Internal-combustion engines – Intake manifold – For engine having radiating cylinders
Reexamination Certificate
2002-05-14
2004-04-27
Wolfe, Willis R. (Department: 3747)
Internal-combustion engines
Intake manifold
For engine having radiating cylinders
C123S184360
Reexamination Certificate
active
06725822
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an intake system for a multi-cylinder engine, in which an intake air inlet is provided in an intake air-dispensing box to lead to an intake passage in a throttle body; the inside of the intake air-dispensing box is divided by a partition wall into first and second dispensing chambers communicating with the intake air inlet; first and second intake branch pipes opening into the first and second dispensing chambers and leading to intake ports in first and second banks of the engine are connected to the intake air-dispensing box; and an on-off valve is mounted in the partition wall and capable of permitting the first and second dispensing chambers to be put into and out of communication with each other, so that the air-charging characteristic can be changed by opening and closing the on-off valve depending on the operational state of the engine, thereby maintaining a high outputting performance in a wider operational range from a low speed to a high speed.
2. Description of the Related Art
A conventional intake system for a multi-cylinder engine is already known, as disclosed, for example, in Japanese Patent Application Laid-open No. 9-88746.
In the intake system disclosed in the above Japanese Patent Application Laid-open No. 9-88746, the partition wall supporting the on-off valve and having a valve bore opened and closed by the on-off valve is interposed between a dispensing box body and an intake manifold. Therefore, to carry out the maintenance of the on-off valve, a troublesome operation of disassembling the dispensing box body and the intake manifold from each other is required, so that the maintenance property is not good.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an intake system of the above-described type for a multi-cylinder engine, wherein the maintenance of the on-off valve can be carried out only by removing a lid mounted outside the intake air-dispensing box from the box, leading to a good maintenance property.
To achieve the above object, according to a first aspect and feature of the present invention, there is provided an intake system for a multi-cylinder engine, in which an intake air inlet is provided in an intake air-dispensing box to lead to an intake passage in a throttle body; the inside of the intake air-dispensing box is divided by a partition wall into first and second dispensing chambers communicating with the intake air inlet; first and second intake branch pipes opening into the first and second dispensing chambers respectively and leading to intake ports in first and second banks of the engine respectively are connected to the intake air-dispensing box; and an on-off valve capable of permitting the first and second dispensing chambers to be put into and out of communication with each other is mounted in the partition wall; wherein the intake air-dispensing box is comprised of a dispensing box body which includes the intake air inlet, the first and second intake branch pipes and one of halves of the partition wall and which has an opening provided in its outer wall opposite from the first and second intake branch pipes to extend between the first and second dispensing chambers, and a lid detachably coupled to the dispensing box body to close the opening and having the other half of the partition wall, the lid being made of a light alloy by casting, and a valve bore permitting the first and second dispensing chambers to be put into communication with each other and bearing bores for supporting a valve shaft of the on-off valve for opening and closing the valve bore are defined in the other half of the partition wall.
With the first feature, a single assembly is formed by the lid and the on-off valve and hence, the maintenance of the on-off valve and the members around the on-off valve can be carried out easily by removing the lid from the dispensing box body, thereby contributing to an enhancement in maintenance property.
Moreover, the lid made of the light alloy by casting is small in size and simple in shape, as compared with the dispensing box body integral with the intake branch pipes and hence, can be precisely formed by casting such as high-pressure die-casting. Therefore, the post-processing of the valve bore is not required and moreover, the lid having such a high quality that deformation cannot be generated therein even due to a change in the surrounding temperature, can be produced easily, and the good opening and closing operation of the on-off valve supported on the lid can be always ensured irrespective of the change in the surrounding temperature.
According to a second aspect and feature of the present invention, in addition to the first feature, the other half of the partition wall is divided into a main partition other-half body and a partition piece so that the valve bore is divided along the bearing bores into halves, the partition piece being bolted to the main partition other-half body.
With the second feature, when the main partition other-half body and the partition piece of the partition wall are produced by casting, the halves of the valve bore included respectively in the main partition other-half body and the partition piece can be die-formed simply, and a troublesome processing for the valve bore is not required after the casting, leading to an enhancement in productivity.
According to a third aspect and feature of the present invention, there is provided an intake system for a V-type engine for an outboard engine system, which is disposed with a crankshaft placed vertically and with heads of left and right banks directed rearwards and which is covered with an engine hood; wherein an intake air inlet is provided in vertically one side of a longitudinally flat intake air-dispensing box disposed between the left and right banks and a rear wall of the engine hood so that the intake air inlet leads to an intake passage in a throttle body; the inside of the intake air-dispensing box is divided by a partition wall into left and right dispensing chambers communicating the intake air inlet and extending vertically; an on-off valve capable of permitting the left and right dispensing chambers to be put into and out of communication with each other is mounted in the partition wall; left and right intake branch pipes opening into the left and right dispensing chambers respectively and leading to intake ports in the left and right banks respectively are connected to a front wall of the intake air-dispensing box; the intake air-dispensing box is comprised of a dispensing box body which includes the intake air inlet, the left and right intake branch pipes and one of halves of the partition wall and which has an opening provided in its outer wall opposite from the left and right intake branch pipes to extend between the left and right dispensing chambers, and a lid which is made of a light alloy by casting and detachably coupled to the dispensing box body to close the opening and which has the other half of the partition wall; the on-off valve is mounted to a valve shaft rotatably supported in the other half and extending vertically; an operating lever is secured to an outer end of the valve shaft protruding toward the vertically other end of the intake air-dispensing box; and an actuator for turning the operating lever to open and close the on-off valve is mounted at the other end of the intake air-dispensing box and accommodated within an area of a vertically projected view of the intake air-dispensing box.
With the third feature, resonant supercharging intake systems corresponding to low-speed and high-speed operational ranges of the engine are formed by opening and closing of the on-off valve, whereby a high outputting performance can be exhibited in a wider operational range. Moreover, the longitudinally flat intake air-dispensing box is disposed in proximity to the heads of the left and right banks of the engine and hence, can be disposed in a narrow space between the engine and the rear wall of the
Ikuma Tomonori
Kikuchi Masahiko
Matsumoto Takashi
Wada Tetsu
Arent & Fox PLLC
Honda Giken Kogyo Kabushiki Kaisha
Wolfe Willis R.
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