Internal-combustion engines – Engine speed regulator – Open loop condition responsive
Utility Patent
1999-04-23
2001-01-02
Solis, Erick (Department: 3747)
Internal-combustion engines
Engine speed regulator
Open loop condition responsive
C123S339130, C251S308000
Utility Patent
active
06167867
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a throttle lever assembly for controlling the delivery of air to the combustion chamber of an internal combustion engine.
BACKGROUND OF THE INVENTION
In a conventional air/fuel system for an internal combustion engine, a throttle body assembly provides a means for controlling the air provided to the engine in response to the operator's actuation of an accelerator pedal and/or command from a cruise control system. Generally, the throttle body includes a lever assembly mounted pivotally to a throttle housing that controls the opening of a throttle valve. The degree of rotation of the lever assembly is directly proportional to the opening of the throttle valve which provides air to the engine.
Typically, the throttle lever assembly has a number of components and subassemblies attached to a throttle shaft, each of which perform a specific function. One such subassembly is a return cam mounted to one end of the shaft. The cam alters the engine's acceleration in response to input provided by the operator. The cam may be formed of plastic molded onto a metal insert, or two metallic pieces joined together. The return cam includes a U-shaped channel for receiving one end of an accelerator cable which has another end interconnected to the accelerator pedal.
When the accelerator pedal is depressed, the cable is retracted to rotate the lever assembly to open the throttle valve which increases the amount of air provided to the engine. The lever assembly is rotated back to its initial or idle position by a return spring when the accelerator pedal is released or pressure on the pedal is reduced. The return spring is maintained coaxially about the shaft by a spring retainer mounted to the shaft inboard of the throttle cam.
The return cam throttle lever assembly also includes an idle stop lever which is secured to the shaft, abutting the return cam. The idle stop lever extends radially from the shaft and is oriented to engage an idle stop screw threaded within a depending member of the throttle housing at an idle position, wherein the throttle valve is opened a small amount. The idle stop screw is used to adjust the idle position of the lever assembly. The idle stop lever may also include a second engagement surface to provide a wide open throttle stop for the lever assembly.
The lever assembly may also include a cruise control lever or cam mounted to the end of the shaft, abutting the return cam. The lever extends radially from the shaft at a predetermined angle and distance to engage a cable or linkage of the cruise control system which provides control of the throttle body independently of the operator input. A stud extends axially outward from the end of the idle lever to provide a means to engage the linkage or cable of the cruise control system.
The lever assembly, return cam and idle stop lever are secured to the end of the shaft by assembling each of the subassemblies onto the shaft and spinning or expanding the end of the shaft to secure the subassemblies thereto. Each of the subassemblies have a central bore shaped to receive the end of the shaft having a complimentary shape. To maintain the subassemblies in a fixed radial relation to each other, the shaft is milled to form a “D” or “double D” profile.
This throttle lever assembly functions adequately for its intended purpose, however, the assembly requires a number of subassemblies and steps to manufacture the throttle lever assembly. Consequently, the process of manufacturing and assembling the throttle assembly is costly and time consuming.
SUMMARY OF THE INVENTION
The present invention provides a relatively inexpensive solution to reduce the number of components and subassemblies required to produce a throttle lever assembly for use in a throttle body by incorporating the components into a return cam that is overmolded onto a throttle shaft. An object of the present invention may be to provide a throttle lever assembly having a return cam that may be overmolded onto one end portion of the shaft and a portion of the idle stop lever, secured to the shaft, to secure the return cam in fixed relation relative to the shaft and idle stop lever assembly to reduce the number of components required for the throttle lever assembly.
Another object of the present invention may be to provide a throttle body having a throttle lever assembly wherein the return cam is integrated with a stud for engagement with a cruise control system to reduce the number of subassemblies in the assembly and thereby reduce the cost and time to manufacture and assemble the components.
Another object of the invention may be to provide a throttle body having a throttle lever assembly wherein the integrated return cam is formed of polymeric material to reduce the mass of the lever assembly.
Another object of the invention may be to provide a throttle body having a throttle lever assembly wherein the return cam is integrated with a stud for engagement with a cruise control system to reduce the size of the assembly and thereby reduce the packaging room required for the throttle lever assembly in the engine compartment.
Another object of the present invention may be to provide a throttle lever assembly having a throttle shaft with a semi-circular groove disposed transversely across an end portion thereof to retain the return cam that is overmolded over the end portion of the shaft to maintain the return cam in fixed radial and axial relationship to the shaft.
These and other objects, advantages and features of the present invention will become more apparent from the following description and drawings.
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patent: 5666988 (1997-09-01), Becker
patent: 5746177 (1998-05-01), Criss et al.
patent: 5762044 (1998-06-01), Hollister et al.
patent: 6009772 (2000-01-01), Papenhagen et al.
Delphi Technologies Inc.
Solis Erick
VanOphem John A.
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