Internal-combustion engines – Combustion chamber means combined with air-fuel mixture... – Air or combustible mixture entering the combustion chamber...
Reexamination Certificate
2000-01-11
2002-04-30
Kwon, John (Department: 3754)
Internal-combustion engines
Combustion chamber means combined with air-fuel mixture...
Air or combustible mixture entering the combustion chamber...
Reexamination Certificate
active
06378495
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an engine with a valve resting function, which is intended to rest at least one of a plurality of intake valves in a specific operational region.
2. Description of Background Art
The engine of this type has been known, for example, from Japanese Patent Publication No. Sho 62-56327.
The above-described related art engine is configured to rest one of a pair of intake valves in a specific operational region for allowing lean combustion by forming a swirl in a combustion chamber, thereby reducing fuel consumption. However, in a state in which one of the intake valves is rested, fuel remains in an intake passage corresponding to the rested intake valves, and consequently, when the operational state in which one of the intake valves is rested is switched into the operational state in which all of the intake valves are opened/closed, the remaining fuel flows in the combustion chamber to temporarily make dense the concentration of the fuel in the combustion chamber. This may reduce the engine output and increase the occurrence of unburned hydrocarbon.
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 an engine with a valve resting function, which is capable of preventing the flow-in of the remaining fuel in a combustion chamber when the rested intake valve is switched to be opened/closed, thereby preventing the reduction in engine output and preventing the increase in unburned hydrocarbon.
To achieve the above object, according to the present invention there is provided an engine with a valve resting function, including a plurality of intake valve ports provided in a cylinder head in such a manner as to face to a combustion chamber. A plurality of intake passages are provided in the cylinder head in such a manner as to be individually connected to the intake valve ports; and a valve system is provided for driving a plurality of intake valves capable of individually opening/closing the intake valve ports, the valve system is configured such that it can rest at least one of the intake valves in a specific operational region. A communication passage for communicating the intake passage corresponding to the intake valve opened/closed even in the specific operational region to the intake passage corresponding to the intake valve rested in the specific operational region is provided in the cylinder head.
With this configuration, when at least one of a plurality of the intake valves is rested in a specific operational region, an air-fuel mixture flows from the intake passage corresponding to the rested intake valve to the intake passage corresponding to the opened/closed intake valve via the communication passage, with a result that it is possible to prevent the fuel from remaining in the intake passage corresponding to the rested intake valve. Accordingly, even if the operational state in which at least one of the intake valves is rested is switched into the operational state in which all of the intake valves are opened/closed, the remaining fuel does not flow in the combustion chamber, to prevent the mixing ratio of the air-fuel mixture flowing in the combustion chamber from being made unstable, thereby preventing the reduction in engine output and preventing the increase in occurrence of unburned hydrocarbon as much as possible.
According to the present invention an intake system including a carburetor common to the intake passages is connected to the intake passages. With this configuration, even if the intake system connected to a plurality of intake passages is configured to have the single carburetor, it is possible to avoid the inconvenience that the mixing ratio is made unstable when the operational state in which part of the intake valves is rested is switched into the operational state in which all of the intake valves are opened/closed. That is to say, it is possible to prevent the fuel from remaining in the intake passage corresponding to the intake valve which is rested due to the configuration of the present invention and hence to prevent the mixing ratio from being made unstable even by using the intake system with a simple structure in which the air-fuel mixture is formed by the carburetor common to respective intake passages.
According to the present invention the communication passage is formed as a hollow portion upon formation of the cylinder head by casting. With this configuration, it is possible to form the communication passage simultaneously with the formation of the cylinder head by casting, and hence to reduce the number of the steps of forming the cylinder head.
According to the present invention the communication passage is formed by cutting, from the combustion chamber side. With this configuration, the communication passage can be simply formed in the cylinder head without use of any special means.
According to the present invention, the communication passage is formed in such a manner as to be tilted toward the combustion chamber in the direction from the intake passage corresponding to the intake valve opened/closed even in the specific operational region to the intake passage corresponding to the intake valve rested in the specific operational region. With this configuration, the opening end of the communication passage to the intake passage corresponding to the intake valve rested in the specific operational region can be disposed at a position being as close to the combustion chamber as possible, so that when the intake valve is rested in the specific operational region, the intake passage corresponding to the rested intake valve can be communicated to the intake passage corresponding to the opened/closed intake valve at the position being as close to the combustion chamber as possible. This makes it possible to make the amount of the remaining fuel in the resting state of the intake valve as small as possible.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: B2 6256327 (1987-11-01), None
Kumagai Yoshihiko
Okamoto Tomoyuki
Tsukui Takaaki
Birch & Stewart Kolasch & Birch, LLP
Honda Giken Kogyo Kabushiki Kaisha
Kwon John
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