A valvetrain for an engine includes a pair of valves that are disposed in a spaced apart relation to one another, and in which each of the valves has an elongated valve stem. The valvetrain further includes a valve bridge that is coupled to the pair of valves. The valve bridge is configured to define a pair of receptacles to at least partly receive the pair of valve stems therein. The valve bridge further defines a central recess that is located midway between the pair of receptacles and disposed in a co-planar relationship with the pair of receptacles.

An apparatus (201) and method for controlling intake valves (23) in an internal combustion engine (5), as well as an internal combustion engine and a vehicle comprising the apparatus, and an electronic processor for performing the method is disclosed. The apparatus comprises a hydraulic system (3) configured to hydraulically actuate a first intake valve (23a) and a second intake valve (23b) of a first combustion chamber (25) of an internal combustion engine (5). The apparatus also includes a controller (9) configured to control the hydraulic system (3) in at least a first mode of operation and a second mode of operation. In the first mode of operation, the controller (9) is configured to control the hydraulic system (3) to cause lifting of the first and second intake valves (23a, 23b) of the first combustion chamber (25) during each intake stroke of a respective cylinder piston (27). In the second mode of operation, the controller (9) is configured to control the hydraulic system (3) to cause lifting of the first intake valve (23a) of the first combustion chamber (25) during an intake stroke of the respective cylinder piston (27) and disable actuation of the second intake valve (23b) of the first combustion chamber (25) during that intake stroke.

A control system for internal combustion engines having four valves per cylinder. An inlet valve and an exhaust valve are controlled by a basic camshaft. Another inlet valve and another exhaust valve are controlled by a control camshaft. The two camshafts are connected to a crankshaft and engine torque is managed by an electronic control unit. The system comprises a motor/generator unit, connected to the control camshaft; a differential, connected to the crankshaft and to the control camshaft; a control shaft, connected to the differential; an actuator, connected to the control shaft; a one-way restrictor valve connected to a shut-off valve and to the actuator; an oil circuit, connected to the actuator by means of the shut-off valve and a control solenoid that acts on the shut-off valve.

An exhaust system includes a plurality of cylinders, and each cylinder includes a scavenge exhaust valve and a blowdown exhaust valve. A scavenge path leads from the scavenge exhaust valves and a blowdown path leads from the blowdown exhaust valves. An arrangement activates and deactivates the scavenge exhaust valves and the blowdown exhaust valves. Further included is a cam shaft including a plurality of scavenge cams and a plurality of blowdown cams. During rotation of the cam shaft, the scavenge cams interact with the scavenge exhaust valves to open and close the scavenge exhaust valves when the scavenge exhaust valves are activated. Additionally, during rotation of the cam shaft, the blowdown cams interact with the blowdown exhaust valves to open and close the blowdown exhaust valves when the blowdown exhaust valves are activated, and at different times with respect to the opening and closing of the scavenge exhaust valves.

A variable valve train with at least two functionally identical gas-exchange valves per cylinder, having primary cam and a secondary cam generated valve strokes that are transmitted by a switchable cam follower selectively to the gas-exchange valves. The respective cam follower has a primary lever in tapping contact with the primary cam and in switching contact with the gas-exchange valve and a secondary lever that is in tapping contact with the secondary cam and is coupleable with the primary lever by a control pin. The respective control pins are connected by connecting elements to respective first and second elongated switching elements, which are arranged above the cam followers parallel to the camshaft and are displaceable longitudinally by a linear actuator from a home into a switched position. The control pins of the cam follower of functionally identical gas-exchange valves are in switching connection with a respective one of the first and second elongated switching elements for common movement.

Disclosed is a control device for an engine provided with a first intake valve and a second intake valve in an intake port. The control device comprises: a variable valve operating mechanism (72) configured to control a valve opening timing and a valve closing timing of an intake valve (21a); and a variable valve operating mechanism (72) configured to control a valve opening timing and a valve closing timing of an intake valve (21b), independently of the intake valve (21a). The latter variable valve mechanisms (72) is operable, in an intake stroke of the engine, to close the intake valve (21b) after the elapse of a delay time rt since the intake valve (21a) is closed. The delay time rt is a time period during which a pressure wave generated upon closing of the intake valve (21a) reaches the intake valve (21b) through the intake port (16).

A variable camshaft timing device (10) that adjusts phase between a camshaft and a crankshaft including a camshaft ring gear (22) having a plurality of radially-inwardly facing gear teeth (24) each of which has an involute gear tooth profile; a sprocket ring gear (14) axially spaced from the camshaft ring gear (22) having a plurality of radially-inwardly facing gear teeth (18) each of which has an involute gear tooth profile; a compound planetary gear (26) having a camshaft planetary gear (74) and a sprocket planetary gear (72) that each face radially outwardly and include a plurality of radially-outwardly facing gear teeth (76, 78) having involute gear tooth profiles; and an eccentric shaft (28) that communicates rotational force from an electric motor (30) to the compound planetary gear (26) relatively displacing the camshaft ring gear (22) with respect to the sprocket ring gear (14).

A variable valve duration system may include a camshaft, a first cam portion including a first cam, into which the camshaft is inserted and of which a relative phase angle of the first cam with respect to the camshaft is variable, an inner bracket transmitting rotation of the camshaft to the first cam portion, a slider housing into which the inner bracket is rotatably inserted, a first rocker arm having a first end contacting the first cam and a second end connected to a first valve, a rocker shaft to which the first rocker arm is rotatably connected, a solenoid valve to selectively supply hydraulic pressure, and a position controller to selectively change a position of the slider housing according to the selective supplying of the hydraulic pressure from the solenoid valve.

A variable valve train (1) of a combustion engine for applying a load on two equally acting gas exchange valves (2, 3) for each cylinder of the combustion engine is provided, including a switchable valve train element (4, 5) with an outer part and an inner part ((6, 7), (8, 9)) that can move relative to each other allocated to each of the two gas exchange valves (2, 3). The outer and inner parts ((6, 7), (8, 9)) are selectively connectable to each other by an associated coupling slide mechanism (10, 11). The valve train (1) further includes a control shaft (12), on which a control cam (13, 14) is applied for each coupling slide mechanism (10, 11), and the control cams contact an outer end face (15, 16) of the respective coupling slide mechanisms (10, 11) for displacement thereof in one direction, and the two control cams (13, 14) can rotate separately from each other on the common control shaft (12).

A cylinder head (4) for an internal combustion engine has a first inlet duct (8) that is configured to bring about a first tumbling movement and a second inlet duct (9) that is configured to bring about a second tumbling movement of the air quantities that flow through the cylinder head (4) and into a cylinder of the internal combustion engine (1). An internal combustion engine and a method for operating an internal combustion engine also are provided.