component substantially concentric with the output shaft assembly, the stationary engagement component interfacing with the orbital engagement component, the interfacing between the stationary engagement component and the orbital engagement component applying a force to the x-axis component to maintain contact between the internal ring gear and the output pinion gear.