JPS6037303B2 - Exhaust recirculation device in engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exhaust gas recirculation system for automobiles and other engines.

The applicant previously proposed that in this type of device, a negative pressure outlet near a throttle valve in the intake passage is provided in an exhaust recirculation passage formed between an exhaust passage of an engine and an intake passage of the engine. A negative pressure response type recirculation control valve having a negative pressure chamber extending from the negative pressure passage extending from the intake passage is intervened, and from the downstream side of the throttle valve of the intake passage, an area having a constant area ratio with the area of the venturi portion of the intake passage is inserted. An air passage that opens to the atmosphere through an orifice having A negative pressure responsive regulating valve having a negative pressure chamber communicating with the negative pressure air between the orifice and the air control valve is provided so that the negative pressure in the negative pressure passage is leaked by the regulating valve. A formula was developed in 1974 that made the amount of exhaust gas recirculation approximately proportional to the amount of intake air of the engine.
No. 69858 (Japanese Unexamined Patent Publication No. 54-160927), but in this case, it is preferable that the reflux amount, that is, the reflux rate, be able to be corrected as necessary.

The present invention is aimed at obtaining a device that meets the above requirements, and includes a restrictor in the exhaust gas recirculation passage formed between the exhaust passage of the engine and the intake passage of the engine. A negative pressure-responsive recirculation control valve having a negative pressure chamber extending into the negative pressure passage extending from the negative pressure outlet near the valve is inserted, and a venturi portion of the intake passage is inserted into the intake passage from the downstream side of the throttle valve. An air passage connecting to the atmosphere is branched through an orifice having an area of a certain area ratio to the area of further comprising a negative pressure-responsive regulating valve having a pressure chamber extending within a negative pressure chamber between the orifice in the air passage and the air control valve; In the type that allows the negative pressure inside to leak, a separate controlled negative pressure can be freely introduced into the negative pressure chamber of the air control valve or the atmospheric pressure chamber on the opposite side.

Embodiments of the present invention will be described with reference to the attached drawings. In the drawings, 1 is an engine, 2 is an exhaust passage of the engine, and 3 is an intake passage of the engine 1. An exhaust gas recirculation passage 4 is formed between the exhaust passage 2 and the intake passage 3, and the intake passage is A negative pressure-responsive recirculation control valve 9 having a negative pressure chamber 8 extending into a negative pressure passage 7 extending from a negative pressure outlet 6 near the throttle valve 5 of the passage 3 is intervened.

The valve 9 is normally closed by a spring 11 via a diaphragm 10, and opens against the spring 11 when the negative pressure in the negative pressure chamber 8 is applied. An air passage 13 that is closed to the atmosphere is branched from the downstream side of the throttle valve 5 of the intake passage 3 through an orifice 12 having an area of a certain area ratio with the area of the venturi portion of the intake passage. A negative pressure responsive air control valve 15 having a negative pressure chamber 14 extending into the negative pressure passage 7 is interposed.

Similar to the valve 9 described above, the valve 15 is normally closed by the spring 17 via the diaphragm 16, and opens against the spring 17 due to the negative pressure in the negative pressure chamber 14. configured. Furthermore, the orifice 1 in the air passage 13 described above
2 and the control valve 15, the negative pressure responsive type regulating valve 21 has a negative pressure chamber 20 that extends through a passage 19 into the negative pressure space 18 between the control valve 15 and the negative pressure chamber 20.
The valve 21 is configured to leak the negative pressure in the negative pressure passage 7 described above. That is, the valve 32 is provided opposite the leak hole 22 extending from the negative pressure passage 7 described above, and is normally pressed by the spring 24 via the diaphragm 23 to close the leak hole 22. According to an increase in the negative pressure in the negative pressure chamber 20, the opening 22 is configured to move back against the spring 24 and open the hole 22 accordingly. In this case, the inside of the chamber 25 in front of the valve 21 is passed through the passage 28 to the negative pressure outlet 27 of the venturi part 26 in the intake passage 3, and is subjected to venturi negative pressure. Configured to respond by differential pressure. Therefore, when the throttle valve 5 is opened near the upstream side of the negative pressure outlet 6, the negative pressure in the intake passage in the vicinity becomes large, and the negative pressure in the negative pressure chamber 14 increases, causing the control valve 15 to open. is opened, and the opening of the control valve 15 increases the negative pressure in the negative pressure space 18 of the air passage 13, so the diaphragm 23 of the regulating valve 21 opens the leak hole 22 between the venturi portion 26 and the negative pressure chamber 14. The low negative pressure of the venturi section 26 is introduced into the negative pressure chamber 14 and the control valve 15 is
is immediately closed, and by repeating this, feedback control is performed so that the open area of the control valve 15 is maintained at a constant ratio with the entrance area of the throttle valve 5. Orifice area ratio 12
The flow rate of the air passage 13 is controlled to a constant ratio with the flow rate of the intake passage 3, and the recirculation control valve 9 is controlled by using the operating negative pressure of the negative pressure chamber 14 of the control valve 15 of the air passage 13 as an output.
The flow rate of the intake air passage 3 is also accurately controlled in proportion to the flow rate of the intake air passage 3. Although the above is not particularly different from the following, according to the present invention, in such a device, a controlled negative pressure can be freely introduced into the air control valve 15, and in the embodiment shown in the first figure, Atmospheric pressure chamber 29 in front of the diaphragm 16 in the valve 15
The inside can be freely switched between a passage 31 which is connected to the atmosphere side through a switching valve 30, and a negative pressure introduction passage 32 which connects to the passage 19 described above, so that atmospheric pressure is normally introduced into this passage, but it can be switched as necessary. Valve 30 was operated to provide negative pressure within the passageway 19.

According to the introduction of this negative pressure, the valve 15 becomes closed, and the negative pressure in the negative pressure space 18 in the air passage 13 decreases accordingly, and accordingly, the selected negative pressure is Pressure chamber 20
As the negative pressure inside decreases, the leakage regulating valve 21 closes, and the amount of leakage from the valve 21 decreases, causing the control valve 9 to open, which tends to increase the amount of exhaust gas recirculation. did.

This can be advantageously used, for example, during warm-up operation, and is used to keep the exhaust gas circulation amount to a relatively small amount during warm-up, and to increase this amount after the engine is warmed up. In addition, it is also possible to adjust the amount depending on the shift position of the mission. FIG. 2 shows a modification example in which a separate negative pressure, for example, a negative pressure downstream of the throttle valve 5 in the intake passage 3, that is, an intake negative pressure, can be freely introduced into the negative pressure chamber 14. . That is,
A negative pressure introduction passage 32 connected to a negative pressure source is branched into the negative pressure passage 7 connected to the negative pressure chamber 14, and each throttle valve 3 is connected to each passage 7, 32.
3 and 34, negative pressure is introduced into the negative pressure chamber 14 through these, and the valve 15 is corrected to the open side, and the negative pressure in the negative pressure space 18 increases accordingly. Adjustment valve 2
1 is set to the open side, and as a result, the amount of leakage increases and the control valve 9 becomes the closed side, so that the amount of recirculation is reduced. For example, the recirculation amount should be adjusted depending on the engine's intake negative pressure.
It can be used advantageously. Furthermore, in this case, the throttle valve 34 in the negative pressure introduction passage 32 described above, as shown in the third figure, for example.
It is also possible to use a negative pressure responsive type or other variable type.
In this way, according to the present invention, a separate negative pressure can be freely introduced into the negative pressure chamber of the air control valve inserted in the air passage or into the chamber on the opposite side, and a type of air control valve that adjusts the exhaust gas recirculation rate can be used. It has the effect of being simple and easy to obtain.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram of one example of the device of the present invention, FIG. 2 is a diagram of another example, and FIG. 3 is a diagram of a part of a modification thereof.

DESCRIPTION OF SYMBOLS 1... Engine, 2... Exhaust passage, 3... Intake passage, 4... Exhaust recirculation passage, 5... Throttle valve, 6... Negative pressure outlet, 7... Negative pressure passage, 8... ... Negative pressure chamber, 9... Reflux control valve, 12... Orifice, 13... Air passage,
14... Negative pressure chamber, 15... Air control valve, 18...
Negative pressure space, 20...Negative pressure chamber, 21...Adjusting valve, 32...
・Negative pressure introduction passage.

Figure 1 Figure 3 Figure 2

Claims (1)

[Scope of Claims] 1. An exhaust recirculation passage formed between an exhaust passage of the engine and an intake passage of the engine is connected to a negative pressure passage extending from a negative pressure outlet near the throttle valve of the intake passage. A negative pressure-responsive reflux control valve having a negative pressure chamber is inserted into the intake passage from the downstream side of the throttle valve through an orifice having an area that is a constant area ratio to the area of the vent lily portion of the intake passage. A negative pressure responsive air control valve having a negative pressure chamber connected to the aforementioned negative pressure passage is interposed by branching the air passageway opening to the atmosphere, and furthermore, the orifice in the air passageway and the air control valve are interposed therein. A negative pressure response type regulating valve having a negative pressure chamber connected to a negative pressure space between the air control valve and the negative pressure passage, wherein the regulating valve leaks the negative pressure in the negative pressure passage. An exhaust gas recirculation device for an engine, which reduces the amount of exhaust gas recirculation at low loads when the intake negative pressure of the engine is relatively large by introducing a controlled negative pressure downstream of a throttle valve into the negative pressure chamber of the valve. 2. The exhaust gas recirculation passage formed between the exhaust passage of the engine and the intake passage of the engine has a negative pressure chamber connected to the negative pressure passage extending from the negative pressure outlet near the throttle valve of the intake passage. A negative pressure responsive reflux control valve is inserted, and an air passage opens to the atmosphere from the downstream side of the throttle valve to the intake passage through an orifice having an area that is a certain area ratio to the area of the vent lily portion of the intake passage. A negative pressure-responsive air control valve having a negative pressure chamber connected to the above-mentioned negative pressure passage is intervened, and the negative pressure between the orifice in the air passage and the air control valve is In a type that is equipped with a negative pressure-responsive regulating valve having a negative pressure chamber communicating with the space and causing leakage in the above-mentioned negative pressure passage by the regulating valve, there is no pressure in the atmospheric pressure chamber of the air control valve. An exhaust gas recirculation device for an engine, which increases the amount of exhaust gas recirculation according to operating conditions by introducing a controlled negative pressure into the negative pressure air.