Gas and liquid contact apparatus – Fluid distribution – Valved
Reexamination Certificate
2002-12-24
2004-04-20
Chiesa, Richard L. (Department: 1724)
Gas and liquid contact apparatus
Fluid distribution
Valved
C261S039400, C261S064600
Reexamination Certificate
active
06722638
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an improvement in a control system for a choke valve of a carburetor, including a choke-operating lever for opening and closing the choke valve of the carburetor, a choke spring for biasing the valve in an opening direction, and a damper for controlling the opening motion to a lower speed, when the choke valve is opened from its fully closed position by a biasing force of the choke spring. The choke-operating lever, the choke spring and the damper are connected to the choke valve of the carburetor, so that after starting of an engine with the choke valve closed, the choke valve is opened automatically in response to the progress of the warming operation of the engine, thereby providing the stabilization of the warming operation and a reduction in fuel consumption.
2. Description of the Related Art
In a conventional control system for the choke valve of the carburetor, the damper an air type in which the opening motion of the choke valve is slowed down by a damping force generated upon passing of air through an orifice (see Japanese Utility Model Application Laid-open No. 63-24354.
For providing the stabilization of the warming operation and a reduction in fuel consumption, it is important that the time required from the full closing to the full opening of the choke valve after starting of the engine is controlled in accordance with the level of the environmental temperature of the engine. Namely, it is necessary to provide the choke valve control system with the characteristic that the lower the environmental temperature, the longer the required time for the valve to go from fully closed to fully open.
In the control system for the choke valve of the carburetor using the air damper, as described above, however, the damping force generated in the air damper is constant irrespective of the level of the environmental temperature of the engine and hence, the time required for fully opening the choke valve controlled by the control system is also constant. Thus, it is impossible to satisfy the above-described required characteristic.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a control system for a choke valve of a carburetor, which is designed so that the above-described required characteristic can be satisfied.
To achieve the above object, according to the present invention, there is provided a control system for a choke valve of a carburetor, comprising a choke-operating lever for opening and closing the choke valve of the carburetor, a choke spring for biasing the valve in an opening direction, and a damper for controlling opening motion of the choke valve to a lower speed, when the choke valve is opened from its fully closed position by a biasing force of the choke spring, the choke-operating lever, the choke spring and the damper being connected to the choke valve of the carburetor, wherein the damper is an oil type using a damper oil whose viscosity is increased in accordance with a temperature drop or decrease.
With the first feature, a damping force generated by the oil damper is increased in accordance with the decrease of the environmental temperature of the engine. Therefore, the time required from the full closing to the full opening of the choke valve can be controlled, so that the time is longer when the environmental temperature is lower, and the time is shorter when the environmental temperature is higher. Thus, it is possible to satisfy the easy/ready startability of the engine, the stabilization of the warming operation of the engine and a low fuel consumption.
According to a second feature of the present invention, in addition to the first feature, the damper comprises a damper housing, a rotor rotatably housed in the damper housing, and the damper oil accommodated in a sealed manner in the damper housing and applying a viscosity resistance to the rotation of the rotor, the damper housing being supported on a stationary structure, and the rotor being connected to the choke valve so that the rotor is rotated in operable association with the opening and closing of the choke valve.
With the second feature, the damper can be constructed compactly by a small number of parts, which can contribute to a reduction in cost of and the compactness of the choke control system.
The stationary structure corresponds to a bracket
14
in each of embodiments of the present invention which will be described hereinafter.
According to a third feature of the present invention, in addition to the first or second feature, a driven member is connected to a valve stem of the choke valve, and a resilient driving member is connected to the choke-operating lever and adapted to be flexed to urge one side of the driven member in operable association with the operation of the choke-operating lever in a direction of closing of the choke valve, thereby closing the choke valve.
With the third feature, fabrication errors of various portions of the choke valve control system are absorbed by the flexing of the resilient driving member, and the choke valve can be brought reliably and at any time into the fully closed state.
The driven member and the resilient driving member correspond to a driven pin and a resilient driving plate
47
in each of the embodiments of the present invention which will be described hereinafter.
According to a fourth feature of the present invention, in addition to the second feature, a cam adapted to be rotated in operable association with the opening and closing operation of the choke-operating lever, and a cam follower adapted to be moved following a cam surface of the cam to open and close the choke valve are interposed between the choke-operating lever and the choke valve.
With the fourth feature, after starting of the engine with the choke valve fully closed, the time required for fully opening the choke valve is controlled by the damper, E and the opening degree of the choke valve during such controlling is controlled by the cam surface. Therefore, a desired opening degree characteristic assuring that the fully closed state is maintained, can be provided to the choke valve during the passage of time by the selection of the shape of the cam surface, thereby providing the stabilization of the warming operation and an enhancement in low fuel consumption.
According to a fifth feature of the present invention, in addition to the first feature, the damper comprises a damper housing and the damper oil accommodated in a sealed manner in the damper housing and applying a viscosity resistance to the rotation of a rotor, the damper housing being supported on a stationary structure, and wherein the rotor and the cam are connected to each other through an accelerating mechanism for accelerating the rotation of the cam to transmit it to the rotor.
With the fifth feature, a damping force generated by the damper is increased in accordance with a drop or decrease of the environmental temperature of the engine. Therefore, the time required for fully opening the choke valve can be controlled automatically, so that the time is longer when the environmental temperature is lower, and the time is shorter when the environmental temperature is higher. Thus, it is possible to satisfy the easy/ready startability of the engine, the stability of the warming operation of the engine and a low fuel consumption.
Moreover, the damper can generate sufficient damping force, although the damper is compact, by transmitting the rotation of the cam to the rotor of the damper through the accelerating mechanism and thus, it is possible to provide a satisfactory time required for fully opening the choke valve.
According to a sixth feature of the present invention, in addition to the first feature, the damper comprises a damper housing, a rotor rotatably housed in the damper housing and the damper oil which is accommodated in a sealed manner in the damper housing and whose viscosity is increased in accordance with a temperature drop to apply a viscosity resistance to the relati
Kojima Hiroaki
Moriyama Hiroshi
Tamamoto Ryuhei
Blackman William D.
Carrier Joseph P.
Carrier Blackman & Associates P.C.
Chiesa Richard L.
Honda Giken Kogyo Kabushiki Kaisha
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