A pre-mixing engine system may include a plurality of cylinders that are combusted in a predetermined sequence; an intake manifold connected to the cylinder; a variable valve apparatus controlling an intake valve closing timing of each cylinder; an injector injecting a fuel inside each cylinder; an operation state measuring device detecting an operation state of an engine to output a corresponding signal; and a controller configured for controlling operations of the injector and the variable valve apparatus depending on the corresponding signal of the operation state measuring device, wherein the controller determines whether the operation state of the current engine is a predetermined general operation mode requirement state or a predetermined pre-mixing mode requirement state and controls the operations of the variable valve apparatus and the injector in the case of the pre-mixing mode requirement state to output a mixture of the corresponding cylinder to the intake manifold.

A method for controlling valve timing is provided for a turbo engine provided with a continuous variable valve duration (CVVD) device, a two stage variable valve duration device (VVD) and a continuous variable valve timing (CVVT) device. The method includes: classifying control regions; retarding an intake valve closing (IVC) timing and controlling an exhaust valve to limit a valve overlap in a first region; applying a maximum duration to an intake valve and applying a long duration to the exhaust valve in a second region; applying the long duration to the exhaust valve and advancing the IVC timing in a third region; controlling a throttle valve to be fully opened, applying a short duration to the exhaust valve and retarding an exhaust valve opening (EVO) timing in a fourth region; and controlling the throttle valve to be fully, applying the long duration to the exhaust valve and retarding the IVC timing in a fifth region.

A method for controlling engine operations, is provided herein. The engine includes at least a first bank having a first cylinder and a second cylinder associated with at least a turbocharger or an exhaust gas recirculation system. Each of the first and the second cylinder has a respective intake valve. The method determines an exhaust back pressure for each one of the first and the second cylinder. Further, the method determines an intake mass flow rate for each one of the first and the second cylinder based at least on the determined exhaust back pressure for the respective first and the second cylinder. The method adjusts a time duration of an open position of the respective intake valve for each one of the first and the second cylinder based on the determined intake mass flow rate for the corresponding first and the second cylinder.

A multi-cylinder spark-ignition internal combustion engine includes a plurality of first and second intake valves disposed between the air intake system and a corresponding plurality of engine cylinders. The engine also includes a dedicated-cylinder exhaust gas recirculation (EGR) system including an exhaust runner fluidly connected between exhaust valve(s) of one of the cylinders and the air intake system of the engine. A controllable intake valve activation system is configured to control openings of the plurality of first and second intake valves. A controller is operatively connected to the engine and the controllable intake valve activation system, and includes an instruction set to monitor operation of the engine, and control openings of the plurality of first intake valves and control openings of the plurality of second intake valves to generate in-cylinder mixing of a cylinder charge that achieves combustion stability for an engine speed/load operating point.

A variable-lift valve train for a gas exchange valve of an internal combustion engine includes a lift adjuster, a lift actuator, and a lift lever. The lift adjuster has a working curve that is arrangeable at least in a first working position for setting a partial lift and in a second working position for setting a maximum lift. The working curve has a lift region and a base circle region. The lift actuator, which has an actuating contour configured to deflect the lift adjuster. The lift lever, which is deflectable via the working curve and thereby actuates a lift of the gas exchange valve. The valve train is configured to, in the first working position and in the second working position, actuate the gas exchange valve with an at least substantially equal maximum valve acceleration.

An internal combustion engine includes a cylinder block that defines a cylinder and a cylinder head mounted to the cylinder block. A reciprocating piston is arranged inside the cylinder for compressing an air and fuel mixture at a geometric compression ratio of at least 10:1. A crankshaft is arranged in the cylinder block and rotated by the piston. An intake valve is operatively connected to the cylinder head and controls delivery of air to the cylinder for combustion therein. A mechanism provides a constant peak lift of the intake valve over an angle of rotation of the crankshaft that is at least 5 degrees, i.e., an extended dwell at peak lift. A multi-stage boosting system having first and second gas compressors is selectively controlled to pressurize air that is received from the ambient for delivery to the cylinder. A vehicle having such an engine is also disclosed.

A variable valve duration apparatus may include a first cam rotating with a camshaft; a second cam rotating with the camshaft; a first operation device that is operated by the first cam to generate a valve lift; a second operation device that is operated by the second cam to generate the valve lift; and a controller controlling the first operation device or the second operation device to generate the valve lift according to an operation state of an engine.

In response to decrease of a requested torque to a reference value or smaller, a value of a virtual air-fuel ratio that is used in calculation of a target air amount for achieving the requested torque is changed from a first air-fuel ratio to a second air-fuel ratio that is leaner than the first air-fuel ratio. The target air amount is calculated backwards from the requested torque by using the virtual air-fuel ratio. After the value of the virtual air-fuel ratio is changed from the first air-fuel ratio to the second air-fuel ratio, the target air-fuel ratio is switched from the first air-fuel ratio to the second air-fuel ratio. A target EGR rate is calculated by using the virtual air-fuel ratio. The target EGR rate is preferably determined by minimum value selection between a first target value of an EGR rate that is calculated by using the virtual air-fuel ratio, and a second target value of the EGR rate that is calculated by using the target air-fuel ratio.

A method for controlling valve timing of an engine includes: classifying control regions depending on an engine speed and an engine load, and applying a maximum duration to an intake valve and controlling a valve overlap in the first control region; advancing an intake valve closing (IVC) timing and applying the maximum duration to the exhaust valve in the second control region; advancing both the IVC timing and an exhaust valve closing (EVC) timing in the third control region; fixing an exhaust valve opening (EVO) timing and approaching the EVC timing to a top dead center (TDC) in the fourth control region; controlling a wide open throttle valve (WOT) and retarding the EVO timing in the fifth control region; and controlling the WOT, advancing the EVO timing, and approaching the EVC timing to the TDC in the sixth control region.

An internal-combustion engine has a plurality of cylinders each with two intake valves driven by respective pumping pistons operatively associated to cams of a camshaft, by respective hydraulic circuits. The hydraulic has its pressure chamber communicating with hydraulic actuators of the two intake valves, so that the two intake valves of each cylinder are controlled, via two different hydraulic circuits, by cams associated to two different cylinders. Each cam is configured to give rise to a cycle of opening and closing of each of the intake valves in an angular range of rotation of the crankshaft less than 180 such that, in each operating cycle of a cylinder, only the first intake valve initially opens and closes while the second intake valve remains closed, and then the second intake valve opens and closes while the first intake valve remains closed.