Internal-combustion engines – Engine speed regulator – Specific throttle valve structure
Reexamination Certificate
1999-08-06
2001-02-20
Solis, Erick (Department: 3747)
Internal-combustion engines
Engine speed regulator
Specific throttle valve structure
C123S339130, C251S307000
Reexamination Certificate
active
06189506
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to combustion air induction systems for internal combustion automotive engines. More particularly, it relates to methods and devices for adjusting throttle plate position of a combustion air throttle valve.
BACKGROUND OF THE INVENTION
Internal combustion engines are often provided with a throttle valve within their combustion air induction systems to control combustion airflow rate. The throttle valve is typically in the form of a butterfly valve, having a disk secured to a throttle shaft which is journaled to the generally cylindrical internal wall surface of a throat of a throttle body. The diameter of the disk is only slightly smaller than is the inside diameter of the throat, whereby the throttle plate may block all but a small portion of the air from passing through the throat in an idle condition. Typically, a return spring is used to bias the throttle shaft and butterfly closed with respect to the throat, shutting off almost all the airflow past through the throttle valve.
Provisions are made for adjusting the throttle valve to compensate for variations between particular engines, differences in their operating environments, gradual changes in characteristics due to wear, etc.
Adjusting the almost-closed position of the throttle valve is generally performed by rotating an adjusting screw that abuts the throttle arm. The throttle arm is affixed to the throttle shaft, and is disposed to approach a fixed surface of the engine when closed. The adjusting screw is typically screwed into either the arm or the fixed surface, and abuts the other. By rotating the adjusting screw, the almost-closed position of the throttle valve can be precisely regulated.
While a long thread engagement is not needed in such a low-force application, engagement of at least several threads is desirable to avert cross-threading and stripping of threads. This has necessitated the arm being constructed of metal having a thickness sufficient to accommodate the several threads when the adjusting screw is threaded into the arm.
Alternatively, it is known to threadedly engage an idle adjusting screw with a threaded aperture in a fixed surface disposed such that the end of the screw abuts the arm (U.S. Pat. No. 3,269,713, Beck, 1966; U.S. Pat. No. 4,161,928, Teague et al., 1979; U.S. Pat. No. 4,200,596, Iiyama et al., 1980; U.S. Pat. No. 4,502,436, Bonfiglioli et al., 1985; and U.S. Pat. No. 4,940,031, Mann, 1990). All such idle adjusting screws have a feature to enable rotation (e.g., a head having a screwdriver slot) located at the free end; i.e. the end not abutting the arm. In some configurations, and particularly in engine installations wherein there are many surfaces and pieces of auxiliary equipment near the engine, it is difficult to access such an adjusting screw.
It would be advantageous to provide for an engine throttle idle adjusting screw which is threadedly engaged with a fixed surface, abuts an arm of a throttle shaft for limiting rotation of the throttle shaft and thereby of a throttle plate, and is rotatably adjustable from the abutting end.
SUMMARY OF THE PRESENT INVENTION
An aspect of the present invention pertains to a combustion air throttle for an internal combustion engine, the engine operable at an idle speed, the throttle including a throttle body having a throat, a valving member movably disposed within the throat for throttling flow of combustion air and having an idle position corresponding to the idle speed; a throttle shaft projecting outside the throat, coupled to the valving member, and having a radially extending arm, wherein the arm includes an opening; and an idle speed throttle stop threadedly engaged with an aperture within a fixed surface of the throttle, having an end adjustably positioned and disposed to abut the arm in the idle position and thereby adapted to adjust the idle speed of the engine, and wherein a central portion of the end of the throttle stop which abuts the arm includes an engagement feature which is configured for engagement with an adjusting tool and is disposed within the opening when the arm is in the idle position; the opening thereby providing access for the adjusting tool through the arm to the throttle stop.
Another aspect of the present invention pertains to a method of adjusting an idle speed of an engine at a throttle, the method including the steps of operating the engine at an idle speed; inserting a throttle stop adjusting tool through an opening within an arm of a rotatable throttle shaft, the throttle shaft coupled to a valving member of the throttle, the arm abutting a throttle stop when the engine is operating at idle speed, the throttle stop threadedly engaged with a fixed surface and located in alignment with the opening of the arm; and engaging and rotating the throttle stop to adjust the idle position of the arm and thereby of the throttle shaft and of the valving member.
REFERENCES:
patent: 2190738 (1940-02-01), Schweiss
patent: 3269713 (1966-08-01), Beck
patent: 4086900 (1978-05-01), Marsh
patent: 4161298 (1979-07-01), Teague et al.
patent: 5979871 (1999-11-01), Forbes et al.
patent: 6065483 (2000-05-01), Tanaka et al.
patent: 52-40234 (1977-03-01), None
patent: 57-105533 (1982-07-01), None
patent: 58-47144 (1983-03-01), None
Siemens Canada Limited
Solis Erick
LandOfFree
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