Internal-combustion engines – Means to whirl fluid before – upon – or after entry into...
Patent
1987-12-17
1989-07-25
Cross, E. Rollins
Internal-combustion engines
Means to whirl fluid before, upon, or after entry into...
123188M, F22B 502
Patent
active
048503177
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to an intake port device for an internal combustion engine in which an intake port having a special shape is combined with a valve so that the direction of intake air flowing into a combustion chamber of the engine can be changed according to the load of the engine.
BACKGROUND ART
It is desirable that air taken into a combustion chamber of an internal combustion engine is suitably swirled in order to promote mixing of air with fuel. This swirl is commonly provided by giving directivity to intake air by an intake port formed into a helical shape. When the load of the engine is light, a swirl is produced to promote mixing of intake air with fuel thereby improving the combustion efficiency. However, when the engine is heavy-loaded, and suction of a large quantity of intake air is required, a large resistance against intake air is caused by the helical shape of the intake port, resulting in a decrease in the charging efficiency. With a view to obviate such a drawback, a partition wall or a separate port is commonly provided in the intake port according to the prior art, and an associated valve is provided so as to change the magnitude of the swirl.
In the prior art device described above, the provision of the partition wall or the separate port in the intake port or the additional provision of the valve results in a complex structure of the intake port and is undesirable from the viewpoints of operation, manufacture and cost.
When the valve provided in the intake port is full closed, such a trouble has occurred in which the inclination angle of the valve relative to the centerline of the intake port becomes large thereby producing a large resistance against flow of intake air. To avoid such a trouble, an attempt is made in which the length of the valve from its root end to its front end is extended to decrease the inclination angle of the valve when closed. When such a valve is used, the resistance against intake air flow can be decreased to decrease the loss of energy. However, the use of the valve having such a large length gives rise to the defect that the shape of the intake port is subject to various design restrictions, and the force required for actuating the valve becomes also large resulting in a large loss of power for driving the valve, although the loss of energy of intake air flow is decreased. In order that the swirl can be produced regardless of the shape of the intake port, the valve may be arranged to be inserted into and withdrawn from the interior of the intake port. However, even when such a withdrawable valve is used, the defect attributable to the increased resistance against intake air flow is not still obviated although the shape of the intake port is now free from various design restrictions.
DISCLOSURE OF THE INVENTION
In view of the prior art situations described above, it is an object of the present invention to provide an intake port device in which an intake port formed into a special shape is provided without provision of any partition wall or the like, and a valve, which produces a very small resistance against intake air flow and the design of which is not limited by the shape of the intake port, is disposed on the inlet side of the intake ports and regulated to provide flow of air having a quantity and shape corresponding to the load of the engine, so that the manufacture of the intake port can be facilitated, its cost can be reduced, and its performance under a heavy-loaded condition can be improved.
An intake port device of the present invention is featured by the provision of an intake pot providing a passage of intake air flowing into a combustion chamber of a cylinder of an internal combustion engine, the intake port including a straight part forming an upper half of the intake port with respect to the axial direction of the cylinder and a helical part formed integrally with the straight part without provision of any partition wall therebetween to form a lower half of the intake port with respect to the axial direction of the
REFERENCES:
patent: 4240387 (1980-12-01), Motosugi
patent: 4470386 (1984-09-01), Okumura
patent: 4481922 (1984-11-01), Sugiura
Akishino Katsuo
Danno Yoshiaki
Dogahara Takashi
Hirako Osamu
Katsumoto Takehiko
Cross E. Rollins
Mitsubishi Jidosha Kogyo Kabushiki Kaisha
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