Internal-combustion engines – Engine speed regulator – Having plural throttle valve structure
Patent
1997-10-01
1999-03-02
Argenbright, Tony M.
Internal-combustion engines
Engine speed regulator
Having plural throttle valve structure
12318461, 123337, 251148, 251367, F02M 3510, F02D 910
Patent
active
058757589
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an engine air intake system, particularly a resin air intake system provided with an intake control valve, designed to make the air intake system be provided with an air intake control valve of a resin.
2. Description of Related Art
Requirements for higher performance engines in recent years have resulted in using a variety of systems for air intake systems. There is known a so-called variable air intake system to improve both the engine torque in the medium to low speed range and to improve output in the high speed region. These try to increase the engine fueling efficiency by varying the essential air intake type lengths or capacity of the air intake system according to the engine operating conditions, so as to make effective use of inertial and resonance actions under a given situation.
In order to change the air intake tube length or capacity, such a variable air intake system equips the air intake constituting part, such as an air intake manifold, with air intake passages open to be connected to each combustion chamber of an engine with intake control valves rotatably, which are supported by a shaft having an axis in the direction perpendicular to the axes of the openings. Driving this shaft with an external actuator is designed to control the opening and closing of the intake control valve.
There is known a lean combustion engine for improved engine fuel consumption rate for energy saving, in which its air intake manifold is provided with a plurality of air intake passages per cylinder, and controlling the opening and closing of an intake control valve provided for one of the air intake passages is designed to give an air intake with a swirl within the designated operating range.
In general, such an air intake manifold is cast from a metal such as aluminum and bearing holes to support the above shaft rotatably are drilled by machining after casting. A split butterfly valve for a manifold is disclosed in FR-A-2606115. Two halves of the manifold can be molded from a metal or an appropriate plastic. The butterfly is positioned on a shaft and secured in the split housing. The securing and positioning means are complicated in that recesses are cut into positioning flanges on both halves.
SUMMARY OF THE INVENTION
From the standpoint of energy saving, requests for reducing engine weight are still intense, for which attempts and proposals have been made to make an engine air intake system from a resin. Among these approaches, there are examples in which part of an air intake system, such as a simple design air duct and an intake manifold with no movable parts have already been made of a resin, but there is yet no example in which a resin is used to make an air intake system provided with the above intake control valve, particularly in an air intake manifold.
Having no such example may be rationalized in terms of the insufficient development of materials which can possess the heat resistance in a high temperature engine compartment and have strength enough to endure the shaking resulting from engine vibration.
Furthermore, another lack of such example may be due to the fact that an air intake manifold provided with an intake control valve, or the like, is too complicated in configuration to allow an ease of fabricating the molds or cores therefore. In particular, if an intake control valve, and the like, are provided, there is a need for having a bearing opening which rotatably supports the shaft for the intake control valve, but drilling such an opening by machining after molding from a resin will not allow taking advantage of molding by a one-shot molding operation, while fabricating it by molding alone will aggravate the difficulty in making such a mold for it.
In addition, when a plurality of intake passages are arrayed in parallel, machining such a bearing hole opening incurs extreme difficulty in achieving a precision axis center in the case of the resin. Therefore, the problem has been that since the machining of
REFERENCES:
patent: 4523560 (1985-06-01), Motosugi et al.
patent: 4768487 (1988-09-01), Yamamoto et al.
patent: 4907547 (1990-03-01), Daly
Argenbright Tony M.
E. I. Du Pont de Nemours and Company
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