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 camshaft assembly for a vehicle engine includes a camshaft member, a cam phaser and a cam nose. The camshaft member includes a front end and a rear end. The camshaft member may be configured to actuate at least one intake valve of a combustion chamber. The cam phaser affixed to the front end of the camshaft member while the cam nose may be disposed at the front end of the camshaft. The cam nose further includes a cam nose face with a curvilinear groove surrounding a central axis region of the cam nose. The curvilinear groove may be configured to engage with the cam phaser to prevent oil leakage out from the central axis region and/or to rotationally lock the cam phaser to the camshaft member.

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.

Methods, devices, controllers, and algorithms are described for operating an internal combustion engine wherein at least some firing opportunities utilize low temperature gasoline combustion (LTGC). Other firing opportunities may be skipped or utilize some other type of combustion, such as spark ignition. The nature of any particular firing opportunity is dynamically determined during engine operation, often on a firing opportunity by firing opportunity basis. Firings that utilize LTGC produce little, if any, nitrous oxides in the exhaust stream and thus, in some implementations, may require no aftertreatment system to remove them from the exhaust stream.

Methods, devices, controllers, and algorithms are described for operating an internal combustion engine wherein at least some firing opportunities utilize low temperature gasoline combustion (LTGC). Other firing opportunities may be skipped or utilize some other type of combustion, such as spark ignition. The nature of any particular firing opportunity is dynamically determined during engine operation, often on a firing opportunity by firing opportunity basis. Firings that utilize LTGC produce little, if any, nitrous oxides in the exhaust stream and thus, in some implementations, may require no aftertreatment system to remove them from the exhaust stream.

A variable valve mechanism includes a variable arm including a first arm and a second arm. The second arm is pivotally supported so as to be swingable by a support shaft. A position of the support shaft is a position where, during a base circle phase, in side view, a second segment connecting an axis of a roller to an axis of the support shaft is longer than a first segment connecting the axis of the roller to an axis of a camshaft, and an angle of the second segment formed with respect to a third segment connecting the axis of the roller to a swing axis of a roller arm is 60 to 120 toward the camshaft. The second arm extends from the support shaft such that a distal end portion of the second arm protrudes in between a cam and the roller.

When it is determined that the initial combustion is unstable, the engine speed is forcibly increased. When the engine speed is forcibly increased, fluidity in the cylinder increases. When the fluidity in the cylinder rises, homogeneity of the homogeneous air-fuel mixture is improved. Therefore, it is possible to enlarge the flame kernel. When the flame kernel is enlarged, the initial flame resulting from the flame kernel is also enlarged. Then, the initial flame becomes easy to involve the closest fuel spray thereby the initial combustion can be stabilized.

A control apparatus for an internal combustion engine includes an electronic control unit that is configured to perform an operation of making a lift amount of a specific valve corresponding to one of either intake ports or exhaust ports for a specific cylinder in which an amount of condensate water produced in the port or flowing into the port is larger than in the other cylinders when the engine is stopped, in a case where production of condensate water in the ports or inflow of condensate water into the ports is predicted.

A continuous variable valve duration apparatus may include: a camshaft; first and second cam portions on which a cam is formed respectively; first and second inner brackets transmitting rotation of the camshaft to the first and second cam portions respectively; a slider housing in which the first and the second inner brackets are rotatably inserted; first and second guiding portions formed on the slider housing; a control shaft parallel to the camshaft; a control rod eccentrically formed on the control shaft; a positioning protrusion connected to the control shaft; a guide head on which a head guiding portion and a head hole are formed; a cam cap supporting rotations of the first and the second cam portions and guiding movement of the slider housing, a control portion selectively rotating the control shaft; and a stopper unit limiting movement of the positioning protrusion.

A continuous variable valve duration apparatus may include: a camshaft; first and second cam portions on which a cam is formed respectively; first and second inner brackets transmitting rotation of the camshaft to the first and second cam portions respectively; a slider housing in which the first and the second inner brackets are rotatably inserted; first and second guiding portions formed on the slider housing; a cam cap on which a cam cap guide contacting the second guiding portion is formed; a control shaft parallel to the camshaft; a control rod eccentrically formed on the control shaft; a guide head on which a head guiding portion and a head hole are formed; a control portion selectively rotating the control shaft; and a stopper limiting movement of the guide head. The head guiding portion is connected to the first guiding portion, and the control rod is inserted into the head hole.