JPS6157941B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a negative pressure-responsive recirculation flow control valve that is interposed in the exhaust gas recirculation path that branches from the exhaust path of the engine and reaches the intake path, and adjusts the operating negative pressure of this control valve. The present invention relates to an exhaust gas recirculation control device for an engine, which controls the amount of exhaust gas recirculated to the intake passage.

Conventionally, while the engine is running, a portion of the exhaust gas is returned to the intake passage through the exhaust recirculation passage to suppress the excessive rise in the combustion temperature of the air-fuel mixture and prevent the generation of nitrogen oxides, which are a factor in air pollution. This has already been done in automobile engines, but in this case, in order to more effectively suppress the generation of nitrogen oxides, it is necessary to make the amount of exhaust recirculation proportional to the amount of intake air in the engine. It is necessary to keep the ratio of exhaust gas recirculation amount (exhaust recirculation rate) constant.
Furthermore, it is required that this exhaust gas recirculation rate can be easily set to any value depending on the performance, specifications, and operating conditions of the engine.

An object of the present invention is to provide a simple and effective device that can satisfy such requirements.

In order to achieve this purpose, the present invention
A negative pressure-responsive recirculation flow control valve is interposed in the exhaust gas recirculation passage that branches from the exhaust passage of the engine and reaches the same intake passage. A negative pressure response type adjustment that connects a first negative pressure passage communicating with the downstream part of the throttle valve and a second negative pressure passage extending from a predetermined pressure source, and opens and closes the second negative pressure passage. A valve is interposed between the regulating valve and the intake passage, and a negative pressure chamber of the regulating valve is interposed in the middle of the controlled intake passage extending from the downstream part of the throttle valve of the intake passage and reaching the atmosphere opening port, and the negative pressure chamber of the regulating valve is interposed between the regulating valve and the intake passage. A negative pressure-responsive air valve for opening and closing the control intake passage is interposed in the control intake passage, and a negative pressure chamber of the air valve is communicated with the negative pressure chamber of the recirculation flow control valve. The present invention is characterized in that at least a pair of orifices are provided in the intake passage, sandwiching the negative pressure chamber of the regulating valve therebetween.

Hereinafter, an embodiment in which the present invention is applied to an automobile engine will be explained with reference to the drawings.First, there is a first embodiment shown in FIG. Insulated tube It at the upstream end of its intake manifold Mi
The carburetor C is attached via the. Thus, the intake manifold Mi, the heat insulating cylinder It, and the carburetor C constitute an intake path of the engine.

The intake path 1 of the carburetor C is provided with a choke valve 2 on the upstream side and a throttle valve 3 on the downstream side of the bench lily 1a in which the fuel nozzle 4 opens.

Furthermore, in the intake passage 1, a first negative pressure detection hole _D1 is provided near the throttle valve 3, and a second negative pressure detection hole D1 is provided in the vent lily 1a.
A negative pressure detection hole D ₂ is provided, and the first negative pressure detection hole D ₁ is located upstream of the throttle valve 3 at the idle opening position, and when the throttle valve 3 is at a predetermined opening position larger than the idle opening position. It moves to the downstream side of the throttle valve 3 when the throttle valve 3 is opened more than 30 degrees, that is, when the engine is operating under load.

An exhaust gas recirculation amount 5 that branches off and extends from the exhaust port of the engine E is connected to the intake manifold Mi, and a recirculation amount control valve 6 is provided in the middle thereof. This valve 6 has a diaphragm 8 connected to a needle-shaped valve body 7 that adjusts the opening degree of the exhaust gas recirculation amount 5, and a negative pressure chamber 9 formed above the diaphragm 8 that urges the valve body 7 toward the closing side. The valve spring 10 is compressed to form a negative pressure responsive type.

First and second negative pressure passages L 1 and _{L 2} extending from first and second negative pressure detection holes D ₁ and D ₂ are connected to the negative pressure chamber 9 of this reflux amount control valve 6, and Negative pressure passage
_L1 is provided with a solenoid valve 11 and an orifice 12 located downstream thereof in series. When the solenoid is energized, the solenoid valve 11 closes the upstream side of the negative pressure passage _L1 and communicates the downstream side with the filtered atmosphere opening 13.

The second negative pressure passage L ₂ is provided with a negative pressure control valve V, which controls the operation negative pressure of the negative pressure responsive regulating valve V ₁ that controls the opening and closing of the second negative pressure passage L ₂ and the return flow control valve 6. It consists of an air valve V ₂ which is also a negative pressure responsive type and which controls the feedback regulating valve V ₁ .
The configuration of each valve will be explained in turn.

First, the regulating valve _V1 has a valve chamber 20 formed in the middle of the second negative pressure passage _L2 , and a diaphragm 2 above the valve chamber 20.
1, a flat valve body 23 that is attached to the diaphragm 21 and can open and close the downstream valve port 25 of the first negative pressure passage _L1 , and It is composed of a valve spring 24 that biases the valve.

Next, the air valve V ₂ is a valve chamber 30 formed in the middle of a control intake passage L 3 that branches from the intake passage downstream of the throttle valve ₃ (insulated cylinder It in the illustrated example) and reaches the atmosphere opening port 14 with a filter. and diaphragm 3 above it
1, a valve body 33 attached to the diaphragm 31 that adjusts the opening of the valve port 35 on the downstream side of the control intake passage _L3 , and a valve body 33 that is connected to the negative pressure chamber 32 adjacent to the valve body 32 through the diaphragm 31; It is comprised of a valve spring 34 that biases.

The valve body 33 is formed to have a substantially similar shape to the valve body 7 of the recirculation amount control valve 6, and the negative pressure chamber 32 is connected to the valve port 25 of the regulating valve _V1 via the communication passage 36, and thus to the valve body 7 of the recirculation amount control valve 6. It communicates with the negative pressure chamber 9 of the reflux control valve 6 .

The negative pressure chamber 22 of the regulating valve V ₁ is formed so as to intervene in the control intake passage L ₃ upstream of the valve chamber 30 of the air valve V ₂ , and has a pair of orifices sandwiching the negative pressure chamber 22 therebetween. J ₁ and J ₂ are provided in the control intake path L ₃ and their throttle openings are the same, or the upstream one J ₁
The downstream one J is set smaller than ₂ .

In addition, an orifice 40 and a solenoid valve 41 are installed in series in the second negative pressure passage L ₂ on the upstream side of the regulating valve V ₁ , and this solenoid valve 41 operates according to the operating state of the engine, that is, the engine temperature, the load, etc. , which is controlled according to changes in vehicle speed, etc., and when the solenoid is energized, the upstream side of the second negative pressure passage _L2 is cut off, and the non-flow side is communicated with the filtered atmosphere opening 14. ing. In this way, in the illustrated example, the atmosphere opening port 14 of the solenoid valve 41 and the atmosphere opening port 14 of the control intake path _L3 are one common, but they can be made independent.

In the present invention, the upstream side of the negative pressure passage refers to the negative pressure source side, and the upstream side of the intake passage refers to the atmosphere opening side.

Next, to explain the operation of this embodiment, it is assumed that the electromagnetic valves 11 and 41 are currently in a non-energized state as shown in the figure. Therefore, when the throttle valve 3 is opened to a predetermined opening degree or more to operate the engine E under load, and the negative pressure generated in the intake passage on the downstream side of the throttle valve 3 is detected in the first negative pressure detection hole _D1 , the The negative pressure Pc is transmitted to the negative pressure chamber 32 of the air valve _V2 via the solenoid valve 11 and the orifice 12,
When it overcomes the set load of the valve spring 34, the valve body 33 is pulled up via the diaphragm 31, and the control intake passage _L3 is made conductive.

When the control air intake path L ₃ becomes conductive, the atmosphere release port 14
Outside air is sucked into the negative pressure chamber 2 of the regulating valve V ₁ .
After the flow rate is regulated by the two orifices J ₁ and J ₂ , it is sucked into the intake passage of the engine E via the valve chamber 30 and valve port 35 of the air valve V ₂ . Accordingly, the negative pressure chamber 22 of the regulating valve V ₁ and the valve chamber ₃ of the air valve V 2
Negative pressures P ₁ and P ₂ are generated at 0, respectively, and the ratio of these negative pressures is determined by the throttle ratio of the orifices J ₁ and J ₂ .

Thus, in the regulating valve V ₁ , the upward force of the diaphragm 21 due to the differential pressure between the negative pressure P ₁ in the negative pressure chamber 22 and the detected negative pressure Pv in the second negative pressure detection hole D ₂ causes a set load on the valve spring 24 . If the pressure is overcome, the valve body 23 is pulled up through the diaphragm 21 and the valve port 25 is opened, so that a part of the negative pressure Pv passes through the valve port 25 and dilutes the negative pressure that passed through the orifice 12 first. This creates a negative pressure Pe, which acts on the negative pressure chamber 9 as the operating negative pressure of the reflux control valve 6.

According to the above-mentioned dilution of the negative pressure, the decrease in the operating negative pressure Pe is fed back to the negative pressure chamber 32 of the air valve V ₂ through the communication passage 36, and the negative pressure in the chamber 32 decreases.
Accordingly, the opening degree of the valve port 35 of the air valve V ₂ decreases, so that the negative pressure P ₁ of the negative pressure chamber 22 and the negative pressure P ₂ of the valve chamber 30 are reduced to the orifice due to the decrease in the air flow rate in the control intake passage L ₃ . The pressure decreases while maintaining the pressure ratio set by J ₁ and J ₂ , and accordingly, the valve body 23 closes the valve port 25 . Then, the operating negative pressure Pe rises, which is fed back to the air valve _V2 , and the valve body 23 opens the valve port 25 by the opposite action to the above, and the same action is repeated thereafter, and this repetition is performed very quickly. so that negative pressures Pv and Pe can be given a constant pressure ratio equal to that of negative pressures P ₁ and P ₂ .

Therefore, if the intake air amount of the engine E is small, the negative pressure P ₁ is higher than the negative pressure Pv, so the valve body 23 of the regulating valve V ₁ is located on the open side, and the operating negative pressure Pe of the recirculation amount control valve 6 is On the contrary, if the amount of intake air increases, the negative pressure Pv increases, so the valve body 23 moves to the closing side, and the operating negative pressure Pe increases. Thus, since the air valve V ₂ and the recirculation amount control valve 6 operate at the same negative pressure Pe, the amount of air flowing through the control intake path L ₃ is proportional to the amount of exhaust recirculation, and the amount of intake air of the engine is proportional to the amount of exhaust recirculation. , the exhaust gas can be sucked into the engine E at a constant reflux rate, and the exhaust reflux rate is determined by the pressure ratio of Pv and Pe, and therefore by the orifice.
It is determined in advance by the aperture ratio of J ₁ and J ₂ .

If it is necessary to reduce the exhaust gas recirculation rate depending on the operating state of the engine, the electromagnetic valve 41 is energized. That is, when the solenoid valve 41 is energized, the downstream side of the second negative pressure passage L ₂ communicates with the atmosphere opening port 14 as described above, so the valve chamber 20 of the regulating valve V ₁ is maintained at atmospheric pressure, and the valve body 23 is located on the open side, the operating negative pressure Pe decreases and the opening degree of the recirculation amount control valve 6 decreases, resulting in a decrease in the exhaust gas recirculation rate.

Further, when it is necessary to stop the recirculation of exhaust gas, the solenoid valve 11 is energized. That is, when the solenoid valve 11 is energized, the downstream side of the first negative pressure passage _L1 is communicated with the atmosphere opening port 13 as described above, so that the operating negative pressure is reduced.
Pe becomes atmospheric pressure, the recirculation amount control valve 6 is closed, and the recirculation of exhaust gas can be stopped.

FIG. 2 shows a second embodiment of the present invention, which is different from the previous embodiment in the means for adjusting the exhaust gas recirculation rate, and the difference will be explained next.

As in the previous embodiment, orifices J ₁ and _{J 2} are provided in the control intake passage L ₃ with the negative pressure chamber 22 of the regulating valve V ₁ sandwiched between them. First and second bypass passages 50 and 51, which are provided with an orifice J ₁ a between them and bypass this orifice J ₁ a, are connected to the control intake passage L ₃ , and the first bypass passage 50 has an orifice J ₁ b and a A closed solenoid valve 52 is installed in series, and only a normally closed solenoid valve 53 is installed in the second bypass path 51. The aperture opening of the above orifice is
Orifice J ₁ a is smaller than J ₁ , and orifice
Orifice J ₁ b is set smaller than J ₁ a, and energization of solenoid valves 52 and 53 is controlled according to the operating state of the engine. The rest of the structure is the same as that of the previous embodiment, and parts in FIG. 2 that correspond to those in FIG. 1 are given the same reference numerals.

Therefore, the flow path resistance of the control intake path _L3 from the atmosphere opening port 14 to the orifice _J1 is determined by the solenoid valves 52, 5.
When solenoid valve 52 is closed (when energized), the orifice J ₁ a sets it to the maximum value, and when only the solenoid valve 52 is open (when energized), the parallel orifices J ₁ a and J ₁ b set it to the intermediate value. Both orifices open when valve 53 is opened.
J ₁ a and J ₁ b are disabled and adjusted to their minimum values, which is equivalent to adjusting the opening degree of the orifice J ₁ in three stages. Therefore, as the flow path resistance increases or decreases, the ratio between negative pressures _P1 and _P2 , and therefore the ratio between negative pressures Pv and Pe, changes, and the exhaust gas recirculation rate decreases or increases.

FIG. 3 shows a specific example of the negative pressure control valve V in both of the above embodiments, and the valve case 60 is divided into three parts: an upper case 60a, a middle case 60b, and a lower case 60c.
These are connected by bolts 61 and the like. Upper box 6
An air valve V ₂ is provided between Oa and the middle box 60b, and a regulating valve V ₁ is provided between the middle box 60b and the lower box 60c, so that both valves V ₁ and V ₂ are integrated into a unit.

More specifically, the diaphragm 31 of the air valve V ₂ is held between the joint surfaces of the upper case 60a and the middle case 60b, and the negative pressure chamber 32 on the upper side is connected to the upper case 60a.
Further, a lower valve chamber 30 is formed in each inner box 60b. The upper end of the valve spring 34 compressed in the negative pressure chamber 32 is supported by a spring holding plate 62, and this holding plate 62 is supported by an adjustment screw 63 screwed into the upper case 60a. Therefore, the set load of the valve spring 34 can be adjusted by moving the spring holding plate 62 up and down by turning the adjustment screw 63. Also Nakabako 60b
A guide tube 64 on which the valve body 33 slides is fitted,
A valve port 35 that cooperates with the valve body 33 is provided at the lower end of the guide tube 64 . Although the valve body 33 is separated from the diaphragm 31, it is always maintained in a connected state with the diaphragm 31 by the upward biasing force of a spring 65 in the guide tube 64, which is much weaker than the valve spring 34. By separating the diaphragm 31 and the valve body 33 in this way, even if the diaphragm 31 is shaken or tilted, the valve body 33 will not be affected.
It is effective in opening and closing it reliably.

On the other hand, the diaphragm 21 of the regulating valve _V1 is formed into an annular shape, and its outer circumferential portion is clamped on the joint surface with the lower case 60c, and a flat valve body 23 is molded onto its inner circumferential portion via a reinforcing metal plate 23a. combined. The upper negative pressure chamber 22 of the diaphragm 21 is formed in the middle case 60b, the lower valve chamber 20 is formed in the lower case 60c, and the valve port 25 that cooperates with the valve body 23 is formed in the lower case 60c. .

A connecting pipe L 3 a that communicates with the negative pressure chamber 22 and has an orifice J ₁ formed therein is fitted into the inner box 60 b, and a connecting pipe L ₃ b that communicates with the valve port ₃₅ is integrally protruded. The connecting pipe L ₃ a is located upstream of the control intake passage L ₃ .
Further, the connecting pipes L ₃ b are connected downstream. Furthermore, a part of the control intake passage _L3 connecting the negative pressure chamber 22 and the valve chamber 30 is bored in the inner box 60b, and an orifice _J2 is formed therein.

The lower box 60c has a connecting pipe L ₂ a communicating with the valve chamber 20.
and a connecting pipe L ₂ b communicating with the valve port 25 are integrally provided, and the connecting pipe L ₂ a is provided upstream of the second negative pressure passage L ₂ , and the connecting pipe L ₂ b is provided downstream thereof. Continuing. A communication path 36 connecting the valve port 25 and the negative pressure chamber 32 is formed by penetrating the three parts 60a, 60b, and 60c.

In addition, in the above embodiment, the first negative pressure detection hole
D ₁ is opened in the vicinity of the throttle valve 3 in the intake passage, and the first negative pressure passage L ₁ is throttled only when the engine is under load, that is, when the throttle valve 3 is opened to a predetermined opening or more, which is larger than the idling opening. The valve shown is connected to the intake passage on the downstream side of the valve 3, but the first negative pressure detection hole
Even if D ₁ is opened on the downstream side of the throttle valve 3 in the intake passage and the first negative pressure passage L ₁ is always communicated with the downstream side of the throttle valve 3, when the engine is operated under load, the case of the above embodiment It goes without saying that since the detected negative pressure of approximately the same magnitude is introduced into the first negative pressure passage _L1 , the same effects as in the embodiment described above can be obtained.

As described above, according to the present invention, a negative pressure-responsive recirculation flow control valve is interposed in the exhaust recirculation path that branches from the exhaust path of the engine and reaches the same intake path, and the negative pressure chamber of the recirculation flow control valve is , during load operation of the engine, a first negative pressure passage communicating with the downstream part of the throttle valve of the intake passage and a second negative pressure passage extending from a predetermined pressure source are connected, and the second negative pressure passage is connected to the second negative pressure passage. A negative pressure-responsive regulating valve is installed to open and close the control valve, and the negative pressure chamber of the regulating valve is interposed in the middle of the control intake passage extending from the downstream part of the throttle valve in the intake passage and reaching the atmosphere opening port. A negative pressure-responsive air valve that opens and closes the controlled intake passage is interposed in the controlled intake passage between the regulating valve and the intake passage, and the negative pressure chamber of this air valve is connected to the negative pressure of the recirculation amount control valve. At least a pair of orifices are provided in the control intake passageway, which communicate with the control intake passageway, and sandwich the negative pressure chamber of the regulating valve between them. Accordingly, the opening degree of the recirculation amount control valve can be automatically controlled, so that the recirculation amount of exhaust gas is proportional to the intake air amount of the engine, and a predetermined exhaust gas recirculation rate can be obtained. Moreover, the exhaust recirculation rate can be accurately set to any value by simply selecting the aperture ratio of the pair of orifices, making it widely applicable to various engines with different performance and specifications, and facilitating mass production. has. In particular, if the aperture ratio is made adjustable, the exhaust gas recirculation rate can be adjusted accurately depending on the operating conditions of the engine, thereby further reducing the emission concentration of the exhaust gas, improving engine drivability, and improving fuel consumption. Furthermore, the structure is simple, mass-producible, and can be provided at low cost.

[Brief explanation of the drawing]

The drawings show an embodiment of the device of the present invention.
1 is a schematic overall view of the first embodiment, FIG. 2 is a similar view of the second embodiment, and FIG. 3 is a vertical sectional view showing a specific example of the negative pressure control valve in the apparatus of the present invention. E... Engine, C, It, Mi... Carburetor, heat insulating cylinder, intake manifold, J ₁ , which constitutes the intake path,
J ₂ , J ₁ a, J ₁ b ... Orifice, L ₁ , L ₂ ... 1st,
2nd negative pressure passage, L ₃ ... control intake passage, V ₁ ... adjustment valve, V ₂ ... air valve, 1a ... bench lily, 3 ...
...Throttle valve, 5...Exhaust gas recirculation path, 6...Return amount control valve, 9...Negative pressure chamber thereof, 22...Negative pressure chamber of regulating valve, 32...Negative pressure chamber of air valve, 36... Communication path.

Claims (1)

[Scope of Claims] 1. A negative pressure-responsive recirculation flow control valve is interposed in the exhaust recirculation path that branches from the exhaust path of the engine and reaches the same intake path, and the negative pressure chamber of this recirculation flow control valve is connected to the exhaust gas recirculation path of the engine. During load operation, a first negative pressure passage communicates with the downstream part of the throttle valve in the intake passage, and a second negative pressure passage extends from a predetermined pressure source.
The second negative pressure passage is connected to the negative pressure passage, and a negative pressure-responsive regulating valve is interposed in the second negative pressure passage to open and close the second negative pressure passage, and the controlled intake air extends from the downstream part of the throttle valve in the intake passage and reaches the atmosphere opening port. A negative pressure chamber of the regulating valve is interposed in the middle of the control valve, and a negative pressure responsive air valve for opening and closing the control intake passage is interposed in the control intake passage between the regulating valve and the intake passage. , the negative pressure chamber of the air valve is communicated with the negative pressure chamber of the recirculation amount control valve, and the control intake passage is further provided with at least a pair of orifices sandwiching the negative pressure chamber of the regulating valve between them. Exhaust recirculation control device. 2. In what is stated in claim 1,
An exhaust gas recirculation control device for an engine, wherein the pressure source is inside a bench lily formed in the intake passage and upstream of the throttle valve. 3 In what is stated in claim 1,
An exhaust gas recirculation control device for an engine, wherein the pressure source is the atmosphere. 4 In what is stated in claim 1,
An exhaust gas recirculation control device for an engine, comprising a plurality of orifices that can adjust flow path resistance in a section between the atmosphere opening port of the control intake path and the air valve. 5 In what is stated in claim 4,
Any one of the plurality of orifices is operated according to the operating state of the engine,
Engine exhaust recirculation control device.