JPS635582B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an intake air temperature control device for an internal combustion engine, and more particularly to an improved arrangement of a negative pressure control valve for the device provided in an engine air cleaner.

[Prior art]

In order to prevent icing on the carburetor and improve atomization of gasoline fuel, gasoline engines with a carburetor generally use an air cleaner with an intake air temperature control device (abbreviated as automatic temperature control device) that warms the intake air with exhaust heat before the low-temperature engine. air cleaner).

Now, an internal combustion engine equipped with a conventional intake air temperature control device will be explained with reference to FIG.
(See Publication No. 67356).

In Figure 1, 1 is an intake pipe, 2 is an air cleaner, 3 is a carburetor, 4 is an exhaust manifold, 5 is a manifold cover, 6 is a hot air intake pipe, 7 is a vacuum motor, 8 is an on-off valve, and 9 is a negative pressure control valve. , 10
is the intake manifold.

After warming up, the intake air is normally guided from the outside air introduction duct 1a to the air cleaner 2 via the intake pipe 1, and after dust is removed by the filter element 2a,
Fuel is mixed in the carburetor 3 and the intake manifold 1
0 and is introduced into the combustion chamber.

Before warming up, the intake air temperature is low, so the heated air on the exhaust manifold 4 is introduced into the air cleaner 2 from the manifold cover 5 using the flexible hot air intake pipe 6 to prevent icing on the carburetor 3 and to drain the fuel. It also promotes atomization.

The intake air temperature is adjusted at this time by adjusting the opening degree of an on-off valve 8 provided at the connection between the intake pipe 1 and the warm air intake pipe 6 using the vacuum motor 7. The vacuum motor 7 operates the opening/closing valve 8 to an appropriate opening degree in balance with the spring force of the spring 7b by introducing negative pressure controlled by the negative pressure control valve 9 into the negative pressure chamber 7a.

The negative pressure control valve 9 is
Inside the clean side 2b of the air cleaner,
It is attached to the air cleaner main body 2C by a mounting stopper 14, and the valve body 12 is moved by the thermal deformation of the bimetal 11, and the atmosphere that dilutes the intake negative pressure introduced from the hose 10b is introduced according to the intake air temperature, and the hose 10a is Vacuum motor 7 through
Adjust the operating negative pressure.

In addition, 13 is a protector that takes charge of the reaction force when opening the valve body 12 of the negative pressure control valve 9, 15 is a blow-by hose that returns blow-by gas to the air cleaner 2, and 16 is a part of the exhaust gas that is returned to the intake manifold 10. It is the EGR valve.

However, in such a conventional intake air temperature control device, in order to open and close the on-off valve 8, the negative pressure control valve 9 controls the intake negative pressure by diluting it with the atmosphere according to the intake air temperature. Since this diluted atmosphere was directly inhaled from the clean side 2b inside the filter element 2a of the engine air cleaner 2, fine dust and oil in the blow-by gas that passed through the filter element 2a were transferred to the valve element 1 of the negative pressure control valve 9. and the orifice 12a or 12b, and due to the accumulation of both over time, the valve body may become stuck or the orifice may become clogged, resulting in insufficient negative pressure introduced into the negative pressure chamber 7a of the vacuum motor 7, and the intake air There was a problem with the temperature control being poor.

In other words, the air cleaner's role is to remove hardening dust such as alumina silicate to prevent wear on the engine cylinders, so the aforementioned minute dust and oil are inevitably passed through without being removed. For example, if the valve body becomes stuck due to the accumulation of minute dust and oil, the above-mentioned problems will occur. Therefore, it is conceivable to further increase the dust removal ability of the air cleaner, but in that case, another problem arises in that the suction resistance increases and engine output and fuel efficiency deteriorate.

[Purpose of the invention]

This invention was made by focusing on such conventional problems, and its purpose is to solve the problem of sticking of the valve body of the negative pressure control valve or clogging of the orifice without making any changes to the conventional engine air cleaner. The purpose is to prevent the temperature control function from deteriorating even if it is lost.

[Structure of the invention]

In order to achieve the above object, the present invention includes an on-off valve that is provided at the connection between the intake pipe and the hot air intake pipe of an engine air cleaner and operates with negative pressure, and a shut-off valve that is provided on the clean side of the air cleaner to dilute the intake negative pressure with the atmosphere. and a negative pressure control valve for controlling the operating negative pressure of the on-off valve, in which the negative pressure is controlled in a filter case equipped with a filter that is narrower than the filter element of the air cleaner. The gist is that a control valve is provided.

[Effect]

After warming up, when the valve body opens due to thermal deformation of the bimetal, atmospheric air on the clean side attempts to flow into the filter case due to negative pressure in the valve chamber of the negative pressure control valve. At this time, minute dust and oil in the atmosphere are removed by a narrow-mesh filter provided in the filter case, so only normal air flows in, preventing the valve body from sticking or the orifice from clogging.

The removed fine dust will eventually be sucked into the engine cylinder, but since these are tiny and combustible, they will not cause cylinder wear, and since the air cleaner is an original element, it will increase suction resistance. Not.

The present invention will be explained below based on the drawings.

〔Example〕

FIG. 2 is a diagram showing an embodiment of the present invention. First, the configuration will be explained. In Figure 2, 9
17 is a negative pressure control valve, 17 is a filter, and 18 is a filter case. The negative pressure control valve 9 is located inside the clean side 2b of the air cleaner as in the prior art, but is further characterized in that it is provided inside the filter case 18.

The filter case 18 is in contact with the resin case 19 of the control valve with an O-ring 20, covered from above to ensure sealing, and is attached to the air cleaner main body 2C with bolts 21. This may be made of sheet metal or resin.

The filter 17 has a filtration precision of 20 to 40μ, and the filtration precision of the filter element 2a of the air cleaner
The filter case is made thinner than 70 to 80 μm and installed by adhesive or the like so as to close the upper hole of the filter case 18.

Note that the negative pressure control valve 9 includes a bimetal 11, a valve body 12 integrated therewith, a valve seat 22, as in the conventional case.
A pipe member 23 having an orifice 12a, a pipe member 24 having an orifice 12b, a valve chamber member 25,
It consists of a protector 13 and a resin case 19.
It is attached to the air cleaner main body 2C from above through, and inserted and fixed into the attachment stopper 14. Then, as in the conventional case, it is connected to the vacuum motor 7 and the intake manifold 10 as shown in FIG. 1 through hoses 10a and 10b.

Next, while referring to FIG. 1, the operation of the above embodiment is explained.
This will be explained with reference to FIG.

(a) Before warming up Before warming up when the intake air temperature is low, such as 38°C or less, the bimetal 11 is in a state of being warped upward, and the valve body 12 is in close contact with the valve seat 22 as shown in Fig. 2. , since the valve chamber 26 is completely closed,
The intake negative pressure of the intake manifold 10 remains the same.
It is transmitted to the negative pressure chamber 7a of the vacuum motor 7 via the hose 10b, the valve chamber 26, and the hose 10a. Therefore, the on-off valve 8 is lifted against the spring 7b and opens the passage of the warm air intake pipe 6, so that air warmed by the exhaust manifold 4 is introduced into the air cleaner 2.

(b) After warm-up After warm-up when the intake air temperature is high, such as 48° C. or higher, the bimetal 11 warps downward and the valve body 12 moves downward, so that the valve chamber 26 becomes open to the atmosphere. Therefore, the intake negative pressure is diluted to approximately atmospheric pressure, and the negative pressure in the negative pressure chamber 7a disappears.
The spring 7b causes the on-off valve 8 to move downward, closing the warm air intake pipe 6 and opening the outside air introduction duct 1a. As a result, cold air from the outside world is introduced into the air cleaner 2. In the above, the valve body 1
2 opens and the atmosphere dilutes the negative pressure in the valve chamber 26.
Even if the air contains minute dust or oil that has passed through the filter element 2a of the air cleaner 2, it is filtered through the thin mesh filter 17 and introduced as clean air. Therefore, the valve body 12 and the orifice 12a or 12b do not have dust or oil attached to them, so they do not become stuck or clogged due to the accumulation of dust or oil, and therefore can perform a stable intake air temperature control function over a long period of time.

Note that the removed dust or oil will eventually be sucked into the engine cylinder, but since these are minute and flammable, they will not adversely affect the wear of the cylinder.

In addition, since the negative pressure control valve 9 is provided inside the resin case 19 and the filter case 18, it operates stably in response to sudden changes in intake air temperature due to less heat transfer compared to conventional devices. Average temperature control will be performed. Therefore, fuel atomization and fuel efficiency are further improved than before, and hunting of the on-off valve is prevented, so the durability and sealing performance of the on-off valve are also improved.

Note that when the intake air temperature is between 38° C. and 48° C., that is, during warming up, the control negative pressure of the vacuum motor is at an intermediate value, so the opening degree of the on-off valve is set to an appropriate degree depending on the temperature.

FIG. 3 shows another embodiment. In this embodiment, the filter case of the embodiment shown in FIG. 2 and the resin case of the control valve are integrally molded with resin, and the number of parts is small and the structure is simple.

Furthermore, since the filter case 18 is made of resin with low thermal conductivity, the operation of the negative pressure control valve 9 becomes more stable against sudden changes in intake air temperature than when it is housed in a metal case.

〔Effect of the invention〕

As explained above, according to this invention,
The configuration is such that the negative pressure control valve is installed on the clean side of the engine air cleaner, and the negative pressure control valve is placed inside the filter case, which has a filter that is narrower than the filter element of the air cleaner. Fine dust and blow-by oil that have passed through the element can be removed by the filter in the filter case, which prevents the valve body of the negative pressure control valve from sticking and the orifice from clogging, resulting in long-term deterioration of the temperature control function. The effect is that it can be prevented over a long period of time.

[Brief explanation of the drawing]

Figure 1 is a sectional view of an internal combustion engine equipped with a conventional device;
FIG. 2 is a sectional view showing one embodiment of the negative pressure control valve according to the present invention, and FIG. 3 is a sectional view of another embodiment. (Explanation of symbols representing main parts of drawings) 1
...Intake pipe, 2...Air cleaner, 2a...Filter element, 2b...Clean side, 3...Carburetor,
4... Exhaust manifold, 6... Warm air intake pipe, 7... Vacuum motor, 8... Open/close valve, 9... Negative pressure control valve,
10...Intake manifold, 17...Filter, 18
...filter case.

Claims (1)

[Claims] 1. An on-off valve provided at the connection between the intake pipe and the hot air intake pipe of the engine air cleaner and operated by negative pressure, and an on-off valve provided on the clean side of the air cleaner that dilutes the intake negative pressure with the atmosphere to reduce the operating negative pressure of the on-off valve. In the intake air temperature control device for an internal combustion engine, the negative pressure control valve is disposed in a filter case equipped with a filter that is narrower than the filter element of the air cleaner. An intake air temperature control device for internal combustion engines.