Title of Invention

"A STARTING FUEL REGULATOR FOR A CARBURETOR"

Abstract To provide a starting fuel regulator which is compact and precisely controllable, and improves heat maintaining capabilities of wax. The starting fuel regulator comprises a retainer, a thermosensitive driver, a casing, a piston, a throttle valve, an electric heater, and a synthetic resin cover. The retainer is fixedly attached to a carburetor body, and houses the casing with a part of the casing projecting therefrom. The piston is axially movable in accordance with expansion or contraction of wax housed in the casing. The throttle valve is operable following the movement of the piston. The synthetic resin cover includes a tubular member covering one end of the casing and the electric heater. [Means to accomplish the Object] In the cover 55, the cylindrical portion 56a of the tubular member 56 is blocked by the end wall portion 56b which is thicker than the cylindrical portion 56a, and functions as a heat accumulator. [Reference Drawing
Full Text [Detailed Description of the Invention]
[Field of the Invention]
The present invention relates to a starting fuel regulator for a carburetor. The starting fuel regulator comprises: a throttle valve for controlling an open area of a starting air intake path; a retainer extending along a sliding direction of the throttle valve and having a base fixedly supported by a carburetor body; thermosensitive driving means including a casing fitted in the retainer with one end thereof extending outwardly from an end of the retainer, wax housed in one end of the casing, and a piston being axially movable in accordance with expansion or contraction of the wax with temperature variations and projecting from the other end of the casing, being coupled to the throttle valve and being operable following the operation of the throttle valve; an electric heater for heating the wax and being coupled to the one end of the casing; and a synthetic resin cover including a tubular member covering the retainer, the one end of the casing and the electric heater, and being detachably attached to the retainer.
[Description of the Related Art]
The foregoing starting fuel regulator is well-known and is disclosed in Japanese Utility Model Publication No. Hei 3-6844, for example.
[Problems to be solved by the Invention]
In the foregoing starting fuel regulator, an air-fuel mixture having a concentration depending upon an ambient temperature is supplied to an engine. After the engine is started, wax is heated by an electric heater and is expanded, thereby operating a throttle valve to a completely-closed position. This is because the wax generally expands or

contracts in response to the ambient temperature when the engine is started, and a starting air intake path is opened by the throttle valve which is actuated in accordance with the expansion or contraction of the wax. It is assumed here that the engine is temporarily stopped for a short time and is then re-started in a hot state. If the wax becomes hot too quickly when an engine temperature is relatively high, the air-fuel mixture supplied to the engine tends to be too rich. In order to overcome this problem in the related art, a pneumatic adiabatic space is maintained between the wax and a cover, and the cover is protected by a thermal insulating member. Sometimes, the wax is substantially prevented from becoming cold by a metallic heat mass.
However, the pneumatic adiabatic space or the metallic heat mass for heat insulation of the wax is large, and tends to enlarge the starting fuel regulator. The metallic heat mass also needs a large space, which inevitably makes the starting fuel regulator larger. Conversely, when the pneumatic adiabatic space is made smaller, a thermosensitive driver should improve its thermal insulating efficiency in order to offset a disadvantage caused by a reduced heat mass, This will not lead to down-sizing of the starting fuel regulajjqr.
The present invention is aimed at overcoming the problems of the related art, and providing a starting fuel regulator for a carburetor, which has improved heat maintaining capability for the wax, is compact, and is easily controllable.
[Means to solve the Problems]
Ion the invention disclosed claim 1, there is provided a starting fuel regulator comprising: a throttle valve for controlling an open area of a starting air intake path; a

retainer extending along a sliding direction of the throttle valve and having a base fixedly supported by a carburetor body; thermosensitive driving means including a casing fitted in the retainer with one end extending outwardly from an end of the retainer, wax housed in one end of the casing, and a piston being axially movable in accordance with expansion or contraction of the wax with temperature variations and projecting from the other end of the casing, being coupled to the throttle valve and operable following the operation of the throttle valve; an electric heater for heating the wax and being coupled to the one end of the casing; and a synthetic resin cover including a tubular member covering the retainer, the one end of the casing and the electric heater, and being detachably attached to the retainer. The tubular member of the cover includes a cylindrical portion for covering the retainer and an end wall portion blocking one end of the cylindrical portion, and the end wall portion is thicker than the cylindrical portion and serves as a heat accumulator.
In the invention disclosed in claim 2, in addition to the configuration of the invention disclosed in claim 1, the synthetic resin cover includes, as an integral part, a pair of heater terminals for connection with the electric heater, and a coupler facing the heater terminals.
The present invention relates to a starting fuel regulator for a carburetor,
the starting fuel regulator comprising: a throttle valve for controlling an open area of a starting air intake path; a retainer extending along a sliding direction of the throttle valve and having a base fixedly supported by a carburetor body; thermosensitive driving means having a casing fitted in the retainer with one end extending outwardly from an end of the retainer, wax housed in one end of the casing, and a piston being axially movable in accordance with expansion or contraction of the wax with temperature variations, projecting from the other end of the casing, being coupled to the throttle valve and being operable following the operation of the throttle valve; an electric heater for heating the wax and being coupled to the one end of the casing; and a synthetic resin cover having a tubular member covering the retainer, the one end of the casing and the electric heater, and being detachably attached to the retainer,
wherein the tubular member of the cover has a cylindrical portion covering the retainer and an end wall portion for blocking one end of the cylindrical portion, and the end wall portion is thicker than the cylindrical portion and functions as a heat accumulator.
[Brief Description of the Drawings]
Fig. 1 is a section of the starting fuel regulator, taken along line 1-1 in Fig. 2.
Fig. 2 is a cross section taken along line 2-2 in Fig.
1.
Fig. 3 is an enlarged cross section taken along line 3-
3 in Fig. 2.
Fig. 4 is graph showing characteristics of an air flow-rate in response to the operation of the throttle valve.
Fig. 5 is a graph showing the relationship between ambient temperature and air-to-fuel ratio.
Fig. 6 is a cross section showing a part of the
carburetor immediately after it is cast.
Fig. 7 is a graph showing an operated amount of the throttle valve in accordance with temperature variations.
Fig. 8 is a view similar to Fig. 1, showing a modified thermosensitive driver.

[Description of Embodiment]
The invention will be described with reference to an embodiment shown in the accompanying drawings.
Fig. 1 to Fig. 7 show a first embodiment of the invention. Specifically, Fig. 1 is a section of a starting fuel regulator, taken along line 1-1 in Fig. 2. Fig. 2 is a cross section of a carburetor body, taken along line 2-2 in Fig. 1. Fig. 3 is an enlarged section taken along line 3-3in Fig. 2. Fig. 4 is a graph showing characteristics of air-flow rate in accordance with the operation of a throttle valve. Fig. 5 is a graph showing the relationship between an ambient temperature and air-to-fuel ratio. Fig. 6 is a section of a carburetor body immediately after it is cast. Fig. 7 is a graph showing an operated amount of the throttle valve in accordance with temperature variations.
Referring to Figs. 1 and 2, a float chamber 12 defined by a float chamber body 11 is coupled to a carburetor body
10 to be mounted in a motor cycle. The float chamber body
11 is made of light metal such as aluminum alloy, and is
made by diecasting.
The carburetor body 10 includes a main air intake path 13, and a starting air intake path 15 communicating with upstream and downstream ends of the main air intake path 13 in an air intake direction 14. A starting fuel regulator 21 is disposed inside the starting air intake path 15.
The starting air intake path 15 includes: an upstream portion 16 which communicates with the upstream end of the air intake path 13, extends linearly from the main air intake path 13 toward a downstream side, and has a circular cross section; a downstream path 17 which communicates with the downstream end of the main air intake path 13 and extends linearly from the main air intake path 13 toward an upstream side; an upstream opening amount adjusting region 18 communicating with an upper end of the upstream portion 16; and a downstream opening amount adjusting region 19 communicating with the a lower end of the downstream path 17. The upstream and downstream opening amount adjusting region 18 and 19 are parallel to the main air intake path 13, and are spaced away from the main air intake path 13 at their upstream and downstream ends.
The starting fuel regulator 21 comprises a starting fuel nozzle 22, a throttle valve 23 for adjusting an open area of the starting air intake path 15, a needle valve 24 supported by the throttle valve 23 and being movable in the starting fuel nozzle 22, a thermosensitive driver 25 for operating the throttle valve 23, and a PTC type electric heater 26 coupled to one end of a casing 46 of the thermosensitive driver 25.
The throttle valve 23 is fitted in a hollow 20 in the carburetor body 10. The hollow 20 has a circular cross section, and is orthogonal to the upstream and downstream opening amount adjusting regions 18 and 19, so that these opening amount adjusting regions 18 and 19 open on an inner surface of the hollow 20 and face each other via the hollow 20.
A starting fuel chamber 28 is formed between the carburetor body 10 and the float chamber body 11, and extends coaxially with the hollow 20. The starting fuel chamber 28 communicates with the hollow 20 via a diaphragm 27 at the bottom of the hollow 20. The starting fuel nozzle 22 is fitted and fixed in a hole 29 on the diaphragm 27, and extends into the starting fuel chamber 28 at its lower end. The upper end of the starting fuel nozzle 22 is positioned slightly above the bottom of the hollow 20.
The float chamber body 11 includes a fuel jet 30 which is forcibly fitted and fixed therein, and communicates with the lower part of the starting fuel chamber 28 and the lower part of the float chamber 12. The carburetor body 10 includes a path 31 communicating with the float chamber 12 at an area above a fuel level L and the upper part of the starting fuel chamber 28.
The upstream and downstream opening amount adjusting regions 18 and 19 have cross sectional shapes as shown in Fig. 3. Specifically, the opening amount adjusting regions 18 and 19 have semi-circular upper portions 18a and 19a and lower elongate oval portions 18b and 19b extending from the upper portions 18a and 19a along the periphery of the hollow 20. The lower oval portions 18b and 19b are wider than the upper portions 18a and 19a in a direction orthogonal to the periphery of the hollow 20, i.e. in the moving direction of the throttle valve 23. Further, the bottom of the downstream opening amount adjusting region 19, i.e. the bottom of the lower elongate oval portion 19b, is located a height difference h lower than the bottom of the upstream opening amount adjusting region 18 (i.e. the bottom of the lower elongate oval portion 18b). [0018]
The upstream and downstream opening amount adjusting regions 18 and 19 enable the open area of the starting air intake path 15 to be relatively large when an ambient temperature is relatively high. Referring to Fig. 4, an amount of air introduced via the starting air intake path 15 can be increased (shown by a solid line) compared with when the upstream and downstream opening amount adjusting regions 18 and 19 are coaxial with each other and have completely circular cross sections (shown by a dashed line). Thus, it is possible to effectively prevent the air-fuel mixture from becoming too rich, and to improve the starting efficiency of the engine during hot weather.
It is assumed that the throttle valve 23 gradually closes the upstream and downstream opening amount adjusting regions 18 and 19 as the ambient temperature rises. If the opening amount adjusting regions 18 and 19 are simultaneously closed since there is no height difference
between them, a negative pressure acting on the starting fuel nozzle 22 will be reduced. This causes a reduced amount of fuel to be sucked in, which will lead to a steep decrease in the air-to-fuel ratio, as shown by a dashed line in Fig. 5. However, the bottom of the downstream opening amount adjusting region 19 is lower by the height difference h than the bottom of the upstream opening amount adjusting region 18. Thus, the downstream side opening amount adjusting region 19 remains slightly open even when the opening amount adjusting region 18 is closed. Thus, an area upstream from the starting fuel nozzle 22 is subject to choking in order to raise the negative pressure acting on the starting fuel nozzle 22 and to prevent a sudden fall of the air-to- fuel ratio, as shown by a solid line in Fig. 5.
Not only the upstream and downstream opening amount adjusting regions 18 and 19 having the special shapes but also a circular opening 32 on a side of the carburetor body 10 are formed using cores (not shown) when the carburetor body 10 is cast. Refer to Fig. 6. The opening amount adjusting regions 18, 19 and the circular hole 32 should be parallel to the main air intake path 13. In other words, when the carburetor body 10 is cast, the opening amount adjusting regions 18, 19 and the circular hole 32 are formed by pulling the cores in the direction (shown by an arrow 34) from the upstream opening amount adjusting region 18 to the downstream opening amount adjusting region 19, i.e. in a direction parallel to the direction in which the core for the main air intake path 13 is pulled. Further, a cast hole 20' which is smaller than the hollow 20 is formed in the carburetor body 10 together with the upstream and downstream opening adjusting regions 18 and 19, and the circular hole 23, as shown by a dashed line. The cast hole 20' is shaved in order to form the hollow 20. The circular hole 32 is blocked by a ball 33 forcibly fitted thereinto, as shown in
Figs. 1 and 2.
Returning back to Fig. 1, the throttle valve 23 has a support plate 35 near its bottom as an integral member. A needle valve 24 passes through the support plate 35, and has a stop ring 36 attached at its top. The stop ring 36 is engaged with the upper surface of the support plate 35, and is pressed to the support plate 35 by a spring 37, so that the needle valve 24 is held by the throttle valve 23. The throttle valve 23 has at its top a brim 38 radially extending toward its center. A projection 40 which is present at the lower end of a set collar 39 is engageable with the lower surface of the brim 38. The spring 37 is disposed, in a contracted state, between the set collar 39 and the stop ring 36, urging the stop ring 39 toward the support plate 35, and enabling the projection 40 to be engaged with the brim 38.
In the carburetor body 10, a retaining canister 41 larger than the hollow 20 is present around the hollow 20, is coaxial with the hollow 20, and forms a step 42 surrounding the periphery of the hollow 20. The retainer 43 extending in the sliding direction of the throttle valve 23 is fitted in the retaining canister 41 such that the base of the retainer 43 comes into contact with the step 42. A stop 44 is fixedly attached to the top of the retaining canister 41 by a screw member (not shown). The stop 44 is engaged with a regulating step 45 surrounding the periphery of the retainer 43. Thus, the base of the retainer 43 is fixedly attached to the carburetor body 10.

The thermosensitive driver 25 includes a casing 46 which is housed in the retainer 43 with one end projecting from the retainer 43. The casing 46 includes a cylindrical case main body 47 which has a step made of a conductive
metal, and a cap member 48 which is made of conductive metal, and is coupled and caulked to one end of the case main body 47. The periphery of the diaphragm 49 is sandwiched between the case main body 47 and the cap member 48. Thus, the electric PTC type heater 26 comes into contact with one end of the casing 46 or the cap member 48.
Wax 50 is housed between the cap member 48 and the diaphragm 49. Within the case main body 47 there is a non-rigid member 51 such as rubber, silicone or the like contacting the diaphragm 49 on the opposite side to the wax 50, a sealant 52, and a piston 53, all of which are arranged one on top of the other. The piston 53 partially projects from the casing 46, i.e. the other end of the main body 47. '~ [002D]
The casing 46 is air-tightly fitted into the retainer 43 with the cap member 48 projecting from the end of the retainer 43. In the retainer 43, the case main body 47 is fitted and is slidable in the upper part of the set collar 39. The piston 53 is coaxial with the set collar 39, and an end of the piston 53 projecting from the casing 46 is in contact with the set collar 39. A spring 54 is inserted, in a contracted state, between the base of the retainer 43 and the set collar 39. The spring 54 urges the casing 46 upward via the set collar 39 and the piston 53, so that the piston 53 is in continuous contact with the set collar 53. Thus, the piston 53 is interlocked with the throttle valve 23 via the set collar 39, thereby being operable through the throttle valve 23. {'0026 J"
A synthetic resin cover 55 is detachably attached to the retainer 43, and includes a tubular member 56 surrounding the retainer 43, one end of the casing 46 and the PTC type heater 26. The cover 55 is screwed to the retainer 43, for example.
The tubular member 56 includes a cylindrical portion 56a surrounding the retainer 43 and an end wall portion 56b stopping the end of the cylindrical portion 56a. The end wall portion 56b is thicker than the cylindrical portion 56a, and functions as a heat accumulator.
The end wall portion 56b has, on its inner surface, a cavity 57 for receiving one end of the casing 46 (i.e. a part of the cap member 48), and a cavity 58, and a cylindrical projection 59. The cavity 58 is smaller than the cavity 57, and is coaxial with the cavity 57. The top of the cylindrical projection 59 is flush with the bottom of the cavity 57.
A hole 60 is formed in an area where the cylindrical portion 56a and the end wall portion 56b join with each other. The cylindrical projection 59 is fitted into the hole 60, so that a heater terminal 62 can be fitted into the cover 55 without becoming loose. Further, the end wall portion 56b has a hole 61 for receiving a heater terminal 63. The heater terminal 63 has a claw 63a which elastically engages in and disengages from the cavity 58. Thus, the heater terminal 63 can be fitted into the cover 55 without becoming loose.
The cap member 48 is fitted in the cavity 57 so as to sandwich the PTC type heater 26 between itself and the heater terminal 63. Since the casing 46 is urged upward by the spring 54, the heater terminal 63 is pushed toward and fixed on the end wall portion 56b so as to establish an electrical connection with the heater 26. A spring 64 in a contracted state is disposed between the casing 46 and the heater terminal 62. The spring 64 is made of conductive metal and has a spring constant smaller than that of the
spring 54. The heater terminal 62 is pushed toward and fixed on the end wall portion 56b by the spring 64. The heater 26 is electrically connected to the heater terminal 62 via the spring 64 and the casing 46.
The cover 55 is protected by a synthetic resin protection cover 68 with an air space 70 kept therebetween. The protection cover 68 has a plurality of projections 69 on its inner surface so as to be in elastic contact with the lower edge of the cover 55. The cover 55 has, as integral members, a plurality of ribs 66 for maintaining an interval between the cover 55 and the protection cover 68. Further, the protection cover 68 has a plurality of projections 71 on its inner surface so as to maintain an interval between the cover 55 and the protection cover 68.
The cover 55 includes a male coupler 65 extending outwardly from the tubular member 56. A pair of heater terminals 62, 63 confront the male coupler 65. A female coupler 67 is detachably interlocked to the male coupler 65. A pair of cables 72 are used to electrically connect the heater terminals 62, 63 after the female coupler 67 is interlocked to the male coupler 65. The cables 72 pass through and are supported by a cable guide 73 formed on the outer surface of the protection cover 68 as an integral part. One of the cables 72 is connected to a charging/generating coil of an AC generator mounted on the motorcycle, while the other cable is grounded. Thus, when the engine is actuated, the PTC type heater 26 is electrically activated. As it is being heated, the heater 26 becomes more resistant. When the heater 26 has a high resistance value, an amount of current flowing thereto is regulated.
The operation of the first embodiment will be described hereinafter. During the initial operation of the engine,
the wax 50 in the thermosensitive driver 25 expands in accordance with an ambient temperature. The piston 53 also projects from the casing 46 in accordance with the ambient temperature. Thus, the operating position of the throttle valve 23 also depends upon the ambient temperature.
When a main switch is operated so as to crank the engine, air is introduced into the engine via the starting air intake path 15 in accordance with the operated position of the throttle valve 23. Introduced air is mixed with fuel sucked in via the starting fuel nozzle 22, thereby producing an air-fuel mixture, which is supplied to the engine. f0035]
In response to the operation of the engine, the AC generator electrically actuates the heater 26. The wax 50 is heated by the heater 26, thus expanding, and causing the piston 53 to push the throttle valve 23 downward via the set collar 39 and the spring 37. The throttle valve 23 operates to reduce the open area of the starting air intake path 15. Finally, the starting air intake path 15 is completely closed, thereby interrupting the starting fuel.
With this starting fuel regulator 21, the upstream and downstream opening amount adjusting regions 18, 19, which are at the middle of the starting air intake path 15, are formed in the carburetor body 10. The throttle valve 23 is slidably fitted in the hollow 20, in which both of the opening amount adjusting regions 18 and 19 confront. The hollow 20 is formed in the carburetor body 10. The throttle valve 23 directly controls the open areas of the opening amount adjusting regions 18 and 19. This throttle valve 23 is advantageous with respect to Lhe reduced number of components and the reduced number of assembly steps, compared with a throttle valve which is slidably attached to a sleeve forcibly inserted into the carburetor body 10. This
is because no sleeve is used for the throttle valve 23 in the present invention. Further, when a sleeve is used, an area between the carburetor body 10 and the sleeve for introducing air inevitably varies in the starting air intake path 15 because of errors of manufactured sleeve, and errors in assembling a sleeve in the starting air intake path 15. Therefore, control of the amount and concentration of air-fuel mixture may be adversely affected by the varying area for introducing air. However, in the present invention, the throttle valve 23 directly and precisely controls the open areas of the opening amount adjusting regions 18 and 19 with respect to the hollow 20.
The opening amount adjusting regions 18 and 19 have cross sectional shapes defined by semi-circular upper portions 18a and 19a and lower elongate oval portions 18b and 19b extending from the upper portions 18a and 19a along the periphery of the hollow 20. Further, the bottom of the downstream opening amount adjusting region 19 is located a height difference h lower than the bottom of the upstream opening amount adjusting region 18. The opening amount adjusting regions 18 and 19 are formed using cores (not shown) together with the circular hole 32 on the outer side surface of the carburetor body 10, when the carburetor body 10 is cast. Thus, the opening amount adjusting regions 18 and 19 can be made without difficulty. Further, the opening amount adjusting regions 18, 19 and the circular hole 32 extend in parallel to the cast hole for the main air intake path 13, so that a casting device can be simplified, which is effective in improving the productivity and reducing manufacturing cost.
The synthetic resin 55 having the tubular member 56 is detachably fixed on the retainer 43. The tubular member 56 includes the cylindrical portion 56a covering one end of the
casing 46, and the end wall portion 56b which is thicker than the cylindrical portion 56a and functions as a heat accumulator. Thus, it is possible to enlarge a heat mass of the end wall portion 56b. This enables the wax 50 in the casing 46 to be kept hot. Further, it is possible to make the air space 70 as thin as possible between the tubular member 56 and the protection cover 68. The starting fuel regulator 21 can be made compact. Temperature raising and lowering characteristics of the heater 26 can be moderated, which enables the wax 50 to be controlled in a wide temperature range.
The foregoing structure can keep the wax 50 hot as mentioned above, so that the thermosensitive driver 25 can be made compact, and the starting fuel regulator 21 can be further reduced in size. Referring to Fig. 7, a stroke of the piston 53 is usually large in the related art thermosensitive driver 25, as shown by a dashed line. It is possible to shift an inflection point between a necessary stroke and an ineffective stroke to a lower temperature side, and to make the ineffective stroke smaller after the inflection point. In the related art, when the starting fuel regulator 21 is made compact, its heat mass is also downsized. Therefore, it has been very difficult to make the starting fuel regulator 21 smaller. However, in the present invention, since a heat maintaining capability of the wax 50 is improved because of an increased heat mass of the cover 55, the reduction of the heat mass of the thermosensitive driver 25 can be offset by minimizing the ineffective stroke of the piston as shown by a solid line in Fig. 7. The temperature raising and lowering characteristics of the thermosensitive driver 21 can be kept equal to those of the related art even when the starting fuel regulator 21 is made compact.
However, when the heat mass of the casing 46 in the thermosensitive driver 25 is reduced, it is necessary to prevent the throttle valve 23 from closing quickly as the heater 26 becomes hotter, compared with the related art throttle valve. This problem can be overcome by setting an internal resistance of the heater 26 larger than that of the related art heater, or by disposing a resistor between the heater 26 and the charging/generating coil.
The cover 55 includes, as an integral part, the coupler 65 facing the heater terminals 62 and 63. The coupler 67 is detachably interlocked with the coupler 65. Thus, the couplers 65 and 67 extensively increase the heat mass of the cover 55, so that the heated wax can be reliably kept hot. This structure facilitates the electrical connection to the heater 26, and maintenance of the starting fuel regulator.
Fig. 8 shows a modified example of the thermosensitive driver. Identical parts have identical reference numbers to those used in the foregoing embodiment.
A starting fuel regulator 212 comprises a starting fuel nozzle 22, a throttle valve 23 for controlling an open area of a starting air intake path 15, a needle valve 24 supported by the throttle valve 23 and being movable in the starting fuel nozzle 22, a thermosensitive driver 252, a
casing 76, and a PTC type heater 26 coupled to one end of the casing 76.
The casing 76 is housed in a retainer 43 with one end projecting therefrom, and includes a cylindrical body 77 and a cap 78. The cylindrical body 77 is made of conductive metal, and has a bottom. The cap 78 is caulked to the cylindrical body 77 so as to block it. An open end of a bag-shaped member 79 is held between the cylindrical body 77

and the cap 78, so that the bag-shaped member 79 is inserted into the cylindrical body 77. The bag-shaped member 79 is made of a flexible material such as rubber. A PTC type heater 26 is in contact with the blocked end of the cylindrical body 77.
Wax 50 is housed in part of the casing 76, i.e. between the cylindrical body 77 and the bag-shaped member 79. A piston 80 is coaxially movable through the cap 78, and extends into the bag-shaped member 79. The piston 80 is in coaxial contact with a set collar 39 at its end projecting from the cap 78.
One end of the casing 76 or a part of the cylindrical body 77 is fitted in the end wall portion 56b so as to sandwich the heater 26 together with a heater terminal 63. Further, the cylindrical body 77 is in contact with a heater terminal 62'. The heater terminals 63 and 62' are juxtaposed facing a coupler 65 which is integral with the cover 55.
This modified example is as advantageous as the starting fuel regulator of the foregoing embodiment.
The invention has been described with reference to the embodiment disclosed herein. It is not confined to the details set forth and this application is intended to cover all such modifications or changes as may come within the purposes of the improvements or the scope of the following claims.
The retainer 43 may be interlocked with the carburetor body 10 as an alternative measure.
[Effects of the Invention]

According to the invention disclosed in claim 1, in the cover, the cylindrical portion of the tubular member is partially blocked at its bottom by the thick end wall portion, which functions as the heat accumulator. It is possible to make the heat mass of the cover relatively large around the wax. This improves heat maintaining capabilities for the wax. Thus, it is possible to maintain the wax in a wide temperature range when temperature raising and reducing characteristics of the heater are controlled to be moderate. Further, it is possible to reduce ineffective strokes of the throttle valve. The compact thermosensitive driver having a small heat mass is effective in precisely operating the starting fuel regulator and in reducing the size thereof.

According to the invention disclosed in claim 2, in addition to the configuration of the invention disclosed in claim 1, a pair of heater terminals are fixedly attached to the cover. The cover includes, as an integral part, the coupler which faces the heater terminals. This extensively increases the heat mass of the cover, and improves heat maintaining capability for the wax. The foregoing structure facilitates electrical connections to the heater, and simplifies maintenance of the starting fuel regulator.
[Description of the Numerals] 10 carburetor body
15 starting air intake path
21, 2\2 starting fuel regulators
23 throttle valve
251, 252 thermosensitive drivers
26 PTC type electric heater
43 retainer
46, 76 casings
50 wax
53, 80 pistons
55 cover
56 tubular member
56a cylindrical portion
56b end wall portion
62, 62', 63 heater terminals
65 coupler





WE CLAIM:-
1. A starting fuel regulator for a carburetor, the starting fuel regulator comprising: a throttle valve (23) for controlling an open area of a starting air intake path (15); a retainer (43) extending along a sliding direction of the throttle valve (23) and having a base fixedly supported by a carburetor body (10); thermosensitive driving means (25i, 252) having a casing (46, 76) fitted in the retainer (43) with one end extending outwardly from an end of the retainer (43), wax (50) housed in one end of the casing (46, 76), and a piston (53, 80) being axially movable in accordance with expansion or contraction of the wax (50) with temperature variations, projecting from the other end of the casing (46, 76), being coupled to the throttle valve (23) and being operable following the operation of the throttle valve (23); an electric heater (26) for heating the wax (50) and being coupled to the one end of the casing (46, 76); and a synthetic resin cover (55) having a tubular member (56) covering the retainer (43), the one end of the casing (46, 76) and the electric heater (26), and being detachably attached to the retainer (43),
wherein the tubular member (56) of the cover (55) has a cylindrical portion (56a) covering the retainer (43) and an end wall portion (56b) for blocking one end of the cylindrical portion (56a), and the end wall portion (56b) is thicker than the cylindrical portion (56a).

2. The starting fuel regulator as claimed in claim 1, wherein the
synthetic resin cover (55) has as an integral part a pair of heater
terminals (62, 63; 62', 63) for connection with the electric heater
(26), and a coupler (65) facing the heater terminals (62, 63; 62',
63).
3. A starting fuel regulator for a carburetor substantially hereinbefore
described with reference to and as illustrated in the accompanying
drawings.

Documents:

1688-del-1997-abstract.pdf

1688-del-1997-claims.pdf

1688-del-1997-correspondence-others.pdf

1688-del-1997-correspondence-po.pdf

1688-del-1997-description (complete).pdf

1688-del-1997-drawings.pdf

1688-del-1997-form-1.pdf

1688-del-1997-form-13.pdf

1688-del-1997-form-19.pdf

1688-del-1997-form-2.pdf

1688-del-1997-form-3.pdf

1688-del-1997-form-4.pdf

1688-del-1997-form-6.pdf

1688-del-1997-gpa.pdf

1688-del-1997-petition-137.pdf

1688-del-1997-petition-138.pdf

abstract.jpg


Patent Number 215299
Indian Patent Application Number 1688/DEL/1997
PG Journal Number 11/2008
Publication Date 14-Mar-2008
Grant Date 25-Feb-2008
Date of Filing 23-Jun-1997
Name of Patentee HONDA GIKEN KOGYO KABUSHIKI KAISHA
Applicant Address 1-1, MINAMIAOYAMA 2-CHOME, MINATO-KU, TOKYO, JAPAN.
Inventors:
# Inventor's Name Inventor's Address
1 MINORU UEDA C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN.
2 MICHIO TAHATA C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN
3 SHUNJI AKAMATSU C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN
PCT International Classification Number F02M 3/05
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 HEI-8-187295 1996-07-17 Japan