JPS591346B2 - control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a butterfly valve provided in a main passage, such as a control valve that allows fluid in a sub passage to be introduced into the main passage in conjunction with the movement of a noise suppressor or an intake throttle valve. be.

Exhaust gas recirculation (hereinafter referred to as BG), which recirculates a portion of exhaust gas to the intake side, has traditionally been used to reduce harmful components in exhaust gas from internal combustion engines, especially nitrogen oxides (hereinafter referred to as NOx).
R) has been considered valid.

Various EGR devices have been developed and provided.
However, most of these are applicable to gasoline engines, and due to the characteristics of diesel engines, none can be applied directly to diesel engines. Therefore, there was a demand for the development of a bent leg valve that performs EGR that corresponds to the characteristics of diesel engines. The first object of the present invention is to meet this demand by providing a butterfly valve in the exhaust gas recirculation introduction section according to the opening degree of the butterfly valve, which has been conventionally provided in the intake system of diesel engines. It is an object of the present invention to provide a method for controlling the introduction of reflux gas by activating a control valve.

The second object of the present invention is not only to apply it to an EGR device of a diesel engine, but also to apply it to an EGR device of a diesel engine, and furthermore, when mixing a secondary fluid with a main fluid, a secondary It is an object of the present invention to provide something that can also be applied to introducing fluid into the main fluid passage.

A third object of the present invention is to provide a device that has a simple structure that can be heat-resistant and that operates accurately in order to achieve the first and second objects. be.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings, with reference to a control valve used to introduce exhaust gas from a diesel engine into its intake system.

Figure 1 is a conceptual diagram when used for the above purpose. In the figure, 1 is an intake pipe of a diesel engine, 2 is an air cleaner interposed in the middle of the intake pipe 1, 3 is an exhaust pipe of a diesel engine, and 4 is an air cleaner installed in the middle of the intake pipe 1. An inlet pipe that communicates the intake pipe 1 and the exhaust pipe 3; 5 an actuator that adjusts the degree of opening and closing of the butterfly valve of the noise suppressor; 6 a control valve according to the present invention; In addition to the function of a conventional noise suppressor, it also has the function of guiding part of the exhaust gas from the exhaust pipe 3 into the intake pipe 1. 7 is the piston,
8 is a fuel injection nozzle, 9 is an intake and exhaust valve, and 10 is a crankshaft.

FIG. 2 is a longitudinal sectional view showing the structure and operating state of the control valve of the present invention. In the figure, 11 is a main passage interposed in the middle of the intake pipe 1, and 12 is an on-off valve typified by a butterfly valve (e.g. , noise suppressor) of the butterfly valve 12
3 is rotatably mounted on a shaft perpendicular to the main passage 11, and rotated in conjunction with the actuator 5, thereby controlling the butterfly valve 12 to adjust the opening/closing degree of the main passage 11.

Reference numeral 14 denotes a sub-passage branched at a right angle near the secondary side of the butterfly valve 12 in the main passage 11, the other end of which is connected to the introduction pipe 4, and an opening on the main passage 11 side at both ends of the sub-passage 14. Valve seats 15 and 16 are provided at the guide tube 4 side opening, respectively.

Reference numeral 17 denotes a valve body fitted in the sub passage 14 between both valve seats 15 and 16 so as to be able to reciprocate and slide.Both end surfaces of the valve body can be seated on both valve seats 15 and 16, respectively, and can open and close both. can.

A suitable number of passages 18 are bored in the valve body 17, and a valve seat 15
, 16 are in communication. 19 connects the valve body 17 to the valve seat 1
5 side, 20 is a piston fitted in parallel to the valve body 17 so as to be able to reciprocate, and 21 is a mouth protruding from the valve seat 15 side of the piston 20. ,
The butterfly valve 12 is inserted through the opening of the valve seat 15.
It is made to be able to freely come into contact with a seat 23 bored on the back surface of the holder.

22 is a second spring that constantly presses the piston 20 in the direction of the main passage 11 within the valve body 17.

The operation of the control valve according to the above configuration will be explained with reference to the states shown in FIGS. 2A, B, and C.

A: In this state, the butterfly valve 12 is fully closed leaving a minimum ventilation path.

In this case, the rod 21 does not come into contact with the seat 23, so the valve body 1
7 is seated on the valve seat 15 by the pressing force of the first spring 19, and closes the sub passage 14. Therefore, the exhaust gas is stopped from flowing back into the intake pipe 1. B In this state, the butterfly valve 12 is moderately open and the main passage 1
This is a state in which the amount of intake air passing through 1 is not restricted.

In this case, the rod 21 protrudes by a predetermined amount depending on the opening degree of the butterfly valve 12. The second one according to the amount of protrusion.
The spring 22 pushes against the valve body 17 against the first spring 19.
is pushed toward the valve seat 16 side, the valve body 17 is unseated from the valve seat 15, and the auxiliary passage 14 is opened. Therefore, the exhaust gas flows through the exhaust pipe 3, the guide pipe 4, the valve seat 16, the passage 18,
It reaches the intake pipe 1 via the valve seat 15 and the main passage 11, and then flows back into the diesel engine. C In this state, the butterfly valve 12 is fully closed and the intake air passing through the main passage 11 is not restricted at all.

In this case, the rod 21 is protruded to the maximum extent by the butterfly valve 12. For this purpose, the second spring 2
2, the valve body 17 is pressed against the first spring 19, is seated on the valve seat 16, and the sub passage 14 is closed. Therefore, the exhaust gas is prevented from flowing back into the intake pipe 1. Now, regarding the frequency of use of a diesel engine, areas 2, b, c, and d in FIG. 3, where the rotational speed and load are expressed in relation to the x and y axes, are most frequently used.

Therefore, in areas A, b, c, and d, which are frequently used in diesel engines, the most effective way to reduce NOx in diesel engines is to recirculate exhaust gas into the intake air and reduce the generated NOx as much as possible. It can be considered as a means. The range of areas A, b, c, and d depends on the engine combustion method, structure,
Although it differs somewhat depending on the output etc., there is no change in the fact that it generally tends to occupy the medium load and medium speed area as shown in Fig. 3. Therefore, under medium load and medium speed operation, E
There is a demand for implementing GR. In addition, the third
In the figure, W indicates the maximum load value, and N indicates the maximum rotational speed.
On the other hand, regarding the degree of opening required for the noise suppressor, it is desired that the butterfly valve has a medium degree of opening as shown in FIG. 2B in the areas A, b, c, and d of FIG. 3.

Also, the opening degree of the butterfly valve shown in (C) is required for low speed and low load, while for high speed and high load operation. That is, the portion where EGR is desired to be performed and the moderate opening degree of the noise suppressor almost match. Therefore, the control valve of the present invention has a function that fully satisfies the above-mentioned EGR requirements.

In order to bring the control valve 6 into the states (A), (B), and (C) described above, a detector (not shown) is used to measure the load and rotational speed of the engine.

) and guided to a computer (not shown).
All you have to do is calculate and send a signal to the actuator 5 to operate it. The effects of the control valve of the present invention described above are as follows.

(1) No structure such as a ring mechanism is required, and the direct drive is performed by a butterfly valve, so the structure is simple, the operation is accurate, and there are few failures.

(2) The structure consists of only the valve body, piston, rod, and spring, so it can withstand high temperatures.

(3) Also, clogging due to fine particles such as carbon in the passing fluid is less likely to occur.

(4) By adjusting the opening and closing of the butterfly valve in the main passage, the sub passage can be easily controlled in three states: closed, open, and closed.

(5) From the above points, especially the E
It is suitable as a control valve that performs GR.

(6) In that case, since the control valve itself can be directly connected to the intake pipe, the temperature rise of the valve itself can be alleviated.

[Brief explanation of the drawing]

The drawings show an example of the implementation of the present invention, and FIG. 1 is a conceptual diagram showing a state in which the present invention is applied to EGR of a diesel engine, that is, recirculating exhaust gas to its intake system, and FIG. 2 A, B , C are longitudinal sectional views showing the operating state of the present invention,
FIG. 3 is a conceptual diagram showing frequently used areas of a diesel engine. In the above figure, each symbol indicates the following.

Claims (1)

[Scope of Claims] 1. A sub-passage is branched off from the main passage provided with the butterfly valve, and two valve seats are provided in series facing each other in the sub-passage, and both valve seats are arranged on both end surfaces between the two valve seats. A valve body which can be freely seated is provided in each of the valve bodies so as to be able to reciprocate and slide under elastic pressure in the direction of the main passage by a first spring, and a piston is further slidable in the reciprocating manner under elastic pressure in the direction of the main passage by a second spring within the valve body. A control valve characterized in that the tip of a rod that can be fitted together and directly connected to the piston is connected to the opening and closing of the butterfly valve of the noise suppressor. 2. Claim 1, in which the main passage is interposed in the intake pipe of a diesel engine, and the auxiliary passage is connected to the middle of the exhaust pipe, so that part of the exhaust gas of the diesel engine is returned to the intake pipe. Control valve as described in section.