A valve timing change device includes: a housing rotor (10); a vane rotor; a fastening bolt (40) for fastening the vane rotor to a cam shaft; and an advance angle oil passage that constitutes a ring-shaped groove communicating with an advance angle chamber and a delay angle oil passage that constitutes a ring-shaped groove communicating with a delay angle chamber, via oil passages which are open at intervals on an outer circumferential surface of the fastening bolt. The vane rotor includes: a rotor body (20) having a small-diameter inner circumferential portion (23) and a large-diameter inner circumferential portion (24); and a rotor sleeve (30) that is fitted into the large-diameter inner circumferential portion, is in tight contact with the outer circumferential surface (41a) of the fastening bolt, and demarcates the advance angle oil passage (23a) in cooperation with the small-diameter inner circumferential portion.

An engine variable valve train is provided with a cylindrical cam carrier fitted on a camshaft in a manner axially slidable to and co-rotatable with the camshaft. The cam carrier has therearound mutually adjoining low-speed and high-speed cam lobes selectively acting on the engine valve and being different in cam profile. The cam carrier has therearound lead grooves to be engaged with or disengaged from changeover pins for axial shift of the cam carrier. The lead grooves include a speed-increasing lead groove for changeover from the low-speed to the high-speed cam lobe and a speed-decreasing lead grooves for changeover from the high-speed to the low-speed cam lobe. The speed-increasing and speed-decreasing lead grooves are different in groove contour. This enables the cam carrier to axially shift smoothly and to improve the durability of the lead grooves.

An engine variable valve train is provided with a cylindrical cam carrier fitted on a camshaft in a manner axially slidable to and co-rotatable with the camshaft. The cam carrier has therearound mutually adjoining low-speed and high-speed cam lobes selectively acting on the engine valve and being different in cam profile. The cam carrier has therearound lead grooves to be engaged with or disengaged from changeover pins for axial shift of the cam carrier. The lead grooves include a speed-increasing lead groove for changeover from the low-speed to the high-speed cam lobe and a speed-decreasing lead grooves for changeover from the high-speed to the low-speed cam lobe. The speed-increasing and speed-decreasing lead grooves are different in groove contour. This enables the cam carrier to axially shift smoothly and to improve the durability of the lead grooves.

An internal combustion engine system includes an engine with a plurality of pistons housed in respective ones of a plurality of cylinders, an air intake system to provide air to the plurality of cylinders through respective ones of a plurality of intake valves, an exhaust system to release exhaust gas from the plurality of cylinders through respective one of a plurality of exhaust valves, an aftertreatment system to treat exhaust emission from the engine, and a controller coupled to at least one sensor and configured to control a cam phaser for thermal management of the aftertreatment system.

A four-stroke internal combustion engine is disclosed. A camshaft and a crankshaft if the engine are synchronized to rotate at a same rotational speed. A first linkage arrangement is configured to change the motion of an exhaust valve head. A second linkage arrangement is configured to change the motion of the intake valve head. A control unit is configured for controlling the first linkage arrangement to selectively prevent the motion of the exhaust valve head and for controlling the second linkage arrangement to selectively prevent the motion of the intake valve head.

A four-stroke internal combustion engine is disclosed. A camshaft and a crankshaft if the engine are synchronized to rotate at a same rotational speed. A first linkage arrangement is configured to change the motion of an exhaust valve head. A second linkage arrangement is configured to change the motion of the intake valve head. A control unit is configured for controlling the first linkage arrangement to selectively prevent the motion of the exhaust valve head and for controlling the second linkage arrangement to selectively prevent the motion of the intake valve head.

A four-stroke internal combustion engine is disclosed. A camshaft and a crankshaft if the engine are synchronised to rotate at a same rotational speed. A first linkage arrangement is configured to change the motion of an exhaust valve head. A second linkage arrangement is configured to change the motion of the intake valve head. A control unit is configured for controlling the first linkage arrangement to selectively prevent or reduce the motion of the exhaust valve head and for controlling the second linkage arrangement to selectively prevent or reduce the motion of the intake valve head.

A four-stroke internal combustion engine is disclosed. A camshaft and a crankshaft if the engine are synchronised to rotate at a same rotational speed. A first linkage arrangement is configured to change the motion of an exhaust valve head. A second linkage arrangement is configured to change the motion of the intake valve head. A control unit is configured for controlling the first linkage arrangement to selectively prevent or reduce the motion of the exhaust valve head and for controlling the second linkage arrangement to selectively prevent or reduce the motion of the intake valve head.

A valve timing system including a crankshaft drive gear coupled to the crankshaft in working communication with a crankshaft connecting rod gear further including a primary connecting rod disc with a first-journal, the first-journal configured to receive at least two connecting rods at respective first-rod-ends in a side-by-side orientation and each connecting rod is coupled to a respective one of the intake disc and the exhaust disc via an intake-journal and an exhaust-journal, respectively. At least two secondary connecting rod discs are coupled to at least two plate-shaft drive gears to drive at least two plate-shaft-gears, the two plate-shaft-gears are connected to the two plate-shafts, respectively. At least two plate-shafts are coupled to an intake cam-groove plate and an exhaust cam-groove plate, the intake cam-groove plate and the exhaust cam-groove plate cammingly-manipulate the intake valve stem connector and the exhaust valve connector to drive each valve assembly.

A gas engine is disclosed. The gas engine may include a combustion cylinder. The combustion cylinder may include an intake with an intake valve. The combustion cylinder may include an exhaust with an exhaust valve. The gas engine may include a gas admission valve assembly coupled to the intake. The gas admission assembly may include a trimmable electro-hydraulically actuatable gas admission valve to control a gas flow into the intake.