JPS5990748A - Deflection angle correction type automatic choking device - Google Patents

Abstract

PURPOSE:To obtain the high emission characteristics for high altitude controlling and to improve the mechanical strength by a method wherein a related structure with respect to an electric heater for automatic operation of a choke valve and a configuration part for correction of deflection angle is improved. CONSTITUTION:A disc 31, the outer peripheral part of which is pivotally supported to the internal surface of a housing and which shares an axial load, is provided onto an operating shaft 30, which is pivoted through a lever 12 by means of a deflection angle correction means, when a certain fixed warming up region is reached. A collar-shaped heating plate 32 is integrally formed onto the bimetal holding part 30B of the operating shaft 30 and located between the disc 31 and a bimetal 5. A heater 33 is directly installed onto the heating plate 32. The heating plate 32 is supported at one side of the disc 31 by means of a cup-shaped holding member 34. In addition, a thrust plate 36, which also serves as an earth plate, absorbs the thrust load of the disc 31 by holding the disc 31 over its outer peripheral part at one side.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an automatic choke device of deviation angle correction type applied to a carburetor of a vehicle engine, and particularly relates to an electric heater for automatic choke valve operation and an deviation angle correction type automatic choke device applied to a carburetor of a vehicle engine. The present invention relates to a declination correction type automatic choke device that specifically realizes a configuration that provides high eminsion characteristics for high altitude regulation by improving the structure related to the angle correction component.

[Prior art]

Conventionally, the specifications of a starting system for a vehicle engine have generally been set with starting characteristics at low temperatures as the main factor.

For this reason, when the engine is warmed up, the air-fuel mixture generally has a tendency to overrun, resulting in emissions based on p, CO, and NOx.
Alternatively, it may cause poor fuel efficiency.

Furthermore, recently, there has been a desire to tighten exhaust gas regulations from the standpoint of environmental hygiene, and particularly in highlands where the oxygen concentration in the air is low, even more advanced exhaust gas regulations, so-called high-altitude regulations, are being implemented.

For this reason, conventionally, the choke valve has been opened automatically in conjunction with the increase in cooling water temperature when starting the engine. An automatic choke device has been developed that is equipped with a declination compensation mechanism that forces the choke valve to open rapidly.

However, with the conventional device 6, it is structurally difficult to obtain a choke valve opening that meets strict exhaust gas regulations.
In particular, it has been difficult to provide sufficient emission countermeasures for high-altitude regulations.

That is, to explain the conventional device and its characteristics with reference to FIGS. 1 to 3, a cylindrical housing 2 is attached to a carburetor 1. An operating shaft 3 is inserted into two end walls of the housing 2 via a bearing 4 for rotation. The center portion of the coiled bimetal 5 is supported on the insertion end side of the operating shaft 3 into the housing 2. A lever 7 for opening the choke valve 6 is connected to the deformed portion of the bimetal 5, that is, to the outer circumferential side. Note that 8 is a choke valve shaft that connects the lever 7 and the choke valve 6. The housing 2 houses an electric heater 9 for heating the bimetal. This heater 9 will be explained in detail later.

On the other hand, a choke piston 10 for declination correction is connected to the protruding end side of the operating shaft 3 from the housing 2 via a connecting rod 11 and a lever 12 for giving a command to quickly open the choke valve 6 in a certain warm temperature range. ing. Although not shown, the choke piston 10 pushes and pulls the connecting rod 11 using a diamond slam provided inside, and its operation is based on the internal pressure (negative pressure) of the carburetor 1.

That is, the choke piston 10 opens a downstream negative pressure outlet 15 of the throttle valve 14 via a connecting pipe 13, and a solenoid pulp 16 provided in the middle of the connecting pipe 13 controls the water temperature switch 17 and the vehicle speed. By controlling the switch 18, negative pressure is introduced into the choke piston 10 when the engine reaches a certain warm-up range, and the operating shaft 3 is rotated via the lever 12, whereby the entire bimetal 5 rotates to open the choke valve. A correction operation is performed to rapidly open the valve 6. Note that the operating shaft 3 is in a circumferential state until a certain level of warm air 1 is reached, and therefore, immediately after the engine is started, the choke valve 6 gradually opens only due to thermal deformation of the bimetal 5 by the heater 9 □. To explain the heater 9 here, the heater 9t/'i is designed to apply radiant heat to the bimetal 5, and is housed at a distance from the bimetal 5 via a ground plate 19 that also serves as a hot plate fixed to the housing 1. It is connected to a lead wire 20 and a contact 21 provided on the housing. The housing 1t/'i is split into two parts in the axial direction, and for example, a metal Thermo-Using IA and a resin Thermo-Cover IB are integrally assembled using a fastener 22 with a ground plate 19 sandwiched between them. It is written in the same way. In order to stabilize the axial position of the operating shaft 3, the operating shaft 3 is pressed toward the projecting side with a predetermined pressure by, for example, a compression coil spring 23.

Next, the characteristics will be explained with reference to FIG.

The vertical axis shows the choke valve opening degree, and the horizontal axis shows the engine cooling water temperature and time. In the conventional structure, that is, when the bimetal 5, the heater 9, and the hot plate 19 are placed apart from each other, the heat from the head 9 is transmitted to the bimetal 5 by radiation.
After the engine starts, the bimetal expands relatively slowly. Therefore, in this case, as shown by the characteristic line a in FIG. 3, the throttle valve opening only rises gradually as the engine cooling water temperature rises. That is, in the engine warm-up region (idle operation), a relatively high concentration of fuel continues to be supplied. Therefore, the engine cooling water temperature is at point B (
Since high concentration fuel is supplied even when the temperature reaches 50 to 60 C), the emission characteristics are not suitable, and the fuel is likely to be particularly non-compliant with high altitude regulations.

Therefore, by the declination correction means based on the declination correction choke piston 10, the operating shaft 3 is forcibly rotated when it reaches the point B, so that it shifts to the characteristic line C in FIG. 3. In this case, since the choke valve opening rapidly approaches the fully open state, the emission characteristics can be improved compared to the case where only the heating action based on the heater 9 is used.

However, according to the inventors' study results, the characteristic #il
It has been found that even if it is shifted to a-+c, it cannot completely comply with the high-altitude regulations due to emission characteristics.

From the time (2 to 3 seconds) when the choke valve opening reaches the complete explosion opening θ1 (25°) (point A in Figure 3), the choke valve opening reaches 13 points (50 to 60C). θ2 (30
It was found that the fuel concentration on the way to @) was still too high and the emission characteristics were unsatisfactory. Therefore, when we tried to improve the material of the heater 9, for example by using a PTC heater as the heat source, we found that it was possible to improve the rise characteristics of the choke opening to some extent, as shown by the characteristic line in Figure 3. However, in this case as well, I was unsatisfied with the high altitude regulated vehicles.

On the other hand, instead of the radiant heating type heating structure shown in FIG.
The idea was to connect the hot plate and heater directly to create a conductive structure for the bimetal. With a structure like this,
As shown by the characteristic line d in FIG. 3, the ascending angle becomes large from the midpoint between point A and point 13, and it was found that emission characteristics complying with the high-altitude regulations were obtained. However, if a conduction structure and a declination correction mechanism are adopted, d in Fig. 3
A desirable characteristic in which C and C are connected can be obtained.

However, in the case of such a structure, if an attempt is made to simply adopt a heater structure directly connected to the operating shaft in contrast to the conventional structure shown in FIG. 2, the operating shaft 3 becomes a cantilever structure due to the bearing 4, The axial load applied to becomes very large,
It becomes difficult to obtain mechanical strength that can withstand actual use. For example, the operating shaft 3 is bent by the load of the heater, hot plate, bimetal, etc., and the bearing 4 is damaged, causing rattling.

[Purpose of the invention]

The present invention has been made in view of these circumstances, and the present invention is based on the third aspect.
It is an object of the present invention to provide a highly stable declination correction type automatic choke device that can realize good choke valve opening characteristics over the characteristic line d −+ C shown in the figure with sufficient mechanical strength.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention has an operating shaft rotatably inserted through a bearing into one end wall of a cylindrical housing attached to a carburetor, and a coiled bimetallic metal on the insertion end of the operating shaft into the housing. At the same time, a lever for opening the choke valve is connected to the deformed part of the bimetal, and an electric heater for heating the bimetal is housed in the housing, and the high end side of the operating shaft from the housing is connected to the deformed part of the bimetal. In a declination correction type automatic choke device that connects a declination correction choke piston for applying a quick opening and movement command to a choke valve in a warm temperature region, a bearing part to the housing of the operating shaft is connected. and the bimetal support part, a disk for shaft load sharing whose outer peripheral part is rotatably supported on the inner surface of the housing is provided, and the heater is located between the disk and the bimetal and is integrated with the operating shaft. It has a structure in which it is directly attached to a flange-shaped hot plate formed in the.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 4 and 5. The operating shaft and electric heating structure, which are the main components of the present invention, will be mainly explained, and parts common to the conventional structure shown in FIGS. The explanation will be omitted.

In the declination correction type automatic choke device according to this embodiment, the operation shaft 30 is provided with a disk 31 for sharing the shaft load, the outer peripheral portion of which is rotatably supported on the inner surface of the housing. This disc 31 is arranged between the bearing part 30A and the bimetallic support part 30B to the housing. Further, a flange-shaped hot plate 32 is located between the disk 31 and the bimetal 5 and is integrally formed on the operating shaft 30B.
The heater 33 is directly attached to the heater 2.

That is, in this embodiment, the shaft main part of the operating shaft 30 is separated into a bimetal side and a bearing side toward the housing, and the thermo cover IB that constitutes the operating shaft 30At/i housing of the bearing section is The bearing 4 and the disk 31 form a beam on both sides to prevent deflection. A hot plate 32 formed at one end of the other operating shaft 30B that supports the bimetal 5 is formed in a cup shape on one side of the disk 31, which is a component of the thus reinforced l'llll structure. It is connected to the integral rotary unit by a support member 34 made of Kinpo. In detail, the separated operation shaft 30A
Disk 3 consisting of a separate part at the insertion end into the housing of
1 are integrally fitted and connected. In addition, there is a slot to the housing.
1 (A thrust washer 35 is installed inside the receiver 4 and positioned between it and the disk 31.

Further, the outer circumferential portion of the disk 31 is supported in sliding contact with the inner circumferential surface of the thermo cover IB with a slight gap, and
One side (bimetal side) of the outer periphery is brought into contact with a thrust plate 36, which also serves as a ground plate and is sandwiched between the thermo cover IB and the thermo housing IA, so as to absorb the load in the thrust direction. This thrust plate 36
The contact portion 31A of the disk 31 is coated with chrome plating, nickel plating, or Teflon coating to minimize sliding resistance. still,
The thermo cover 113 is made of resin, thermo housing LA, zinc, aluminum, or the like. A notch 31B (see FIG. 5) is formed in a portion of the disc 31 corresponding to the housing fastener 22, so that the disc 31 crosses the fastener 22. In addition, notch 3
The angular width α of 1B is 10 to 20 degrees. 9 [J] It is sufficient that the disc 31 has an opening width of 10 to 20 degrees.

This will be explained in detail later, but the effect of the choke valve opening on the air-fuel ratio is greatest in a certain angle range at the beginning of opening, and as the choke valve approaches full opening, the effect on the air-fuel ratio becomes smaller. For example, 02 to θ3 in Fig. 3
This is because it is sufficient to correct the throttle valve opening only in the range corresponding to .

In this way, the opening width is regulated by the disk 31. 1161130 A, 30 EtriI
It is sufficient if it has a corrected opening degree of 0 to 20 degrees. Note that 37 and 38 are contacts A for supplying current to the heater 33, and the same contacts tJ provided on the axis side of the disk 31.
It is fixed by a shaft 39. Further, '40 is a spring for stably bringing the outer circumference of the disc 31 into contact with the thrust plate 36.

Next, the connection of each operating shaft 30A, 30B and the structure of the heater section will be explained. Disc 31 of bimetal side operating shaft 30B
A flange-shaped hot plate 32 provided on the neck portion facing the disk and a support member 34 whose inner circumferential portion is fixed to the hot plate 32 are integrally connected to one side of the disk 31 by a connecting portion 41. . That is, the load of the bimetal 5 and the operating shaft 30B is shared by the disk 31. In this case, an excessive shaft load does not act on the operation 11b30AK on the bearing 4 side. Connecting portion 4 connecting support member 34 to disk 31:
One end of 4'41 is the thrust plate 3 which also serves as a ground plate.
It is in contact with 6. Thus, a circuit structure is formed on the ground side of the heater 33 which is directly attached to the hot plate 32. Tsumashi,
Electric heating flow is supplied to the heater 33 via the lead wire 20, the contact 37, the mounting shaft 39, and the contact 38, and the hot plate 32,
The circuit configuration is completed through the supporting member 34, the connecting member 41, and the thrust plate 36 which also serves as a ground plate.

According to the device of the above embodiment, the heater 33 can supply conductive heat to the bimetal 5 via the operating shaft 30B having the heat plate 32, so the choke opening degree due to the bimetal is as indicated by the characteristic line dK in FIG. In addition to this, the declination correction mechanism shifts to the characteristic line C, and as mentioned above, the emission characteristic conforms to the high altitude regulations.
It goes without saying that the Vc is fully satisfied, but the mechanism for realizing such characteristics can now be provided as a stable one due to the support structure of the operating shaft 30 based on the disk 31, which is far superior to that achieved in the past. We can provide a concrete structure that has been a national problem.

In particular, by separating the operation shaft 30 into the bearing side 30A and the bimetal side 30B and connecting them with the support member 34 as in the example !8, the heater 33 can be moved with the axis>'i]
If the heater 33 is arranged in a straight line, it is possible to achieve a bimetallic 5Kk structure in which the heater 33 has a straight line, and a uniform heat effect can be obtained satisfactorily.

In the above-mentioned embodiment, a single heater 33 is provided on the hot plate 32 to provide so-called one-stage heating, but the present invention is not limited to this. For example, as shown in FIG. 3
2, a plurality of heaters 33A, 33B are provided, and a contactor 38A is provided for each heater.

It is also possible to adopt a configuration compatible with 38I3. In this case, one of the heaters 33A is used for primary heating to perform a normal heating action, and the other heater 33.11 is used for secondary heating with a predetermined time delay.

According to such a configuration, the heating action can be clearly performed in stages, so that, for example, the clear rise characteristic of the rising angle of the choke valve opening 1w until it reaches the 13th point of the characteristic line d shown in FIG. It will be effective for you.

The embodiment shown in FIG. 6 is the same as the embodiment shown in FIG. 5 except for the heater and its circuit configuration, so in FIG. 6, the same parts as those in FIG. omitted. In FIG. 6, 50 is a contact that constitutes a secondary circuit, 51 is a disk bimetal, 52 is a conductive plate having a contact, 53 is a conductive plate, 54 is an insulating plate, 5
5 is a rivet. That is, this secondary electric heating circuit is configured such that the contact point 52 is brought into contact with the contact point 50 when the one foot angle is reached due to the heating effect of the primary heating of the disk bimetal 51.

〔Effect of the invention〕

As described above, the present invention provides a disc on the support shaft and also provides a heater integrally with the support shaft, thereby simultaneously strengthening the bearing structure of the support shaft and improving heating efficiency.For example, it is possible to improve emission characteristics and fuel efficiency. By overcoming the problems with the mechanical components, we are now able to reliably realize this, and we are now able to provide products that are suitable for actual use, not only as regular vehicles, but also as vehicles for height regulation in particular. Become.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the declination correction mechanism, Fig. 2 is a sectional view of the main part showing the conventional structure, Fig. 3 is a characteristic line diagram showing the opening characteristics of the choke valve, and Figs. The figures show an example of a fruit of the present invention, Fig. 4 is a sectional view of the main part, and Fig. 5 is a
-V@ sectional view, FIG. 6 is a sectional view of a main part showing another embodiment of the present invention. 1... Carburizer, 2... Housing, 4... Bearing,
5... Bimetal, 7... Lever for opening the choke valve, 10... Choke piston for declination correction, 30 (30
A. No. 1 No. 2 No. 3 Water temperature at Cape Nshin Ling (°C)

Claims (1)

[Claims] 1. An operating shaft is rotatably inserted through a bearing into one end wall of a cylindrical nozzle attached to the carburetor, and ξ is operated l1l.
A central part of a coiled bimetal is supported on the insertion end side of the i+ into the housing, and a choke valve opening lever is connected to the deformed part of this bimetal, while an electric heater for heating the bimetal is housed in the housing. , and a declination correction type automatic choke device d, wherein a declination correction choke piston is connected to the end protruding from the nozzle of the operation shaft for giving a rapid opening command to the choke valve in a constant temperature range. A disk for shaft load sharing, the outer circumferential portion of which is rotatably supported on the inner surface of the housing, is provided between the bearing portion of the operation shaft to the housing and the bimetal support portion, and the heater is arranged between the disk and the bimetal support portion. 1. A declination correction type automatic choke device, characterized in that it is directly attached to a flange-shaped hot plate located between a bimetal and integrally formed on the operation shaft. 2. The upper part of the operating shaft is separated from the heat plate part and the disk part, and the heat plate part and the disk part are connected to each other by a cup-shaped support member that also serves as a conductive member to the heater, and 2. The deviation angle correcting automatic choke device according to claim 1, wherein the heater is mounted at the center of the hot plate. 3. The deviation angle correction type automatic choke device according to claim 1, wherein the heater is constituted by a plurality of heaters that are heated sequentially with a time difference.