JPS6145067B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for preventing the icing phenomenon (freezing phenomenon) in a carburetor of an internal combustion engine.

It is known to prevent icing by heating the necessary parts of the carburetor with cooling water in the engine. However, when heating the carburetor with engine cooling water in this way, if the temperature of the cooling water is high, the heating of the carburetor may become excessive and problems such as vapor lock or percolation may occur in the carburetor. will occur.

Therefore, Japanese Patent Application Laid-open No. 53-25713 as a prior art proposes to provide a thermo valve that operates at the cooling water temperature in the heating cooling water supply passage to the vaporizer to heat the vaporizer when the cooling water temperature is high. The above-mentioned icing can be prevented by stopping or reducing the icing, or by providing a thermo valve that operates at atmospheric temperature in the heating cooling water supply passage to the vaporizer, the vaporizer can be operated only when the atmospheric temperature is low. It is proposed that icing can be prevented by heating the product.

However, the relationship between icing and atmospheric temperature and humidity during steady operation of the engine (operation with the engine warmed to a predetermined temperature) is that icing occurs in region (B), as shown in Figure 1. Icing occurs particularly in region (A), and occurs when the engine cooling water temperature is high but the atmospheric temperature is low.

Therefore, of the two icing prevention means described in JP-A-53-25713, stopping or reducing the heating of the vaporizer when the cooling water temperature is high does not prevent the vaporizer from heating. Even if it is possible to prevent excessive heating, it is not possible to completely prevent icing from occurring when the atmospheric temperature is low.

In addition, icing is caused by latent heat of vaporization when fuel vaporizes in the carburetor. When the atmospheric temperature is low, icing occurs because there is not enough heat to evaporate the fuel. Performing heating of the carburetor only when the temperature is low not only fails to prevent icing from occurring during engine warm-up, but also prevents excessive heating of the carburetor during steady engine operation. It is not possible.

The present invention prevents icing by heating the carburetor with engine cooling water, and controls the heating of the carburetor by the engine cooling water based on both atmospheric temperature and cooling water temperature. This makes it possible to accurately prevent all icing, regardless of the temperature range of the engine and the atmosphere, without excessive heating of the carburetor.

For this reason, the present invention provides a method for controlling the temperature of the cooling water in the engine and the atmospheric air in the cooling water introduction passage to the heating cooling water passage provided for the carburetor, or in the cooling water delivery passage from the heating cooling water passage. In relation to both temperature, closing or reducing the passage area when the cooling water temperature and atmospheric temperature are high, when the cooling water temperature is high and the atmospheric temperature is low, and when the atmospheric temperature is high and the cooling water temperature is low; The structure includes a flow rate control means that increases the passage area when the atmospheric temperature and the cooling water temperature are low.

Hereinafter, the drawings of the embodiment will be explained. In the drawing, 1 is a water-cooled internal combustion engine, and a cooling water outlet 3 with a thermo valve 4 attached to the outlet part 2 of the cooling water jacket in the engine 1 is connected to the radiator via a passage 5. The lower tank 8 of the radiator 6 is connected to the cooling water pump 1 through a passage 9 to the hot water tank 7 of the radiator 6.
0 suction side. Further, a passage 11 connected to the outlet section 2 of the cooling water jacket in the engine 1 is connected to a cooling water circulation suction passage 9 to the cooling water pump 10 via a bypass passage 12, and a manually operated heater valve 14. When the engine cooling water temperature is lower than the set temperature at which the thermo valve 4 in the outlet 3 is opened, the cooling water is Although it circulates only through the bypass passage 12,
When the temperature rises and the thermo valve 4 is opened, the cooling water is circulated through the radiator 6, and when the heater valve 14 is opened, part of the cooling water flows to the car heater 13, so that the car heater is activated.

Further, in the figure, reference numeral 15 denotes an intake manifold of the internal combustion engine 1, and the lower surface of the intake manifold 17 is provided with a preheating jacket 16 that communicates with the cooling water jacket of the engine, so that the intake air to the engine is supplied by the cooling water of the engine. It is designed to preheat,
Moreover, on the upper surface of the gathering part 17, a double carburetor 18 having a primary side 19 and a secondary side 20 has a flange 21 at its lower end connected to a flange 22 of the intake manifold 15 with a plurality of bolts 23. An air cleaner 24 is provided upstream of the carburetor 18. At the joint between the carburetor 18 and the intake manifold 15, a metal spacer 25 with good thermal conductivity and an insulator 26 made of a heat insulating material such as phenol resin are installed between the flanges 21 and 22. Hold it face down.

The spacer 25 and the insulator 26 have through holes 27 and 28 that match the primary side 19 of the carburetor 18, and a through hole 29 that matches the secondary side 20.
30 respectively, and a cooling water passage 31 for heating the vaporizer is carved in the spacer 25 so as to surround the primary side passage hole 27 and the secondary side passage hole 29. 31, an inlet socket 32 is located near the primary side through hole 27, and the secondary side through hole 2
An outlet socket 33 is provided at a location close to 9.

Then, the socket 34 connected to the preheating jacket 16 in the intake manifold 15 is connected to the inlet socket 32 in the spacer 25 via the cooling water introduction passage 35, while the spacer 2
The outlet socket 33 at 5 is connected to the cooling water delivery passage 3.
6 to the car heater 13 and the passage 11 to the bypass passage 12, the cooling water in the preheating jacket 16 in the intake manifold
After entering the heating cooling water passage 31 in the spacer 25 via the cooling water introduction passage 35, it is configured to flow into the passage 11 via the cooling water delivery passage 36, and the cooling water is configured to flow into the passage 11 via the cooling water delivery passage 36 or the cooling water introduction passage. The passage 35 is connected to a cooling water temperature thermovalve 37 which is related to the temperature of the engine cooling water and is closed when the temperature becomes high enough to cause excessive heating of the carburetor 18. In addition to providing
The atmospheric temperature thermovalve 38, which is a flow rate control means based on atmospheric temperature, is opened when the temperature becomes low enough to cause icing on the carburetor during steady operation of the engine. 37 in parallel.

In this configuration, when the engine is warmed up to a predetermined temperature and is in steady operation, and when the atmospheric temperature is high, both the thermo valves 37 and 38 are closed, so that the heating cooling water passage in the spacer 25 is closed. The supply of cooling water to 31 is controlled to be cut or reduced to prevent excessive heating of carburetor 18. When the atmospheric temperature is low during steady operation of the engine, even if the cooling water temperature thermovalve 37 is closed, the atmospheric temperature thermovalve 38 is closed.
Since the opening operation is performed, cooling water is sent to the heated cooling water passage 31 in the spacer 25 to warm the vaporizer 18, and icing is prevented in this temperature state. Furthermore, even when the atmospheric temperature is high, icing may occur in the carburetor when the engine is not warmed up sufficiently, such as during warm-up after a cold start. In such a state, even if the atmospheric temperature thermovalve 38 is closed, the cooling water thermovalve 3
7 is opened, and cooling water that increases in temperature as the engine temperature rises is supplied to the heating cooling water passage 31 in the spacer 25, so that the carburetor 18 is quickly warmed up almost simultaneously with the engine, and icing is prevented. . When both the atmospheric temperature and the cooling water are low, both the thermo valves 37 and 38 open.
Since a larger amount of cooling water flows through the heating cooling water passage 31 in the spacer 25 than when only one of the thermo valves is open, the temperature of the carburetor is almost the same as the temperature rise of the engine. It rises without delay and prevents icing.

Further, in the above embodiment, two flow rate control means, a cooling water temperature thermovalve 37 and an atmospheric temperature thermovalve 38, are used in the cooling water introduction passage 35 or the cooling water delivery passage 36 to the spacer 25. In other embodiments, there may be one flow control means related to both cooling water temperature and ambient temperature. FIG. 5 and FIG. 6 are examples of this case.

Thermo valve 3 which is the flow control in this embodiment
9, as shown in FIG. 6, a holder 44 supported by a spring 43 is provided in a hollow valve box 42 having a cooling water outlet socket 40 at one end and a cooling water inlet valve seat 41 at the tip. , a temperature sensing portion is provided in the holder 44 by sealing wax 47 with a diaphragm 45 and a cap body 46;
A valve body 49 is slidably provided at the tip of the valve body 42 to open and close the valve seat 41 at the tip of the valve box 42 and is biased in the normally open direction by a spring 48. The valve body 49 is configured to move in a direction closer to the valve seat 41 when the wax 47 expands in volume due to a rise in temperature through the slidable pin 50.
It is attached to the preheating jacket 16 etc. of the intake manifold 15 so that its valve seat 41 looks inside the jacket and the temperature sensing part is located outside the jacket, and its socket 40 is connected to the spacer 25 through a passage. Connect to the cooling water inlet socket 32 of the

In this way, the portion of the thermovalve 39 that protrudes from the jacket 16 into the atmosphere is exposed to the wind from the vehicle, and heat exchange occurs between the internal cooling water and the atmospheric air. The temperature sensing section 39 is affected not only by the temperature of the cooling water but also by the atmospheric temperature. In other words, the temperature sensing part divides the temperature difference between the cooling water temperature and the atmospheric temperature by a fixed ratio determined based on the heat exchange between the cooling water and the atmosphere. This internal temperature changes approximately in proportion to the change in the cooling water temperature and the change in the atmospheric temperature. It closes when the atmospheric temperature is high during engine operation (when the cooling water temperature is high), and opens when the atmospheric temperature is low during steady engine operation (when the cooling water temperature is high), or when the atmospheric temperature is high and the engine temperature is low. , and when both the atmospheric temperature and the cooling water temperature are low, the opening is wide, so the same effect as in the previous embodiment is achieved.

In addition, if the spacer 25 is inserted between the carburetor 18 and the intake manifold 15 and the cooling water passage 31 for heating the carburetor is provided in the spacer 25 as in both of the above embodiments, the main body of the carburetor can be Since there is no need to provide a cooling water passage for heating, the structure of the vaporizer is simplified, but the present invention is not limited to this, but can also be applied to cases where a cooling water passage for heating is provided in the main body of the vaporizer. In addition, in the case of a double-barreled vaporizer, icing occurs mainly on the primary side, so cooling water for heating the vaporizer is introduced into the passage from a location close to the primary side, as in the above embodiment. It is effective to make it exit from a part close to the secondary side.

As described above, the present invention automatically controls the heating of the carburetor by the engine cooling water based on both the atmospheric temperature and the cooling water temperature, so that the carburetor is not heated excessively. Under these conditions, the vaporizer can be heated only in a state where icing occurs, and this has the effect of accurately preventing icing without causing any malfunction to the vaporizer.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the state of icing generation, Figure 2
The figure is a piping diagram of the first embodiment, FIG. 3 is an enlarged sectional view of the joint between the intake manifold and the carburetor in FIG. 2, FIG. FIG. 6 is a cross-sectional view of the same part as FIG. 3 in the second embodiment, and FIG. 6 is a longitudinal sectional front view of the thermovalve which is the flow rate control means in the second embodiment. 1...Internal combustion engine, 15...Intake manifold,
18... Carburizer, 25... Spacer, 31... Cooling water passage for heating the vaporizer, 35... Cooling water introduction passage, 36... Cooling water delivery passage, 37, 38, 39...
...Thermo valve.

Claims (1)

[Claims] 1. In the cooling water introduction passage to the heating cooling water passage provided for the carburetor, or in the cooling water delivery passage from the heating cooling water passage, there is a temperature related to both the cooling water temperature in the engine and the atmospheric temperature. to close or reduce the passage area when the cooling water temperature and atmospheric temperature are high, and to close or reduce the passage area when the cooling water temperature is high and the atmospheric temperature is low, and when the atmospheric temperature is high and the cooling water temperature is low. 1. An icing prevention device for a vaporizer, characterized in that a flow rate control means is provided to increase the passage area when the temperature is low.