A first timing belt transmits rotation of a crankshaft to an exhaust valve operating camshaft whose rotation is in turn transmitted through a second timing belt to an intake valve operating camshaft. A pair of adjusting pulleys are provided which is brought into contact with a tension side section and a slack side section of the second timing belt and movable in unison with each other toward and away from the timing belt sections to vary the lengths of same and thereby vary the phase of the intake valve operating camshaft relative to the exhaust valve operating camshaft in accordance with operating conditions of the engine.

Double overhead camshaft engines

Valve timing control device for an internal combustion engine

The camshaft of an internal combustion engine is driven by a chain drive from an adjacent parallel intermediate shaft, which itself is driven with a toothed belt by the engine crankshaft. For a four valve cylinder head having two overhead camshafts, one camshaft is used as the intermediate shaft. By means of a hydraulic tensioning device applied at the chain drive, the relative rotating position of both camshafts and thus also the control time of the valves can be changed.

Camshaft drive for an internal combustion engine

A camshaft driving device for use in an internal combustion engine having a cylinder block, a cylinder head disposed on the cylinder block, a driving shaft rotatably mounted at the lower portion of the cylinder block and at least one camshaft rotatably mounted at the upper portion of the cylinder head, wherein a mounting boss for mounting the reduction gear thereon is formed on an upper deck disposed on the cylinder block, while a driving force from the driving shaft is transmitted to the camshaft through the reduction gear. A transmitting portion of the reduction gear on the side of the camshaft is outwardly disposed from the engine as compared with another transmitting portion thereof on the side of the driving shaft and the transmitting portion of the latter is disposed in a space immediately below a journal boss formed at the upper portion of the cylinder head for rotatably mounting the camshaft therein.

Camshaft driving device for internal combustion engine

A camshaft drive mechanism operates the inlet valves of a first cylinder through a variable valve timing (VVT) mechanism at one end of an engine block and the inlet valves of a second cylinder through a VVT mechanism at the other end of the block. In a four cylinder engine the first cylinder is No 1 and the second cylinder is No 4, cylinders Nos 2 and 3 having separate VVT mechanisms adjacent the VVT mechanisms of cylinders Nos 1 and 4 respectively. A preferred form of VVT mechanism includes an eccentric sleeve which provides a journal for a driving member. Rotation of the eccentric sleeve in an offset bore alters the valve timing. By having the offset equal to the eccentricity of the sleeve the potential wear of the components of the VVT mechanism is reduced.

Internal combustion engine camshaft drive mechanism

L'ARBRE A CAMES D'UN MOTEUR A COMBUSTION INTERNE EST ENTRAINE PAR LE VILEBREQUIN AU MOYEN D'UN ARBRE INTERMEDIAIRE PARALLELE ET SITUE A PROXIMITE. QUAND IL S'AGIT D'UNE CULASSE QUATRE SOUPAPES AVEC DEUX ARBRES A CAMES SITUES AU-DESSUS, L'UN DES ARBRES A CAMES SERT D'ARBRE INTERMEDIAIRE. IL EST POSSIBLE DE MODIFIER LA POSITION EN ROTATION RELATIVE DES DEUX ARBRES A CAMES ET DE CE FAIT EGALEMENT LES TEMPS DE COMMANDE DES SOUPAPES AU MOYEN D'UN DISPOSITIF TENDEUR HYDRAULIQUE COOPERANT AVEC L'ENTRAINEMENT PAR CHAINE.

Commande d'arbre a cames d'un moteur a combustion interne

1,167,947. Gearing conveying rotary motion. BIRMINGHAM SMALL ARMS CO. Ltd. 21 May, 1968 [1 June, 1967], No. 25305/67. Heading F2Q. [Also in Division F1] Twin overhead cam-shafts are driven by a chain drive from a sprocket 3 on the crankshaft 2 to a sprocket 5 journalled on the cylinder block adjacent to the cylinder head, which sprocket is fast with a gear-wheel 7 that transmits the drive to an idler gear 8 journalled on the cylinder head and meshing with gears 9 on the crank-shafts 10. The chain is tensioned by tensioner 11 and the gears 7 and 8 are adjustably mounted e.g. in eccentric bushes.

Double overhead camshaft engines

Citations

Valve timing control device for an internal combustion engine

Camshaft drive for an internal combustion engine

Camshaft driving device for internal combustion engine

Internal combustion engine camshaft drive mechanism

Commande d'arbre a cames d'un moteur a combustion interne

References

Camshaft Drives for Internal Combustion Engines.

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Overhead valve engine