Honda Giken Kogyo Kabushiki Kaisha

Honda Motor Co., Ltd.

Tomonori Niizato

Kazuyuki Iwata

Tsutomu Saka

Noriyuki Yamada

Toshihiro Oikawa

Yukihiro Matsumoto

Kiyoshi Tsukimura

Kazuhide Kumagai

Masataka Ikawa

Tsuneo Tanai

Katsumi Noguchi

Kazuhiro Kasahara

Kenji Yoshihara

Tetsuya Kajiura

A valve operation control system for an internal combustion engine in which hydraulic pressure applied to a valve operation mode changing mechanism is controlled by hydraulic pressure control means that is formed from a holder mounted on a cylinder head, a spool valve formed by slidably housing a spool valve body in a valve body, and an electromagnetic open/close valve for controlling hydraulic pressure of a pilot hydraulic chamber, wherein the holder () is formed by integrally connecting a housed portion () and a projecting portion () by means of a connection portion (), the housed portion () being housed between the cylinder head (R) and a head cover, the projecting portion () projecting outside the cylinder head (R) and the head cover and having the electromagnetic open/close valve () mounted thereon, a seal face () with the head cover is formed on the connection portion (), and the valve body () is provided so as to be connected to the housed portion () while being housed between the head cover and the cylinder head (R). This enables the sealing properties between the holder and the head cover to be enhanced.

Valve operation control system for internal combustion engine

A casing accommodating therein a pair of balance shafts below the cylinder block comprises an upper casing and a lower casing that can vertically be split, and an oil pump body is molded integrally with one of the upper and lower casings. In addition, one end of each of the two casings is inserted into the oil pump body for support therein, and the two balance shafts are each supported on a bearing provided between the two casings in such a manner as to be split into two halves at an intermediate portion or the other end thereof. With this construction, the oil pump body can be molded together with the casing, thereby making it possible to reduce the number of components used and man hours for assembling. In addition, since the bearings can be split into two halves, when compared with other portions of the balance shafts, the journal portion can be thinned, thereby making it possible not only to reduce the sliding friction but also to make the casing smaller in size and lighter in weight. More over, the degree of freedom of designing balance shafts can also be improved. With the balance shaft supporting structure for an engine the durability of a balancer, as well as the degree of freedom of designing the same are improvided without making the engine larger in size and increasing the number of components used.

Engine balance shafts supporting structure

A balancing device for a reciprocating engine is provided which is improved so as not to disturb the compactification of an engine. There is provided a balancing device for a reciprocating engine comprising two balance shafts,L,,R gear connected to each other, a chain/sprocket mechanism,for coupling at least one,L of the balance shafts with a crankshaft,in an interlocking fashion, a chain tensioner,for automatically adjusting the tension of the chain,and a pump receiving portion,integrally provided in a balance shaft holder,for supporting the balance shafts for receiving a rotor,B of a lubricating oil pump,, the balancing device being characterized in that the rotor of the lubricating oil pump is directly connected to the other balance shaft,R, and that the chain tensioner is disposed on an shaft end side of the other balance shaft. In accordance with the balancing device constructed as described above, the chain tensioner can be displaced within a range that does not project largely from a triangular contour formed by the two balance shafts and the crankshaft.

Balancing device for reciprocating engine

A cylinder head structure for a multiple cylinder engine, comprising, at least for each of its cylinders (1) located at either longitudinal end of its cylinder bank: a combustion chamber (13) defined by the cylinder and a piston received therein; an intake passage (18) communicated with an intake manifold (20) at its one end and with said combustion chamber at its other end; and exhaust passage (19) communicated with an exhaust manifold (21) at its one end and with said combustion chamber at its other end; at least one of said intake passage and said exhaust passage being curved toward a longitudinally central part of said cylinder bank as it extends from its other end to its one end. Hence, the size and weight of the intake manifold and/or the exhaust manifold can be reduced. In particular, if the passage is communicated with the combustion chamber by a pair of ports (14a, 14b, 15a, 15b, 14a', 14b', 15a', 15b', 58Ea, 58Eb, 58 Ia, 58Ib, 114a', 114b', 115a', 115b') controlled by valves and arranged along a longitudinal direction of the cylinder bank and different flow rates are assigned to these ports depending the operating conditions of the engine, a significant improvement in the performance of the engine may be attained by symmetrically arranging these ports with respect to a longitudinal center of the cylinder bank.

Cylinder head structure for multiple cylinder engines

In a valve operating system for an internal combustion engine that includes a valve operation mode changing mechanism capable of changing at least one of either the lift amount of opening of an engine valve openably and closably carried in an engine body or the opening or closing timing in accordance with a variation in hydraulic pressure supplied to the changing mechanism. A selector valve is provided and includes a valve element slidably received in a housing attached to the engine body to change the supply of hydraulic pressure to the valve operation mode changing mechanism. The housing of the selector valve is provided with a working oil chamber which receives an oil pressure for driving, toward a position to supply a higher hydraulic pressure to the valve operation mode changing mechanism, a valve element biased toward a position to supply a lower hydraulic pressure to the valve operation mode changing mechanism. The working oil chamber is connected through a leak jet to a drain chamber provided in the engine body. The leak jet permits the hydraulic pressure to be quickly released from the working oil chamber when the valve element of the selector valve is driven to block the communication between the hydraulic pressure supply source and the valve operation mode changing mechanism, thereby leading to a quick changing operation of the valve operation mode changing mechanism.

Valve operating system for internal combustion engine

A lubricant supplying system for a DOHC type multicylinder internal combustion engine comprising a plurality of cylinders arranged in series in a cylinder block, a pair of cam shafts parallel to each other and rotatably supported by a cylinder head and cam holders fixed to the cylinder head at opposite sides of the respective cylinders along the cylinder arranging direction, a plurality of cams including low speed cams corresponding to intake and exhaust valves of the respective cylinders and fixed to the cam shafts, a plurality of rocker arms in slidable contact with the respective cams corresponding to the intake and exhaust valves of the respective cylinders, and a connection switching mechanism for switching connection and disconnection of the rocker arms in response to a hydraulic pressure to vary the operating states of the valves responsive to the operating state of the engine, wherein a hydraulic pressure supply passage independent from an oil supply passage for supplying a hydraulic pressure to the connection switching mechanism is provided in the cylinder head substantially at its center portion along the cylinder arranging direction so as to extend vertically, and a branch oil passage is provided to have intake and exhaust side portions disposed in one cam holder of substantially center location along the cylinder arranging direction for communicating with the upper end of the hydraulic pressure supply passage to supply oil to the slidably contacting portions of low speed cams of the respectively cylinders at both intake and exhaust sides with the rocker arms and the cam journal portions of the cam shafts.

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Saitama, Japan

Tomonori Niizato