JPS59192855A - Control apparatus for heating of carburetor - Google Patents

Abstract

PURPOSE:To prevent icing of a carburetor, by providing a heater controlled by the atmospheric temperature at a position located downwards of an idle port of the carburetor. CONSTITUTION:A heater 17 consisting of an annular PTC element is provided at a position located downwards of an idle port 6 of a carburetor, and heat-insulating members 15, 16 are attached to the upper and lower surfaces of the heater 17. The heater 17 is energized when all of an ignition switch 22, a humidity switch 21 for detecting the humidity of the atmosphere at which tendency to cause icing is high, and an atmospheric temperature switch 20 that is closed when the atmospheric temperature is lowered to a level at which the carburetor begins to cause icing are closed. By thus heating the carburetor, it is enabled to prevent icing of the carburetor and to keep the same at a proper temperature by means of the PTC element.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a heating control device for a carburetor used in an internal combustion engine.

Prior Art If you start the engine when the outside air temperature is low and the outside air temperature is high, the temperature of the inner wall surface of the carburetor intake passage will drop due to the heat of vaporization taken away when the fuel vaporizes, and as a result, the temperature of the inner wall surface of the carburetor intake passage will drop, resulting in The moisture generated may freeze on the carburetor throttle valve or around the slow boat or idle boat.
A so-called icing phenomenon occurs. However, if the area around the throttle valve freezes, the suction resistance increases when the amount of intake air is small, such as during idling, and a large negative pressure acts on the slow boat and idle port, resulting in a large negative pressure being applied to the slow port and idle port. Since more fuel than necessary is sucked out, a problem arises in that the air-fuel mixture supplied into the engine cylinder becomes too rich. On the other hand, when the area around the slow boat or idle boat freezes, the flow area of the slow boat or idle boat is narrowed, so the fuel sucked out from the slow boat or idle boat decreases, and the mixture supplied into the engine cylinders decreases. This causes the problem of becoming overly alert. If the air-fuel mixture supplied into the engine cylinder becomes too rich or too lean, idling becomes unstable or the engine stops, so it is necessary to prevent this icing phenomenon from occurring. be. To prevent the eyesink phenomenon from occurring, for example, Japanese Patent Application Laid-Open No. 52-10463
It is possible to heat the vaporizer main body as described in Publication No. 2, but if the vaporizer main body is heated when the outside temperature is high, the vaporizer temperature becomes too high, causing problems such as percolation.

OBJECTS OF THE INVENTION An object of the present invention is to provide a heating control device for a vaporizer that prevents the vaporizer temperature from increasing more than necessary (ie, prevents the occurrence of the icing phenomenon).

Structure of the Invention The structure of the present invention includes a temperature-sensitive switch that responds to outside temperature, and a heating device that heats the vaporizer body in response to the temperature-sensing switch, when the outside temperature is below a predetermined temperature. The heating device is activated only when the vaporizer body is heated.

Referring to the first example, ■ is the carburetor main body, 2 is the flange for attaching to the intake manifold (not shown), and 3
indicates the throttle valve, 4 indicates the main nozzle, 5 indicates the slow boat, 6 indicates the idle boat 1, and 7 indicates the float chamber.
Slow port 5 and idle boat 6 are connected into float chamber 7 via slow fuel passage 8 . In the slow fuel passage 8, a slow jet (>,) 9 and an economizer jet 10 are inserted, as is well known, and a pair of air bleed jets (>,) 9) are inserted into the slow fuel passage 8.
Air is supplied via 11 and 12.

As shown in FIGS. 1 and 2, an annular groove 13 is formed in the mounting flange 2 of the carburetor body 1, into which an annular heating device 14 is inserted. In the embodiment shown in FIG.
45, 16, and an annular heating element 17 inserted between these annular insulating members 15, 16.
, 16 and the outer peripheral surface of the annular heating element 17 are the insulating member 1
Surrounded by 8. The annular heating element 17 consists of, for example, a nichrome wire wound around mica or a PTC element (positive temperature coefficient thermistor element). One terminal of the annular heating element 17 is directly connected to the power source 19, and the other terminal of the annular heating element 17 is connected to the power source 19 through a temperature sensitive switch 20, a humidity switch 21 and an ignition switch 22. . The temperature-sensitive switch 20 and the humidity switch 21 are provided in the engine compartment of a vehicle (not shown).

The temperature-sensitive switch 20 is turned on when the atmospheric temperature in the engine room, that is, the outside air temperature, is below a predetermined temperature, for example, 5°C, and is turned off when it is above 5°C. On the other hand, the humidity switch 21 is turned on when the atmospheric humidity in the engine room is higher than a predetermined humidity, and turned off when it is lower than a predetermined humidity.

Therefore, when the ignition switch 22 is turned on to start engine operation, if the outside temperature is low and the humidity is high, the temperature-sensitive switch 20 and the humidity switch 21 are turned on, so that the heating device 14 is energized. Heating element 1
7 is made to generate heat.

In this way, when the outside temperature is low, the temperature of the inner wall surface 23 of the carburetor intake passage drops considerably due to the vaporization effect of the fuel, and if the humidity is high at this time, the intake air contains a large amount of moisture. Moisture tends to freeze on the throttle valve 3 or around the slow port and idle boat 6. However, in the present invention, when the condition is such that it is easy to freeze, the heating element 17 generates heat as described above, and as a result, the inner wall surface 23 of the intake passage around the slow boat 5 and the idle port 6 and the throttle valve 3 are heated. This prevents moisture contained in the intake air from freezing.

On the other hand, when the outside temperature is high, even if the fuel is vaporized, the temperature of the intake passage inner wall surface 23 does not drop much, so freezing does not occur, and when the humidity is low, the moisture in the intake air decreases, making it difficult to freeze. When the ice is no longer frozen, or when it has even started to freeze, that is, when the outside temperature is high or the humidity is low, the temperature-sensitive switch 2 is activated.
0 or because the humidity switch 21 is turned off, the heat generation action of the heating device 14 stops. Therefore, the vaporizer main body 1 is not heated excessively, so the vaporizer main body 1 does not reach a high temperature (thus, there is no risk of percolation).Also, when the outside temperature is low and the humidity is high, Since only the heating device 14 is activated, the power consumption of the power source 19 is reduced.

Incidentally, since the freezing phenomenon occurs only when the outside temperature is low, as described above, the humidity switch 21 can be omitted. However, in this case, the heating device 14 is operated even when the humidity is low, so that some power is wasted.

Another embodiment is shown in FIGS. 3 and 4. In this embodiment, an annular cooling water passage 25 is formed in the mounting flange 2 of the carburetor main body 1, and a cooling water supply pipe 26 and a cooling water discharge pipe 27 are connected to this cooling water passage 25. The cooling water supply pipe 26 is connected to a water pump 29 via a solenoid valve 28, and the cooling water discharge pipe 27 is connected to the inside of the water jacket of the engine. One terminal of the solenoid valve 28 is connected to a power source 19, and the other terminal of the solenoid valve 28 is connected to the power source 19 via a temperature sensitive switch 20, a humidity switch 21, and an ignition switch 22. In this embodiment, when the outside temperature is low and the humidity is high, the solenoid valve 28 is opened and cooling water is supplied into the cooling water passage 25, so that the carburetor main body 1 is heated by the cooling water 1. (This can prevent moisture in the intake air from freezing. On the other hand, when the outside temperature is high or the humidity is low, the solenoid valve 28 closes and the supply of cooling water is stopped. This can prevent the carburetor main body 1 from being excessively heated.Furthermore, in this embodiment, even when the engine is started, the supply of cooling water is stopped if the outside temperature is high or the humidity is low. The heat of the engine cooling water is not used to heat the carburetor main body 1, so warm-up of the engine can be promoted.

Effects of the Invention When the outside temperature is high or the humidity is low, the vaporizer body is not heated, so the vaporizer temperature does not become excessively high, and thus percolation does not occur.

Therefore, it is possible to prevent the occurrence of icing of the vaporizer while preventing the occurrence of such percolation. In addition, since the heating device is activated only when the outside temperature is low and humidity is high, the power consumption of the power supply can be reduced when an electric heating means is used as the heating source, and when engine cooling water is used as the heating source. can help warm up the engine when the outside temperature is high or the humidity is low.
Ru.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a carburetor according to the present invention, FIG. 2 is a sectional view taken along the line U-U in FIG. 1, and FIG. 3 is a side sectional view of another embodiment of the carburetor. Figure 4 is IV-I of Figure 3.
It is a sectional view taken along the V line. ■... Carburetor body, 2... Mounting flange, 14...
・Heating device, 20... Temperature-sensitive switch, 21... Humidity switch, 22... Ignition switch, 25...
...Cooling water passage, 28...Solenoid valve. Patent applicant Toyota Motor Corporation Patent application agent Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney Kyosuke Tsuchinakayama Patent attorney Akira Yamaguchi

Claims (1)

[Claims] It is equipped with a temperature-sensitive switch that responds to the outside temperature, and a heating device that heats the vaporizer body in response to the temperature-sensing switch, and operates the heating device only when the outside temperature is below a predetermined temperature. A heating control device for a vaporizer that heats the main body of the vaporizer.