Internal-combustion engines – Poppet valve operating mechanism – With means for varying timing
Reexamination Certificate
2000-01-11
2001-11-20
Lo, Weilun (Department: 3747)
Internal-combustion engines
Poppet valve operating mechanism
With means for varying timing
C123S090330, C123S19800E, C123S193300
Reexamination Certificate
active
06318316
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a multi-cylinder engine for a motorcycle, including a cylinder block having a plurality of cylinder bores arranged in the width direction of a body frame, a cylinder head connected to the cylinder block with combustion chambers formed between pistons slidably fitted in the cylinder bores and the cylinder head, intake valves and exhaust valves provided in the cylinder head for each of the combustion chambers, a hydraulic valve resting mechanism capable of resting, in a specific operational region, at least one of the intake valves and the exhaust valves, and a hydraulic control valve mounted on the cylinder head for controlling the hydraulic pressure of working oil supplied to the valve resting mechanism.
2. Description of Background Art
A multi-cylinder engine in which a hydraulic control valve for controlling the hydraulic pressure of working oil supplied to a valve resting mechanism is mounted in a cylinder head has been known, for example, from Japanese Utility Model Publication No. Hei 6-34563.
In a motorcycle in which a multi-clinder engine is mounted on a body frame in such a manner that a plurality of cylinder bores provided in a cylinder block are arranged along the width direction of the body frame, it is expected that the length of the multi-cylinder engine along the arrangement direction of the cylinder bores, that is, along the width direction of the body frame is made as short as possible. In the multi-cylinder engine disclosed in the above document. However, the hydraulic control valve is mounted on the cylinder head on one end side along the arrangement direction of the cylinder bores, and accordingly, if such an engine is applied to a motorcycle, it is required to ensure a space in which the hydraulic control valve is disposed in the width direction of the body frame, so that it is difficult to shorten the length of the multi-cylinder cylinder engine along the width direction of the body frame.
SUMMARY AND OBJECTS OF THE INVENTION
In view of the foregoing, the present invention has been made, and an object of the present invention is to provide a multi-cylinder engine for a motorcycle, which is capable of making the length of the engine in the width direction of a body frame as short as possible although a hydraulic control valve is mounted on a cylinder head.
To achieve the above object, according to the present invention, there is provided a multi-cylinder engine for a motorcycle, including: a cylinder block having a plurality of cylinder bores arranged in the width direction of a body frame; a cylinder head connected to the cylinder block with combustion chambers formed between pistons slidably fitted in the cylinder bores and the cylinder head; a hydraulic valve resting mechanism capable of resting, in a specific operational region, at least one of a plurality of kinds of engine valves provided in the cylinder head for each of the combustion chambers; and a hydraulic control valve, mounted on the cylinder head, for controlling the hydraulic pressure of working oil supplied to the valve resting mechanism; wherein the hydraulic control valve is mounted on a side surface of the cylinder head to which a plurality of intake ports individually corresponding to the combustion chambers are opened along the longitudinal direction of the body frame.
With this configuration, since the hydraulic control valve is mounted on the side surface of the cylinder head in the longitudinal direction of the body frame, that is, in the direction perpendicular to the arrangement direction of the cylinder bores, it is possible to avoid an inconvenience that the length of the multi-cylinder engine along the arrangement direction of the cylinder bores becomes large due to the mounting of the hydraulic control valve on the cylinder head, and hence to make the length of the multi-cylinder engine along the width direction of the body frame as short as possible and prevent adverse effect of exhaust heat from being exerted on the hydraulic control valve.
According to the present invention, the hydraulic control valve is mounted on the side surface of the cylinder head at a position between two adjacent intake ports. With this configuration, it is possible to dispose the hydraulic control valve by making effective use of a space between the two adjacent intake ports, and hence to make shorter the length of the multi-cylinder engine along the width direction of the body frame.
According to the present invention, a working oil intake passage for introducing working oil from an oil pump to the hydraulic control valve is provided in the cylinder head, the cylinder block, and a crank case. With this configuration, it is possible to eliminate the necessity of the provision of an additional pipe line for introducing working oil from the oil pump to the hydraulic control valve and hence to simplify the appearance of the multi-cylinder engine.
According to the present invention, a water jacket is provided in the cylinder block and the cylinder head, and two parts, corresponding to the cylinder block and the cylinder head, of the working oil intake passage are disposed outside the water jacket. with this configuration, it is possible to effectively cool working oil flowing in the working oil intake passage.
According to the present invention, the working oil intake passage includes: a first passage provided in the cylinder head in such a manner as to extend in a straight line along the side surface in a region between the side surface on which the hydraulic control valve is mounted and the water jacket; a second passage provided in the cylinder block in such a manner as to be coaxially connected to the first passage; and a third passage provided in the crank case connected to the cylinder block in such a manner as to be coaxially connected to the second passage and to extend in a straight line therefrom.
With this configuration, it is possible to make the working oil route from the oil pump to the hydraulic control valve as short as possible and hence to make a loss in hydraulic pressure in the working oil intake passage as small as possible.
According to the present invention, a containing hole for containing a means for driving cam shafts is provided in the cylinder head at a position between the adjacent two, on the central side along the arrangement direction, of the cylinder bores of the even number of four or more in such a manner as to partition the cylinder head into first and second head portions located on both sides of the containing hole. A first working oil discharge passage is provided for supplying working oil to the valve resting mechanism for each of the combustion chambers on the first head portion side in the first head portion. The passage being connected to the hydraulic control valve mounted on the side surface of the cylinder head at a position between a pair of the intake ports of a plurality of the intake ports arranged on the first head portion side. A second working oil discharge passage is provided for supplying working oil to the valve resting mechanism for each of the combustion chambers on the second head portion side in the second head portion. One-end of the first and second working oil discharge passages is opened to a mounting seat formed on the side surface of the cylinder head in such a manner as to cross between the first and second head portions. The first and second working oil discharge passages are communicated to each other via a cover fastened to the mounting seat.
With this configuration, the containing hole for containing the means for driving the cam shafts is provided in the cylinder head at a position between the adjacent two, on the central side along the arrangement direction of the cylinder bores, of the cylinder bores, it is possible to keep the desirable balance of the cylinder head along arrangement direction of the cylinder bores, and thereby the desirable balance of the multi-cylinder engine as a whole, and also it is possible to simply communicate the first
Mizumura Sakae
Tsukui Takaaki
Birch & Stewart Kolasch & Birch, LLP
Honda Giken Kogyo Kabushiki Kaisha
Lo Weilun
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