JPS6233430B2 - - Google Patents

Description

[Detailed Description of the Invention] An exhaust gas recirculation system that recirculates a portion of the exhaust gas to the intake manifold and re-burns it as a means of removing nitrogen oxides (NOx) among harmful components generated in the combustion chamber of an internal combustion engine. (EGR system) has been proposed. This exhaust gas recirculation system generally includes an exhaust gas recirculation control valve (EGR valve) placed between the exhaust pipe and the intake manifold, and operates this control valve in response to negative pressure fluctuations in the intake system. The recirculation of exhaust gas to the intake manifold is controlled, but the timing and amount of recirculation of exhaust gas to the intake manifold are determined by the exhaust purification efficiency,
Since the exhaust gas recirculation control valve has a strong influence on output or drivability, it has been strongly desired to operate the exhaust recirculation control valve accurately.

This invention was developed focusing on the above-mentioned points, and includes a new negative pressure modulator valve that controls the output negative pressure by changing and controlling the airflow from the negative pressure port and the atmospheric port using a negative pressure signal. is intended to provide.

Embodiments of the invention will be described with reference to the accompanying drawings.

The illustrated system includes a negative pressure modulator valve 1,
It has an exhaust gas recirculation control valve (referred to as EGR control valve) 2 and a negative pressure regulator valve 3.

A first port 4 provided in the body of the negative pressure modulator valve 1 communicates with an intake air passage 6 of the internal combustion engine via a first air passage 5. Intake air path 6
further communicates with a first chamber 8 defined by the diaphragm 7 of the negative pressure regulator valve 3 via a second air passage 9, and the second chamber 10 communicates via a first negative pressure passage 11. It communicates with a negative pressure source of the intake system 12, that is, a negative pressure source located upstream of the throttle valve when it is not activated and downstream of it when it is activated. A second port 13 provided in the body of the negative pressure modulator valve 1 connects the second chamber 10 of the negative pressure regulator valve 3 and the negative pressure passage 1.
4. An outlet port 15 provided in the body and open to both ports 4 and 13 communicates with an operating chamber 17 of the EGR control valve 2 via a signal passage 16. The negative pressure modulator valve 1 has a chamber divided into two by a diaphragm 18, one atmospheric pressure chamber 19 is open to the atmosphere, and the other negative pressure chamber 20 is open to the atmosphere.
communicates with the ventilate section 22 via the second negative pressure passage 21.

The EGR control valve 2 moves the diaphragm 2, which is biased on one side by a spring due to the differential pressure between the working chamber 17 and the atmospheric pressure chamber 23, which receives the signal pressure from the signal passage 16, to open the valve member 25. operate the exhaust pipe 26 to the intake manifold 2.
7 through the reflux passage 28.

The negative pressure regulator valve 3 has a valve member 30 that closes a valve hole 29 of a diaphragm 7 that is biased on one side by a spring 40 . It is in the illustrated position where it communicates with the negative pressure passage 14. When the negative pressure in the second chamber 10 exceeds a predetermined value, the diaphragm 7 moves together with the valve member 30 urged by the spring 31 against the spring 40, and the valve member 30 moves into the first negative pressure passage 11. The second chamber 10 is isolated from the first negative pressure passage 11 by contacting the lower end of the duct 41 connected to the second chamber 10 . When the negative pressure in the second chamber 10 is large enough to move the diaphragm 7 further upward in the figure, the lower end 42 of the diaphragm 7 forming the valve hole 29 is prevented from moving by the lower end of the duct 41. The first chamber 8 and the second chamber 10 are placed in communication with each other apart from the regulated valve member 30. Air is therefore introduced into the second chamber 10 and
The negative pressure in the chamber 10 is reduced, and the spring 40
, the diaphragm 7 moves downward and the lower end 42
contacts the valve member 30 to close communication between the chambers 8 and 10. Thereafter, by repeating such an operation, the second chamber 10 and therefore the negative pressure passage 14 are filled with
A predetermined negative pressure is applied regardless of the negative pressure in the intake system 12 that fluctuates due to the operation of the throttle valve.

A fixed orifice 32 and a filter 43 are provided between the ports 4, 13 and the outlet port 15 of the negative pressure modulator valve 1, respectively, and an obstruction 33 is interposed between the orifices 32. This obstruction 33 is formed by a diaphragm 18 which is urged downwardly by a spring 44.
It is fixed to the swinging member 45 of the diaphragm 18 and moves between the two orifices according to the movement of the diaphragm 18 to selectively change the flow of fluid from the first port 4 or the second port 13 and the flow to the outlet 15. work to change. Negative pressure chamber 20 is adapted to receive the aforementioned ventilary negative pressure via port 46. In the illustrated position where the negative pressure of the ventilator is small, the upper large-diameter portion 33a of the obstruction 33 is located at a position corresponding to both orifices 32, and the degree of obstruction to the airflow generated between the two orifices becomes large, and the airflow velocity decreases. As a result, the absolute value of the negative pressure at the output port 15 decreases. When the negative pressure of the ventilator becomes large and the diaphragm 18 is displaced upward against the spring 44, and the intermediate small diameter portion 33b of the obstruction 33 is located between the two orifices 33,
The degree of obstruction of the airflow is reduced, the airflow velocity is increased, and the absolute value of the negative pressure at the output port 15 is increased. When the negative pressure of the ventilator increases further and the lower large diameter portion 33c of the obstruction 33 reaches between the two orifices 32,
Similar to the first position described above, the absolute value of the negative pressure at the output port 15 increases. In other words, the negative pressure modulator valve 1 can change the absolute value of the output negative pressure from small to large and small according to the increase in the ventilary negative pressure, and the output negative pressure is controlled by the effect of the negative pressure regulator valve 3. This allows the pressure to be set to a pressure that is sufficiently greater than the ventilate pressure. In addition, both orifices 32
The output negative pressure characteristics can be changed or adjusted by appropriately selecting the effective orifice diameter.

In the above system, when recirculation of exhaust gas is not required at the initial stage of starting the internal combustion engine, no negative pressure is generated in the intake system 12 upstream of the throttle valve, so no operating negative pressure reaches the EGR control valve 2. do not have. In addition, at this time, the negative pressure modulator valve 1 is in a position where the output negative pressure reaching the EGR control valve 2 can be reduced, so the intake system 12
Even if the EGR control valve 2 is connected to the intake manifold downstream of the throttle valve, the EGR control valve 2 is held in the non-operating position, and thus may be configured in this manner.

When the throttle valve is rotated and negative pressure is generated in the intake system 12, the negative pressure is regulated by the negative pressure regulator valve 3 as described above and reaches the port 13 of the negative pressure modulator valve 1. At this time, the diaphragm 1 of the negative pressure modulator valve 1 is
8 is displaced and the small diameter portion 33b of the obstruction 33 is in a position corresponding to both orifices 32, as described above.
The output negative pressure reaching the EGR control valve 2 becomes a value sufficient to operate the EGR control valve 2, and the exhaust gas is recirculated to the intake manifold 27.

When the ventilator negative pressure becomes even larger, such as when the vehicle is running at high speed, the output negative pressure of the negative pressure modulator valve 1 becomes smaller as described above, and the EGR control valve 2 is placed in the non-operating position.

As is clear from the above, in this example, an obstruction is fixed to the diaphragm of the negative pressure modulator valve, and this obstruction is activated according to the ventilary pressure.
Controls the operating negative pressure to the EGR control valve and controls exhaust gas recirculation.In addition to responding to the amount of intake air with a simple system, the EGR control valve operating negative pressure is controlled using a relatively small ventilator negative pressure as a signal. death,
Therefore, accurate exhaust gas recirculation becomes possible.

[Brief explanation of the drawing]

The figure is a system diagram of an example of this invention. In the figure: 1... Negative pressure modulator valve, 2... Exhaust gas recirculation control valve, 3... Negative pressure regulator valve, 4, 13...
Port, 5, 9... Air passage, 6... Intake air passage, 1
1, 21... Negative pressure passage, 12... Ventilation part, 1
4... Negative pressure passage, 16... Signal passage, 27... Intake manifold.

Claims (1)

[Claims] 1 Atmospheric port 4 communicating with the air passage 6 of the intake system of the internal combustion engine, negative pressure port 13 communicating with the negative pressure source 12 of the intake system, a pair of orifices 32 arranged in the passage communicating both ports, negative pressure A rocking member 45 defining the chamber 20 and the atmospheric pressure chamber 19; an obstruction 3 fixed to the rocking member and extending between the orifices;
3. The housing has an outlet port 15 communicating with the passage, the negative pressure chamber 20 is connected to the ventilary part 22 of the intake system, and the obstruction extends toward the outlet port 15 and has an irregular shape. the obstruction is moved according to the pressure of the negative pressure chamber, and the irregularly shaped part changes and controls the airflow from the atmosphere and the negative pressure port, thereby making the negative pressure applied to the outlet port variable. A negative pressure modulator valve characterized by: